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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [ericMPro] [ In reply to ]
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ericMPro wrote:
determinator wrote:
Hi Eric,

I’ve attached my last Tri bike fit. Apologies as the measurements are different to the ones you specify.
Sadly don’t have this anymore so can’t input the x and y coordinates you refer to. Had a look at my road bike but not all that helpful.

It was a 54 P2, I’m 176.5cm and longer torso and shorter legs. Bars were 3T aura pro. I have long arms. Saddle height is 77cm from BB. Looking at pics of me on this I do wonder if it was a bit small as knees and elbows were a bit close.

Interested in a new p series, p3x or p5d, whichever fits best. Mainly olympic distance and 70.3s and potentially IM eventually. Can DM you other fit images with me on it if helpful?
Many thanks.


OK, let me work on this... do you have a picture of you on the bike?


Hi Eric,
Thanks for getting back to me, much appreciated. Please see attached fit photos.
Last edited by: determinator: Jul 30, 20 5:48
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [ericMPro] [ In reply to ]
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ericMPro wrote:
I guess it depends on what you're intending to do with your bike.... not that both bikes can't do all triathlons.

P3x incentivizes long course athletes with fluids and calories. With a Pad Stack of 640 and Pad Reach of 450 you could fit on M or an L, sort of "high mid-forward" on the M and "middle back" on the L.

P5 is likely faster in a "light" configurations.... you'd be a 54cm or a 56cm.... "high-mid" on the 54cm and "mid-back" on the 56cm.

Do you have a pic from your fitter? My recommendation would depend on where you might go with your position in the future.

Eric


tomljones3 wrote:
Eric, I'm trying to decide between a P5 and a P3X

A fitter last night placed my Pad Y at 640 but I have been riding 660
Pad X (Rear) is 450
Sorry, I don't know the Pad Z
Saddle height is 795

Thanks for the help!

I went with the P3X medium and I think the "high mid-forward" position is causing the bike to be more responsive than I would like.

In your opinion, if I move up to a large frame would that solve my handling problem?


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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [determinator] [ In reply to ]
Quote | Reply
determinator wrote:
ericMPro wrote:
determinator wrote:
Hi Eric,

I’ve attached my last Tri bike fit. Apologies as the measurements are different to the ones you specify.
Sadly don’t have this anymore so can’t input the x and y coordinates you refer to. Had a look at my road bike but not all that helpful.

It was a 54 P2, I’m 176.5cm and longer torso and shorter legs. Bars were 3T aura pro. I have long arms. Saddle height is 77cm from BB. Looking at pics of me on this I do wonder if it was a bit small as knees and elbows were a bit close.

Interested in a new p series, p3x or p5d, whichever fits best. Mainly olympic distance and 70.3s and potentially IM eventually. Can DM you other fit images with me on it if helpful?
Many thanks.


OK, let me work on this... do you have a picture of you on the bike?


Hi Eric,
Thanks for getting back to me, much appreciated. Please see attached fit photos.


Thanks. I think I get it now...

OK, so before we begin you need to know what my fit philosophy and what my priors and tendencies are, as that knowledge will help you understand what I'm going to tell you and also how I might be different or the same as other fitters.

Generally, I feel like you should always use the right tool for the job, that your bike should work for you and not you for your bike, that you should always get the fastest bike for the purpose (or future purpose!) all things being equal, and finally and most importantly as it relates to fit and orthodoxy I feel that you should always get the longest bike possible that is still able to get low enough for your position (or future position!).

This last part is pertinent because I tend to trend longer than my peers with bike fits, which then leads to clients being on a bike one size bigger than they thought, than their peers thought, or their LBS thought they should be on. IMO, there's no point in a bike that's too small/short! Spacers under stems are not a good idea, unless you are a UCI Pro Tour cyclist doing an ITT in which case I could make the point that smaller is better, for a number of reasons that don't really apply to us and merit passing over here. Too long OTOH, as long as it's low enough, is like having money in the bank for a rainy day in the future. If your position change (and it almost always changes in my direction), your bike will work for your new position. If you get a too small bike, it won't. This reasoning also informs which bike you choose. Your focus is short/medium *now*, but an IM is in your eventual future. Pick the bike that can do all three as functionally and as aerodynamically as possible.

Now, you're admittedly a long torso guy, you thought your bike was a little too small from your perspective, and then finally me looking at your pics I felt the same way. I'd call that good supporting evidence for a decision. You could do with a longer bike. "But you're only 5'9"!" Don't listen to them. The bike works for you, not the other way around. We'll put your contact points in space and bring the bike up to meet them as functionally and as aerodynamically as possible. The size of the bike compared to your height is irrelevant when you're on a well designed well built bike doing triathlon. If it fits it fits.

