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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [ericMPro] [ In reply to ]
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Thank you for doing this, Eric. I'm deciding between a P5 disc and the P-Series.

Here's the current set up on my 2016 Felt B2

Pad stack: 679mm
Pad reach: 440mm
Pad width (CtoC): 220mm

Best
Luiz
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [KodioMN] [ In reply to ]
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KodioMN wrote:
Thank you for doing this, Eric. I'm deciding between a P5 disc and the P-Series.

Here's the current set up on my 2016 Felt B2

Pad stack: 679mm
Pad reach: 440mm
Pad width (CtoC): 220mm

Best
Luiz

hi Luiz, thanks for reaching out.

With a Pad Stack of 679mm and a Pad Reach of 440mm you're in the very upper left quadrant of a size 56cm P5d. "Upper left" is code for upright or slack or upright and slack, so I feel like you've got some evolving to do with your position. If you were to migrate toward a more orthodox position, something longer and lower (and likely enabled by the correct saddle for you in that particular position as well as shorter cranks), you'd have 40-60mm of additional reach to work with not to mention about 90mm of stack to play with going downward.

Caveat: 40-60mm sounds like a lot, but really it's not. It's just about 2 inches, or about one elbow contact patch. I could see an edge case where, after seeing me in person and receiving postural coaching from me and working through all of the various fit possibilities on a dynamic fit bike, you could be at something longer than 480mm of reach, in which case you'd wish you bought a 58cm instead of a 56cm P5d. It's not likely, it's an edge case, but it's possible. This is less of an issue with a P-Series because you can always swap out stems if need be. You can also increase the reach of a P5d with the P3x mono-riser, which at this point I feel like I prescribe that swap for people here as a standard prescription when buying a P5d.

Anyway, does this make sense? Before I commit to a size recommendation, how tall are you and what's your inseam? Do you have a pic of yourself in the TT position on your current bike?

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.”
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [ericMPro] [ In reply to ]
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Yes, Eric. It makes sense.
I've been fitted twice over the last 3 years by different professionals on this same Felt B2 58 frame. I have not had any major issues until very recently (patella pain). I have limited basic understanding in the subject of bike fitting but looking at pictures I can see what you mean.
I'm 6'1" (186cm), inseam 35 3/8 in
Attached are two different pictures. One taken at home (DIY measurements be aware) and another during a race when I usually inadvertently move forward and lift my head.

I highly appreciate this, Eric.

Cheers
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [KodioMN] [ In reply to ]
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What is your crank arm length?
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [jimatbeyond] [ In reply to ]
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172.5
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [KodioMN] [ In reply to ]
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Based on this picture I can absolutely see you getting much longer and hitting a 58cm P5d.

And Jim@Beyond is right, shorter cranks which will also make you longer as you rotate your pelvis forward.

Make sense?

E



Eric Reid AeroFit | Instagram Portfolio
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“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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Sounds good, Eric. Thank you again!
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [KodioMN] [ In reply to ]
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What crank arm length are you going to try?
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [jimatbeyond] [ In reply to ]
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jimatbeyond wrote:
What crank arm length are you going to try?


Foot stomp ;)

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 [jimatbeyond] [ In reply to ]
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jimatbeyond wrote:
What crank arm length are you going to try?

I would not know. I scheduled time with a local reputable fitter who will help me pre and post purchase.
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [KodioMN] [ In reply to ]
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Your fitter should be able to help you determine the proper crank arm length during the fit session.

Do they have the ability to change crank arm length on the fit bike?
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [ericMPro] [ In reply to ]
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Hello,

Considering a medium P3X.
I'm currently on a size 54 P2. Front center is 602 and wheelbase is 995.
The medium P3X has a front center of 587 and wheelbase of 980.
I'm concerned about how a smaller frame size will handle compared to my current bike.
Have read a bit about how front center affects handling, but not sure if or how I can determine how much front center or wheelbase is right for me.
Any idea how might I do on a medium?

