palle22

Hi

I have bought a 24" bike for my 6 year old son - he tried a different brand in a shop, and the 20" was almost too small - the 24" was suggested by the retailer. He measures 121 cm.

However; he cannot reach the ground when seated, and he stretches his legs out almost entirely when riding.

It's a nice bike and he likes it, so we will keep it anyway - but should I buy a 20" for him, that he could ride for the next year or so - or will he get used to the "a little too big" bike? Maybe it's too dangerous, or maybe even damaging his knees?

Thanks in advance from Denmark!

palle22

Inseam 56 cm without shoes, lowest seat height 70 cm.

AnthonyG

I'm an adult, 152cm, and I ride a 24" wheeled bike these days. I'm of the view that most people, children and adults alike are fitted to bikes that are too large for them so yes, I would put your son on a smaller bike for a while.

I just remembered. I rode a 16" wheeled bike until I was 12. Then I rode an 18" wheeled bike until I was 15 before I got a 24" wheeled bike for the first time. Later on I moved to even larger wheeled bikes yet in hindsight I should have stayed with 24" wheeled bikes.

dabac

Being able to reach the ground from the saddle is a rather unimportant feature in bike fit. It’s very common only to reach with the toes. It’s generally recommended to be able to straddle the bike off saddle and have some margin to the top tube.
Legs ”almost straight” when pedalling sounds just fine, as long as he doesn’t have to flex his foot to pedal with his toes.
Another thing to look for is if he’s rocking his hips to reach the pedals. That’s a fairly reliable sign of a too high saddle.
On numbers alone, a 24” bike sounds big for a 6-year old. But I’m not there. Sizing and fit issues are easier judged visually.

Very likely. Or grow into it.

IMO, that would be more dependent on how he is able to handle the bike than the fit as such. If he has to stretch a lot forward-and-out to reach the bars, that would interfere with bike control. Perhaps enough to add an important amount of risk. However, at that age, the biggest contribution to risk comes from judgement error. I’m not sure if changing handling ability a few % would be important in the big picture.
Not saying it’s impossible, but it’s FAR more common to trigger knee issues by riding with the saddle too low.

hermanchauw

If he has standover clearance and can mount it fine, then just use it. I have seen kids riding adults fixies that are "too big".

hermanchauw

I am with you. The wheel size does not determine the frame size. Mini velos and 20 inch (and smaller wheels) exist for adults.

Iride01 

I can't reach the ground with both my feet when seated in the saddle. I'm just on a road bike though. Don't know if it should be different for a mountain bike.

But the norm for being stopped on a bike is to be off the saddle. I do sometimes stay in the saddle but lean to one side standing with one foot on the ground.