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bike fit(13 posts)

bike fitmealex
Nov 3, 2002 9:19 AM
I was wondering if anyone knew of any online bikefit resources.(pay or not pay......matters, not). I live in the middle of nowhere, and there isn't a qualified bikefitter within 400 miles. I know that nothing substitutes for a qualified fitter, but I don't really have many options.

Thank you,
re: bike fittronracer
Nov 3, 2002 9:34 AM

bottom right hand corner
beware of wrench science...C-40
Nov 3, 2002 1:39 PM
I plugged in my dimensions at wrench science and got bad recommendations for reach (way too long). The site has no way to take into account upper & lower leg proportioning or preferred knee to pedal relationship.

It's easy to come up with an accurate vertical frame size. Measure from the floor to hard crotch contact in bare feet and use either the formula .67 times inseam or subtract 28-29cm from inseam. I like to use a bike as the measuring tool. Block up the wheels until the top tube produces saddle-like pressure in the crotch, when standing over it in bare feet. Then measure from the floor to the top of the top tube for an accurate cycling inseam.

Check out the fit info a or also has fit info, but as you'll find, not everyone agrees on what's important with regard to fit. I certainly don't subscribe to some of his ideas.
Nov 3, 2002 4:46 PM
WS worked well for me and matched the various formulas I used before I bought a new bike last year, including CC and a couple others. I think the key to WS, however, is talking one-on-one with Tim. Granted, a phone conversation is no substitute for an in-person fitting, but he was nonetheless able to tweak my needs to produce a bike that fits quite well.

As always, the key is having a great LBS with a skilled fitter. Unfortunately, we don't all have that resource at our disposal.

On a related note, I've found Cyfac's fitting paradigm and the new web page intruging. In fact, I've emailed back and forth with George several times about it. They can and will do a quick fitting for you, but their full "paradigm" fit sequence asks you to really go to town with regards to the specific bars, stem, pedals and saddle that you intend to use.

I agree with what you said, though. Fit is specific to our various body dimensions.
re: bike fitDaveG
Nov 3, 2002 10:05 AM

I haven't used this service; I just ran across it. If you use it, it would be interesting to post your experience here good or bad.
Try thisKerry
Nov 3, 2002 2:44 PM

These will give you a hint if you need a custom - if the dimensions you get from these sizing calculators suggest a frame that isn't available "stock" then you know the answer. For adjusting the fit of the bike, there are roughly five starting points:

1. Seat height (top of saddle to center of pedal axle) at 108-110% of inseam.
2. Saddle parallel to ground.
3. Saddle fore/aft adjusted so that a plumb bob from the bony protrusion just below the kneecap passes through the pedal axle when the cranks are horizontal. This is known as KOPS (Knee Over Pedal Spindle)
4. Front hub axle obscured by the handlebars when riding in your "regular" position (drops, hoods, or tops).
5. Top of handlebars 1 to 4.5+ inches below the top of the saddle depending on your flexibility and size.

These are all starting points for "average" proportioned people, and many folks like to move away from these starting points as they learn what makes them more comfortable, powerful, or efficient. You want to get the fit of the frame as close as you can, then do minor adjustments with the stem, seat post, saddle position, etc.
re: bike fittarwheel
Nov 4, 2002 5:59 AM
I would be cautious of relying too heavily on wrenchscience, colorado cyclist and other on-line formulas. They will get you in the ballpark regarding fit, but in my experience they err on the side of recommending too small a frame. That is fine if you like a large a saddle-to-handlebar drop, but if you like to ride with fairly high handlebars (eg, 0-2" drop), they will recommend too small a frame. Particularly with the threadless forks/stems being put on almost all new cycles, it is very hard raising handlebars to sufficient height if your frame is on the small side.

You might try contacting I was considering buying a frame from them (and they have a good selection of frames at reasonable prices), and they seemed to do a better job assessing my fit than all of the on-line fit formulas I've used -- and even better than the Serotta fitting I had done at a shop. Kyle had me fill out a worksheet and email some photos of me on my bike, and made some recommendations that were very on target.
head tube length...C-40
Nov 4, 2002 10:07 AM
If getting the bars up to an adequate height is a problem, the head tube length is an important dimension (and one that is rarely listed on geometry charts).

When comparing head tube lengths, you must also include the headset stack height. A standard threadless headset has a stack height around 25mm, while an integrated type may only be 6mm. This makes a pretty significant difference in bar height. Some frames with integrated headsets have headtubes that are on the short side, which can be a problem.

A sloping top tube frame can occasionally be the answer by providing a taller headtube with more standover clearance, if the top tube length doesn't become too long.
Sloping top tube..........Len J
Nov 4, 2002 2:43 PM
As I look around for a new bike and reflect on my old one it seems that the only way to get a good fit with a threadless stem, (if you don't want Tons of spacers and you want bars less than 2 inch drop from seat) is to opt for a sloping top tube (In addition to a headtube extension). This makes sense if you comapre the amount of stem showing on a Quill stem compared to a threadless system.

Now if I could just get used to the idea of a sloping top tube.

head tube length...mealex
Nov 4, 2002 8:49 PM
a terribly naive question, from someone who has not a clue what they're talking about(namely, me).......but could a stem, that has some degree of up-slope, not help with the reach adjustments?

again, i apologize for my ignorance, but you folks are just so bloody helpful........and extraordinarily nice, to newbies, too.

need help tooandydave
Nov 6, 2002 5:03 PM
I need help too. I'm from old school. I have an old Ciocc with a Cinelli quill stem. It has apporx 1.5-2" of rise before going out horizontally (the old "7" look). Why are spacers with the new threadless stems generally considered a bad thing? Have frame geometries changed over time? Are people riding more drop in their handlebars? If someone can explain, it would really be appreciated.
need help toomealex
Nov 6, 2002 7:09 PM
good q, andy. i can't answer it.....maybe you should post it as an independent q..........this thread is 100+ deep in the archives.

need help tooandydave
Nov 6, 2002 7:22 PM
good suggestion! Look there for new responses.