Current fit numbers are:

pad x 510 to pad center. I've experimented with longer and I think 510 is the longest I would want to go. More like 505 or even 500 might be ideal.
pad y 605. I'm pretty convinced I could go a couple of cm lower then this. Via the cervelo calculator a large size frame will only go 1 cm lower.
edit: looks like I can't get a pic uploaded right now. Do have a video link though: https://m.youtube.com/watch?v=aIqjsXwBxaQ
Last edited by: TCoBGuy: Sep 30, 20 9:19
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First TT bike coming off road bike + aerobar position [ In reply to ]
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Hi Eric -

Great thread and I really like this concept of pad x/y to understand the fitting - it has significantly de-mystified things for me! What I'm struggling with a bit more is trying to relate that to the rim brake models, esp. the 2014+ P3s.

Some background that may help understand where I'm at:

Height - 5'11.5", Inseam - 32"
Pax X = 419 to back of pad, 463 to center
Pad Y = 706
Pad Z - I'm not 100% sure how this is measured but my pads are 5" inside-edge to inside-edge, or 9.5" measuring between the points that they curve upwards. (and thus 7.25" between the centers of the flat parts)

I have been using a redshift seat/aerobar setup on a Trek H2 geometry 56 cm road bike for the past year after discovering "aero" - making periodic steps down in 5 mm increments, training about 50/50 in both TT and road positions. Combined with reducing stem from +13 to -6 deg and increasing my reach a bit with the stem change have all helped me improve speed a lot. Have been doing some 10 mile TTs each week and recently did my first 40k TT at just under 59 mins, flat 3-lap no wind course, at 248W - comfort felt great, esp. with the redshift seatpost - so I think I'm not in a terrible position, but I suspect I should work to get longer/lower when on aerobars. I just don't want to keep pushing my road bars lower to make it happen as I don't always ride with the aerobars. I've enjoyed it enough to want to get a TT bike to have more freedom in position. Goals are unlikely to go beyond 40k - not into triathlons - just cycling.

To keep my costs somewhat in control, I have been looking at 2014-2020 rim P3s. In addition to being well regarded as highly adjustable, I believe they should handle my existing rim brake 65 mm aero wheels that are max 28 mm width but taper down to ~26.7 mm max tire width when using GP5000TL 25s.

I feel like I have ample room to go lower, which is probably obvious in my pad x/y result coming off the road bike w/clip-ons. What I can't find is a X/Y parallelogram chart for the P3 - only the newer P3x. The P3x suggests to me I'd want a L/56 as I'm at the very upper left (which I'd expect given starting on a somewhat constrained road bike aerobar position) and I'd absolutely anticipate moving into that 56 sizing chart on a dedicated TT bike setup from day 1. But does this chart apply to the rim P3 as well?

I'm also not averse to a rim P5 if the right deal came along, but it seems like I'm dangerously far off the parallelograms for the P5. Still, the closest here also looks like 56 although it would take a big jump long/low just to get into that zone, and I like the idea of standard components on the P3 to have more flexibility to follow a fit roadmap being newer to this. And if I understand some discussion in this thread correctly, the P2/P3 platform may be able to expand these "parallelogram" zones more broadly with bigger range of stem sizes - in which case maybe I should stay away from P5 for now?

I also understand the P2 is identical frame, but I'd also be a bit more worried about front fork clearance with my wheels.

Given all of this, would greatly appreciate your input on whether 56 is indeed the right call across the Cervelo rim models - and please let me know if anything else would be helpful!

Thanks,
Colin
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Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [TCoBGuy] [ In reply to ]
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TCoBGuy wrote:
Hello,

Considering a medium P3X.
I'm currently on a size 54 P2. Front center is 602 and wheelbase is 995.
The medium P3X has a front center of 587 and wheelbase of 980.
I'm concerned about how a smaller frame size will handle compared to my current bike.
Have read a bit about how front center affects handling, but not sure if or how I can determine how much front center or wheelbase is right for me.
Any idea how might I do on a medium?

Current fit numbers are:

pad x 510 to pad center. I've experimented with longer and I think 510 is the longest I would want to go. More like 505 or even 500 might be ideal.
pad y 605. I'm pretty convinced I could go a couple of cm lower then this. Via the cervelo calculator a large size frame will only go 1 cm lower.
edit: looks like I can't get a pic uploaded right now. Do have a video link though: https://m.youtube.com/watch?v=aIqjsXwBxaQ

With a Pad Stack of 605mm and a Pad Reach of 460mm (to back of pads), I could make a strong case for putting you on a size L P3x, and not a size M as you might have thought. In fact, with those numbers you could fit on a size S, M, *and* L.

