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position question: road bike position vs MTB position?(9 posts)

position question: road bike position vs MTB position?weiwentg
Aug 1, 2002 12:55 AM
I can't figure whether to post this here or on MTBR, but there seem to be a lot of people who also mountain bike here, so here goes.
my road bike has a 535mm TT and a 100mm stem. Airborne's site says that the total reach should be about 2cm shorter, and my intended frame (Weyless Ultra) has a 565mm TT. so, I need a 5cm (!!) stem. yes? no? and how much rise and spacers(guesstimate)?
Doesn't sound right to me.Leisure
Aug 1, 2002 4:15 AM
Something's wrong somewhere. Bet you need a smaller mountain frame than they're recommending. I have to wonder also if your road fitting is really all that spot on, but some of my questioning could fairly be my personal biases.
smaller frame?weiwentg
Aug 1, 2002 6:52 AM
there IS no smaller frame - I'm looking at a 14" MTB frame, and I'm riding a small TCR (before that, a 48cm Specialized Allez).
re: position question: road bike position vs MTB position?divve
Aug 1, 2002 5:31 AM
It depends what you want to do with your mountain bike. If you're in for all day epic comfort get something with a comparable top tube length to a road bike and a saddle to handle bar drop of zero or a rise. On the other hand, for pure XC get something with a longer top tube for better weight distribution during ascending/descending and a saddle to handle bar drop comparable to a race level road bike.
pure XC for me ... nmweiwentg
Aug 1, 2002 6:54 AM
Ride a bunch of built bikes and bring a tape measure.Quack
Aug 1, 2002 6:34 AM
I would not go by any magic formula for road v. mtn bike setup. Go to a local bike shop and ride a few different bikes in your size and see how the various positions feel. I would urge you to go with a more upright position than your road fit as long-term off-road comfort will improve with a more upright position. 2 cm might be close to what you will want but I would definintely check it out thoroughly before spending $$. By the time you take into account the drop bar and the fact that you ride on the hoods of a road bike, you could be out 10cm or more past the stem. Just changing the road drop bar with a flat 3 degree mtn bar may actually be 11-12cm tighter than the road setup without any other changes. With a 2cm shorter effective TT length, your mountain position may still be a 8-10cm shorter reach than your road bike.

Good luck!
right. so, approximately how much shorter reach shouldweiwentg
Aug 1, 2002 6:55 AM
I shoot for, assuming I'm doing pure XC riding?
I'll measure tonight and let you know the results.Quack
Aug 1, 2002 10:30 AM
I've got two MTB, a road bike, and a fixie. I'll check the reaches of each tonight and let you know the difference. One of the mtn bikes is a stretched out XC race machine and the other a compact extreme trail basher. Going with a measurement somewhere between the two mtn bikes should be perfect. I'll post later tonight or tomorrow.
re: position question: road bike position vs MTB position?pa rider
Aug 1, 2002 7:40 AM
I ride mtb for 10 years now and bought alot of wrong bikes that didn't fit me right. I also do some mtb racing and found a good formula.

The stem height is about 1 inch from seat height in difference and seems to help for the climbs. As for going downhill I liked the long toptube as the other posters mention. If you hit a rock or log and your forward (short top tube or weight not back) your going over the bars.

I found that the front wheel hub should be seen in front of the stem/bar combo when looking down at the wheel. My two bikes top tube total lenght have a 2 inch difference. My point is that unless your road bike has a stretch length toptube, than it's hard to compare your fit to be the same.

If you can find a shop who will leave you ride a demo bike, before buying, go for it man. That helps alot of questions get answer quickly for you. Also helps to decide if you like that companies model.

I had a Gary fisher sugar 3 moel last year and found that the "V" shape toptubes are great for standover height. Never have to worry about hitting your boys, plus easier to handle the bike. The 2 inch rule applies for standover, but I'm never comfortable about going over logs with a bike having less. That's what I likes about the "V" toptubes.

Alot of the mtb are in three or four sizes (small to xlarge). If you plan on riding fireroad, get the model that fits you the best. Alot of guys get a smaller frame with a long seatpost because they ride better in the single track trails.

I think this is where the "V" shape frame helped and all you try to get in the size is having the correct length and height on the bars.

Hope this helps,