hub gears?

[mike]

I'm fed up with the mud clagging up my MTB drivetrain, it means I cant use most of the 'fun' lanes round here because parts are ankle-deep in wet mud and the last half of every ride is in 1 gear, and it takes about half an hour to clean the bike down when I get home - if I've managed to avoid bending anything.

So I'm gonna fit a hub gear.  The Shimano Alfine one looks rather good, few gears than a rolhoff ( but about the same weight and a damn site cheaper (about 120 quid vs. 850 for the R'f)

Anyone else tried this?  What else should I look out for?

[rogerzilla]

They have a torque limit, which means you may not get a real granny gear.  I'm running 44 x 21 on a Shimano Nexus 8-speed (Mrs Z's bike), which gives a 20"-something bottom gear and it's coping, but I wouldn't go any lower, especially if you pedal like Chris Hoy.

The Shimano ones need regreasing, or at least "dipping" every 2 years as preventive maintenance.  Neglect this, and by the time it's started to play up, it's usually knackered.  Few bike shops really understand them, and they're uneconomic to fully strip and fix, even if spare parts were available.

If these don't worry you, go for it.  The Shimano one is quite nice to use.

[PhilO]

The Genesis io uses a 32:16 set up, so presumably this is within the design parameters.

According to Sheldon's gear calculator, that's a range of 27.3 to 83.8 inches.

I manage adequately on a 47 inch geared SS in the Welsh Valleys, so I'd say that's plenty.

[mike]

The Genesis io uses a 32:16 set up, so presumably this is within the design parameters.

According to Sheldon's gear calculator, that's a range of 27.3 to 83.8 inches.

I manage adequately on a 47 inch geared SS in the Welsh Valleys, so I'd say that's plenty.

isnt the genesis a singlespeed? 

I recon down to 20" ish should be OK.

I would go SS but it's all quite flat round here, and there's quite a lot of road work so it'd be quite spinny....

[tonycollinet]

I will be getting a new commuter on the cycle to work scheme in January. It will have an alfine hub gear.

A friend at work has the nexus and likes it now that it has run in (felt a bit draggy when new). He has also used them in an electric car project with a local school (they have just won the national championships). On that project they have opened the gear up and put light oil in in place of the grease - but that does not result in a low maintenance solution.

One other point - I haven't tried it, but understand that the cable linkage is fiddly, so removing the rear wheel (eg for puncture repair) can be tricky.

[Craig]

The Genesis io is singlespeed, the Genesis io ID has an Alfine hub. According to this the io ID is 36:18, so the same ratio.

[rogerzilla]

On that project they have opened the gear up and put light oil in in place of the grease - but that does not result in a low maintenance solution.

It depends.  If the hub retains oil reasonably well (which is unlikely if it's designed to run on grease) then it's low maintenance in the sense that it should never need opening up again - just a few drops of oil occasionally like an old Sturmey AW.  It's trivial to drill the shell and fit an oiler, or just an M6 bolt.

Grease is all very well, but replenishing it requires at least a partial stripdown.

Rohloff take a different approach - their hubs have oil seals and the oil is literally changed every year by the owner.  A Sturmey uses a total loss system, maybe because nitrile rubber O-rings weren't available in 1902.  The Rohloff is designed to retain 50ml of oil; a Sturmey is designed to retain 10ml if you're lucky - it can't really contain any free oil because it leaks out round the ball ring/shell threads*, so you're merely aiming for a thick film on all moving parts, which is sprayed around a bit in use.  The Rohloff is more of a "bath", with a bit of free oil.

*I suspect new-fangled PTFE tape would make these seal pretty well.

[PhilO]

The Genesis io is singlespeed, the Genesis io ID has an Alfine hub. According to this the io ID is 36:18, so the same ratio.

Oops! That'll teach me to rush! 

[PhilO]

I would go SS but it's all quite flat round here, and there's quite a lot of road work so it'd be quite spinny....

If it's flat, you definitely don't need to go down into the low 20's...

In fact, why not go 'Twinglespeed'? 

[Notsototalnewbie]

One other point - I haven't tried it, but understand that the cable linkage is fiddly, so removing the rear wheel (eg for puncture repair) can be tricky.

The cable link on the Nexus is fiddly if you don't read the instructions and practise before you need to remove the rear wheel. I've had the back wheel off a few times and it's easy when you know how.

The only problem I had with it was that it was not low enough on hills (but then I am not a strong rider) so I've put a bigger sprocket on, because I don't care if I spin out downhill. I am rarely found pedalling on big downhills anyway.

[rower40]

Nexus wheel removal:
There's a very convenient hole in the rotating thingy that the gear cable pulls round.  Put a centrepunch in that hole, and turn it round, and bingo! out comes the cable connector.
I too fitted a larger sprocket (*).  Partly because I'm a overweight unfit lump, but mostly because the chain really was "a bit slack", and the brake reaction arm was at the limit of its adjustment. So the larger sprocket put the wheel position right in the middle of the adjustment, with the chain nice and tight.

(*) Is this an untruth? LBS did it for me

[Pneumant]

What about Charge bikes, they do a nice looking alfine hub bike called the Duster 8:

Charge. A bicycle company.

I'm very tempted too because the off-roading here is hellsih in the winter because of the  clay choking up the gears, I quite like the idea of something requiring a bit less tlc after every non-gooey ride too.

_{The Shimano ones need regreasing,}

Roger - what does this involve exactly? Will there be bits of hub pinging about my shed if I were to delve into an alfine's internals

[bikenerd]

I'm very tempted too because the off-roading here is hellsih in the winter because of the  clay choking up the gears, I quite like the idea of something requiring a bit less tlc after every non-gooey ride too.

I had a single speed for a while (in Oxford) but I didn't ride it enough to warrant having another bike in the shed.  Shame, as it was a nice old steel Rockhopper.  Not having to decake the front derailleur after a ride was great but riding on the inevitable road sections was super spinny.
If the spacing problem could be got around, and you were happy to use a rear v-brake, an old Sturmey 3 speed could work well.  Normal gear as 32:16, plus a lower gear for big hills and a higher gear for road work.
Wonder why no one has tried this?

[Pneumant]

I had Sturmey's on my pseudo racing bikes as a child ,  too many false neutrals and slipping gear triggers to make me want to have another one, plus I don't think they would take the torque of a low gear, the alfine hub sounds like it might be a lot better.....

[Pneumant]

Saw a very smart 'Moots' MTB with a Rohloff hub gear this AM, looked like a special, frame may have been Ti, had a Chris King Headset too

[PhilO]

Saw a very smart 'Moots' MTB with a Rohloff hub gear this AM, looked like a special, frame may have been Ti, had a Chris King Headset too

Aye. Moots are a high-end custom Ti frame builder. The most expensive bike I ever rode was one of theirs, round the test circuit at SSMM 3 or 4 years ago. It was £2200, frame only! 

And I hated it*! 

*TBF, since it was a custom frame this would have had more to do with my requirements differing from those of the owner, than anything to do with the frame quality.