If you were to go with a size L, you'd have the longer front center and wheelbase, but could only go about 12mm lower in the future, so essentially slammed.

On a size M stack would not be a factor, and you'd be riding in the center-low quadrant, so not way off the front or something, and you'd be riding a first-in-class designed bike with regard to handling, so you're OK on that front as well. TTs and triathlons are sometimes technical and perhaps even dangerous, but it's a safety and bike handling *skill* thing, and not a technical limitations of the frame geometry design thing. Staying alert will net you 98% of whatever the additional 27mm of front-center might get you.

That said, if you're absolutely *sure* you'd never go lower than 593mm, you could slam a size L but I think you'll be OK on a size M P3x, not to mention slammed pads might be slower than pads up a bit on a mono-riser. Allegedly ;)

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: First TT bike coming off road bike + aerobar position [hvvelo] [ In reply to ]
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hvvelo wrote:
Hi Eric -

Great thread and I really like this concept of pad x/y to understand the fitting - it has significantly de-mystified things for me! What I'm struggling with a bit more is trying to relate that to the rim brake models, esp. the 2014+ P3s.

Some background that may help understand where I'm at:

Height - 5'11.5", Inseam - 32"
Pax X = 419 to back of pad, 463 to center
Pad Y = 706
Pad Z - I'm not 100% sure how this is measured but my pads are 5" inside-edge to inside-edge, or 9.5" measuring between the points that they curve upwards. (and thus 7.25" between the centers of the flat parts)

I have been using a redshift seat/aerobar setup on a Trek H2 geometry 56 cm road bike for the past year after discovering "aero" - making periodic steps down in 5 mm increments, training about 50/50 in both TT and road positions. Combined with reducing stem from +13 to -6 deg and increasing my reach a bit with the stem change have all helped me improve speed a lot. Have been doing some 10 mile TTs each week and recently did my first 40k TT at just under 59 mins, flat 3-lap no wind course, at 248W - comfort felt great, esp. with the redshift seatpost - so I think I'm not in a terrible position, but I suspect I should work to get longer/lower when on aerobars. I just don't want to keep pushing my road bars lower to make it happen as I don't always ride with the aerobars. I've enjoyed it enough to want to get a TT bike to have more freedom in position. Goals are unlikely to go beyond 40k - not into triathlons - just cycling.

To keep my costs somewhat in control, I have been looking at 2014-2020 rim P3s. In addition to being well regarded as highly adjustable, I believe they should handle my existing rim brake 65 mm aero wheels that are max 28 mm width but taper down to ~26.7 mm max tire width when using GP5000TL 25s.

I feel like I have ample room to go lower, which is probably obvious in my pad x/y result coming off the road bike w/clip-ons. What I can't find is a X/Y parallelogram chart for the P3 - only the newer P3x. The P3x suggests to me I'd want a L/56 as I'm at the very upper left (which I'd expect given starting on a somewhat constrained road bike aerobar position) and I'd absolutely anticipate moving into that 56 sizing chart on a dedicated TT bike setup from day 1. But does this chart apply to the rim P3 as well?

I'm also not averse to a rim P5 if the right deal came along, but it seems like I'm dangerously far off the parallelograms for the P5. Still, the closest here also looks like 56 although it would take a big jump long/low just to get into that zone, and I like the idea of standard components on the P3 to have more flexibility to follow a fit roadmap being newer to this. And if I understand some discussion in this thread correctly, the P2/P3 platform may be able to expand these "parallelogram" zones more broadly with bigger range of stem sizes - in which case maybe I should stay away from P5 for now?

I also understand the P2 is identical frame, but I'd also be a bit more worried about front fork clearance with my wheels.

Given all of this, would greatly appreciate your input on whether 56 is indeed the right call across the Cervelo rim models - and please let me know if anything else would be helpful!

Thanks,
Colin

Well you can thank our forum moderator and fearless leader Dan Empfield, creator of the tri bike, the tri wetsuit, and the triathlon and now all bikes X/Y coordinate fit system for that. It's one of those discoveries that was impossible to make but completely obvious in hindsight, like it was a property of the universe just waiting to be discovered.

