Weight Weenies

I have my eye on a Cervelo P2C but i am in doubt if i should go for the size 51 or 54. My roadbike has a TT of 55cm which i ride with a 12cm stem and 6cm saddle setback. My reach from saddle tip to bars is 55cm. As I intend to use the P2C with a steep angle of 78, i am inclined to go for the size 54.. What do you guys think ?

p.s. I am 178cm tall with a 85cm inseam. My saddle height is 75.2cm

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If you are riding a 55 TT on your road bike, definitely a 54. A 51 is a 53TT and will be way too short - especially in a forward position.

very nice strobbokoen might look at one of those myself next year!!
tikka

For road I ride a 54 solost Carbon with a 130 stem and a Handle bar with 82 reach.

For TT I ride a 51 P2C with a 100 stem and a Easton TT bar size M and the shifters are right in my hands.

Forgot to mention I will be using it for triathlon.

On my roadbike I have a 56 cm tt - I am 180cm with a 89 cm inseam

I have just recently ordered a P2C in size 56. In the front positoon on the saddle, that will give me a 54.5 cm tt, which would be more or less ideal for me. I thought about a 54 but the seller told me, that it would be a way to aggressive psoition for tri's - the P2's should be very small in the sizing, so he wouldn't recommend it smaller.

ajh wrote:For road I ride a 54 solost Carbon with a 130 stem and a Handle bar with 82 reach.

For TT I ride a 51 P2C with a 100 stem and a Easton TT bar size M and the shifters are right in my hands.

Wow, if ever a case for not buying on geometry, here's one. Assuming from "for road" you run the soloist at 73STA, your effective top tube is 54.5 + 13(stem) = 67.5cm. Your 51 p2c: 51 + 10(stem) = 61cm!

All I can figure from this is that the TT bars have a lot to do with it.

Usually tri and TT bikes should have a shorter top tube than a road bike.

Many CSC riders use a smaller size TT bike than road bike. Double world champ Cancellara for exmple ride a 58 cm road bike and a 54 cm TT bike.

But of course the best way to find out is to find a good and experinced bike fitter who can find the best tri/TT setup for you.

Quite a range of fittings here! My feeling would be to go for a similar size designation of a road bike when going for a tri bike with steep seat angle. Let's say your road bike fit is a TT of 55cm and you want to get a tri bike setup with 78 sta, a effective TT of 53cm or so for the tri bike sounds about right to me, not a 51 ?

A 54 P2C would allow you to get 17cm of saddle-bar drop with 78deg STA (15mm setback). With a 120mm stem it would have the same saddletip to bar reach as your road bike. My saddle to bar measurements are the same for road and P2C but I do have a fairly stretched position, you may not want to match the road bike reach at first.

2 wheels wrote:Usually tri and TT bikes should have a shorter top tube than a road bike.

Many CSC riders use a smaller size TT bike than road bike. Double world champ Cancellara for exmple ride a 58 cm road bike and a 54 cm TT bike.

But of course the best way to find out is to find a good and experinced bike fitter who can find the best tri/TT setup for you.

Any idea what size Dave Z rides?

I'd suggest that you not try to buy a P2 without a proper fitting. They seem to be a lot longer in the top tube than Cervelo claims. Granted that I am riding in a UCI legal position (as much a matter of principle as a requirement since I'll probably never be measured), here are my stats:

Road bikes (six of them, different makes and models) - 57 cm top tube, 12 cm stem

P2SL - a 56 with a 9 cm stem and thinking of going to 8 because it feels long. It's better this year since I cut off the last cm or so of the aerobars, but I'd still prefer that I be placed farther back on the armrests.

In my tri days, I rode an early Quintana Roo (78 degree seat tube) with a 56 cm top tube and 8 cm stem.

And at 185 cm, I'm a lot taller than you. I think that a 54 even in the forward position might be large for you. That's why I think you actually have to try it out.

DZ rides a 56 road. Don't know his TT. His "training" SRM R3 is supposedly on Ebay now and that is the size he rides per Cervelo's forum. Cancellara goes 58road to 54TT, but I swear he is hitting his elbows a lot and rides amazingly low for his 185cm height. I'd guess he also fits the long leg/short torso body type.

I pulled the trigger on a 56 P3C having been perfectly happy w/56 Cervelo road, 56.5TT, and a 120 stem (-20, no spacers). I haven't been fitted, but I had a 54 P3C on loan and with a 100 stem it was almost silly low (w/45mm spacers), and inside. At 183cm, I'm expecting plenty low and, at worst, a 90mm stem. But C50jim's post makes me wonder, since he's taller. I always thought 80mm stems were the "Oops, I bought the wrong size frame" option, but perhaps that's different with TT. I'd be curious of your inseam and hazard a guess its ~90cm?

I'm 175 cm tall with a 76.2cm inseam and ride a 51 cm P2SL with a 8cm stem. Seat post is forward and saddle height is 70.2cm.

I fit very well with room to go forward or back. I do plan on extending the stem, shortening the clipons so that I can be more comfortable on the bullhorns when sprinting or climbing. I feel a bit cramped on the Vison tech base bar right now. I am rarely on the base bar, but some local TT courses have some sub 20mph climbing.

another thing to consider is how long the headtube is and if you can get the stem low enough. I only have a 5mm spacer left to take out on the steerer and arms rest on lowest extensions already. Next option will be a 17 degree stem or a Look Ergo stem.

Hope this helps,
Ray

edit:sorry typo and added some more info!!

I assume you mean 67.2cm saddle height ?

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