I'm estimating your current pad stack and reach is 630mm pad stack, 435mm pad reach. I feel like you could be about 50mm longer once you figure your fit out. You need a bike that is able to hit 485mm to back of pad eventually. Your current fit would be a 54cm P5d, but as you add reach you move into the 56cm P5d realm. The minimum reach for a 56cm P5d at your pad stack height is 448mm. I feel very confident that you could handle a sudden 15mm increase in reach if purchasing the P5d as a new bike. I don't feel confident that a 54cm would serve your needs in the future as your fit evolves.

By that rationale, and with those coordinates, you'd fit a size M or size L P3x, and you'd lean toward the size L. Minimum pad reach for the size L P3x is 430mm for you, so already within range, and goes out to a whopping 510mm at your stack height. This is your bike... size L. The P3x would carry and store all your nutrition, hydration, and flat kit stuff for an IM but would be plenty fast and functional for OD or 70.3. Actually, in the times of COVID and what I think racing will look like going forward, the ability to do a half IM self-supported will be useful as well. Self-supported but totally aero storage for the various bottles you'd need to port for a self-supported HIM.

Does all of this make sense? I'm not saying a P5d can't be kitted out to do an IM, just that the P3x would do it as well as the short course stuff just as easy. Same with the sizing recommendations... do those make sense as well? Let me know.

thanks,
Eric

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”
Last edited by: ericMPro: Jul 23, 20 14:09
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [tomljones3] [ In reply to ]
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tomljones3 wrote:
ericMPro wrote:
I guess it depends on what you're intending to do with your bike.... not that both bikes can't do all triathlons.

P3x incentivizes long course athletes with fluids and calories. With a Pad Stack of 640 and Pad Reach of 450 you could fit on M or an L, sort of "high mid-forward" on the M and "middle back" on the L.

P5 is likely faster in a "light" configurations.... you'd be a 54cm or a 56cm.... "high-mid" on the 54cm and "mid-back" on the 56cm.

Do you have a pic from your fitter? My recommendation would depend on where you might go with your position in the future.

Eric


tomljones3 wrote:
Eric, I'm trying to decide between a P5 and a P3X

A fitter last night placed my Pad Y at 640 but I have been riding 660
Pad X (Rear) is 450
Sorry, I don't know the Pad Z
Saddle height is 795

Thanks for the help!


I went with the P3X medium and I think the "high mid-forward" position is causing the bike to be more responsive than I would like.

In your opinion, if I move up to a large frame would that solve my handling problem?

I Tom, thanks for reaching back out.

I would never recommend not moving to the longer bike for a variety of reasons, not the least of which handling. I'm not 100% sure however that a larger bike will *solve* your handling issues, but I think by "responsive" you mean twitchy, and if so longer would probably help. The size L has a 30mm longer wheelbase, all in the front/center so you'd likely notice this.

Also, in the pic you attached, you have a very solid fit. However, and FWIW, I personally would certainly like you to be a touch longer and could easily see you getting longer in the future as you settle in to and learn how to sit on your saddle. You could also even come up some. Using that mental model, and the new numbers you provided, I think the size L P3x would be better for you. It would accommodate your current position in the mid-mid quadrant/range and be there for you if you lean into your bars a bit and get a little longer.

So it's a win-win from position and handling perspectives for the size L P3x.

Make sense?

Eric

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [ericMPro] [ In reply to ]
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ericMPro wrote:

I Tom, thanks for reaching back out.

I would never recommend not moving to the longer bike for a variety of reasons, not the least of which handling. I'm not 100% sure however that a larger bike will *solve* your handling issues, but I think by "responsive" you mean twitchy, and if so longer would probably help. The size L has a 30mm longer wheelbase, all in the front/center so you'd likely notice this.

Also, in the pic you attached, you have a very solid fit. However, and FWIW, I personally would certainly like you to be a touch longer and could easily see you getting longer in the future as you settle in to and learn how to sit on your saddle. You could also even come up some. Using that mental model, and the new numbers you provided, I think the size L P3x would be better for you. It would accommodate your current position in the mid-mid quadrant/range and be there for you if you lean into your bars a bit and get a little longer.

So it's a win-win from position and handling perspectives for the size L P3x.

Make sense?

Eric

That does make sense. Thanks for such a fast response. Your points about how my position might change mirror the conversation that I had with the fitter, so you definitely have a good eye for it.

