Mountain Biking - Bike Sizing

OK, I'm one step closer to buying that new bike, but I have a question for you all. I know different bikes fit differently but I just wanted a general consensus on sizing. Like what size are you and what size bike do you ride. I'm 5'11" with a 32" inseam. I think I'm between a medium and a large. I've heard it's better to go with the smaller. What are your thoughts and what size do you ride? Thanks for any help. DG

The smaller bike is easy to "man handle". I am 5'10'' and with a 32 inseam and I ride an 18'' bike. I like it, just a shade big but I still have an inch or so to grow.

I prefer smaller. Makes the bike more nimble, easier to throw around, easier to jump and a bit lighter. A bigger bike will be more stable.

Just be careful when comparing sizes between manufacturers. Everyone measures different. Some are small, med, large. Others are in inches, but how they measure inches varies: Center of BB to Center of Top tube, Center to Top of Top Tube, Center to Top of Seat tube. It's enough to drive you crazy!

If you're comparing bikes in shops and maybe getting to ride some of them, why not take along a small tape measure (you can get a good retractable cloth one for around $2 in the sewing-goods section of a drugstore or dept. store) and measure crucial dimensions and keep a note of them? That way you wouldn't have to worry about standards being different....

DG,

You definitely have to be very careful with sizing between companies. My first bike was small, while my newer bike is a medium.

Should you go with a smaller size or a slightly bigger frame? Well, I think that depends on what kind of riding you do. If you mainly ride tight, slow, twisty singletrack, I would go with a smaller frame. It will be more nimble.
If you mainly ride fireroads or have lots of downhills, I would get a slightly bigger frame. It will be more stable at speed.

I've heard several times that you should stand over the frame with your feet on the ground and there should be one inch in between your nads and the bar.

Originally posted by Trekn
I've heard several times that you should stand over the frame with your feet on the ground and there should be one inch in between your nads and the bar.
I've read a recommended one inch on a road bike, and two inches on an MTB. But if the top tube is slanted, as on so many MTB's, there's going to be an easy two inches anyway.

Its really hard to just attach a size to a person of a certain height. Some people have crazy long legs and a relatively short torso, while others have longer torsos and legs that are a little shorter.

Top tube length is the most important measurement.

I'm 6'2", my frame measures 23.3" center to center for the top tube, and 19.5" for the seat tube.

If the seat tube was 18.5 or 20.5, the "size" of the bike would likely be labled as different, but it wouldn't make much difference to the ride because I have the correct TT length.

Originally posted by JonR

I've read a recommended one inch on a road bike, and two inches on an MTB. But if the top tube is slanted, as on so many MTB's, there's going to be an easy two inches anyway.

Actually 3 - 4 inches on an MTB is more common. At least if you will be riding off road. There are some valuables you want to keep safe after all!:D