Another thing Dan articulates is how to build a mortal bike, and in his (and my) opinion, you start with the bars and work back. When he published his project, the bar du jour was the 3T Ventus, actually the only fast option at the time really, but now there are lots of good options like Vision and TriRig. Once you know what bar you want you work backwards to bike brand and bike size, etc.

I say that because while the Cervelo NP3 was and is a fast bike, the OEM bars that it came with weren't always the best in terms of what you'd get now with a P5d, P3x, or even P-Series.

At any rate... Pad Stack of 709mm and Pad Reach of 419mm. You are in the upper left quadrant my friend, ie. slack or upright. On a mortal bike that means unsightly spacers under the stem to get you where you need to be. I'm questioning this fit... on the P3x charts you are too high for a size L and too far to the left for a size XL... off the charts IOW.

You say you've been "adapting", working downward in 5mm increments. Have you tried going longer in a similar manner? This would bring you into the orthodox fit range and likely make you more comfortable. That said, whatever you're doing is working because 59:xx 40km TT on 248w AP is amazing.

How tall are you? I would ride a 58cm NP3 if it were me and I'm 6'2". Really I'd ride a 61cm but I'm vain. You might do well on a 58cm with a short stem, or on a 56cm with a longer stem and some spacers. Best to find a cockpit system that allows you to raise pads and extensions independently of the basebar. So yes, the general relative quadrants of the charts apply to the NP3 as well. A tri bike will automatically bring you forward and down some, and when it does you'll land in the 56cm frame size fit range.

Make sense?

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: First TT bike coming off road bike + aerobar position [ericMPro] [ In reply to ]
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Purely hypothetical here.

Let's say my fit coordinates are these:

The World's Fastest Scott Plasma 3 in existence, size Medium
Tri rig Alpha 1 & gamma 24s
Y = 615
x = 460
CdA = .211 averaged over 6-7 runs of my current position

Should I get rid of my Scott plasma 3 for a Cervelo P3x with some fancy aftermarket upgrades including the P5x basebar/extension clamp/monoriser?

If so should it be the Med or a L since I fall into both sizes?

Brian Stover USAT LII
Accelerate3 Coaching
Insta

Last edited by: desert dude: Sep 30, 20 12:33
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Re: First TT bike coming off road bike + aerobar position [ericMPro] [ In reply to ]
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ericMPro wrote:


I say that because while the Cervelo NP3 was and is a fast bike, the OEM bars that it came with weren't always the best in terms of what you'd get now with a P5d, P3x, or even P-Series.

At any rate... Pad Stack of 709mm and Pad Reach of 419mm. You are in the upper left quadrant my friend, ie. slack or upright. On a mortal bike that means unsightly spacers under the stem to get you where you need to be. I'm questioning this fit... on the P3x charts you are too high for a size L and too far to the left for a size XL... off the charts IOW.

You say you've been "adapting", working downward in 5mm increments. Have you tried going longer in a similar manner? This would bring you into the orthodox fit range and likely make you more comfortable. That said, whatever you're doing is working because 59:xx 40km TT on 248w AP is amazing.

How tall are you? I would ride a 58cm NP3 if it were me and I'm 6'2". Really I'd ride a 61cm but I'm vain. You might do well on a 58cm with a short stem, or on a 56cm with a longer stem and some spacers. Best to find a cockpit system that allows you to raise pads and extensions independently of the basebar. So yes, the general relative quadrants of the charts apply to the NP3 as well. A tri bike will automatically bring you forward and down some, and when it does you'll land in the 56cm frame size fit range.

Make sense?


Hi Eric -

Thank you very much for the input here!