It really helps to have a little confirmation before I drop that kind of money a second time.

On the up-side, I switched the medium sized bike over to LOML size and she absolutely loves it and is threatening to not give it back, so at least it has a good home.
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [tomljones3] [ In reply to ]
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tomljones3 wrote:

That does make sense. Thanks for such a fast response. Your points about how my position might change mirror the conversation that I had with the fitter, so you definitely have a good eye for it.

It really helps to have a little confirmation before I drop that kind of money a second time.

On the up-side, I switched the medium sized bike over to LOML size and she absolutely loves it and is threatening to not give it back, so at least it has a good home.

Awesome, and thanks!!!

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [ericMPro] [ In reply to ]
Quote | Reply
ericMPro wrote:
determinator wrote:
ericMPro wrote:
determinator wrote:
Hi Eric,

I’ve attached my last Tri bike fit. Apologies as the measurements are different to the ones you specify.
Sadly don’t have this anymore so can’t input the x and y coordinates you refer to. Had a look at my road bike but not all that helpful.

It was a 54 P2, I’m 176.5cm and longer torso and shorter legs. Bars were 3T aura pro. I have long arms. Saddle height is 77cm from BB. Looking at pics of me on this I do wonder if it was a bit small as knees and elbows were a bit close.

Interested in a new p series, p3x or p5d, whichever fits best. Mainly olympic distance and 70.3s and potentially IM eventually. Can DM you other fit images with me on it if helpful?
Many thanks.


OK, let me work on this... do you have a picture of you on the bike?


Hi Eric,
Thanks for getting back to me, much appreciated. Please see attached fit photos.


Thanks. I think I get it now...

OK, so before we begin you need to know what my fit philosophy and what my priors and tendencies are, as that knowledge will help you understand what I'm going to tell you and also how I might be different or the same as other fitters.

Generally, I feel like you should always use the right tool for the job, that your bike should work for you and not you for your bike, that you should always get the fastest bike for the purpose (or future purpose!) all things being equal, and finally and most importantly as it relates to fit and orthodoxy I feel that you should always get the longest bike possible that is still able to get low enough for your position (or future position!).

This last part is pertinent because I tend to trend longer than my peers with bike fits, which then leads to clients being on a bike one size bigger than they thought, than their peers thought, or their LBS thought they should be on. IMO, there's no point in a bike that's too small/short! Spacers under stems are not a good idea, unless you are a UCI Pro Tour cyclist doing an ITT in which case I could make the point that smaller is better, for a number of reasons that don't really apply to us and merit passing over here. Too long OTOH, as long as it's low enough, is like having money in the bank for a rainy day in the future. If your position change (and it almost always changes in my direction), your bike will work for your new position. If you get a too small bike, it won't. This reasoning also informs which bike you choose. Your focus is short/medium *now*, but an IM is in your eventual future. Pick the bike that can do all three as functionally and as aerodynamically as possible.

Now, you're admittedly a long torso guy, you thought your bike was a little too small from your perspective, and then finally me looking at your pics I felt the same way. I'd call that good supporting evidence for a decision. You could do with a longer bike. "But you're only 5'9"!" Don't listen to them. The bike works for you, not the other way around. We'll put your contact points in space and bring the bike up to meet them as functionally and as aerodynamically as possible. The size of the bike compared to your height is irrelevant when you're on a well designed well built bike doing triathlon. If it fits it fits.

I'm estimating your current pad stack and reach is 630mm pad stack, 435mm pad reach. I feel like you could be about 50mm longer once you figure your fit out. You need a bike that is able to hit 485mm to back of pad eventually. Your current fit would be a 54cm P5d, but as you add reach you move into the 56cm P5d realm. The minimum reach for a 56cm P5d at your pad stack height is 448mm. I feel very confident that you could handle a sudden 15mm increase in reach if purchasing the P5d as a new bike. I don't feel confident that a 54cm would serve your needs in the future as your fit evolves.

By that rationale, and with those coordinates, you'd fit a size M or size L P3x, and you'd lean toward the size L. Minimum pad reach for the size L P3x is 430mm for you, so already within range, and goes out to a whopping 510mm at your stack height. This is your bike... size L. The P3x would carry and store all your nutrition, hydration, and flat kit stuff for an IM but would be plenty fast and functional for OD or 70.3. Actually, in the times of COVID and what I think racing will look like going forward, the ability to do a half IM self-supported will be useful as well. Self-supported but totally aero storage for the various bottles you'd need to port for a self-supported HIM.

