RoadBikeReview.com's Forum Archives - General


Archive Home >> General(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 )


About what size of Frame should I look for, help appreciated(7 posts)

About what size of Frame should I look for, help appreciatedJoker
May 31, 2001 10:25 AM
Hello, I'm looking to pick up a used road bike and expect that I might buy it off this site. I'm new to road bikes and was hoping some one would give me a suggestion on what size I should look for, knowing that changes in stem length may be necessary to dial the fit in. I'm about 6'1"-6'2" inseam in bare feet and a book between my legs is about 35" and I have a fairly longish arms. I though some where between a 58cm-62cm might work, any suggestions on which end of that range I should stick to would be appreciated. The bike I want to buy is more for day rides and speed than anything else, I have a large mountain bike frame that I have converted for a touring/commuting rig.
Thanks!
re: About what size of Frame should I look for, help appreciatedCima Coppi
May 31, 2001 10:59 AM
According to the information you have provided, let's first convert all measurements to cm. This makes your inseam 88.9 cm. According to Greg Lemond's book in the fitting chapter, the seat tube length should be 65% of your inseam. This puts the seat tube length at 57.785cm ( we'll round up to 58cm). However, Colorado Cyclist clarifies that taller riders should simply subtract 27-28cm from their inseam measurement to get the proper frame size. This would put the frame size at about 60cm. This is the method I have chosen, and the frame is very comfortable.

The next step is figuring out the optimum top tube length. This is very important since an improper fit here can produce a very uncomfortable ride. Some say this can be adjusted by lengthening or shortening the stem, but too short of a top tube will cause your shoes to rub the front tire in corners. You'll need to measure your upper body for this, and Colorado Cyclist give a good guide figuring this measurement.

Go to http://www.coloradocyclist.com/bikefit/

For stem fit, really there is only one mode of thought here. When you ride on the drops of the bars, the tops of the bars should eclipse the front hub when you look down at it. A stem is easy to size, as they all come in 1cm increments.

Hope this helps, and good luck!!
Toe OverlapPsyDoc
May 31, 2001 11:05 AM
I thought there is a certain amount of toe overlap on most bikes. I have a 56cm bike with 700x23's and there is toe overlap and I have tested a 57cm bike with the same size tires and there is toe overlap. Now, a 57cm bike outfitted with 700x20's has no toe overlap for me. But, I am rarely in a situation where toe overlap is a problem.
Toe OverlapCima Coppi
May 31, 2001 11:16 AM
Toe overlap is not dependant on the seat tube length of the bikes you rode. I would bet both probably have too short of a top tube for you. Tire size will not make a whole lot of difference either, as the sidewall height of the tire is not very different between 700x20 and 23. You may not have encountered a situation where your toe overlap was an issue, but it could happen. Admittedly, I have not yet encountered this situation yet either, but my frame builder swears to prevent this to begin with.
Toe OverlapHaiku d'état
May 31, 2001 11:44 AM
have overlap on my more aggressive road bike, and not on my JRA road bike. i've put nearly 1000 miles on the former in the last few months, and only had a problem with the overlap until i learned to adjust for it. the problems only arose at VERY slow speeds and VERY tight turns, or starting from a standing stop into a turn. otherwise, you live with it. it's not overwhelmingly common, but is certainly not unheard of. had i the chance to buy it again or make another choice, i'd buy it again.
Thanks, excellent information! (nm)Joker
May 31, 2001 12:13 PM
best vertical fit with a 61 or 62...C-40
May 31, 2001 4:17 PM
With an 89cm inseam, subtracting 27-28cm leaves 61-62. With the use of threadless stems, smaller frame sizes can create problems in obtaining sufficient bar height.

I always check the head tube length, to be sure it's not too short. I like to be able to use a standard 80 degree stem with only a few millimeters of head tube spacers.