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Hi everyone, this is my 1st post on Slow Twitch or any online forum; so please be nice, lol!
Iím sure this question has been asked (YES, I have searched for an answer, but I would like some more personalized advice), but I have an opportunity to get a really amazing deal on a Cervelo P2C 54cm. My question is: Is a 54 too big?
Iím 5í-7Ē barefoot, proportional torso to legs and arms. I am flexible and ride aggressively.
I am an engineer and I put my body dimensions and both a 51cm and 54cm bike into CAD. From what I can determine, I can make both bikes work. It appears that I have the options to make the 51cm larger/longer or make the 54 smaller/shorter, but Iím no expert. I am going to get a fitting done once I get a TT/triathlon bike.
What Iím looking for you all is: advice, opinion, suggestion. Someone please steer me in toward the correct frame.
P.S.: By the way, I currently ride a Cervelo Team (S1) 54cm in both the tri position and traditional road position. Both positions work and feel fine. Getting a fitting on that next week!
Last edited by:
: Apr 7, 10 10:54
It depends really on how you want to ride the head tube is taller on the 54 so you will be able to sit up higher. I would go get on a bike shop and see how they both feel.
For instance i'm 6'0 and the next cervelo tt bike i get will be a 51 because a 54 is too long.
As was mentioned above, the best way to find out is to go to a bike store and try them out. I am 6' and ride a 54 P2C.
FWIW - I am also 5'7" with a 30" inseam. I have been comfortably riding a 51cm P2C for three seasons and couldn't imagine riding a bigger bike because this one fits me so well.
USAC & USAT level 2 certified coach
Yes... I have to agree. It's more then worth your time and money to go in a get a proper bike fit from a professional. This will also probably improve your performance more then all the "aero" accessories (wheels helmet etc.) you can buy. Once you have your "Fit Coordinates" you should be able to determine if the 54 (or any bike for that matter) can be adjusted to fit you.
6' and wanting to ride a 51 P2C. Are you sure the long and low Cervelo is your best fit? Going from the 54 to a 51 means you are going to need 3cm more stack/spacers. I would think something like a 54 Slice may be worth considering since it will be close to the stack of the 54 p2c and the reach of the 51 p2c. Just my 2cents.
Wow...thanks for the fast responses...much appreciated.
A friend told me to try the competitive cyclist calculator. This is what it spit out:
Lower Leg: 21
Sternal Notch: 54.5
Total Body Height: 67.25
The Aero Fit
Top Tube Range: 49.7 - 51.7
Stem Length Range: 8.0 - 10.0
Saddle-Bottom Bracket Position: 73.2
Saddle-Pedal Position: 90.4
Saddle-Ground Position: 98.2
Aero Bar Size: M
Saddle-Aero Bar Pad Drop Minimal: 4.8
Saddle-Aero Bar Pad Drop Moderate: 9.9
Saddle-Aero Bar Pad Drop Intense: 12.1
Saddle-Aero Bar Pad Drop Maximal: 15.8
Pad-Ground Position Minimal: 93.4
Pad-Ground Position Moderate: 88.3
Pad-Ground Position Intense: 86.1
Pad-Ground Position Maximal: 82.4
I would think the 54 would be way too big for you. Yeah, you could make it work, but it would still be the wrong size.
You should be on a 51, unless you have -really- abnormally long inseam and arm length for someone your height...
I'm 5-6.5 and ride a 51cm P2C. I did purchase the bike used from someone who was 5-9 (she was all legs and had a very long seat post). Prior to purchasing, I tried out the 54 at my LBS. The 54 was WAY too big - I can't remember what the exact fit problems were but, end of the day, it was too big. Even if the bike is a great deal, you'll have to spend additional money trying to get the bike to fit you better and, most likely, it never will fit you quite right. That said, its not worth the price, no matter what it is -- you'll just end up getting something different later on.
Here's some food for thought (my measurements from competitive cyclist - which are similar to yours):
Lower Leg: 20.25
Sternal Notch: 55.5
Total Body Height: 66.5
The Aero Fit
Top Tube Range: 52.5 - 54.5
Stem Length Range: 8.0 - 10.0
Saddle-Bottom Bracket Position: 69.7
Saddle-Pedal Position: 86.9
Saddle-Ground Position: 94.7
Aero Bar Size: S
Saddle-Aero Bar Pad Drop Minimal: 3.4
Saddle-Aero Bar Pad Drop Moderate: 8.3
Saddle-Aero Bar Pad Drop Intense: 10.4
Saddle-Aero Bar Pad Drop Maximal: 13.8
Pad-Ground Position Minimal: 91.3
Pad-Ground Position Moderate: 86.4
Pad-Ground Position Intense: 84.3
Pad-Ground Position Maximal: 80.9
Yeah, I think all are correct. The 51 does sound like the better fit and I do want a steep seat tube angle. That's why I'm looking for a specific Tri/TT bike. I wasn't getting aggressive enough on my S1 for my wanting.
Ok, now for another question. I do have an option of picking up a 52cm Cervelo P3 Aluminum 650c off CL in my area. Am I degrading the bike too much (in my mind) because of the 650c wheels? I haven't seen it yet, because no pics were posted, but they want $425 for the frame! I know 650c wheels are still available and frames are still made with them, but am I over analyzing?
hope I'm getting my point across and not rambling. Let me know if I
need to be more clear. Thank you all very much!
5'10" on a 54cm P2C and wishing that I was on a 56 with a 10cm stem and an Adamo saddle in the rear seatpost hole, all the way forward on the rails. Running somewhere between 4.5" and 5" of drop from the saddle to armrests.
I wish that I was on a 56 because I would like a longer cockpit to make it easier to ride a more forward position. I choose a 54 several years ago because that was the size of my road bike.
