Originally Posted by
TEdean
I am 5'11" (63yo) and ride a 58cm Trek Road bike, I like it because it stretches out my back a little, I m looking at a 56cm Trek TT bike, it feels right because your body position changes so much when you stretch out to the aero bars vs riding on the hoods of a road bike.
Is there a "rule of thumb" comparing road bike to TT bikes?
Thanks
Tom
Are you my twin? If so, I'm your older brother. By about a year.
I ride a 56 cm Motobecane Ipro. I started on a 54 cm Trek I borrowed, and I knew it was about an inch or so too small. I wrestled over a 56 or 58, and settled on the 56 and don't regret it. I got a Retul pro-fit, and he said it was very close.
I decided to get a TT bike now that I'm doing Tri's. Had a very limited budget and a lot of spare parts, so I looked for a cheap frame. Got a close out from Nashbar on a Fuji Aloha 1.0, 58 cm. Was a bit concerned that it was too big. But it was a good deal, and I figured I could always build it and sell it.
Finished the bike about a month ago. The 90 cm stem I had on it was just too long. Everyone said I was too stretched out. Got a 60 cm cheap, and set about setting it up. It made a big difference.
I feel really comfortable on the bike, and it has really made a big difference in my average speed. I train several days a week with a group of very experienced Tri guys and gals, and they are quite impressed with what the bike has done for me. I'm sure aero bars on the Moto would accomplish much of that gain, but I'm not doing that now that I have this TT bike.
I'm planning to do a pro-fit when I can save up the $, but I'm not sure what it might do for me. Today I did 93 mi on the bike, 90%+ in the aero position, and the only discomfort I had was my right arm went numb a few times. I had that problem before with the longer stem, and I raised the angle of the aero bars several degrees, and that solved it. Now with the shorter stem I thought I would move the bars back to parallel to the ground. I guess I need to have them up a little.
I've had several positive comments on my position on the bike in the areo position, so I think I'm really close. I think the only thing that a 56 cm frame would do is to require a longer stem. Sure, it would be a bit lighter, but the bike is very heavy anyway. Weight is not such a big deal on a TT bike as most courses don't have much climb or require a lot of acceleration. And the inertia helps.
So for me at least, I managed to do fine with a 58 cm. If my wife hits the lotto perhaps I'll consider a Cervelo P5, 56 cm. Or 58? Or both! lol.
Busta, thanks for that link.. It's a great article, and probably explains why I'm good on the 58.