Help-MTB Frame sizing

[Pot Belgique]

This is probably gonna sound a really stupid question but how do I know if I have the correct size MTB frame?

I'm a 5'10'' male so what size frame should I be riding? everyone elses frame seems to be a lot smaller than mine?

Any (sensible) ideas welcomed

 

[the truth.]

hea
frames differ by companies who size them different. rule of thumb you are into a large 18"/
the xl sizing I ride at 6foot 2 in a kona is a 20" and trek is 20.5" and defo too big.

trek and specializied medium is 17.5 and will be very tight.

check out the latter companies website for detailed fitting.

 

[kiwirider]

This is probably gonna sound a really stupid question but how do I know if I have the correct size MTB frame?

I'm a 5'10'' male so what size frame should I be riding? everyone elses frame seems to be a lot smaller than mine?

Any (sensible) ideas welcomed

There's a good guide on http://www.wrenchscience.com - but it involves a fair bit of measuring and stuff to get it sorted ...

Another rule of thumb - if you have a road bike, go for about 4"/10cm smaller than your road frame. (For me - and I'm also 5'10" tall, with a 83.3cm/32 3/4" inseam - I ride a 54cm/21" roadie and a 43cm/17" MTB - both Cannondale, so that makes things a little easier!) However, as the geometry of an MTB is quite different to a roadie, you need to check that you can still get the same sort of forward reach without either a super long or super short stem.

I am definitely a fan of going smaller rather than larger. I learned my lesson with my very first MTB - go too big and you can't get over the bike and move your weight around as much as you need to. A good test is whether you can get your weight far enough off the back of the seat to head down moderate drop offs. If you can't - your frame's too big.

So, if your comment about size is a reflection of you feeling "stuck" on your bike - then it is definitely too big. If however your comment is just that your friends are riding smaller bikes and you can still ride everything that you want at the speed and in the way that you want - then it's fine.

Sorry to not be more definite in my answer - but hope that helps.

 

[badboyberty]

Kiwirider is spot on.

At 5'10" you'll probably be looking for something marked as a 17" or 18", but due to different geometries, and measuring protocols, these sizes are guides only. I believe that most people fit between two frame sizes, for aggressive off-road work, the smaller bike will always be better, for long distance back-country riding or loaded touring, the longer frame is often better. Generally smaller is better, as long as you can turn the bars without smacking your knees into them and you don't require a seatpost longer than 400mm to get full extension, things should be all good. It's the effective top tube length (the imaginary line that runs from the centre of your headstem to where it meets the centre of the seat post) that is the most critical. Too long and your stretched out to far to be able to move around on the bike, to short and you'll be cramped, with knees where they shouldn't be and the risk of a sore neck and shoulders.

There's no such thing as the right bike for a given height. I'm almost exactly the same total height as a friend of mine, but I'm all legs and he's all torso. I can ride a smaller frame more comfortably than him, but my seat is always higher.