If you think you might need more reach someday in the future, take the Large. If you think you might need to get lower in the future, take the Medium. If your position is absolutely dialed, take the Medium, unless it's not available and then take the large.

E

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Eric Reid AeroFit | Instagram Portfolio
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That all pencils. Thanks a lot for your time. Asset to the forum!

Thanks! You guys make it easy :)

E

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The PX is the P3X, Cervelo have dropped numbers other than 5 (which is for top tier)



As Eric has said - you can go either way based on availability. Unless you think your bars will go lower in the future I'd be inclined towards the bigger bike.

Thanks a ton. Appreciate you!!

Thanks Eric. Do you suggest smaller crank for bike fit purposes will be better? Given the bike will be smaller than the 61cm originals and in our chat you suggest I will fit it fine, I am assuming that is regardless of crank size and that would more be rider choice, compared to fit or performance requirement. My threshold is >350W and being rather competitive I am weighing up the bike fit and comfort with performance. I feel like the jury is still out on crank length cadence and performance. Thanks again!

Based on handling, fit, or resultant aerodynamics?

Thanks
Eric

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Cranks are currently sourced in relation to bike size, more or less. The sizes are arbitrary, made up. “Small” bikes come with “small” cranks, medium medium, etc. Crank lengths are legacy, up to 175mm, and really based on road bike fitment and industry inertia.

Instead, crank size should be based on your fit, which is partially related to your morphology but also partly related to your pedal stroke, bike fit and position / hip angle, etc.

For sub maximal efforts, and definitely for sub maximal efforts where aerodynamics matters and with a run off the bike, shorter cranks are better.

I’m 6’2” with a threshold of 300w and use 165mm and am considering going to 160mm. There are pro men *averaging* 350w for the bike at Kona on 165mm or shorter.

Does this make sense?

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Thanks Eric it does. Especially as I have enjoyed the shorter cranks. I was a bit surprised Cervelo wouldn't allow the customer to request an alternative crank size to the one that comes with the bike. Just frustrating as I now need to source the same cranks/power meter smaller size after I get the bike. I think it does help me put the effort in to get the 172's swapped for 165 where I can. Thanks again!

Pad X (stack from BB): 613 mm
Pad Y (reach from BB): 502 mm
Pad Z (center to center): 156 mm

I'm currently on a Trek Speed Concept in a size L with a Alpha X cockpit with arm pads tilted up 10 degrees. The stack range on it is good for me but I'd ideally have 10-15ish mm additional reach to stretch out further so I'm looking for more length.

Interested in a P5d. The Cervelo online fitting tool puts me right in between the size 56 and 58 I assume with the EX10 since that it what it is sold with now. I'd be slammed on the 58, but I'd have more reach, but then I won't be able go lower if I want to. On the 56, I could go lower if I wanted but it appears I am at the limit of reach using the above coordinates.

From what I can tell, the 58 would be better for me reach-wise, but I'm a little afraid the bike will feel too big for me compared to the L that I am on for the Speed Concept. The wheel base appears to be close to 2 cm longer on the 58 P5d vs. the L Speed Concept.

Will the P5d fit me? And if so, which size is optimal?

Thanks so much!

Hi thanks for reaching out.

I think it’s either or… if you think you need to get longer than 507mm then you’ll need the 58cm slammed. If lower then the 56cm. I haven’t seen you, but on paper you’re pretty long and low already and might not need to change, but if you did it would probably be more useful to get longer first before lower.

Make sense?

E

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Eric Reid AeroFit | Instagram Portfolio
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Yep, makes complete sense. Do you have any opinion on whether, coming from a Large Speed Concept which is roughly equivalent in length and height (generally speaking overall) to the 56 P5d, that the 58 might feel too "big". The wheelbase and standover height is 18mm greater on the 58 than the 56, and I'm worried that it'll make it feel like a big boat compared to what I'm used to. On the other hand, stability with a longer wheelbase isn't such a bad thing in triathlon where you mostly just want to go fast in a straight line.

Logic tells me that the 58 makes the most sense, but its hard to commit the dollars without knowing how it'll feel in the end. I agree I probably don't need to go any lower, at my age I might start to go up a little. It's really too bad nothing is in stock because a simple test ride would solve this for me.

Thanks Eric!

I really think it’s a toss up and also that the 58cm P5d won’t feel like a boat either. I’m leaning 56cm unless you want to get much longer.

E

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Interesting question. Curious now also.

Hi Eric,
Here are my fit numbers:

Stack 595
Reach 445 (tip of saddle to back of arm pad)
Reach from BB to arm pad 427
Saddle height 687

Had in my radar the P5D or P5X

Thanks

Hi, you are square in the middle of a size Small in the PX and middle-left on a size 51cm P5d, although you could squeeze onto a 48cm although I think a 51cm would be much better.

Make sense?

E

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Awesome. Thanks for quick response!!
Looks like the PX is best fit!!!

Pad x/y attached from several years back. I am 140lbs 5'8". Longs torso with shorter legs.
Currently I ride a tarmac in a relatively aggressive position. I have never owned a tri bike.

Can you resend?

E

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Sorry, I think I forgot to press the upload button. Maybe mobile isn't the best.

If this fit sheet is right I'm not sure how your fitter got a 51cm P5d, with a Pad Stack of 583mm and a Pad Reach to back of pads of 480mm you'd be in the lower right quadrant of a 54cm P5d (long and low).

I think the ST FIST system is to mid-pad, in which case your fitter would *technically* be right, but then I'd be suspicious of someone with a long torso falling in the center or left of the range of a bike, ie. where a short torsoed person usually ends up. I think we could use a pic of your position.

At any rate, if the reach measurement is to mid-pad, then you're in the middle of the range for a 48cm P5d and in the low left for a 51cm. At 5'8" I could see you being any one of these three sizes.

Can you confirm your reach?

E

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Hi
I’m looking to get a P series with an FSA/ Vision Metron TFA handlebar system.

Pad stack is: 651
Pad Reach is: 526
Pad spacing is: still in progress
BB centre to saddle rails height is 775 with a 165mm crank or 765 with a 175mm crank. (I use an adamo TT saddle).

This bike will need to be a UCI TT position.
Can you advise on a size 54, 56 or 58?

I’m leaning towards a 56, but want another opinion.

Thanks!

Is your pad reach to mid-pad by chance?

Eric

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Thanks, yes, the pad-reach was to the middle. it should be:


Pad stack is: 651
Pad Reach is: 490
Pad spacing is: still in progress
BB centre to saddle rails height is 775 with a 165mm crank or 765 with a 175mm crank. (I use an adamo TT saddle).

This bike will need to be a UCI TT position.
Can you advise on a size 54, 56 or 58?

Are you taking the saddle exemption or the extension exemption?

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.”