Hi there,
I am interested in a P3 or Pseries. I currently ride a road bike with clip ons. I know that doesn’t translate well but here are the measurements:

pad stack 690
Pad reach 475
54cm Trek Madone with ProfileDesign Airstryke clip ons

I am 176cm tall w 81cm inseam. The above setup leaves me a feeling a bit cramped upfront I just couldn’t move the pads any further forward given the equipment constraints. I think I am right between a Pseries 54 and 56. Any advice you can offer is appreciated.
Thanks.

Hi, sorry, was out of town and away from a computer for the weekend.

With a Pad Stack of 630mm and a Pad Reach of 470mm you are squarely in the center of the range for a 56cm P5d.

There's no way I'd prescribe a 54cm. The slightest need for increased reach and you're stuck on a bike that's too small. Any gains from the mono-post situation would be lost by having a sub-optimal position. IOW, I could see you getting slightly longer than where you're at in your picture. Besides, even on a 56cm you'd still have nearly 40mm of exposed mono-riser, so likely avoiding elbow pad/basebar interaction.

On a 56cm, you have the flexibility to get out to a reach of 500mm at a stack of 610mm, ie. 20mm lower than you are now, so plenty of room to grow, and could get significantly lower if need be, not that I think you need to but sometimes when you get longer or shorter cranks it's more comfortable a little lower. But back on point, the extra reach of a 56cm might come in handy as, like me, you ride with your elbows at the front of your tilted pads, perhaps an indicator of needing more reach, which jives with what I'm seeing in the picture.

Speaking of tilt, you'll want the newer model P5d that comes with the EX10 tiltable mono-riser. Provides great fit flexibility.

56cm P5d... make sense?

Eric

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hi Keith, thanks for reaching out.


All three of those issues can be fixed by more reach, which I mentioned in your post and you addressed with your changes. Well done. So, with a Pad Stack of 689mm and a Pad Reach of 479mm the question is 58cm or 61cm P-Series. The thing about the 61cm is that it's not the next logical progression size from 54 to 56 to 58 etc. It's not really any longer but a big chunk higher. IMO, it's better to make up that height with a well adjusting cockpit, ie. pads that adjust separately from the basebar, which the new Zipp Vuka cockpit does. OTOH, your stack is high enough that you probably won't notice the additional frame stack of the 61cm. Even so, best to err on the right side, the 58cm, as the Vuka system is somewhat high stack on the P-Series.

Make sense?

Eric

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hi, thanks for reaching out.

With a Pad Stack of 690mm you are very upright and unorthodox compared to others and compared to how you would properly fit on an actual triathlon or time trial bike. But your height and your pad reach give me something to work with, and both of those make me lean toward a 56cm P-Series, and not the 54cm... you just don't need to get as low as a 54cm would allow.

Can you double check something for me? Is your pad reach to back of pad or center of pad? This is important and may affect things.

Eric

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Eric,
I double checked the measurements. Stack was wrong.

Px = 475 to back of pad
Py = 660

Thanks again for the advice.

Yeah, definitely not a 54cm. You're in better range with these updated numbers for a 56cm.

Eric

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Thanks again Eric, this thread is super helpful! What size spacers would I need to order for the Zipp Vuka bars to match my current fit on the size 58 P-series?

The P-Series should come with all hardware necessary for stack changes... let me check the calculator and I'll give you the exact prescription for the size 58cm.

Eric

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Perfect. Thanks for all help Eric, very much appreciated!

Hi Eric,

I'm 170cm tall with a 76cm inseam and currently ride a 2015 Trek Speed Concept 7 series in size S.
50mm offset seatpost with saddle (Bontrager Hilo RXL saddle) set to a height of +-694mm from BB. About 32mm saddle setback and I'm using 165mm Shimano cranks.
Pad X is about 432mm to the center of the pad, Pad Y is about 568mm measured at the center of the pad (top of the pad, pad thickness is about 8mm) with 10-12° of extension tilt, using Revolver Mono Mantis cups (pad width center to center is about 100-110mm, the mono cup is 200mm wide at the widest point) and the stock Bontrager ergo long ski bend extensions. I believe I have the low/far stem with 15mm mono spacer, could be the 25mm one.


This has been my position since mid last year:
https://ibb.co/mFB5KKf

I know the new P5d allows for tilt but the first iteration doesn't, so I would need the P5x extensions or angled spacers if I would buy the previous version. Would I fit on a 48 or do I need a 51?,

Thanks in advance!

hi Joeri, thanks for reaching out. Solid looking position. What are your triathlon or TT goals?

Some opening thoughts. I see the need for you to hide your shoulders somehow. From a frontal view they're going to be sticking out to the side, unless you are using a lot of mental and physical energy to shrug them up to your ears. This is a very easy fix, just add a little more reach and rotate up at the shoulder joints to meet the new pad location. Your shoulders will tuck in behind your ears and in front of your lats and torso neatly.

I say this about the reach because according to your fit numbers, Pad Stack of 568mm and Pad Reach of 382mm (back of pad), you're off the charts left for a size 48cm P5d. Not to worry, at your stack height you only need to be at 405mm, an additional 23mm or almost 1", to get on the charts. If you look at the picture below, imagine articulating your arms, rotating at the shoulder joint, until your elbow touching the pad is forward 23mm from where it is now. There will be an associated rise in stack, a few mm. Then, move your extension out from where they are now to where they need to be after you rotate your arms out and up and you're all set on a 48cm P5d with a Pad Stack of about 570mm and a Pad Reach of 405mm.

Make sense? You'll be on a size 48cm P5d with 31mm of mono-riser exposed and the pads in the rearward configuration. New P5d will allow for tilt, if you get an older P5d you'll need to find the EX10 mono-riser or use aftermarket tilt wedges and the 50* ski bend extensions to get the tilt you need.

