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weird fit question(16 posts)

weird fit questionnyedid
Apr 9, 2002 6:39 AM
i'm looking at one of the trek OCLV bikes, and when i got fit, i tried both a 58cm and a 60cm, both of which the shop owner said could work. however, my inseam also suggests i could ride a 62cm. i found a deal here in town on a 62 and was wondering whether it would be better to err on the side of a little large (i have a long torso, so a little extra top tube can't hurt, i think) as opposed to a little small (the 58cm). the 60cm seemed like a fair balance, but i'm just not exactly sure which one to go for. the fact that there's this deal doesn't exactly make things easier either. help!
re: weird fit questionmixinbeatz
Apr 9, 2002 7:16 AM
Personally, I always tend to go on the smaller side, as long as my stem will not exceed 130mm in length. I once went on the long side and had difficulty finding a smaller stem to work correctly. I would compare your current reach length (top tube # + stem length) and if the 62cm requires a 100mm stem or shorter, I would go for the proper size. You should get fitted and see what position is most comfortable, cause a bike that doesn't fit right is a bike that doesn't get ridden enough.
more infonyedid
Apr 9, 2002 7:26 AM
the thing is, i'm a newbie and don't currently own a road bike. (are you all going to jump on me for posting on here?). i know that the top tube on the 60cm that i tried was 59cm and the stem was a 120. so that would equal a total reach of 71cm. with the 62, i'd be looking at a 90mm stem, then? and you think this is not a good way to go? also, how important a measurement is KOPS? when i got fit on the serotta fit bike, the LBS guy used a plumb bob and used that as a partial factor in recommending the 60cm to me.
KOPSRay Sachs
Apr 9, 2002 7:41 AM
is a rule of thumb, at best. Not a bad place to start but most folks I know end up well behind kops and some in front of it. A 90mm stem shouldn't affect the handling noticeably (I wouldn't go much below 80 though) so if you can get a good deal on the 62, it may be worth checking out. For a newbie, I'd actually recommend a larger frame if the top tube can be made to work because your handlebar level will be closer to seat level. You may want lower bars after a couple of years of riding, but you'll probably want 'em higher at first.

-Ray
some suggestions...C-40
Apr 9, 2002 8:14 AM
You should not be looking at such a broad range of sizes. I will only consider a 1cm variation is size (a 54 or 55cm for me). That's why I hate models that only come in 2cm increments; one size may be too big and the other too small.

Take a look at the Colorado Cyclist website and get an accurate inseam measurement (barefoot to hard crotch contact). Since Trek measures their frames in an unconventional manner (not center to top or center to center), use the standover height as a guide to proper vertical size. The largest size that I would recommend would have a standover height that is 1 inch less than your inseam. 1-1/2 inches would be better, and 2 inches is the absolute maximum that I would recommend. The standover height on the 60cm is 32.5 inches and the 62cm is 33.2inches.

If you end up comparing the 60 and the 62, note that the seat tube angles are not the same. The 60cm has a 73 degree STA with a 58.1cm TT length, the 62 has a 72.5 degree STA and a 59.2cm TT length. The difference in STA reduces the effective TT length of the 62cm frame by .7cm to only 58.5cm (once the saddle is adjusted to the same KOP). There's only .4cm difference in the effective top tube length between these two frames. The vertical size difference is a full 2cm. Let that be your guide.
im confused...SteveO
Apr 9, 2002 8:50 AM
the 60cm has a 73 degree STA; whereas the 62 has a 72.5 STA. Wouldnt the slacker angle effectlively LENGTHEN the TT for the 62?

Seems to me the tighter angles put you moreso over the BB, thereby shortening the effetive TT.

Am i incorrect? Or should I not have skipped my coffee this morning?
yes and nolaffeaux
Apr 9, 2002 9:40 AM
The slacker seat tube does allow for the saddle to possibly be further backwards. However, since your seat can be moved forward or aft, or you can have a set-back or straight set post, the seat tube angle is not the only determining factor in overall cockpit length. The slacker seat tube angle will help give you more room if you have a longer femur, but the seat should be in the same place with respect to the BB, regardless of the seat tube angle.

