3 speed sturmey hub on kids 20" MTB

[twain]

Got an opportunity to get hold of a 20" wheel with sturmey 3spd hub on it.
got me thinking - my eldest son (6yrs) is of the age where i want him to ditch the stabilizers (that's a work in progress and he is autistic so i'm having to be extra patient while i find a way to tackle that respectfully), aside from that, i know he will struggle with gears - but - more so, he will become frustrated with not being able to pedal up hill on a single speed.

i picked up a Ridgeback MX20 recenlty - wheels are in a sorry state, so ideally need replacing or ill have to invest time refurbing.

so - i put to you RBers - would a sturmey 3spd hub on a 20" wheel and 3speed sturmey twist grip be a good compromise for gears / would it provide enough range to tackle gentle climbs (we will mostly be riding gentle path routes - nothing trail like)....???

most importantly, is there any reason i couldn't get the Sturmey hub/wheel to fit the Ridgeback MX20...(since i'm guessing it came from a Raleigh shopper bike - the wheel is Raleigh branded)

thoughts and questions please - im going to pick the wheel up tonight hopefully - the chap is only asking for £5 for it so will get it in the hope that my idea is workable....

bike/hub/grip twister as below...

 

[hamster]

No problem at all with the concept. The risk is that the wheel will be 120mm spacing and the frame 135mm. There are axles available though. SJS Cycles are your best bet.

 

[scottproonly]

Re:

I think it's a brilliant idea-if you can get that hub to fit!
Kes

 

[Bullpup]

Great idea. He may find the original style of finger shifter easier to use.

 

[shedobits]

Re:

Seems to be a great idea. You might have to give some thought to the cableing though. Thinking back S.A. gears needed a pinch clamp on the chainstay to hold the cable.

If the gearing is too tall for him you can always swap the rear cog or even the chain ring. As above SJSC would be a good place to start looking.

Good luck with the build and I hope he has years of fun riding with dad.

EDIT Twist grip may be better, forward to go downhill, back to go uphill.

 

[pigman]

Re:

The rim looks like its steel, so that may hamper braking ... even when riding over wet grass. Bear that in mind, more so if he's autistic, don't wanna spook the little fella.

I spent my childhood on a 3 speed sturmey. It never needed maintenance, so is good in that respect, but it would forever slip into neutral between 2nd and 3rd. I'm surprised I had kids after that. And the standard ratios aren't that wide a range, so work out what cog equivalent the bottom gear will be. I think middle gear is 1:1 and bottom is 0.75 of that if it helps. Maybe check this, it's a long time ago.

As a side issue, my eldest is mildly autistic and no matter how much I tried he never learnt with stabilisers and me holding him didn't work either. Then one day, he just scooted down a gentle slope himself, and on the second go he pedalled at the bottom of the slope and was riding. Once he wanted it, it took less than 5 minutes.

 

[shedobits]

Re:

A long time ago I read an article by a cycle mechanic who reckoned that S.A. hub gears never actually failed but were often lubricated with heavy chain oil which caused them to gum up and give problems. I'm not shure if S.A. gear oil is still available but that was what he recommended. I bet someone on here can add further information.

 

[twain]

Re:

Well I'm glad this looks to be a project worth fulfilling. I'd do whatever it takes to get my son riding.
I totally hear you on the 'when they want it, it'll take no time at all'. He's not severly autistic by any means (still undergoing assessment) but he's definitely got some traits (hyper emotional sensitivities, doesn't like surprises/ last minute plan changes can be traumatic for him..)

I didn't get the wheel tonight, but will tomorrow.

Am moving house next week so this next month will be a research and prep month, then once I'm settled in the new house (with extra large garage) I'll be set to get this well underway!
I'm pretty sure cable guides/attachments for sturmey hubs are around, or at least can be fabricated.
I'm pretty excited by this. And if it works well I have another younger son I can do this all over again for

 

[twain]

No problem at all with the concept. The risk is that the wheel will be 120mm spacing and the frame 135mm. There are axles available though. SJS Cycles are your best bet.

Could I use axle from the MX20?

 

[pigman]

Re:

Dont forget you will need to solder a stop onto the end of the cable where it fits inside the female barrel adjuster that screws onto the toggle chain for the hub gear.

The axle is hollow and if its old skool sturmey might have imperial threads for the nuts and cones. I'm no expert, but the guys in the road section would know better (if you dare venture there)