Does all of this make sense? I'm not saying a P5d can't be kitted out to do an IM, just that the P3x would do it as well as the short course stuff just as easy. Same with the sizing recommendations... do those make sense as well? Let me know.

thanks,
Eric

Hi Eric,
Thank you very much for that really helpful and informative breakdown. Yes, it all makes complete sense and sorry for making it a bit more challenging by not having the fit coordinates. I think the future proofing element is also great advice. I agree and think the P3X in L is the way to gođź‘Ť Thank you again for your time and assistance.
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [ericMPro] [ In reply to ]
Quote | Reply
Hi all,

reposting from another thread as suggested :)

I can get a good deal on a P3X and am undecided between a L and XL (leaning towards XL now).


Arm Pad Stack 680-690mm (depending on distance and not getting any younger)
Arm Pad Reach 450mm (BB to back of pad)
Saddle Height 820mm (from BB, 175mm cranks)

I was contemplating buying L, but the sales guy from a reputable dealer (and being a Cat 1 cyclist himself) is 95% sure the XL would be the way to go. I am ~1.92m tall (6 foot 3), long legs, short torso. Both look feasible from the Cervelo site with my measurements being towards the low end of the XL spectrum. I am currently riding a 2006 P3C in 58cm with a medium Zipp Vuka Stealth in a fairly backward set-up.
In Reply To:
I could return and change the P3X, but obviously would prefer to get it right first time.

Can post pictures later today if helpful).

Any suggestions and opinions welcome ... thanks in advance!
Quote Reply
Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [Hoffmeister] [ In reply to ]
Quote | Reply
Hoffmeister wrote:
Hi all,

reposting from another thread as suggested :)

I can get a good deal on a P3X and am undecided between a L and XL (leaning towards XL now).

Arm Pad Stack 680-690mm (depending on distance and not getting any younger)
Arm Pad Reach 450mm (BB to back of pad)
Saddle Height 820mm (from BB, 175mm cranks)

I was contemplating buying L, but the sales guy from a reputable dealer (and being a Cat 1 cyclist himself) is 95% sure the XL would be the way to go. I am ~1.92m tall (6 foot 3), long legs, short torso. Both look feasible from the Cervelo site with my measurements being towards the low end of the XL spectrum. I am currently riding a 2006 P3C in 58cm with a medium Zipp Vuka Stealth in a fairly backward set-up.

I could return and change the P3X, but obviously would prefer to get it right first time.

Can post pictures later today if helpful).

Any suggestions and opinions welcome ... thanks in advance!

Hi, thanks for reaching out.

Pictures always help, but I think I have some ideas...

With a Pad Stack of 690mm you're pretty close to the top of the range for the size L P3x, but only the top 33% for the size XL. Upper mid quadrant.

OTOH 450mm Pad Reach to back of pad is just on the grid for the XL. You'd be in the mid to upper left quadrant. Sort of hints at the size L for you.

Something seems off though... you're 1.92 meters tall but *only* 450mm of reach, slightly different from orthodox IMO, and much different than me (1.9 meters) slightly "alien" w/ roughly 540mm of reach (including -8cm of saddle setback).

I think your Cat 1 cyclist sales guy dealer is right, but I can't vouch for his reasoning. My reasoning is that you'll most likely never want to go less than 450mm of reach, but could quite conceivably, with perhaps a saddle intervention or a bike fit from a person with a different perspective (which means some postural coaching), go fairly longer than 450mm. At your pad stack height, you only have 40mm more to work with on the size L.

I think I'm trying to tell you that despite your age, and despite me not having seen a picture of you, that you could probably get a bit longer, both from an orthodoxy doctrine and from my own fit philosophy. It might not happen, but if it does.... this line of reasoning would be better achieved on the XL IMO.

Make sense?

Eric

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [ericMPro] [ In reply to ]
Quote | Reply
ericMPro wrote:
Hoffmeister wrote:
Hi all,

reposting from another thread as suggested :)

I can get a good deal on a P3X and am undecided between a L and XL (leaning towards XL now).

Arm Pad Stack 680-690mm (depending on distance and not getting any younger)
Arm Pad Reach 450mm (BB to back of pad)
Saddle Height 820mm (from BB, 175mm cranks)

I was contemplating buying L, but the sales guy from a reputable dealer (and being a Cat 1 cyclist himself) is 95% sure the XL would be the way to go. I am ~1.92m tall (6 foot 3), long legs, short torso. Both look feasible from the Cervelo site with my measurements being towards the low end of the XL spectrum. I am currently riding a 2006 P3C in 58cm with a medium Zipp Vuka Stealth in a fairly backward set-up.

