With Christmas on the way our eldest (almost 10) wants a mountain bike, fair enough.
Now we went to Halfords yesterday to try a few for size (don't really want to buy it there unless someone can convince me otherwise)
He currently is a good fit on the largest kids bike 24in wheels but its almost too good a fit ie he'll probably be grown out of it in no time.
We tried him on a 26in wheel 14in frame adult bike and though it looked too big he could mount it and ride it no problem.
Now our dilemma is do we buy him a bike that is admittedly just a bit too big or do we buy him a he will have grown out of easily in 18 months??
I have to add the adult bike was lighter and better specced for the same sort of money but past experince tells me kids bikes are chucked together
with cheap bits anyway!
I'm not looking for a definitive answer but if anyone has experienced a similar dilemma I'd be interested in their opinions.
Also if anyone can recommend a good bike to go for or place to shop I'm all ears
personally id steer clear of the likes of halfords. try a local bike shop.
Depends how much money you have... personally I would go for the proper adult bike... will last him a while!
Look on ebay, there are loads of second hand fairly good mountain bikes.. the older specialized rockhopper should not be too much....
Do NOT buy a suspension bike from halfords, they are utter cack..
If it was me I would go for the adults bike. It'll last him longer. Unless you spending a pile of cash then please don't buy a dual
suspension bike. There absolute pants.
They have half decent bikes at Halfords in my opinion.
Adults bike is probably the better choice given he's probably about to grow pretty quick. Agree withall above about full suspension.
Try a local bike shop.They'll have better quality bikes that in the long run will save you money. As an alternative to Halfords do you have a
Decathlon near you?Thier bikes are usually good value for money and decent quality.
You definately want something he can grow into. We went through this with my little sister a few years back. Her bike has now lasted about 3 years and
she still fits it fine
Thanks for the replies, that was my thinking, just thought it looked wrong when he was on it yesterday!
f*** this f*****ing mobile broadband, just lost the poo I typed 
rule of thumb:
road frame: trouser inside leg len less 10 inches or 1/3 height
mtb frame: subtract 5 in from above.
for 14 in mtb would mean your son is 4 ft 9 in or taller.
I was on 21 in adult road bike when I was 11.
Go for adult bike as there is still time for him to grow before Christmas
It's about fit first if you want him to control and enjoy the bike. You can get a 26in wheel bike with a 14 inch frame and smaller. I still ride
one as I'm only 5'6". All the kids to late teens ride tiny frames cos it's cool but would not be seen dead on a bike with 24in
wheels. No cred at all.
Go to a proper bike shop. With a half decent bike he gets lightness, good parts,decent fit and you can fit a longer seat post as he grows.
In my view, best option is a Islabikes Beinn 26. Not the cheapest but will last. I've got one for my son and I'm very impressed. It's
designed for childern, not just a small full size one.
Islabikes
That is a nice bit of kit. Isla makes some nice stuff (always has) and you'll get a proper bike rather than an expensive toy.
She wasn't a bad rider either and a nice person to boot.
adrian
Halfords :
If you have a local Halfords with a propper Bike Hut section, you may get dedicated bike staff, who are said to be very good. Normal Halfords rules
apply if not 
Halfords have the Bordman bike range. Generally good value with good kit.
Carrera ones not so good.
+1 for the Local Bike Shop option.
+1 for Isla Bikes - very good quality, designed with Kid friendly geometery. We recommend / subsidise them for our kid's cycling club. They have
a trade-in scheme when kids outgrow them.
The LoCost option is to buy the adult one, but the down side is they will be less able to handle it. Riding in a straight line is one thing, but we
have a lot of experience of watching kids with oversize bikes struggle to get around our MTB and Cyclo-Cross courses (larger turning circle, harder to
control, etc) when compared to "correct" sized bikes. In a couple of cases we have seen kids ditch their smart adult bikes and go back to
their old bikes because they are "more fun" to ride.
Tim.
Don't knock full sussers guys because of personal preference
Cheap full sussers are c£@p but like anything you get what you pay for.
It's the same with hardtails - i've had both and currently ride a hardtail . . . but I wouldn't say that one type was sh1te over the
other. just like the old bec cec thing
Steve
quote:
Originally posted by gottabedone
Don't knock full sussers guys because of personal preference
Steve
Loads for me to at there, many thanks to all
Gadget Show did a test on sub £100 mb's in conjunction with some testers from a UK mb magazine. The best by far was a non-suspension bike they were all really impressed with, think it was a Rockhopper but can't really remember, might be worth checking their web site.