As a few others have said, I'd go with the larger sized frame. I spent several years on a 56cm frame. When I switched to a 59cm, I couldn't believe how much more comfortable I was. Try to take the bikes on a longer ride with steep ascents and decents to see what you like better. On flat groud I was fine on the 56, but on hills the larger frame really helped out. The fact that you said your torso is long, also would make think that the larger size is the better option.
can someone clarify?nyedid
Apr 9, 2002 9:47 AM
well, i'm a little confused: i understand what everyone has been saying, but i need someone to be explicit: should i go for the 60cm if it felt fine, or a 62cm? I didn't try a 62.
can someone clarify?Ray Sachs
Apr 9, 2002 10:14 AM
You really need to try the 62. If the 60 felt better than the 58, it's very possible that the 62 will feel better than the 60. Or maybe not - maybe the 60 is dead on. You shouldn't make the decision based on incomplete information. The difference between feeling "OK" and feeling "dead on" is huge, maybe not on a 20 mile ride but on a 60+ mile ride all the little things start to show up and fit is absolutely King, Queen, Vicar, and God of making longer rides comfortable and efficient.

-Ray
common confusion....C-40
Apr 10, 2002 8:43 AM
Slack seat tube angles shorten the top tube length when the saddle is placed in the same relation to the bottom bracket.

The top tube length is measured from the center of the head tube to the center of the seat tube. On a frame with a slack seat tube angle, the saddle must be forward to place it in the same position relative to the bottom bracket. This saddle movement effectively shortens the top tube length.
My preference is to go a little big...retro
Apr 9, 2002 8:18 AM
Might be because I'm 6'4" and I've ridden too-small bikes most of my adult life, but the difference in comfort for me between 62cm (the largest available in many frames) and the 64 I finally bought last year is huge. A couple of months ago I rode a friend's 27-inch (68cm!) Bob Jackson, and even set up for a guy three inches taller than I am, it felt better than a 62cm Allez I've fiddled with for years.
re: weird fit questionChen2
Apr 9, 2002 8:39 AM
If you are looking at 58 to 62 it would seem likely that the right answer is a 60cm. The Trek OCLV is really not the best bike to buy on the small side because the top tube sits lower on the frame than with comparable bikes, and the head tube is shorter. This can result in a steerer/stem spacer stack height problem. Nothing wrong with the bike but I wouldn't go with the smaller one.
~Al
Can you try it?djg
Apr 9, 2002 10:09 AM
You say there's a deal in town on a 62--won't they let you take a test ride? The tradition is to go a bit small for racing, on the theory that it buys you a lighter & stiffer frame. I tend to think that dropping one or two cm makes at best a negligible difference in weight and stiffness. I tend to err on the side of slightly large for comfort. Of course, way too big (or way too small) just stinks. Hard to see that a 58 is appropriate, if you're inseam says (according to some standard formula) 62 AND you've got a longish torso. If you can ride the 62 and the 60, why not just get what feels better. If it's hard to tell what feels better, and both feel fine, go for the better deal.
How's your back?Turtleherder
Apr 9, 2002 10:55 AM
The larger frame will also mean you have a smaller drop from the top of your seat to the top of your bars which means you are less bent over. So, how young and limber are you? The smaller frame may be ever so slightly faster in a race but you may be more comfortable for the long haul with less bend in the old back and neck.
By god! get another bike! Deal = first reason for poor fit (nm)tempeteKerouak
Apr 9, 2002 11:53 AM
My inclination also...DINOSAUR
Apr 9, 2002 5:44 PM
I can see comtemplating over two sizes. I can ride a 58 or 59, but the important measurement you need to be concerned about is the TT. There is a big difference between a 58 and a 62. If you are not sized right you will feel in on your long rides and will develope all kinds of problems and will be constantly making little adjustments trying to get it to dial in. Try the Wrench Science online fit program and then jump over to the Colorado Cyclist. Or find a different LBS who will do a fitting for you. Don't buy a bike that doesn't fit (been there, done that)..