I could return and change the P3X, but obviously would prefer to get it right first time.

Can post pictures later today if helpful).

Any suggestions and opinions welcome ... thanks in advance!


Hi, thanks for reaching out.

Pictures always help, but I think I have some ideas...

With a Pad Stack of 690mm you're pretty close to the top of the range for the size L P3x, but only the top 33% for the size XL. Upper mid quadrant.

OTOH 450mm Pad Reach to back of pad is just on the grid for the XL. You'd be in the mid to upper left quadrant. Sort of hints at the size L for you.

Something seems off though... you're 1.92 meters tall but *only* 450mm of reach, slightly different from orthodox IMO, and much different than me (1.9 meters) slightly "alien" w/ roughly 540mm of reach (including -8cm of saddle setback).

I think your Cat 1 cyclist sales guy dealer is right, but I can't vouch for his reasoning. My reasoning is that you'll most likely never want to go less than 450mm of reach, but could quite conceivably, with perhaps a saddle intervention or a bike fit from a person with a different perspective (which means some postural coaching), go fairly longer than 450mm. At your pad stack height, you only have 40mm more to work with on the size L.

I think I'm trying to tell you that despite your age, and despite me not having seen a picture of you, that you could probably get a bit longer, both from an orthodoxy doctrine and from my own fit philosophy. It might not happen, but if it does.... this line of reasoning would be better achieved on the XL IMO.

Make sense?

Eric


hi Eric, many thanks :)

Yes, it absolutely makes sense. Here are some pics - if they are too close, I'd need to move the trainer to a bigger room and re-take.

I think I could potentially move the saddle forward another 10-15mm and the position looks a bit tight to my amateur eyes (although it's quite comfortable to me and I had fairly decent IM splits - 5:01 and 5:03 with low 190s NP on flat courses). Getting slightly lower for 5h is possible, but will take me some time. I'd say the chance of me wanting to go to less than 450mm pad reach is about nil - I'd probably have the legs hitting my elbows.






Last edited by: Hoffmeister: Jul 26, 20 15:38
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [ericMPro] [ In reply to ]
Quote | Reply
Eric

Still looking at P5....my Cervelo P4 fit in October 2019 was Arm Pad Reach 425, Arm Pad Stack 636, and Seat Height of 715 on a 172.5 crank (standard). When I put those numbers in the Cervelo size chart it says both 51 and 54 work. My P4 is a 51....but maybe I should be on a 54 now with shorter cranks? Thanks, Dirk
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [ericMPro] [ In reply to ]
Quote | Reply
Thanks again for your help!

I pulled the trigger on the XL and now need to get a new PM (bike shop happy to install the PM during the build). Currently on 175mm, but thinking of getting 170 or 165 cranks .. is it just a matter of increasing the seat height and pad stack by the difference in crank length?
Quote Reply
Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [Hoffmeister] [ In reply to ]
Quote | Reply
Hoffmeister wrote:
ericMPro wrote:
Hoffmeister wrote:
Hi all,

reposting from another thread as suggested :)

I can get a good deal on a P3X and am undecided between a L and XL (leaning towards XL now).

Arm Pad Stack 680-690mm (depending on distance and not getting any younger)
Arm Pad Reach 450mm (BB to back of pad)
Saddle Height 820mm (from BB, 175mm cranks)

I was contemplating buying L, but the sales guy from a reputable dealer (and being a Cat 1 cyclist himself) is 95% sure the XL would be the way to go. I am ~1.92m tall (6 foot 3), long legs, short torso. Both look feasible from the Cervelo site with my measurements being towards the low end of the XL spectrum. I am currently riding a 2006 P3C in 58cm with a medium Zipp Vuka Stealth in a fairly backward set-up.

I could return and change the P3X, but obviously would prefer to get it right first time.

Can post pictures later today if helpful).

Any suggestions and opinions welcome ... thanks in advance!


Hi, thanks for reaching out.

Pictures always help, but I think I have some ideas...

With a Pad Stack of 690mm you're pretty close to the top of the range for the size L P3x, but only the top 33% for the size XL. Upper mid quadrant.

OTOH 450mm Pad Reach to back of pad is just on the grid for the XL. You'd be in the mid to upper left quadrant. Sort of hints at the size L for you.

