Mountain bike sizing

[ttaylor508]

I am looking to buy a new mt. bike and am confused on sizing. I am 5'4" with a 30" inseam. From all the sizing charts, if I go by my height I should get a 15", but if I go by my inseam, I should be on a 16"-17". My road bike is a womens specific 54" (the geometry is closer to a men's 52" though). I am looking to buy used, so I am just trying to get a basis on what size I should be looking for. Any insight from someone of my size would be great!

thanks

[Irulan]

Random thoughts on MTB sizing.

Every manufacturer is different.
Try before you buy.
Cock pit length is probably more important than standover.
You are better off with a bike that feels smaller than one where you are too stretched out. WSD in mountain bikes is designed for a longer legged shorter torso female, mostly. Many components can be swapped out for women specific ( handlebars, brake levers, saddle). Esp if you are buying used, you'll want to ride it and see how it feels.
Some companies measure inseam like trousers, some measure from crotch to floor so know what you are looking at for numbers.

FWIW, I am 5-3, 30" crotch to floor inseam measurement, and I ride a 15 man's Kona FS which fits great. For me I already know that a 16 or a 17 (!!) is going to be way too big.

[ttaylor508]

thanks. Sounds like we are pretty close to same size (I think I am actually a tad under 5'4"). I was kind of leaning toward the 15". I found a 2006 Specialized rockhopper in a 15" and think that might work for me.

[atombessy]

I agree with the advice about the cockpit measurement, I'm 5'3 with a 29.5 inseam, and I have really short arms. I fit a small Santa Cruz Juliana. Here's their sizing index:

http://www.santacruzmtb.com/juliana/index.php?sizing=1&x=65

I'm really happy with the WSD design, I used to ride an old 15 Schwinn Moab and the Juliana is a much more secure ride, and a MUCH better fit. (I'm actually moving to a WSD fit on a road bike too since I've had such a good experience with the Juliana!)

[emily_in_nc]

Just to reiterate how different sizing is among manufacturers, my two MTBs are thus:

Titus Racer X size XS (unisex), size 15.5" (second smallest size they make)
Novara Bonita size S (WSD), size 12" (smallest size they make)

Both bikes have virtually identical standover and virtual top tube lengths and both fit me perfectly!

I am 5'2.5" with a 28.5" inseam.

Emily

[ttaylor508]

I tried my friends GT mountain bike (size small) and it felt really big to me. I know that I am just used to my road bike, but I guess I am not really sure what the right fit should feel like. I went and looked at a Kona Cinder Cone size 16 and I think that is too big as well. I feel like I am in foreign territory here. My old mountain bike was very low end and hurt my knees terribly. I used it mainly to follow my kids around the neighborhood on their bikes. Now that they are bigger and are wanting to do more trail riding I need a better bike. I am just not sure testing them for a short ride around the parking lot will give me enough of a feel for what fit is right. Is there a general guide like with road bikes where the handle bars should cancel out your view of the front hub to give me an idea of what size might be right?

[bcipam]

Mountain bike sizing is different than road sizing and I would predict a 16 - 17cm bike is too big for you. You need more standover room on a MT Bike and also need to reach the bars and brakes while extended off the saddle. Make sure the top tube is not too long.

I am 5'8' with long legs and ride a medium - 17. I have 3 bikes - a Specialized Stumpjumper M4 HT, a Specialized Stumpjumper FSR and a Santa Cruz Superlight. All are 17 cm. The two Specialized bikes are much bigger than my Santa Cruz, especially the FSR. Your size is more likely 14 - 15, maybe a 13 or small or extra small depending on the style of bike and fork size.

Look for a used small Santa Cruz Juliana - should fit you perfect.

[Irulan]

bcipam brings up a really good point about cockpit length:


need to reach the bars and brakes while extended off the saddle

The way you'd test this is slighly stand up in the saddle feet at 3 & 9, and then move your torso back. You should ultimately be able to position yourself so that your chest is over your saddle and your butt is over the back tire. Sure, this is an extreme descending position but you never know when you might need it. This is a test is all.

My first bike was too long. I never realized how much too long it was until a friend stopped mid ride and moved my saddle as far forward as it would go. It was amazing how much difference even an inch or two made in shortening up the cockpit. It completely screwed up KOPS but I learned an important fit lesson.

I.

[ttaylor508]

A few weeks ago my LBS told me that the Specialized demo trailer was going to be at a popular mt. biking location so we went to check out a few of the 2008 models on actual trails. I test rode their 15" carbon full suspension bike and bit it around a hair pin turn. Ended up tearing my hamstring (ouch!) as I tried to break my fall. After that crash, I realized that smaller was probably better for me. I ended up buying the 15" WSD Specialized Rockhopper Comp. I think what was hanging me up on the sizing issue is I kept wanting the mt. bike to feel like my road bike and felt like I should be more streched out. I think this will be a good fit for me and will work fine for the type of riding we are doing. My 13 year old daughter who is about my size is already asking to ride it.

thanks for all the advice.:) It was really helpful in making my decision.

[Di bear]

You should have about 2 inches of standover on a MTB frame. I ride a Trek WSD 18". I'm 5'6", have no idea what my inseam is, except I have long legs and short torso (traditional build for a WSD bike).

Take the bike for a test ride to determine if the top tube length is really right for you. You should be able to get your weight way forward for steep climbs, and way back for steep descents. If you can't, go for another bike. :)

[DirtDiva]

I would say at least two inches!

I'm glad you went with the 15", ttaylor508. I think the 16/17" bikes would likely have been to big - you don't want to be particularly stretched out on your mtb. A smaller bike is easier to control too. Sorry to hear you crashed the demo and hurt yourself though!