Three Speed MTB Hub Gear

I’ve been thinking about the potential of a three speed internal hub gear that I could use on my mountain bike and my relatively long distance commuter for some time. Something that retains most of the elegance and strength of a single speed, but with a bit more range and minus quite a bit of the weight of something like an Alfine (potentially over half a kilo). However, the three speed hubs that are currently available tend not to be particularly well sealed from the elements or up to the loadings of off-road use – a ride around W2 at Afan on a stock three speed hub had the cones undoing themselves and dirt sauntering in to the bearings.

One option that I’ve been considering is to design a new hub from scratch, but I lack the time and resources to do this. Given that the general mechanics of a three speed hub are well proven and that the same general design is used by all the manufacturers, an alternative option is to use a number of the key components from an existing hub while replacing or modifying those parts that are not up to the specific job that I want to use it for. This latter option is what I’ve chosen to do.

Shimano, Sram and Sturmey-Archer all make 3-speed hubs in 135mm O.L.D. with a disc rotor mount. Of these three, Sturmey-Archer have the best spare parts support and the most shifter options as well as a strong heritage when it comes to making hub gears. I therefore chose to use a Sturmey Archer S-RK3 as a starting point. I decided not to go for the equivalent rotary hub (the RS-RK3) as the shifter options are more limited and the clutch mechanism more complex, although the fact that the hubs workings are placed completely within the frame is a benefit (although in practice the standard chain driven arrangement is still far less vulnerable than a standard derailleur arrangement even if it does appear a little crude).

So I’ve bought myself a Sturmey Archer and I’ve had some of the existing hubs parts machined to accept some cartridge bearings, along with a few new parts to make it all work together. It’s very early days at the moment, having only just built it up into a wheel and completed my first ride on it. After 44 miles in the Surrey Hills everything is still humming along nicely, but it won’t be until I’ve subjected it to at least a good winters worth of abuse that I will know whether my little experiment has worked. I’m already looking to change the design of the top hat axle bearing seats so that they can better protect the cartridge bearings.

There’s probably a very good reason why the big manufactures haven’t made a three speed hub suitable for off-roading – most likely because I’m the only person on the planet odd enough to want one! But I thought I’d share what I’ve done to find out whether I truly am alone in thinking that this is a great idea or whether anyone else might be interested in one?

Modified Sturmey Archer 3 speed hub with cartridge bearings by Oli Davey[/url], on Flickr

Modified Sturmey Archer 3 speed hub with cartridge bearings by Oli Davey[/url], on Flickr

Modified Sturmey Archer 3 speed hub with cartridge bearings by Oli Davey[/url], on Flickr

What’s the gear range like on it? If its wide enough, I’m in!

Had one years ago on a town bike. There’s, uphill, level and downhill. Smaller front cog possibly more useful on an mtb, sort of like a singlespeed with 2 x bailouts?

As it happens, I had similar thoughts, too.

For ‘recreational’ mountain biking, where having the ‘perfect gear’ at every moment isn’t such a big deal, a 3 or (as I was thinking 4) sped hub gear sounds perfect. Ideally, it should be possible without the planetary gears of a Rohloff so should be efficient and clean.

Rachel

Sounds good.

An old thread that sort of discussed 3 speed hubs and mentioned the very poor sealing –
http://singletrackworld.com/forum/topic/3-speed-igh

Double post.

Gear range maybe 100% IIRC?

Swavis runs one I think. I can see the appeal if your riding is a bit much for single speed.

Would be interesting to ride one of these. Gears are over-rated I think. 10 speed this and 11 speed that… 3 gears is all you need for 95% of rides. It’s basic, but efficient.

Excellent work.

I have a three speed sturmey on my road, commute, long rides bike. Totally rate it. Only faff is rear wheel removal.

Love the idea of using one off road. I’ve converted mine to running in oil lubrication, knowing that the seals tend to leak a bit.

With your mods it should be spot on running oil.

I did that with the 5sp SA. but it didn’t work that well. I was running rim brakes.
I then tried a shimano nexus 3sp, but it died.

3sp SA seems more reliable, judging from the one on the brompton.
thing is, the weight saving isn’t there really. it’s about 1kg for the hub, that’s about the same as 1×10/1×9.
I settled on a hope SS with 1×7, really liked it.
Always wanted to try a hammerschimdt/stumpf 2×1.
it’s a nice idea, I just don’t like the shifting lag. nor the few points of engagement.
the fixed gear one with a shimano/wi freewheel would shift faster/pick up quicker.
I’d be curious to try that out, but I don’t think they do a disc brake version.
I like the idea, and it looks great.

I want much the same.

The 3 speed ratios are exactly what I want for my general purpose bike (road and offroad use). A light, strong hub.

With the direct set at about 60″ it is close to the traditional ratio for road in hilly areas, the low at 45″ is more or less what I’d use on a SS mtb, and the high of 81″ is roughly what I set my fast SS road bike at.