LMK if you have any questions.

Eric

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Thanks a lot for the very elaborate answer! And for the compliment on the position, coming from someone like you that has to mean something ;)

For tri I do mostly Olympic up to half distance and some variants in between (1/3, 111 (1k swim, 100k bike, 10k run), and so on). I've done about 4-5 time trials ranging from 10 to 26 miles which I've enjoyed a lot.

You're right, even though I'm about 146-147lbs and quite lean, I'm only 5'7" and having done combat sports from when I was 6 until I was 18 combined with weight lifting until I was 21, I'm still relatively wide in the shoulders. I can get quite narrow, my elbows and forearms are touching in this picture, but I need to hide my shoulder somehow.

I've put my pads in the next mounting position on my Speed Concept, which is about 20-25mm further forward so I can also check how it feels before purchasing.

Thanks Eric!

Sorry, forgot to ask this but I'm having a hard time finding it elsewhere in the internet.. The size 48 Ultegra di2 variant comes with 165mm Shimano R8000 cranks, right? And any guesses on the range for pad width?

226mm-286mm, outer to outer.

As for cranks, it depends on the build, but Ultegra 8000, SRAM Force AXS, or Dura-Ace 9100. You'll probably want to figure out a shorter aftermarket solution there.

Eric

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Hi Eric -

Thanks again for the advice here and just wanted to share how things concluded... I went ahead with a 56 NP3 and started by duplicating my prior road bike/aerobar position to just spend a few days getting used to the bike.

Then had a full bike fit done last week and it was quite an eye opening change that took me to the other side of the L chart on reach - (to the point that even an XL would be viable) - it also feels very good so far!

Pad reach: 419->505
Pad stack: 709->670

Something else I'm sure you'll appreciate, as my fitter did -

• I did a couple ~8 mile test loops in my road bike aerobar position replicated on the P3 - no detectable improvement over my older road bike - same speed vs. watts within 0.1 mph
• Two days later post fit - the P3 showed 0.8 mph improvement, or ~30W less power to go the same speed looking at lap splits
• Since then, I'm seeing consistently 0.7-0.9 mph improvement on any of my standard out and back segments I ride regularly even as temps are dropping

My conclusion - position matters way more than the aero differences between the bikes - and the P3 is letting me get to a nicely improved position!

Hi

You wrote that the p5d has less reach then the px

"For a P5d, you'd need to make sure you fit as the P5d is 25mm or 1" shorter in reach than the P3x or Px."

But is that measured from the arm pads? If I look at the geometry it is much less then 25mm. Or do I something wrong?

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Pad reach is measured from back of arm pads for Cervelo and for me. For example, the max reach to the back of the pad of the largest P5d, size 58, is about 520mm. The max reach to the back of the pad of the XL PX or P3x is 540mm. This is partly due to a slightly longer frame, but mostly because of cockpit differences.

Make sense? One caveat, with the P3x mono-riser, which the new P5d are coming with, you can get more reach, and I know the fit calculators are being updated at Cervelo to reflect that change. Once that's official my guidance will change.

Eric

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Great to hear! Hope you get some good miles in on the bike.

Eric

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Alrighty, a year or more later, and I'm finally getting to chase down fit on my bike. My original thread on fit was here (fit #1). Since that, I've replaced:
- Saddle with a PR2.0. Never could get the Sitero to not hurt
- Aerobars with a PD Subsonic set-up
- Stem with a -17deg 110mm Profile Design

Much appreciated on the advice.

Yeah, I never did like the Sitero, sort of in between saddle not really doing what it says it was trying to do.

This is probably a topic for your thread on the main forum, but my advice from the other thread still stands... your bike is too small, and you got bad advice from your fitter. What about a new P5d?

Best you could do here is slide saddle forward 20mm, get a 20mm longer stem (130mm), and then shorter cranks based on how that feels and then slide saddle back slightly as you grow into that new fit dynamic.

Also, your saddle looks like it's tilted up... rails level is the baseline for those types of saddles. You need to put some weight on the front end to unweight/neutralize the rest of your body. I'm assuming you're a long course triathlete and not a TT specialist.

E

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Thanks for the reply.

Guess I'll start keeping an eye out for a used bike. If you think the stem on a 54cm needs to be 130mm, is a 56cm bike even going to be sufficient or will that need a longer stem also?

Crank is currently a 165mm. How much shorter?

Looks like I've always had my saddle wrong then. Glad to know how to finally chase level on it.

Depends how you feel when you start getting locked in... you can find out by buying a used 130mm -17 stem and playing around. If you get lower and longer and feel hip angle impingement then go 155mm.

With regard to a bigger bike, what's your current pad stack and pad reach?

Edit: Maybe you can tell me what you think I am seeing... what am I seeing on your current bike that would indicate what I'm hinting at?

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Missed your edit yesterday. On what your hinting at, is this in regard to my bike being too small? I would guess at the arch of my back?

With the saddle at rails level, it felt better once I settled in. Certainly more weight on my arms, but I think that just highlighted that a little more reach would be more comfortable.

I had already moved my seat when I saw this message, so the measurements are based on today's video. I moved the seat to the front edge of the seat post. Any further on the rails and I can no longer fit my Toppeak cage behind. I can head down that road if needed.

Got the plumb bob out and I'm coming up with 443 Reach to back of pad and 655 on the Stack. Now that I get that measured, I'm even more depressed about the wasted money on the initial fitting and bike recommendation.

Latest video below.

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Does comfort really matter that much on 112 miles....


Given where the bike is in the last video, do my numbers from my original Bike Fitting (471 reach, 640 stack) sound reasonable enough as a basis for searching for a new/used bike or do I need to start over with a new fit? Closest fitter is 4 hours away.