Wanted to know - your methods of transfering bike fit

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Wanted to know - your methods of transfering bike fit

Postby Dale E Grind » Thu Aug 07, 2008 11:53 am

You're roadie is set up perfect, but what method/s do you use to tranfer it to your MTB, shopper or commuter?

Do you run an eye over it and just peddle away, plumb bob your KOPS (Knee over pedal spindle), measure your BB to seat height and substract the crank length?????

There a numerous methods on the web and doing a pro bike fit everytime you swap/upgrade is expensive.

Just after some of your thoughts and techniques for the closest, most comfortable, fit and ride.
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by BNA » Thu Aug 07, 2008 1:28 pm

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Postby HappyHumber » Thu Aug 07, 2008 1:28 pm

No specific answer from me, Dal E... but I have often wondered the same thing myself at least between two roadies. I asked a local shop when I ordered my Cross-check through them yonks ago about a series of basic measurements to make off the previous bike (a Trek OCLV roadie) to keep mindful for the second; understanding that the basic geometry is at least subtley different.

I had them scribbled down on a piece of paper I had at the time... used them, and then lost them, :(

I don't know how translatable such measures between basically different types of bikes eg. a Roadie vs. a MTB. Aside from the different shape - you're also likely to be riding in different positions for differing lengths of time - so fatigue points and power requirements are likely to different also.

Comparing apples and oranges maybe ? :?
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Postby Dale E Grind » Thu Aug 07, 2008 1:35 pm

According to the manufacturers of the FitStik, and believing the hyperbole, you can get pretty close with their product.
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Postby sogood » Thu Aug 07, 2008 2:31 pm

Position isn't that transferrable b/n road, MTB and comfort bikes, is it?
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Postby Dale E Grind » Thu Aug 07, 2008 2:32 pm

sogood wrote:Position isn't that transferrable b/n road, MTB and comfort bikes, is it?

Dunno - that's the question
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Postby HappyHumber » Thu Aug 07, 2008 2:58 pm

maybe I'm cynical... but that webpage - I think smacks of a snake-oil type remedy.
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Postby toolonglegs » Thu Aug 07, 2008 4:11 pm

I ride the same front of seat to bb measurement on my mtb...that is it.Set is lower and bars are higher and closer.
Actually you can not transfer bikefit between road bikes unless you have exactly the same bikes and components...that is from Steve Hogg.
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Postby LuckyPierre » Thu Aug 07, 2008 7:09 pm

I don't think that you can transfer measured fit between mtb and road bikes - the geometry is different and your body position is different.
I find the transfer between different road bikes pretty simple - the most significant measurements are centre of BB to effective seat top, seat nose to centre of head tube and seat to bars drop. Seat tube angle will have an impact on KOPS position (but not much). BB drop will impact things a bit too.
There's no real way to do it without proper fitting, but I find that I can get pretty close with just those three measurements.
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Postby toolonglegs » Thu Aug 07, 2008 7:48 pm

LuckyPierre wrote:I find the transfer between different road bikes pretty simple - the most significant measurements are centre of BB to effective seat top, seat nose to centre of head tube and seat to bars drop. Seat tube angle will have an impact on KOPS position (but not much). BB drop will impact things a bit too.
There's no real way to do it without proper fitting, but I find that I can get pretty close with just those three measurements.


What does seat nose to center of head tube tell you?.
Here are two of my bikes...with the same seat nose to bb measurement (ie: how far the seat nose is behind the bb - 9cm for me)...can you spot the difference! (same seat post used on both)...seat tube angle plays a huge part in set up.

Image

Image
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Postby Dale E Grind » Fri Aug 08, 2008 7:13 am

toolonglegs wrote:
Here are two of my bikes...with the same seat nose to bb measurement (ie: how far the seat nose is behind the bb - 9cm for me)...can you spot the difference! (same seat post used on both)...seat tube angle plays a huge part in set up.

Remarkable difference
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Postby Kalgrm » Fri Aug 08, 2008 9:06 am

You can't generalise on this question, because the types of bikes are too different. Even within the range of mountain bikes, there is a large range of uses, each of which will have a different "ideal fit" for any given rider. On a XC mountain bike, you want more weight over the front forks than for a DH bike, and a "trail bike" is between those two extremes.

Fitting a mountain bike to a rider is best done by getting the effective top tube length correct first (ETT). Everything should follow from there - in theory. ;) Luckily, there are usually only 5 frame sizes to choose from (some makers have fewer).

A point to remember is that riding a MTB requires the rider to be out of the saddle a lot more often than on a road bike. That makes a road frame's fit critical, because you're "locked" into that position for long periods with few chances for respite. The style of riding a MTB means there is a little more room for error in fit. I prefer to err on the side of a slightly smaller bike because it means I can throw the bike around a bit more and I'm not stretched out. Some of my friends prefer the other end of the spectrum. I ride a medium frame whilst friends who are the same size choose large frames. Whatever feels right will be the best bike for you ... :roll:

I don't believe the frame measurements are directly are transferable between styles of bike because the reasons for riding them are different.

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