I think so. If there's not you can get a longer seatpost. You can confirm when you test with your LBS.

Eric

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Aerodynamic Retul Bike Fitting

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Hi Eric and thanks for offering to help.
I'm considering getting a P5d but would appreciate your help and guidance on sizing. I'm unfortunately not sure about the measures you are asking but hoping you could help based on my road bike fit and a quick fit estimate from Dan Empfield himself at an "Express fit" event a couple years ago.

Here are the measures I got from Dan which are probably the most reliable:
Saddle height: 70.5
Saddle Set (KSM PR Z0): 0
Saddle to arm rest: 41.5cm
Arm rest elevation: 10.5cm
Here is the video: https://www.slowtwitch.com/...Positions__6292.html (last video of the article)

I ride a Felt AR 51cm road bike and a 51cm 2012 P2 (I was never fitted on the P2 outside of the express fit). I'm leaning towards the 51cm P5.
Here are the key RETUL fit measures of my road bike (I'm 5'5):
saddle height: 711mm
saddle setback: -55mm
eff seat tube angle:74 deg
grip handle: 26 deg
frame stack: 526mm
Frame reach: 378mm
handlebar reach: 521mm
handlebar drop: -89mm
grop reach: 644mm
grip drop: -49mm
BB to grip reach / BB to front end of grip:589mm
Handlebar stack: 579mm
Handlebar reach / BB to center of the bar: 466mm
Bar reach: 32mm

Would be great to get you views! Thanks in advance

I can work with these numbers. You're right, the Express Fit numbers are the most pertinent/reliable. We can do a little trigonometry to estimate your Pad Stack and Pad Reach, which is what we need.

Rough back of the envelope math gives you a Pad Stack of 590mm and a Pad Reach of 415mm (luckily your saddle setback was 0mm so this was easy). With those numbers you are actually off the back of a 51cm P5d and in the 48cm P5d range. You'd need to be 15mm longer to his the 51cm, and based on your fit video below, I'd definitely recommend more reach that what you have in the video.

Does this make sense? In the video, you'd basically just open up your shoulder angle moving your elbows forward and up slightly, and now you've got a platform that pushes *back* rather than your current platform as pictured which pushes *up*. Combine this fit technique with the Cervelo 50 degree extensions (don't get the 30 degree ones!) and some aftermarket tilt wedges for your pads and you're cooking with gas.

You could also swap the EX11 mono-riser that comes with the P5d for the EX10 mono-riser from the P3x... this would not only give you tilt but additional reach fore and aft giving you even more wiggle room on the 51cm P5d.

LMK if you have any questions,
Eric

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That is so helpful and totally makes sense! THANK YOU for lending the time (and sorry for the extra trigonometry exercise). I should have added that after spending a little time in that position I ended up tweaking things a bit and moved my pads/bars forward a bit so looks like the 51 will indeed give more wiggle room with the modifications you’ve recommended even though I will be at the bottom of the range. It’s always challenging to pick a bike as I always end up in the overlap zone between extra-small and small.
I definitely need a (longer) pro fit at some point... maybe a good excuse to come visit North Carolina!
Thanks again so much!

Eric, I know the rules are post stack and reach. I have a more basic question - I’m 6’4” and I wear pants with a 34 inch inseam. Would there be any chance that I would want something other than the largest frame size?

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Aaron Bales
Lansing Triathlon Team

I reverse engineered this but I am no expert. if I am a 56" on the P2, can you confirm, I am still a 56" on the new 2020 P series ?
thx in advance!

to quote you (post #185) i am : "a Pad Stack of 657 and a Pad Reach of 457"

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I edit my posts, a lot.

there could be a few reasons you wouldn't, but it's unlikely. An unorthodox "slack" position with short reach would be one, which for me isn't really a reason because I'd screen that criteria out before selecting. I also have a 34" inseam and would be a 58cm P5d (with the extra reach of the EX10 mono-riser) or an XL PX series bike. XL for most other brands too.

That said, is posting your stack and reach that hard?

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While I can't confirm that if you're on a 56cm P2 now you should be on a 56cm P-Series later because I haven't seen your fit or your cockpit setup, I can however confirm that with a Pad Stack of 657 and a Pad Reach of 457 you'd fit very well on a 56cm P-Series bike.

:)

Eric

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I hesitated because I’m not sure if the numbers are correct and because I wonder about a longer position.

Stack - 690
Reach - 489

Do those numbers make sense?

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Aaron Bales
Lansing Triathlon Team

Makes sense.

With those numbers you’re a 58cm P5d or a L and XL PX or P3x. My gut feel just based on raw numbers is that you could be longer and lower, but it would be hard to get longer on an L so I’d recommend the XL.

Make sense?

Eric

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Thanks. What about the P-Series? 61?

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Aaron Bales
Lansing Triathlon Team

You could do either 58cm or 61cm, as you're not quite that long and the P-Series comes with two very functional aero bars... either Vision or Zipp.

On a 61cm, you'd come very close to hitting your fit coordinates with a 90mm -6 stem on a 5mm dust cap and 10mm of aero spacer under the pads/extensions. So yes, a 61cm could work.

FWIW, the lowest stack height on a 61cm that you could reasonably hit is 648mm. This is with a -17 stem and the Zipp Undermount.

Eric

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Hi Eric,

I have my previous bike fit measurement in PDF. Is there a way I can send it to you for advice?

you could screenshot it and post the pic here, or you could just tell me your stack and reach numbers. PM me if that doesn't make sense.