Yes, this makes sense - if the NP3 fit diagram is similar to P3x, then I was thinking that at 419/706 mm, I'm right on the upper left corner (tried attaching the chart that I think applies to the last rim P3s?) and the second I drop and move forward at all, I'll be working into the meat of the 56 cm chart with lots of room to progress if needed. For bar/bike selection, budget is of course a factor, and with Cervelo having gone all disc, the extra money that would be required to duplicate my excellent rim brake wheels just takes the newest models off the table for me for now. But maybe I'll help someone else upgrade their NP3 into a new disc bike :-)

As to current position, maybe this picture will help - don't laugh at the SPD shoes - it's all I have :-) This is where I converged after some help on the trainerroad forum in the first 3 months with my redshift kit - EXCEPT I later flipped the stem to -6 degrees, with a 5 mm under it. I haven't pushed any longer/lower as it starts to get uncomfortable on 3+ hr road rides without aerobars. I'm about 5' 11.5" so a bit shorter than you. When I went from 13 deg to 6 deg stem, I went + 10mm on the stem - but otherwise haven't gone longer yet. I do find myself starting rides with elbows just behind the pad, and tend to move forward a bit while I ride so probably some room there.

I've probably tweaked the seat position a few mm since this photo and no longer use the same saddle, but it's otherwise the same position I did for my 40k. I also ditched my frame bottles/pump/gloves, used a BTA torpedo, narrower top tube bag and 65 mm wheels - have been lurking and studying these pages trying to learn. I was still surprised to pull it off at 58:56 for 248W, but I never broke position, it was all right turns so never had to touch brakes or turnaround, temp in the 70s and pretty flat and wind-free - very ideal conditions.

I would guess that my current position is still very boxed in being on a road bike and I am planning a serious fit trip soon at what I believe is a very well regarded place. (not sure if we can say names on here)

My thought is that since I had to schedule this appointment months in advance, and it's not easy for me to make this trip often or even schedule it, I may benefit from finding an appropriate sized P3 ahead of time, get some rides in with an initial setup that is a step more aggressive than what I can do on the road bike, and perhaps that will help me provide more informed input to the fit process, esp. coupled with the experience I now have on the road bike TT setup.

In summary, it sounds like I should look for a 56 in the P-series unless you see something in this photo that says "wait, that's all wrong!"
Last edited by: hvvelo: Sep 30, 20 12:28
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Re: First TT bike coming off road bike + aerobar position [hvvelo] [ In reply to ]
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hvvelo wrote:
ericMPro wrote:


I say that because while the Cervelo NP3 was and is a fast bike, the OEM bars that it came with weren't always the best in terms of what you'd get now with a P5d, P3x, or even P-Series.

At any rate... Pad Stack of 709mm and Pad Reach of 419mm. You are in the upper left quadrant my friend, ie. slack or upright. On a mortal bike that means unsightly spacers under the stem to get you where you need to be. I'm questioning this fit... on the P3x charts you are too high for a size L and too far to the left for a size XL... off the charts IOW.

You say you've been "adapting", working downward in 5mm increments. Have you tried going longer in a similar manner? This would bring you into the orthodox fit range and likely make you more comfortable. That said, whatever you're doing is working because 59:xx 40km TT on 248w AP is amazing.

How tall are you? I would ride a 58cm NP3 if it were me and I'm 6'2". Really I'd ride a 61cm but I'm vain. You might do well on a 58cm with a short stem, or on a 56cm with a longer stem and some spacers. Best to find a cockpit system that allows you to raise pads and extensions independently of the basebar. So yes, the general relative quadrants of the charts apply to the NP3 as well. A tri bike will automatically bring you forward and down some, and when it does you'll land in the 56cm frame size fit range.

Make sense?


Hi Eric -

Thank you very much for the input here!

Yes, this makes sense - if the NP3 fit diagram is similar to P3x, then I was thinking that at 419/706 mm, I'm right on the upper left corner (tried attaching the chart that I think applies to the last rim P3s?) and the second I drop and move forward at all, I'll be working into the meat of the 56 cm chart with lots of room to progress if needed. For bar/bike selection, budget is of course a factor, and with Cervelo having gone all disc, the extra money that would be required to duplicate my excellent rim brake wheels just takes the newest models off the table for me for now. But maybe I'll help someone else upgrade their NP3 into a new disc bike :-)

As to current position, maybe this picture will help - don't laugh at the SPD shoes - it's all I have :-) This is where I converged after some help on the trainerroad forum in the first 3 months with my redshift kit - EXCEPT I later flipped the stem to -6 degrees, with a 5 mm under it. I haven't pushed any longer/lower as it starts to get uncomfortable on 3+ hr road rides without aerobars. I'm about 5' 11.5" so a bit shorter than you. When I went from 13 deg to 6 deg stem, I went + 10mm on the stem - but otherwise haven't gone longer yet. I do find myself starting rides with elbows just behind the pad, and tend to move forward a bit while I ride so probably some room there.

