Youth mountain bike sizing

broachboy

Hi forum people,

I have decided to leave road riding after 26 years and take to mountain biking as I don't want to give up riding totally, and my son plans to join me so we can spend some more time together. My problem comes when I started looking into a bike for him, he is 11 years old and a fairly tall chap. I don't want to go down the route of buying him a small wheeled bike, I would rather he had a mtb with a full size wheel, that will probably last him a lot longer. Do the same sizing rules apply to youth bikes as adults and can any of you recommend a good starter hardtail that can be supplied in a small frame size ?

TIA

supersonic

Some good info in this thread:

http://www.bikeradar.com/forums/viewtop ... t=12561336

broachboy

cheers for that

tjm

I think the last post in that thread by Mendipracer is very relevent. Have you actually checked he needs a small bike?
My daughter is 11 and about 5 foot. But, as is the case with a lot of kids has long legs - about 31" inside leg. At the moment she fits a 16" frame perfectly but in a years time she will outgrow it. So we have just ordered her a 18", very slightly large but she still has at least 4 inches of seatpost showing and plenty of crossbar clearance.

If he does have long legs and short torso then the thing that might be more of a problem is reach. My daughter is more than happy with a womens geometry frame - shorter top tube and reach. Your son might not be quite so happy with that label

niblue

The last poster has my a little concerned about the frame sizes mentioned as I'm 5'10" and ride an 18" frame...

I looked at kids bikes when my son needed to move on from his 20" wheeled bike and in the end decided to build him a small framed 26" wheeled bike as it meant we could share spares (plus I could use bits from my spares bin when building the bike).

It was mostly built using 2nd hand parts (includjng a 14" trails frame from Ebay) and has turned out to be excellent in practice:



He's a normal height 12 year old - he's had the bike for about a year and should get another couple of out it before needing something bigger. He was lucky with what I had as spares when I built the bike so it's got an 170mm XT chainset (2 rings plus bash-guard), XT front and rear mechs, disc (Shimano cable), Deore shifters plus some very light air forks. It's much lighter than any off-the-shelf bike we considered and works great in practice.

tjm

The last poster has my a little concerned about the frame sizes mentioned as I'm 5'10" and ride an 18" frame...

don't worry, I am 5'10.5" and I also ride a 18" bike!

I should have mentioned that my daughters bike is a hybrid with rigid forks. Suspension forks push the headtube and hence top tube up quite a lot so it is a bit unfair to compare them. I could of course refer to my road bike which has a 23" frame but that wouldn't be fair either!

The point I was really trying to make is that generalisations about age/height and frame size are dangerous - the only real way of telling is to try them.

Andy B

tjm wrote:

The point I was really trying to make is that generalisations about age/height and frame size are dangerous - the only real way of telling is to try them.

Yup, that's what I tell customers in the shop. I start with the inside leg measurement as a start point though & go from there when picking a size for a customer to test.