In other words almost all contingencies are covered for general cycling. At the moment I’m using an Alfine 8 and really don’t need all those gears.

I have been trying to get my hands on a RS-RK3 for ages, so if you know of a source, let me know please.

Sounds like the perfect setup.

Good work. It seems intuitively a good idea. What does the hub weigh?

That modification also means we could go back to using oil in the hub. 🙂

That modification also means we could go back to using oil in the hub.

Funnily enough, I was wondering whether it would be practical to fit a grease nipple to the hub shell (as has been done for Shimano hubs)

I have a cunning design for a double-speed setup that doesn’t use planetary gears and is efficient.. must create kickstarter account .. 🙂

I put my money down for one of these earlier in the year Efneo 3speed crankset[/url].

Figured it was worth a risk on Indiegogo. 🙂

3 speeds at the crank means the rear hub can be a light singlespeed and the bike’s weight will be balanced.

But from my previous experience with Sturmey-Archer 3 speeds, they are my preferred option. I have 80 year old+ Sturmey hubs that still ride perfectly.

theonlywayisup who posts on here tried a 5-speed SA hub (with disc brake) off-road but didn’t get on with it and sold the wheel to me for use on my frankenbike commuter. It’s fine round town but is a ballache to set up and perpetually seems like it’s not perfectly adjusted. Could just be my ham-fisted mechanicking but I wouldn’t fancy it off-road. 3-speed hubs may be better.

oh i like the look of that!

looked into 3 speed hubs and found the same issues with sealing
myself before i went 1 X 9 on my singlespeed…

i dont even think id need three gears really.. just my normal singlespeed gear ratio and then an easier climbing gear.. so that double speed idea sounds like a plan molgrips.. 😉

very interested to see how well it holds up..

i dont even think id need three gears really.. just my normal singlespeed gear ratio and then an easier climbing gear

The SRAM Automatic looked promising for this (two-speed planetary hub, shifts when the hub rotational speed passes a certain point) but the sealing is meant to be bobbins, and the shift point is only adjustable by taking the whole thing to bits and tweaking the shift spring – more here.[/url]

I like the idea of a light-ish, wide-ish range sealed three speed hub 😀 I love singlespeed, but sometimes would also love a panic gear or two!

I use a 3 speed Nexus for hilly terrain on cargo bike, will check the ratio later as it slips my mind. Always spins out downhill but I don’t mind that, it’s like single-speeding, yet not. So far ultra-reliable.

*Thread bookmarked

kayla1 – Member
I like the idea of a light-ish, wide-ish range sealed three speed hub I love singlespeed, but sometimes would also love a panic gear or two!

My thinking is not so much based on having gears to be used all the time, but because I prefer to ride to my trails, I want a gear for the road (direct) and one for the trail (low). The high gear is a bonus – sometimes there are downhill bits on the road. 🙂

I would probably stick the changer on the seatpost because it would only be needed when transitioning from road to trail and vice versa.

I have played around with dinglespeed to do this, but ended up not changing the chain over because of the faff and the grease, especially when it’s raining.

oliverdavey80 should post his hub here too[/url]

Also, if it’s not something he is planning to take commercial, it would be great if we could have the dimensions he used for the conversion, or the name of the company that did it.

MrNice – Member
theonlywayisup who posts on here tried a 5-speed SA hub (with disc brake) off-road but didn’t get on with it and sold the wheel to me for use on my frankenbike commuter. It’s fine round town but is a ballache to set up and perpetually seems like it’s not perfectly adjusted.

It’s almost certainly a cable problem and not a hub problem (unless you have ridden it extensively maladjusted). Try a new cable.

The only problem with the 5 speed is that it is really heavy – designed for serious abuse on industrial bikes etc.

Whilst I admire your enthusiasm and innovation, and as an ex SS-er I can see the appeal. But you’ve missed the boat really. 1x systems have pretty much made this sort of gear system redundant for most practical purposes for most mountain bikers. Derailleurs are cheap, light, mostly strong (I’ve never broken one in 20 years although some others seem to think they’re the most fragile things in creation ever) and efficient. After-market cogs and expanders have made custom cassettes possible, so I can tailor them to suit my needs.

You may not ‘need’ 10 or 11 speeds but if it’s no heavier than your 3 speed. with none of the possible drawbacks, why would I artificially limit myself?

Same as planetary hubs, internal hubs, belt drive…interesting but pointless all of them. They have limited appeal, as they are not better, just different, almost always no cheaper, or actually more expensive that what they’re trying to replace.

Good work oliverdavey80. I’d definitely have one of those, in fact I reckon with a pair of suspension forks and one of those hubs I could use my current rigid SS as my only MTB.

most likely because I’m the only person on the planet odd enough to want one!

Appears not – looks like plenty of interest.

….whether anyone else might be interested in one?