I've probably tweaked the seat position a few mm since this photo and no longer use the same saddle, but it's otherwise the same position I did for my 40k. I also ditched my frame bottles/pump/gloves, used a BTA torpedo, narrower top tube bag and 65 mm wheels - have been lurking and studying these pages trying to learn. I was still surprised to pull it off at 58:56 for 248W, but I never broke position, it was all right turns so never had to touch brakes or turnaround, temp in the 70s and pretty flat and wind-free - very ideal conditions.

I would guess that my current position is still very boxed in being on a road bike and I am planning a serious fit trip soon at what I believe is a very well regarded place. (not sure if we can say names on here)

My thought is that since I had to schedule this appointment months in advance, and it's not easy for me to make this trip often or even schedule it, I may benefit from finding an appropriate sized P3 ahead of time, get some rides in with an initial setup that is a step more aggressive than what I can do on the road bike, and perhaps that will help me provide more informed input to the fit process, esp. coupled with the experience I now have on the road bike TT setup.

In summary, it sounds like I should look for a 56 in the P-series unless you see something in this photo that says "wait, that's all wrong!"


Yep, that basically sums it up. You'll start hitting the meat of the 56cm P-Series chart once you come slightly forward, which will make you want to come slightly down, which will make you want to go even more forward, etc. I think you'll find the P-Series bars to be *very* versatile and adjustable too.

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: Sep 30, 20 13:35
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Re: First TT bike coming off road bike + aerobar position [desert dude] [ In reply to ]
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desert dude wrote:
Purely hypothetical here.

Let's say my fit coordinates are these:

The World's Fastest Scott Plasma 3 in existence, size Medium
Tri rig Alpha 1 & gamma 24s
Y = 615
x = 460
CdA = .211 averaged over 6-7 runs of my current position

Should I get rid of my Scott plasma 3 for a Cervelo P3x with some fancy aftermarket upgrades including the P5x basebar/extension clamp/monoriser?

If so should it be the Med or a L since I fall into both sizes?

First, the P3x comes with a "good" for us mono-riser, ie. tiltable.

Second, what's the application? If you're a three-bottle IM guy, then maybe for the P3x, if not maybe the P5d. Are you doing another IM??? The tri world wants to know ;)

That said, the only thing to decide about is size, and the only thing I have is anecdote as well as some common sense with regard to pads and basebar interaction. You'd be a size M P3x with more exposed mono-riser than a size L. You'd have 25mm of more reach to play with in size M.

E

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: First TT bike coming off road bike + aerobar position [ericMPro] [ In reply to ]
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ericMPro wrote:

First, the P3x comes with a "good" for us mono-riser, ie. tiltable.
10 degree tilt costs me >10w at - 10yaw. No tilt for me.


ericMPro wrote:
Second, what's the application? If you're a three-bottle IM guy, then maybe for the P3x, if not maybe the P5d. Are you doing another IM??? The tri world wants to know ;)

I'll give you the exclusive breaking news on your fit thread!

Probably not. Never say never though because you know I just might. I think I have a 9:45 in me, yet I don't feel the urge to find out. I'm pretty satisfied with my sub 10 PB. I also have doubts about durability now that I'm older. 35 years of endurance sports has left me fit yet somewhat damaged.

ericMPro wrote:
That said, the only thing to decide about is size, and the only thing I have is anecdote as well as some common sense with regard to pads and basebar interaction. You'd be a size M P3x with more exposed mono-riser than a size L. You'd have 25mm of more reach to play with in size M.

The faster you go the less head tube you want!

Brian Stover USAT LII
Accelerate3 Coaching
Insta

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Re: First TT bike coming off road bike + aerobar position [desert dude] [ In reply to ]
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desert dude wrote:
ericMPro wrote:


First, the P3x comes with a "good" for us mono-riser, ie. tiltable.