Something seems off though... you're 1.92 meters tall but *only* 450mm of reach, slightly different from orthodox IMO, and much different than me (1.9 meters) slightly "alien" w/ roughly 540mm of reach (including -8cm of saddle setback).

I think your Cat 1 cyclist sales guy dealer is right, but I can't vouch for his reasoning. My reasoning is that you'll most likely never want to go less than 450mm of reach, but could quite conceivably, with perhaps a saddle intervention or a bike fit from a person with a different perspective (which means some postural coaching), go fairly longer than 450mm. At your pad stack height, you only have 40mm more to work with on the size L.

I think I'm trying to tell you that despite your age, and despite me not having seen a picture of you, that you could probably get a bit longer, both from an orthodoxy doctrine and from my own fit philosophy. It might not happen, but if it does.... this line of reasoning would be better achieved on the XL IMO.

Make sense?

Eric


hi Eric, many thanks :)

Yes, it absolutely makes sense. Here are some pics - if they are too close, I'd need to move the trainer to a bigger room and re-take.

I think I could potentially move the saddle forward another 10-15mm and the position looks a bit tight to my amateur eyes (although it's quite comfortable to me and I had fairly decent IM splits - 5:01 and 5:03 with low 190s NP on flat courses). Getting slightly lower for 5h is possible, but will take me some time. I'd say the chance of me wanting to go to less than 450mm pad reach is about nil - I'd probably have the legs hitting my elbows.

5hrs on 190w AP is pretty good! I'd say you're doing something right. If you got a P3x with the tilt option you could get longer "for free" and perhaps squeeze out some more time to get under 5hrs thru some Cd savings.

Eric

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [Hoffmeister] [ In reply to ]
Quote | Reply
Hoffmeister wrote:
Thanks again for your help!

I pulled the trigger on the XL and now need to get a new PM (bike shop happy to install the PM during the build). Currently on 175mm, but thinking of getting 170 or 165 cranks .. is it just a matter of increasing the seat height and pad stack by the difference in crank length?

Awesome. Let me know how it goes. 165mm cranks! Increase seat height, increasing pad stack by similar amount optional. Increase reach instead.

Eric

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [DMVD] [ In reply to ]
Quote | Reply
DMVD wrote:
Eric

Still looking at P5....my Cervelo P4 fit in October 2019 was Arm Pad Reach 425, Arm Pad Stack 636, and Seat Height of 715 on a 172.5 crank (standard). When I put those numbers in the Cervelo size chart it says both 51 and 54 work. My P4 is a 51....but maybe I should be on a 54 now with shorter cranks? Thanks, Dirk

For a P5d, with a pad stack of 636mm and a pad reach of 425mm, you're sort of upright and in the very upper left quadrant of a 51cm P5d. Not even on the 54cm chart, but only by a few millimeters. You're very high for a 51cm P4 and also a 51cm P5d.

Because you're so far in the upper left quadrant of a 51cm P5d, and have a high stack in the absolute sense as well, I'm guessing you're a bit "unorthodox", and could stand to be less "slack" or more forward, and if so you'd hit the 54cm chart and be more in the upper third with regard to stack.

Can you post a pic of you and your P4? That might help. Aside from that I'd lean toward the 54cm P5d and work on your fit, saddle choice, and crank length.

Eric

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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [ericMPro] [ In reply to ]
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Eric - Many many thanks. My bike fitter is Retul certified and well known (I am sure you know him). He has said the P4 has limitations and based on everything (bike adjustability, body, cranks, etc) my fit is best outcome. So you both are matching in thoughts (great minds think alike). I like this forum so wanted to check with you. I am traveling, Northwoods Country Inn with wife, and will drop you some pictures in a few days. Thinking cranks......Shimano makes a 165mm but nothing shorter that I have seen. Given my 5’7”” frame do you like a manufacturer that makes a shorter crank that works with Di2? Thanks again....
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [DMVD] [ In reply to ]
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DMVD wrote:
Eric - Many many thanks. My bike fitter is Retul certified and well known (I am sure you know him). He has said the P4 has limitations and based on everything (bike adjustability, body, cranks, etc) my fit is best outcome. So you both are matching in thoughts (great minds think alike). I like this forum so wanted to check with you. I am traveling, Northwoods Country Inn with wife, and will drop you some pictures in a few days. Thinking cranks......Shimano makes a 165mm but nothing shorter that I have seen. Given my 5’7”” frame do you like a manufacturer that makes a shorter crank that works with Di2? Thanks again....

your fitter is right, the P4 is definitely limited. Fast bike though. I raced it for one IM cycle, attempting to qualify and then qualifying for Kona. I felt like my bike split was up there both with my peers' time and also good based on the watts I put out. I had the rear brake all the way loose, and only for emergencies, and was very cognizant of the fact that it might be rubbing when I used it. I had the P4 bottle cut out to use as a flat kit, and I had to do some work with the front end, despite being sort of long and low, because the P4 frame is very long and low. I have another one now, and it's equipped with the TriRig Alpha One and it's glorious. Only used for sprint and olympic races and open TTs.