Eric

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Attached is the screenshot of the report. Which frame size of the Cervelo will be suitable in this case?

Which bike are you thinking about... PX/P3x, P5d, or P-Series? Or are you thinking P2/P3?

These position numbers you gave me are very unorthodox. Pad Reach of 300mm and Pad Stack of 650mm makes you very upright and slack. You are outside the box so to speak. Your pads are above your saddle and your saddle is set back 12mm if I'm reading the chart right. You're probably on the wrong saddle or sitting on the right saddle wrongly.

For a P3x for example, the best I could do at a Pad Stack of 650mm is a reach of 365mm, 65mm more that what you have now. This is the absolute upper left quadrant of the size Small P3x... as high as the mono-riser will go with the pads all the way back.

Something is not right here... while your fit was very thorough I don't think it was very good or useful. I think we should start from square one.

Can you post a pic of your fit?

thanks,
Eric

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I am looking at the P2/P3/P5 models. Could it be due to the reason my current bike is too large for me at 5'3? Should I be going after 650c frame?

Your current bike is ill-fitting because the QR CD.01 is in the "long and low" family of bikes, but you have a "narrow/tall" fit/morphology.

The thing that's tripping me up is the 300mm Pad Reach to back of pads... that's a very short number and way outside of the box, IOW unorthodox. If you could remeasure that number on your actual bike that would help me feel more comfortable making a definitive recommendation.

I don't think you necessarily need a 650c bike just because you're 5'3". I think with a few fit adjustments (shorter cranks, correct saddle, correct way to sit on correct saddle, forward pelvic rotation) and some postural coaching (leaning into the reach of a modern TT bike) you could be much more orthodox and fit just fine on a 51cm or even 48cm P5d.

For example the max stack height for a 48cm P5d is 625mm. The minimum reach at that stack is 385mm. So, we've got some homework to do.

Your current fit is what I could call a road bike fit, a bike shop fit, or a "kitchen table fit". You're sitting down at the kitchen table and leaning your elbows forward on the table top and there you go. It's why your bike doesn't fit as you said. I think you need to get yourself a good triathlon or time trial fit, and if you had that your position numbers would change and that would affect the bikes I'd recommend.

Don't despair, we can figure this out! Rechecking your reach number is priority number one.

Does this make sense?

Eric

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Thanks, Eric. That was very informational. This is my 2nd fitting at a 'kind of reputable' local bike fitter, so I was assuming he knows what he's doing. I agree that there is still room of improvement for better performance/aerodynamic while not neglecting comfort. Given my current stats, what specific size would suit be best (48 vs 51cm) or even what model/brand out of Cervelo (if we are allowed to talk about that)?

Alternatively, as a start, what minor tweak that I can do on my current bike?

Eric,

Thanks for taking all the time you do with helping everyone.

I'm coming from a 54cm Scott plasma 10 (the UCI legal 4 frameset). I had been on it for 4 years now and finding that It was putting me into a very quad dominant position and affecting my run off the bike. I've been re fit on my current set up and there is NO way that it is going to work. So here is what we came up with. I'm 5'11" with a 32.75 inch inseam. 175 lbs. One thing is the need to focus on keeping hips open as I'm just coming off FAI Cam impingement surgery (Where they shave your femur down), Micro fracturing and Torn hip Labrum repair surgery on top of Osteitis Pubis and multiple stress fractures of my pelvis. I'm quite flexible. Riding a Cobb Plus Saddle. It would be a toss up between the new P Series (Cable annoyance, HA!) and a P2/3 built up. I'd also like to avoid too many spacers under the stem and keeping the arm pedestals to the minimum. I'm Looking for something FAST and comfortable (FIT) to run a fast marathon off the bike. I'm hoping you can help?


Pad Stack 659
Pad reach 426
Pad reach mid pad 468
Saddle Height 767
Saddle Setback 11
Saddle to Pad Drop 155
Saddle to Pad Reach 483
Grip reach 742
Grip drop 82
Grip angle 48
Arm pad to grip 347
BB to Grip 773
Arm pad Drop -100

Thanks!!

I think you could work on rotating your pelvis forward and also opening up your shoulder angle, ie. mirw reach. Getting lower ironically helps this happen as you sort of fall into your aero bars. Also you should test a bunch of saddles to find one that works better for you, one that facilitates an orthodox tri position.

I think the 48cm P5d would be best for you.

Eric

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Always missed my p3, on p5x and getting a p5.
Ordered a 51 but worried about size
My retul reach is 405 and arm pad stack is 632, however i have tweaked the fit since rising and on the picture on my p5x my reach is 420 and stack is 600, my seat is at 695. I sit very foward on a cobb jof seat and feel i can go a little further foward as well. Using 165. Ranks and arm pad is 190 to middle of pad.
Appreciate your advice

are you measuring reach to back of pad?

Eric

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Yes back of pad

OK.

your original numbers of 632 pad stack and 405 pad reach are sort of unorthodox and outside the box... you're outside the upper left quadrant of a 48cm P5d and would need the EX10 mono-riser from the P3x just to make it work.

600 Pad Stack and 420 Pad Reach is much more orthodox IMO, and puts you squarely in the upper center of the 48cm P5d. You're just *barely* on the edge of the 51cm reach range with the stock mono-riser, and comfortably in range with the EX10 mono-riser. I'd have to see a picture of your current position (600/420) and a discussion of any future changes you think you might evolve to before making a firm recommendation either way.

Make sense?

Eric

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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.”