Old school (and I am old) thinking was to ride a TT bike in as small of a size as possible with the idea that smaller frame = more aero and stiffer. These days that's not necessarily the case and a larger bike can be faster in some cases e.g. on a bike with a shaped, aerodynamic head tube (Cervelo P2/3/4 for example), the hourglass head tube shape is more aero than the spacers around the steer tube so a 56cm frame with no spacers under the stem will be more aero (minutely) than a 54 with 2cm of spacers. Also the larger bike has a slightly longer wheel base which should make it easier to track a straight line. I would assume that a well made carbon frame doesn't give up much stiffness going from a 54cm frame to a 56cm frame.
If someone was truly between frame sizes and could obtain the desired amount of drop and reach on either frame without resorting to extremely long or short stems, I would tend to recommend the larger frame rather than the smaller
I'll probably get flamed for this but...
Why do you want 650 wheels? All antidoctal thoughts but of the 5-6 people I know that have them, all but one wish that they had 700s.
That's my dilemma as well. I know the engineering and numbers aren't enough to distinguish a clear winner between the two sizes. It isn't that I want 650 wheels. It is that the frame is the right size and price is amazing! We enginer-nerds are frugal!
One more thing..."Flamed out"? Eh? What? Who?
Last edited by:
: Apr 7, 10 12:26
I'm a shade over 5'8" and ride a 54cm P3 it fits perfectly - I WAS previously on a 51cm P3 alu and had to go to a 120 stem to get the fit just right. The way cervelo sizes their bikes means that you should pick the same size as your road bike - but i'd suggest you're on a road bike that's maybe a size too large. I think the 51 will be just right for you as a larger size will have a taller head tube and prevent you from getting that more aggressive position you're looking for.
Regarding the P3 Alu w/ 650's ... I loved mine. However, the P2 will be just as fast, quieter, and you'll have waaaaaayyyy more choices for wheels, tires and tubes. Of course, you'd be able to pick up a nice set of used race wheels for 50% of what they'll run you in 700 ... but I don't think that ends up being an even trade. As much as I like 650's they really seem to be going away.
Because I'm a mere mortal on the slowtwitch boards... (i.e., my average bike speed is less than 20 mph, my marathon PR is a 4:15, and my IM time is a 13:57 -- which I was VERY happy about).
There are a lot of knowledgable people on these boards and a lot of very good athletes. You also have people like me who have learned things through experience but is also a lot slower and probably more recreational than some of the other folks on here. There are a lot of people who take things very seriously... (which is why you can get a lot of good free advice)
the old school was off a bit ... long stems and seat posts add more weight and wiggle to your bike than a slightly larger frame. The longer the stem and post, the longer the lever is to act on the mechanical joint which is not nearly as strong as the tube junctions.
This might be a dumb question, so feel free to correct me.
Is it possible to swap fork for 700c wheel and does the horizontal dropout have enough play/room to accommodate a 700c wheel?
Last edited by:
: Apr 7, 10 13:04
uhh ... no, I'd say not.
If your choice is between a P2 and a P3 alu - they are both fast bikes. The carbon one will be a bit quieter and allow you a greater selection of wheels and tires in the 700 size. But the P3 is great in aluminum - I'd be riding mine happily still if it hadn't been stolen. If you want to go that way - go for it ... BUT trying to engineer your way out of a problem that's not really a problem will make for a sub-optimal result.
650's on a P3 aluminum will be plenty fast, though aerodynamically speaking, the P2 is the equal or a bit better than the P3 alu.
If it's a cost thing and you want the P3 get it and don't worry about the 650 issue - there are enough around.
I made the mistake of buying a P2c... then having the bike fit.
The result was me buying another frame that actually fitted me.
Get the bike fit... then the bike
I had a fitting with a LBS. They ordered a 56 P2C. A 58 came in. LBS convinced me that either size would work. So I took the 58. I am 6' but have a 35.5" inseam measured by LBS. When I measure I get 35".
Ultimately I purchased a 56 in addition to the 58. The issue with purchasing a P2c that is too big is that you can only go so low on a P2C. So even if you start riding a little higher and want to work your way lower. Or you want to do shorter races lower and longer races with a bigger stack a P2C will limit what you can do.
Sure you can use different stems but I prefer to use one and move depending on length of race.
You are almost the exact same dimensions as me. You have a little longer legs but a bit shorter torso. Anyway, I went and got fit and now ride a 51cm P2c. Fits GREAT!!!
Is this the lbs that starts with a "P"? That's VERY poor.
"If you ain't first, you're last." Reese Bobby Talladega Nights
Overall I been very happy with the LBS besides this situation. He ultimately gave me the choice to send back the 58 when I came in to pick it up. Telling me either would work and I choose to keep it. Well for a couple of weeks.
Ultimately I think everyone should learn how to do their own sizing. That is what I do now. There is so much tweaking that is really necessary. Based on how long is the race, where you are at in the season, comfort, power, aero. I made some changes and rode last night and the changes were perfect getting ready for New Orleans next week. I was having some comfort issues. So improved comfort and power. Lost some aero, I believe. Also improved on some knee pain. I have to play around with my fit based also on some knee pain versus a hamstring issue.
I am also now learning to do my own wrenching. Which I am really enjoying and learning a ton. So far it has been easier than I thought it would be.
Could not agree more... I'm about 6-1, 34" inseam, and ride a 58 P2C. I have my saddle position pretty well dialed in, but still shuffle the spacer/stem stack at least 3-4 times each season (coming up on season 3 now with that frame) depending on the situation.
I'm 6'5", not too leggy, and ride a 61 P2C. But I got sized and glad I did because with just a saddle and handlebar adjustment I avoided getting a bike that was to big for me