There's a loose correlation between height and leg length and leg length and crank length, but I've also seen plenty of "short" people handle "long" cranks and plenty of "tall" people need "short" cranks. You may be fine w/ 165mm, the lowest easily available length, but at your height I'd almost certainly want you to try 155mm at the very least.

Any crank, with the right bottom bracket for the crank's spindle diameter and your frame's BB shell width and inner diameter, will work with Di2 AFAIK. Most of my clients who end up on short cranks end up on Cobb alloy cranks and power pedals (Garmin, Assioma), as that's the cheaper alternative to some of the crank based 160mm and below power meter crank combos. Cobb has 24/22mm spindle, ie. SRAM GXP, so you get the right BB for your frame and install the Cobb crank. For the P4 that would be a threaded external BB for SRAM GXP IIRC.

I actually have a Ceramic Speed threaded external BB for GXP if you go that route.

Eric

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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [ericMPro] [ In reply to ]
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Shimano does have the 105 R7000 crankset in 160 mm.

Jeroen

Owner at TRIPRO, The Netherlands
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [TRIPRO] [ In reply to ]
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TRIPRO wrote:
Shimano does have the 105 R7000 crankset in 160 mm.

Jeroen

thanks for that!

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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [ericMPro] [ In reply to ]
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Eric

I agree, my P4 is zippy (we know the rider helps a bit) and carried me to a 70.3 Championship race a few years ago. Only issues I have had is, like you, rear brake rubbing, and my seat post shrunk in a 70.3 race when I hit a poorly maintained small bridge bump.

Thinking about the 155 cranks....creates another issue which is what size chain ring should you move to? My current SRAM Red is 53/39. Again, many thanks to get an unbiased opinion.
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [DMVD] [ In reply to ]
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DMVD wrote:
Eric

I agree, my P4 is zippy (we know the rider helps a bit) and carried me to a 70.3 Championship race a few years ago. Only issues I have had is, like you, rear brake rubbing, and my seat post shrunk in a 70.3 race when I hit a poorly maintained small bridge bump.

Thinking about the 155 cranks....creates another issue which is what size chain ring should you move to? My current SRAM Red is 53/39. Again, many thanks to get an unbiased opinion.

I usually select the largest chainrings possible.

I sort of use the same couple of gears for all races... 75rpm for IM, 80rpm for HIM, 90rpm for OD, 95rpm for Sprint, etc., and I have enough power to get up the steepest climbs in the 28t cog, so big chainrings and a straight chainline are feasible for me. If you ride IM at 100rpm you might want to reconsider.

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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [ericMPro] [ In reply to ]
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Hi,

I am looking to purchase a P5d since my P2 is stuck in storage in USA and I am overseas right now. (Good excuse to buy a new bike, right??) My P2 is a 56, but local fitters have suggested that I am in between 54 and 56 so both would work. Other fitters say definitely a 54.

Here are my measurements from my GURU DFU fitting:

Saddle height: 73.5
Setback -1.5 cm
Pad stack 650
Centerpad reach 475 (back of the pads was 415? I am not sure about this)
Bar reach 460

Background: After a hip tear and moving for work, I have not done any cycling in almost 2 years (IM, HIM). Hoping to build back up to racing soon :)


What do you suggest?
Last edited by: kjohn: Aug 16, 20 9:08
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [kjohn] [ In reply to ]
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kjohn wrote:
Hi,

I am looking to purchase a P5d since my P2 is stuck in storage in USA and I am overseas right now. (Good excuse to buy a new bike, right??) My P2 is a 56, but local fitters have suggested that I am in between 54 and 56 so both would work. Other fitters say definitely a 54.

Here are my measurements from my GURU DFU fitting:

Saddle height: 73.5
Setback -1.5 cm
Pad stack 650
Centerpad reach 475 (back of the pads was 415? I am not sure about this)
Bar reach 460

Background: After a hip tear and moving for work, I have not done any cycling in almost 2 years (IM, HIM). Hoping to build back up to racing soon :)


What do you suggest?

hi there, thanks for reaching out.

