Go Back  Bike Forums > Bike Forums > Commuting
Reload this Page >

Mountain bike sizing

Commuting Bicycle commuting is easier than you think, before you know it, you'll be hooked. Learn the tips, hints, equipment, safety requirements for safely riding your bike to work.

Mountain bike sizing


Old 10-22-14, 08:43 AM
Aspiring curmudgeon
Thread Starter
icepick_trotsky's Avatar
Join Date: Aug 2014
Location: Saint Louis
Posts: 2,666

Bikes: Guerciotti, Serotta, Gaulzetti

Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 99 Post(s)
Mountain bike sizing

Dumb question. I haven't ridden a mountain bike since I was about 15, but I'm scouting CL for one to convert to a SS for winter bad weather commuting. How do you know what size get? I assume that MTBs with a flat top tube are sized more or less the same as road bikes, but what about ones with sloping top tubes? I also plan to put mustache bars on it. Should I get a longer top tube than normal to accommodate the backward sweep?
"Party on comrades" -- Lenin, probably
icepick_trotsky is offline  
Reply With Quote
Old 10-22-14, 11:16 AM
Pedalin' Erry Day
lasauge's Avatar
Join Date: Jun 2011
Location: Colorado Springs
Posts: 915
Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 459 Post(s)
Take a look at this sizing chart, for a mtb that you're going to ride on the road, you'll want one that's somewhere inbetween your ideal road and mountain sizes:

Compared to road bikes, mountain bikes have much shorter seat tubes (so that the back end of the bike can bounce underneath you as you go over rough ground with your weight on the pedals), and put the rider further behind the center of the cranks. If you buy a MTB with the same size seatpost as you'd want on a road bike, you'd end up with an extremely long reach to the bars, and if you buy a mountain bike that's the right size for trail riding you'd need an extremely long seatpost for efficient use on the road (and you'd end up with an extremely short top tube). So go for something that's between your ideal road/mtb sizes, you'll probably need a long zero-setback post and a tall stem too.

This thread in C&V is full of converted mountain bikes (my '84 Stumpjumper is in there) to look at for inspiration and guidance: Show Your Vintage MTB Drop Bar Conversions
Reach me faster by email.
lasauge is offline  
Reply With Quote
Old 10-22-14, 11:19 AM
Senior Member
Join Date: Apr 2005
Location: Northern California
Posts: 10,859
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 99 Post(s)
Practically all mountain bikes have sloping top tubes these days. The method for sizing them is similar to the method for sizing road bikes: get the right top tube length and head tube height for your riding position. Nominal seat tube length is less and less important now that bikes are coming with lots of different top tube and head tube lengths.
johnny99 is offline  
Reply With Quote
Old 10-22-14, 11:43 AM
fietsbob's Avatar
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 38,856

Bikes: 8

Mentioned: 154 Post(s)
Tagged: 0 Thread(s)
Quoted: 5991 Post(s)
smaller if doing Gnarly single track , larger if touring and commuting on the pavement.
fietsbob is online now  
Reply With Quote
Old 11-19-14, 03:52 AM
Join Date: Oct 2014
Posts: 17
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
The size in MTB is different in ROAD bike.if you want to buy the MTB bike ,you can consult with the sell.
mickey1019 is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service