Does this mean if it gets through the winter you might make a batch for sale? Put me down for one if so, 32h if possible!

edit – is the middle gear closest to the normal SS ratio? It’s been a long time since I had a Sturmey Archer bike. I’d have an extra hill gear and decent ratio for road sections.

nickc – Member
…Derailleurs are cheap, light, mostly strong (I’ve never broken one in 20 years although some others seem to think they’re the most fragile things in creation ever)…

When you can show me a derailleur setup that is 80 years old and working perfectly*, I’ll believe you.

Derailleur gears are consumables, hubgears generally aren’t. 🙂

*And likely clocked over 100,000 miles.

With the ever increasing cost of normal gears I can see this sort of thing becoming more popular

tthew – Member
edit – is the middle gear closest to the normal SS ratio? It’s been a long time since I had a Sturmey Archer bike. I’d have an extra hill gear and decent ratio for road sections.

Depends how you set it up, IIRC the middle 1:1 gear is direct drive and thus the strongest and incurs the least wear.

Derailleur gears are consumables, hubgears generally aren’t

I once did a spreadsheet showing payback on just the initial capital spend on a Rohloff. and I think even replacing the whole “normal” drivetrain 3 times, it still took 10 years for the Rohloff to pay for itself, and that was allowing for a front mech and chainrings, which are no longer an issue making the payback even longer.

Not a massive inducement to change is it?

A great idea but the point where the little chain connects to the hub might be problematic as a contaminant ingress point as well a point of extreme stress changing down to a lower gear under load while honking up a hill.

I set mt Puffin up with a 3 speed hub. It’s a weighty beast but other than having to check the bolts are tight it’s never been a problem.

nickc – Member

Derailleur gears are consumables, hubgears generally aren’t

I once did a spreadsheet showing payback on just the initial capital spend on a Rohloff. and I think even replacing the whole “normal” drivetrain 3 times, it still took 10 years for the Rohloff to pay for itself, and that was allowing for a front mech and chainrings, which are no longer an issue making the payback even longer.

Not a massive inducement to change is it?

You’re coming at it from the wrong angle – folk interested in THIS hub (Rohloff is totally different in terms of cost, weight and gearing) aren’t comparing it to a 1 x 10 or 11 etc. They are happy to accept a few gears for less maintenance, costs and hassle.

So give it up!

EDIT

OP do you know that those bearings will cope with the side loads OK? Have you sealed ones in the NDS also?

I don’t think the shifting chain is an issue – you won’t be able to shift while climbing IME.

I have never seen a 5s SA that’s shifted reliably.

I wonder how well the Brompton BWR hub might work wiht way wider ratios? 28H only 🙁

I like the OP’s idea and the fact that he’s gone to the trouble of trying to make a SA 3 speed hub more weather tight and MTB appropriate.

I have been taken with the idea of an SA 3 speed bike in the past, I’ve got a couple of old hubs (Non-disc) I bought from fleabay with the intention of building something up to try ages ago but never got round to it.

I think if I was going to build a hub geared MTB up now though it would probably be used as an excuse to try out a Nuvinci N360, which apparently has a range not too far from a “normal” 1×10 drive but of course without any indexing or mechs… Not a cheap experiment, or one that I have any burning desire to undertake right this minute though…

From Sheldon Brown –

Old English The common Sturmey-Archer three-speed hubs provide a direct drive middle gear, a high gear that is 4/3 of the middle gear, and a low gear that is 3/4 of the middle gear.

so, OP,

They are happy to accept a few gears for less maintenance, costs and hassle.

So give it up!

But the idea that they are less maintenance, cost less and are less hassle isn’t really true.

So, no I won’t as this is, y’know, up for discussion. Sorry, if that bothers you.

It’s not better, it’s not worse, it’s just different

I would love a two speed fit and forget hub for off road. I have not used gears for over 10 years and while I could compromise on the road with a happy medium it is not so easy on MTB as I ride 60/40 off road/road on the loops I do.
The off road is covered with one gear and I am happy with that but the road sections are a slow drag and need something 10-15 GI higher.

Problem is that one of the draws of SS is simplicity so adding another cable, lever etc,. goes against my ethos!

I ride my SS to the trails too, so something like this would be brilliant.

nickc – Member
But the idea that they are less maintenance, cost less and are less hassle isn’t really true.

Hos so then? You’ve quoted figures relating to Rohloff, SA is entirely different, 1/10 the cost!

My point is here’s a thread with folk who are interested in SA, you’re alone here telling them gears are better…but no one’s really interested in that opinion.

.but no one’s really interested in that opinion.

I am.

The point of threads like this is to expand the knowledge base, not to rely on assumptions. You find an alternative that is all those things (cheaper, better, less maintenance and hassle) than a derailleur and folk will be interested, but unless ideas are challenged, and stand up to those challenges, we’re no further forward.

So, without some-one saying BUT… on threads like these, then it becomes an exercise in self-delusion.