10 degree tilt costs me >10w at - 10yaw. No tilt for me.


ericMPro wrote:
Second, what's the application? If you're a three-bottle IM guy, then maybe for the P3x, if not maybe the P5d. Are you doing another IM??? The tri world wants to know ;)


I'll give you the exclusive breaking news on your fit thread!

Probably not. Never say never though because you know I just might. I think I have a 9:45 in me, yet I don't feel the urge to find out. I'm pretty satisfied with my sub 10 PB. I also have doubts about durability now that I'm older. 35 years of endurance sports has left me fit yet somewhat damaged.

ericMPro wrote:
That said, the only thing to decide about is size, and the only thing I have is anecdote as well as some common sense with regard to pads and basebar interaction. You'd be a size M P3x with more exposed mono-riser than a size L. You'd have 25mm of more reach to play with in size M.


The faster you go the less head tube you want!


I wanted to circle back because I don't think I showed my work. I know you, have raced you, and have seen your position. Usually I recommend or err on the side of the larger bike, ie. the longer bike, but that's because 90% of us don't have an optimized position, and it's easier to shorten up a longer bike than it is to sell a smaller bike to get a larger bike. That said, for you, knowing you probably won't get any longer, and even if you do, there's 25mm left to play with, I feel very comfortable steering you toward the smaller bike.

Also, it's not inconsequential to consider that in these pandemic times IM branded and IM 70.3 branded bike course aid stations are going to change and there's some new utility to having a bike that can carry *everything*, and aerodynamically. The P3x or PX certainly do that.

Finally, you don't get your IM PR because of an urge to do it, you get it because you let go of your urges and just yield, give in, give yourself over to the process. It's very scary to lose control that way, but also enlightening and a relief.


E

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: Sep 30, 20 14:13
Quote Reply
Re: First TT bike coming off road bike + aerobar position [ericMPro] [ In reply to ]
Quote | Reply
ericMPro wrote:

I wanted to circle back because I don't think I showed my work. I know you, have raced you, and have seen your position. Usually I recommend or err on the side of the larger bike, ie. the longer bike, but that's because 90% of us don't have an optimized position, and it's easier to shorten up a longer bike than it is to sell a smaller bike to get a larger bike. That said, for you, knowing you probably won't get any longer, and even if you do, there's 25mm left to play with, I feel very comfortable steering you toward the smaller bike.

Also, it's not inconsequential to consider that in these pandemic times IM branded and IM 70.3 branded bike course aid stations are going to change and there's some new utility to having a bike that can carry *everything*, and aerodynamically. The P3x or PX certainly do that.

Finally, you don't get your IM PR because of an urge to do it, you get it because you let go of your urges and just yield, give in, give yourself over to the process. It's very scary to lose control that way, but also enlightening and a relief.

#Truth to aid stations changing forever. Rolling buffets FTW!

Brian Stover USAT LII
Accelerate3 Coaching
Insta

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

Considering a medium P3X.
I'm currently on a size 54 P2. Front center is 602 and wheelbase is 995.
The medium P3X has a front center of 587 and wheelbase of 980.
I'm concerned about how a smaller frame size will handle compared to my current bike.
Have read a bit about how front center affects handling, but not sure if or how I can determine how much front center or wheelbase is right for me.
Any idea how might I do on a medium?

Current fit numbers are:

pad x 510 to pad center. I've experimented with longer and I think 510 is the longest I would want to go. More like 505 or even 500 might be ideal.
pad y 605. I'm pretty convinced I could go a couple of cm lower then this. Via the cervelo calculator a large size frame will only go 1 cm lower.
edit: looks like I can't get a pic uploaded right now. Do have a video link though: https://m.youtube.com/watch?v=aIqjsXwBxaQ


With a Pad Stack of 605mm and a Pad Reach of 460mm (to back of pads), I could make a strong case for putting you on a size L P3x, and not a size M as you might have thought. In fact, with those numbers you could fit on a size S, M, *and* L.

If you were to go with a size L, you'd have the longer front center and wheelbase, but could only go about 12mm lower in the future, so essentially slammed.

