My sons first 26" wheel MTB (custom build)

othello

My 8year old currently rides a 24" wheel Specialized Hotrock FSR. He is getting a bit big for it as the frame is very dropped, and a while back I got thinking about his next bike.

The easy choice would have been an Islabike Creig 26. Very low frame, great kit, lightweight etc. But I wanted to do something a little different, and have a bit of fun myself in the process. So I went for a custom build, a mix of new parts, eBay bargains and bits out of my spares box. The aim? A really lightweight, fast bike with good components, so as he grows I can swap the frame out.

I ended up with this (almost finished, just a few little bits to do): A custom build 13" frame Specialized Rockhopper.



Frame: 2007 Rockhopper 13"
Fork: Rockshox SID race
Wheels: Stans Crest on red Superstar Switch EVO hubs
Tyres: Racing Ralph
Brakes: Shimano Deore and Deore LX
Discs: 160mm
Stem: Deda 60mm
Bars: On-one
Shifter: Deore 10 speed
Chainset: Lasco 152mm arms triple with outer removed
Cassette: SLX 10 speed 11-36
Rear mech: Shimano Deore XT shadow
Pedals: temporary (SPDs off his old bike to be swapped over)
Seatpost: Silver alu off eBay
Saddle: Old specialized kids saddle

Weight: 10.38kg (22.8lb)

All in all I think it has gone pretty well. The 13" frame is a good fit, but the front end is a little higher than I would like, though he seems OK on it. It looks how a 29er looks on a short adult!

Ideally I want to run the bike as a 1x10 (with a chainguide). The front ring is a 32t and I'm hoping with the 11-36 cassette there is enough range for him. If not, I'll make it a double and he can use the 22t inner too.

Getting decent cranks that were short enough was the biggest challenge. I ended up ordering from the USA for a set! But really worth it for his size.

Money-wise it has worked out pretty similar to the Islabike. I did spend a bit on the wheels, but rolling weight is really important for his weight (or lack of it) and they will carry to the next bike. The frame was a bargain at £40 off eBay -- not the lightest but still straight and in pretty good nick.

I'm pleased with the weight, which is approx 1kg lighter than the Islabike.

bartimaeus

Very nice - and very light!

I just got my son - who is 11 - a similar Rockhopper, but very much 'stock' and so much heavier. I better not let him see your post as he'll want SIDs and Crests on his bike. Sub 23lbs is very good. I also went for a short stem and some narrower on-one flat bars to get the front end a bit lower and the reach about right... it makes a big difference.

othello

Bartimaeus wrote:

Very nice - and very light!

I just got my son - who is 11 - a similar Rockhopper, but very much 'stock' and so much heavier. I better not let him see your post as he'll want SIDs and Crests on his bike. Sub 23lbs is very good. I also went for a short stem and some narrower on-one flat bars to get the front end a bit lower and the reach about right... it makes a big difference.

Thanks

Interesting seeing your photo and the comparable heights of the front end. The SID stanchion to crown height is much more than the stock forks, which is raising the height. I need him to try it out and see how he gets on, otherwise if its too big it will have to go in the shed until he grows!

bikaholic

Not for my son, but built for an eight year old (or is he nine?) nonetheless:









The kid rides it with about three inches of exposed seatpost (I always take pictures to show the full capacity of seatposts, so it's raised high in the pictures).

arthur_scrimshaw

Bartimaeus wrote:

Very nice - and very light!

I just got my son - who is 11 - a similar Rockhopper, but very much 'stock' and so much heavier. I better not let him see your post as he'll want SIDs and Crests on his bike. Sub 23lbs is very good. I also went for a short stem and some narrower on-one flat bars to get the front end a bit lower and the reach about right... it makes a big difference.

I recognize that place, Kingley Vale just before the steep slippery bit!

bartimaeus

It is indeed Kingley Vale - right at 'the humps', looking down towards Stoke Clump and Chichester Cathedral. We came up from Walderton along the back and under 'the bar' - so a pretty decent climb.

The Rookie

Can you get riser bars with a zero upsweep and run them inverted, that will drop the front a bit (but maybe look a bit daft!

othello

The Beginner wrote:

Can you get riser bars with a zero upsweep and run them inverted, that will drop the front a bit (but maybe look a bit daft!

First ride on it today on some local trails and he coped very well with it.

I think the front height issue is down to the forks in part. The SIDs are set to 100mm travel and if I get them put back to 80mm that might help him. Though he said it was fine -- it just looks tall on him as he is quite small!

Other thing to note from the ride:

* He is so light (just over 4 stone) that he isn't getting full travel out of the forks even with very low air pressure

* He is a fraction over geared running 1x10. The lowest he has is 32x36. He was able to climb some hills he does normally, but that was down to the lighter bike. I could tell he was pushing a bit harder than he needed to. The Islabike Creig runs a 28x36 which is pretty optimum. But I can't get less than 32t on the middle ring. I didn't want to run 2x10 but having the 22t inner as a fallback might be the only way.

felix.london

what a great little bike!

Just gave my girls Hotrock to friends as she's way too big for it now...she's 14!

Been looking at full-suss frames for her but your little 'hopper has got me thinking...

othello

felix.london wrote:

Been looking at full-suss frames for her but your little 'hopper has got me thinking...

The key is finding a small frame -- it took me ages to find one on eBay. Then you can spend as much, or as little, as you want building it up.

The Rookie

othello wrote:

He is so light (just over 4 stone) that he isn't getting full travel out of the forks even with very low air pressure

The compression damping will be a bit too stiff as well (even on min), maybe put some lighter oil in? Also he's probably too light to open any floodgate?

Gearing wise, tough call, the granny would help but you'd be putting a third of a kilo on the bike, probably route selection and getting him used to it is the best way forward?

othello

The Beginner wrote:

The compression damping will be a bit too stiff as well (even on min), maybe put some lighter oil in? Also he's probably too light to open any floodgate?

So would putting in lighter oil do the job? I've not serviced forks before mind!

The Beginner wrote:

Gearing wise, tough call, the granny would help but you'd be putting a third of a kilo on the bike, probably route selection and getting him used to it is the best way forward?

I might get a 28t inner ring as you can get them for a 64 BCD. That should bring the lower range down a bit and allow him to spin a little more.

The Rookie

Lighter oil will reduce the damping yes.....a simple oil change is easy, remove cap, poor it out, refill!

I thought of a 28T granny, but you'd have to look at correcting the chainline as well!

othello

The Beginner wrote:

Lighter oil will reduce the damping yes.....a simple oil change is easy, remove cap, poor it out, refill!

I thought of a 28T granny, but you'd have to look at correcting the chainline as well!

Will I really need to alter the chain line? If I had a front mech on there the bike could use the granny ring anyway.

The Rookie

Yes but not at the top end of the cassette (smallest gears).....