hub gear for MTB ?

[RufusChucklebutty]

My gears went tits up a while ago and i havent had time to sort them out, i realized that i only ever use 2 or 3 gears on my commuting bike, in fact stuck on one is not so bad, so can i get a 26 inch mountain bike wheel for a fat tyre with a 3 speed sturmey archer hub ?

or could i build one ?

 

[Rickshaw Phil]

You won't find one ready built but it is possible to build it up. For example: parts here, here and here and instructions here.

The company I've linked to for the example also offers a wheel building service if you haven't done it yourself before. Others are available.

The big issue will be the cost. A custom wheel is usually going to cost more than a standard off the shelf one.

 

[Rickshaw Phil]

I need to add; you would also require a new single-speed chain, a chain tensioner if the bike has vertical dropouts (quite likely) a single speed chainset and the appropriate bottom bracket to give the correct chain line.

I hope you weren't looking for a cheap fix.

 

[SatNavSaysStraightOn]

not a cheap solution, probably better to fix what you have.
but from experience,
you don't need a dedicated single speed chain (our 14 speed rohloff hubs run on a 7/8/9 speed chain and did 9,000miles before being changed to identical chain).
you can do away with a chain tensioner if you go over to an eceentric bottom bracket - chain tension is not as important on hub gears but eccentric bottom brackets are not cheap (and I will add sometimes a pain in the ass - tighten you chain and you change the position of your feet vertically & horizontally so have to adjust seat post & saddle rails to compensate - around every 2,500 miles IME).

The good news is that a mtb wheel is fine with a nice wide tyre - our expedition bikes can run on 26x2.25 tyres if we want them to. (expedition bike being an off-road touring bike based around the mtb design but no suspension).

By the time you have done all of that, ££££ you won't want to be using it as an everyday commuter, as @Rickshaw Phil says, not a cheap solution, but it can be done.

Probably best fix the gear shifting and continue to only use 2 or 3 gears.

 

[SatNavSaysStraightOn]

Oh and finally you will need to change the way you change gear, so new gear changers, cables and other bits & pieces...

 

[RufusChucklebutty]

thanks for your replys, i should add i work on house clearances, and have a big pile of various MTB's that i strip the goodies off and make my one or two good bikes, iv'e never bought a bike yet, so i was thinking about spending about, er, nothing ! i can probably find an old 3 speed hub, i usually bin them, are the old ones worth saving ? i know they are pretty heavy. Any model to look out for ?

A Rohloff hub is so far out of my league it might as well be on the moon.

I could get into building my first wheel, if the Sturmey hub has the right holes for a MTB rim ?

So the plan is a cobble together job, then work out any problems.( i am a metal work engineer) I have a nice Dawes street spirit waiting for rebuild.

 

[Rickshaw Phil]

In the absence of further responses I'll give it a go; Yes it may be possible to build up this bike out of old bits but I've never done anything like this so this is all theoretical.

Firstly you'll need to check whether the hub will fit your dropout spacing. It may be that the dropouts will be too wide to take an older hub. If a steel frame, the stays could be narrowed to suit, but on an aluminium alloy frame this is not recommended due to the risk of fatigue failure.

Next: mountain bike rims commonly use 36 spoke holes so you'll need a matching number in the hub. (Very old Sturmey Archer hubs may have 40 holes).

It is unlikely you will find any spokes the exact length for the hub/rim combination to hand. The link I posted earlier includes links to a spoke length calculator. As you are an engineer I presume you'll have facilities to trim spokes to length and thread them for the nipples, but using new spokes and brass nipples will probably build a more reliable wheel.

As already mentioned, if you have verticle dropouts you'll need a chain tensioner. I don't know what others think but if building from spares I'd try using a rear derailleur as a tensioner for this application. You'll need to check what chain the hub sprocket will take as I don't know whether the Sturmey Archers will take the narrower multi-speed chains.

Although I have an interest and have toyed with the idea of building a hub geared bike I don't know much about all the various models over the years so can't advise you on which is best. I understand that most are pretty robust though as long as they've been kept looked after.

Hopefully someone more knowledgable than me can fill in any gaps I've left.

 

[RufusChucklebutty]

looks like it may be too much work to be a practicle project

 

[RufusChucklebutty]

iv'e found a possible bodge on this, the Pashley Mailstar post office bike has a 26 " rear wheel, with 3 speed hub gear, one should be easy to find cheap, i've seen a few about, if i TIG weld on new dropouts to a spare Ally MTB frame to suit, i might get somewhere ?