Grasschopper

Ok so How do you fit a MTB? I am a roadie and I know what I like there but I am unsure how to properly fit a MTB. I am 5'10" with a 31.75" inseam. Last MTB I had was a 2001 Giant XTC SE2 17" which I didn't ride and traded for a bike for my wife. Now I want a MTB again (read I shouldn't have traded the XTC but oh well). I think the XTC fit ok but I didn't ride it too much so I am not overly sure. My Marin Mill Valley is a 17.5" but it is a roadie. What size do I need? The top tube lengths seem WAY longer than roadie TT numbers so it is throwing me off a bit. So one of the bikes I am looking at is a Surly 1X1 but I dont' know weather to get a 16" or an 18". The TT of the 16" is 10mm shorter than my old XTC and the TT of the 18" is 10 mm longer.

Should I go with the 16" and a longer stem or the 18 and a shorter stem? Thoughts?

Killer B

In a word... "Medium".....

Forget the cm thingy....

Peek the Geek

Are you looking at the ACTUAL top tube lengths or the THEORETICAL top tube lengths? Since the TTs on mountain bikes are more sloped than on road bikes, they're going to be longer. When sizing, you want to compare theoretical top tube length, meaning the lenght of an imaginary line, parallel with the ground, from the center of the seatpost to the center of the head tube where it meets the top tube.

MichaelW

Dont forget that drop bars add another 6-8" of extension to your reach beyond the stem. A cx style mtb is usually ridden with quite an aggresive position, comparable with the hoods of a road bike. Meaure up the reach to your hoods and compare.

Grasschopper

Good point on the reach of road bike bars being part of the issue.

For the person that asked I am looking at TT lengths parallel to the ground, not the actual tube. In fact the slopped TT is shorter than the theoretical TT as the seat tube is slopped away from the head tube.

motorhommmer

The most important measurement is from the tip of your saddle to the handlebars. Standover height etc is irrelevant. Read peter Whites Article www.peterwhitecycles.com/fitting.htm.
This is the most important aspect. I have found this through bitter experience. Sheldon Browne also interestingly makes the same point.
Next then is riding style. More forward the bars more aggressive the riding style.

Enjoy

Grasschopper

Yea I have this printed out but I thought it was related to road cycling. I guess I need to reread the article. Basically I need to decide before noon weather a 16" Surly 1X1 is the right size for me or if I would be better off with an 18". I can stand over either with no issue and we are talking frame set so I can put a setback seatpost and a longer stem on the short one if I have to but if I am putting a huge stem on and a setback post I think I am just making too many compromises. I wish anyone in my area stocked Surly. grr.

abramsgunner

Gotta test ride bikes from several manufacturers and see what feels right... then most likely, your first bike won't be right anyway... but you'll get a feeling for what works, and your second purchase will be more on target for your riding style. Stand-over IS important, unless you want to squash the jewels the first time you step off into a hole.. been there, done that

PWRDbyTRD

jump on it...if you bash the boys...go smaller

seely

As for Surly, they seem to use "old school" geometry... the top tube is shorter and doesn't slope as much as you see on the new frames out there.

Killer B

Good One Man !!!!

The Dude's my height, and I can ride any Medium framed bike, hence the post from me earlier.... People are making this stuff too hard IMO.