Your local fitters are right, with a Pad Stack of 650mm and a Pad Reach of 425mm you are a 54cm P5d, but just *barely*. Very upper left quadrant of the fit chart, in other words very upright and very slack. Seeing these numbers would make me question the orthodoxy of your basic fit, and also make me wonder where your fit might progress toward if it's not totally locked in and perfect now.

At that stack height, you have up to 470mm of reach in a size 54cm P5d before the reach runs out. You'd have 77mm of a possible 88mm of mono-riser exposed.

To fit a 56cm P5d, you'd need to be at a minimum pad reach of 437-442mm, or another 12-17mm from where you are now, which isn't much.

A 54cm P5d will work. You're not in dire need of a 56cm or in danger of running out of room on the 54cm, but it's something to consider.

Make sense?

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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [ericMPro] [ In reply to ]
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I see what you mean. He measured from the center of the pad (475) instead of the back because he said that it should be more representative of my reach because the pads vary in size. When he measured the back of the pad, he came up with 415 which is not on the chart??

Since, I have been out of triathlons for about two years now from a hip tear, I am essentially starting over. I believe that my fit process is definitely not perfect at all and should progress a quite a bit. I worry that if I buy a 54, I will end up wishing I bought a 56.

I spoke to another fitter about scheduling something soon. He said that since I am 180cm, I'm probably on the border of 54/56, but he seemed pretty confident that a 56 would be in my best interest because of a hip tear (with the included lower back pain). He suggested that although a 54 may allow a more aggressive position, a 56 will be more comfortable for longer formats? So, I guess that's next on my to-do list.

I live in Thailand and the weather is unbearably hot, humid, and rainy so my goal is to do mainly Oly/HIM races and primarily train indoors with the occasional outdoor cycling tracks (open roads are extremely dangerous here..lol)

I appreciate all your advice! Thanks
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [kjohn] [ In reply to ]
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kjohn wrote:
I see what you mean. He measured from the center of the pad (475) instead of the back because he said that it should be more representative of my reach because the pads vary in size. When he measured the back of the pad, he came up with 415 which is not on the chart??

Since, I have been out of triathlons for about two years now from a hip tear, I am essentially starting over. I believe that my fit process is definitely not perfect at all and should progress a quite a bit. I worry that if I buy a 54, I will end up wishing I bought a 56.

I spoke to another fitter about scheduling something soon. He said that since I am 180cm, I'm probably on the border of 54/56, but he seemed pretty confident that a 56 would be in my best interest because of a hip tear (with the included lower back pain). He suggested that although a 54 may allow a more aggressive position, a 56 will be more comfortable for longer formats? So, I guess that's next on my to-do list.

I live in Thailand and the weather is unbearably hot, humid, and rainy so my goal is to do mainly Oly/HIM races and primarily train indoors with the occasional outdoor cycling tracks (open roads are extremely dangerous here..lol)

I appreciate all your advice! Thanks

a few things that pop out:

1. yes, 415mm would be off the charts to the left, ie. not enough reach to hit the minimum reach for the 54cm. One thing to mention is that you could use the EX-10 mono-riser from the P3x on the P5d and add a little reach flexibility that way. That said, I don't really think you need that little reach, even though I've never seen a picture of you on the bike. With proper postural coaching you can hit the minimum reach for the 54cm or even the 56cm.

2. I'm immediately triggered when I hear your fitter saying that the 54cm "may allow a more aggressive position", for two reasons. First, your position is your position, and it will be the same on either bike, assuming it's achievable on both bikes. Second, "aggressive" is a buzzword red flag for me, ie. there's no such thing. Positions are either orthodox or they're not, they're either optimized or they're not. Aggressive and/or conservative are nonsensical words that make no sense here.

3. I'm also triggered by the logic leap from "conservative" to "being better for long course". There's very good reasons for getting longer and lower, and one of them is that if done right, you actually make yourself more comfortable and more efficient for longer rides. Part of it is getting weight onto the front end and off of your pelvis, but there are other factors as well. At any rate, "more comfortable for long course" is code for "I don't understand long course bike fitting" so be careful.

Finally, seeing as how you are in Thailand, I'm confident that if you purchased a 56cm P5d and we did a remote fit together, I could get you in the right place. Or another competent remote fitter. It's all about saddle choice and coaching about how to sit on it and then postural coaching for the rest.

Finally finally, I'd be curious to see how different crank lengths affect your repaired hip, and have a hunch that shorter cranks and thus smaller range of motion might be better for you. Something to think about.

Eric

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