Youth mtb build - advice please

[TommyC]

I’m building a nukeproof Cub Scout 26 up for my 9 yo boy and need some advice on the drive train.

First of all I want to put 12 speed on it, as I have an XT derailleur I can use, but does he really need it? If I go 12 speed, am I correct in thinking I need a microspline freehub? My intention is to go with 30/32t chainring and max on cassette at 41/42. Is that ok?

Also, on the look out for wheels I’ve found a nos set of stans flow ex with speed tuned hubs (3 pawl, 24 point) and some unbranded rims on wheelhut.co.uk with unbranded hubs (6 pawl, 72 point) at similar prices. Anyone any experience with these wheels? Does my 9yo really need 72poe on his hub?

 

[VWsurfbum]

Buy the cheapest lightest wheels you can, buy the 12 speed cassette that fits the free hub, it could be any of the types. HG/XD/MS there will be a cassette available for it.
On an anlalogue on a younglings bike the 3 pawl 24 point will be fine.

 

[TommyC]

So you can get 12s for HG?

 

[Montana St Alum]

Do what's cheapest. He's 9. He'll hit his growth spurt soon.

 

[VWsurfbum]

So you can get 12s for HG?

Yup, this is just the first one that came up. i've used these on the Eebs no worries so on a smaller persons bike even better.
12 Speed

 

[VWsurfbum]

12 Speed 11-50T Cassette For Mountain Bike MTB & Road fits Shimano/Sram - Hyper Glide

Air Bike is delighted to announce its range of cassettes, designed in close collaboration with one of the world's leading manufacturers. Our distinctively designed Hyperglide-style Cassettes incorporate specially positioned shift ramps and tooth profiles for improved chain control during...

airbike.uk

 

[TommyC]

Do what's cheapest. He's 9. He'll hit his growth spurt soon.

He’s on a 24” at the mo which tbh is still plenty big enough for him. Just decided to build the 26” because the frame was £72 on crc.

Both these set of wheels are around the £160 mark. Can’t find much cheaper as I need thru axles.

 

[TommyC]

Yup, this is just the first one that came up. i've used these on the Eebs no worries so on a smaller persons bike even better.
12 Speed

I’m torn as the 12s stuff is more expensive, but I have the derailleur already. The 10s stuff could still get me up to a 42t on the back. Any suggestions on a cheap 10s derailleur?

 

[steve_sordy]

Go with 10-speed transmission. It's a lot cheaper, more robust and has better ground clearance! With the smaller diameter wheels, the last thing you want is an expensive 12-speed mech being so low to the ground!

I had a 29" rear wheel and I still smashed two mechs. It is not just the expense, it's the inconvenience as well.

 

[TommyC]

Went 10sp Shimano in the end. Just waiting for a few more bits to turn up to finish it for Christmas. Went over budget (£770 total) but he’s got fox 34’s, Shimano 10s matched group set, 85mm dropper and some bling!

 

[VWsurfbum]

Needs some blue nipples and a blue seat clamp.

This was my daughter's build I did for her before she got an Eeb. (and before she went all teenage girl )

 

[TommyC]

Seat clamp is on the way. Don’t fancy rebuilding the wheels!