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Please Help! MTBR buying a new road bike! Sizing??(4 posts)

Please Help! MTBR buying a new road bike! Sizing??NeedySpeedy
May 10, 2001 11:47 AM
I'm about to purchase a new road bike. I can get an awesome deal on the Jamis Eclipse. My question is about sizing, something I dont know much about - I'm a mountain biker, but I want to do more road.

My bike now is old junk. The center of the BB to the top of the top tube is 58mm. The top tube measured from the center of the seatpost along the top tube to the center of the headtube looks like 57mm. I have a 110mm stem on it. I dont feel cramped or over extended, but I dont know if I have the right fit on this bike either.

The Jamis has a 57 & 59 size. The 57 is 57mm from the center of the BB to the top of the top tube and a 57mm top tube center to center. The 59 has a dimension of 59mm BB to top and 58mm top tube. The 57 comes with a 110mm stem & 172.5 cranks and the 59 comes with 120mm stem and 175 cranks. I dont have the luxury of trying each bike. I'm hoping someone can help me make a decision. Is it better to go slightly smaller when faced with this kind of choice? It seems like the choice to go with is the 57, but when I'm spending this kind of money I'd like to be sure. Will it be too small?

The link to the site is: and go to GEO

Thanks for any replies. Oh by the way I'm 6'-0" with a 32"-33" inseam.
re: Please Help! MTBR buying a new road bike! Sizing??Len J
May 10, 2001 11:59 AM
You can probably make the decision just by seeing what matches best to what you know fits you.....however:

Since you are spending real money & you (hopefully) will be spending much time in the saddle. I would recommend that you spend the $50 to $75 for a serrotta fit. I have done this & you get a very good idea of what your fit is. I also got #'s out of this that were relatable to stock measurements. Fit being more important (IMHO) than components or frame material, I wouldn't skimp on this.

Just my 2 cents.
re: Please Help! MTBR buying a new road bike! Sizing??climbo
May 10, 2001 12:40 PM
sounds like you'd be closer to the 59cm. I am the same size as you and would find a 57 cm top tube a little short. My 58cm frame has a 13cm stem to get a good position for me, that's similar to a 59cm TT and a 12cm stem.

If you got the 57, you'd need a longer stem for sure, unless you have really short arms or like to be very upright. I wouldn't want the 172.5mm cranks either, I prefer 175mm.
Get sized or use sizing formulasAFred
May 10, 2001 6:42 PM
It's worth the $ to get sized on the Serotta kit, or at least go to the Serotta website or the half-dozen others on the Web and use the sizing tables to get an approximate idea. I wouldn't worry about the stem length as much as the main triangle measurements. Once you get this right you can tincker with stem height/length. The difference between 172.5 and 175's is negligible. I'm 5' 10" with a 32" inseam and I ride 55 cm c-c frame with a 90mm stem and 172.5 cranks, and it fits me perfectly. Sizing has to be done right or doubts will nag you everytime you ride.