On a size M stack would not be a factor, and you'd be riding in the center-low quadrant, so not way off the front or something, and you'd be riding a first-in-class designed bike with regard to handling, so you're OK on that front as well. TTs and triathlons are sometimes technical and perhaps even dangerous, but it's a safety and bike handling *skill* thing, and not a technical limitations of the frame geometry design thing. Staying alert will net you 98% of whatever the additional 27mm of front-center might get you.

That said, if you're absolutely *sure* you'd never go lower than 593mm, you could slam a size L but I think you'll be OK on a size M P3x, not to mention slammed pads might be slower than pads up a bit on a mono-riser. Allegedly ;)

Make sense?

Eric

Thanks Eric.
Only reason I'm really interested in upgrading is to gain some more adjustability. I'm slammed on my current setup and don't want to be only a cm away from being slammed again on a new platform, so I think a large is out.
Size 54 P5 disc is also an option which would go 3 cm lower then my current stack height with the same front center.
I don't suppose you could look at my position and give me an idea of how much lower I might be able to go, or if I should potentially stay where I am?
Thanks!
https://m.youtube.com/watch?v=aIqjsXwBxaQ


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

This is for my wife, she is currently on a 2011 Cannondale Slice size 58 and wants to switch to a Cervelo to complement her S3 and Caledonia.
Pad X - 530 to center from a fit sheet, I can measure actual to back of pads (PD Ergo) if needed
Pad Y - 625

She does not like the look of the PX series so P5, P-series, NP3 would be the type she'd consider. She doesn't do triathlon, purely TTs which mostly don't care about UCI regulations but may occasionally need to squish into a UCI compliant position.

Hope that's the info you need and thanks for any advice!
Quote Reply
Re: Official FIT ASSISTANCE for Cervelo TT and Triathlon Bikes [TCoBGuy] [ In reply to ]
Quote | Reply
TCoBGuy wrote:
ericMPro wrote:
TCoBGuy wrote:
Hello,

Considering a medium P3X.
I'm currently on a size 54 P2. Front center is 602 and wheelbase is 995.
The medium P3X has a front center of 587 and wheelbase of 980.
I'm concerned about how a smaller frame size will handle compared to my current bike.
Have read a bit about how front center affects handling, but not sure if or how I can determine how much front center or wheelbase is right for me.
Any idea how might I do on a medium?

Current fit numbers are:

pad x 510 to pad center. I've experimented with longer and I think 510 is the longest I would want to go. More like 505 or even 500 might be ideal.
pad y 605. I'm pretty convinced I could go a couple of cm lower then this. Via the cervelo calculator a large size frame will only go 1 cm lower.
edit: looks like I can't get a pic uploaded right now. Do have a video link though: https://m.youtube.com/watch?v=aIqjsXwBxaQ


With a Pad Stack of 605mm and a Pad Reach of 460mm (to back of pads), I could make a strong case for putting you on a size L P3x, and not a size M as you might have thought. In fact, with those numbers you could fit on a size S, M, *and* L.

If you were to go with a size L, you'd have the longer front center and wheelbase, but could only go about 12mm lower in the future, so essentially slammed.

On a size M stack would not be a factor, and you'd be riding in the center-low quadrant, so not way off the front or something, and you'd be riding a first-in-class designed bike with regard to handling, so you're OK on that front as well. TTs and triathlons are sometimes technical and perhaps even dangerous, but it's a safety and bike handling *skill* thing, and not a technical limitations of the frame geometry design thing. Staying alert will net you 98% of whatever the additional 27mm of front-center might get you.

That said, if you're absolutely *sure* you'd never go lower than 593mm, you could slam a size L but I think you'll be OK on a size M P3x, not to mention slammed pads might be slower than pads up a bit on a mono-riser. Allegedly ;)

Make sense?

Eric

Thanks Eric.
Only reason I'm really interested in upgrading is to gain some more adjustability. I'm slammed on my current setup and don't want to be only a cm away from being slammed again on a new platform, so I think a large is out.
Size 54 P5 disc is also an option which would go 3 cm lower then my current stack height with the same front center.
I don't suppose you could look at my position and give me an idea of how much lower I might be able to go, or if I should potentially stay where I am?
Thanks!
https://m.youtube.com/watch?v=aIqjsXwBxaQ

No need to go lower, could even come up some. Size M P3x or size 54cm P5d.

You’re 98% of the way there.

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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