Online Bike Fit Calculator Reliability
Holmesy321
Posts: 37
So I have a CAAD8 56 that I bought as my first road bike, I've had it for about a year now, have had a fit on it and still can't seem to get it comfy. My cyclescheme is up and I'm looking at new bikes.
Online fit calculators (Pedalforce, competitive cyclist) recommend a ~54-55cm top tube, with 10-11cm stems respectively.
Wrenchscience recommends a Top Tube + Stem of 67.8cm - so a little longer overall.
Canyon's online fit system puts me on an M. Giant's sizing recommendation is right on the edge of M and M/L.
I am ~180cm tall, with a ~85.5cm inseam and get lower back pain on my current bike.
When test riding some bikes today (Giant TCR) I found that the longer (M/L) bike felt more comfortable as I could flatten out my back a little more and tilt my pelvis forward. This has a 57cm top tube, and a 110cm stem as opposed to the 55cm/100cm on the M - so is effectively 3cm longer than the M.
Obviously there were other factors here that weren't really considered particularly thoroughly (saddle fore/aft, height was only ballpark, tilt of saddle, bar position etc).
I'm not really sure what to do... Last thing I want to do is buy another bike that doesn't fit me properly. And I don't want to be buying a bike that's basically too big and effectively only feels good because there is less drop from saddle to bars.
Online fit calculators (Pedalforce, competitive cyclist) recommend a ~54-55cm top tube, with 10-11cm stems respectively.
Wrenchscience recommends a Top Tube + Stem of 67.8cm - so a little longer overall.
Canyon's online fit system puts me on an M. Giant's sizing recommendation is right on the edge of M and M/L.
I am ~180cm tall, with a ~85.5cm inseam and get lower back pain on my current bike.
When test riding some bikes today (Giant TCR) I found that the longer (M/L) bike felt more comfortable as I could flatten out my back a little more and tilt my pelvis forward. This has a 57cm top tube, and a 110cm stem as opposed to the 55cm/100cm on the M - so is effectively 3cm longer than the M.
Obviously there were other factors here that weren't really considered particularly thoroughly (saddle fore/aft, height was only ballpark, tilt of saddle, bar position etc).
I'm not really sure what to do... Last thing I want to do is buy another bike that doesn't fit me properly. And I don't want to be buying a bike that's basically too big and effectively only feels good because there is less drop from saddle to bars.
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Comments
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A proper fit is the only real way to get correctly fitted. I had one done a few years by Mike at Bike Dynamics, which opened my eyes to many things. Having those measurements has helped when it comes to buying new bikes, so much so, that I've been able to reliably ignore on line fitment guides from dealers and manufacturers, and instead go by my accurate measurements. If I used an on line guide, I'd be ending up with a bike that is too long for my reach.I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.0
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Don't forget stack and reach http://mx.cervelo.com/en/engineering/th ... d-fit.html0
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I understand the merits of stack and reach, in the fact that it's a measure by which you can compare all bikes irrespective of geometries - and this is how I've been judging frames recently. (The stack/reach ratio giving a good idea of the 'aggressiveness' of a frame).
Only thing it doesn't account for is seat tube angle I guess. Usually these difference could be taken up in saddle setback if required though, and unless you're at the far end of the fore/aft spectrum you should be able to achieve the location you need relative to bars and BB.0
