Hub gears

[FatMog]

I hope you'll forgive me posting this here - it's not about electric bikes but I'm sure someone will know the answer and you're such a helpful bunch...

Having made the decision to sell my lovely sprint cos I can't justify the new battery, I'd like to give normal cycling another go and to that end took out my trek comfort bike for a spin. Unfortunately one thing I have taken away from the leccy bike experience is that I really like hub gears. I know they're not to everyone's taste but they suit me, and I found the 24-speed derailleur a lot of a pain in comparison. I also found that the trek felt really cramped after the sprint - I guess it's a smaller frame.

So what I'm thinking is - sell both bikes and and buy another pedal bike that suits me better. I am delighted to see that sit-up-and-beg granny bikes are very de jour right now so I'm considering something dutch or perhaps a pashley.

But - and here's the meat of the thing - whatever I buy might only come with a measley 3 speed hub. As I (dimly) understand things, it is possible to unbolt the bolts and slide out the inner gubbins and replace them with a differently-geared hub. Thus if it came with a 3 speed nexus would it be possible to easily replace it with an 8 speed nexus, or the shimano alfine? Ditto with sturmey archer, or sram? And is it possible to directly replace, say, a 5 speed SA with a shimano?

This last question is because pashleys come with a 5 speed SA and the 8 speed SA appears to have a bit of an odd gear spread. On my 7 speed nexus, I think goes something like - please forgive the non-techie terminology - gear 4 is roughly 1:1, 1-3 are under this ie. easier up a hill, and 5-7 are above it. The 8 speed SA starts at 1:1 on gear 1 and then everything else is above it. Given that I am completely unfit and have some hills on my route, I think I'm gonna need more help than that!

Otherwise, I guess if I went with something like the 5 speed I could maybe change the sprocket when I got it to lower all the gears while I attempt to get fit, and work up to changing it back when (if!) that happens.

Opinions, advice and comments please!

 

[flecc]

There's no interchangeability between the Nexus 3 and the much later 8 gear hubs, or any other of their hubs for that matter, since the 3 speed shell is much smaller diameter. The 8 speed is very much larger than any of their previous gears in fact. Few bikes fit the 3 speed Nexus now, though the Dutch in their flat country sometimes do, most hub gear bikes using the 7 or 8 speed models. There's also no core interchangeability between brands or within other brand models.

The newer 8 speed Nexus gearhubs are very much more efficient than the older 7 which has no direct 1/1 gear in fact, just one rather close.

The very odd Sunspeed Sturmey 8 gear hub arrangement means that maximum efficiency is obtained in bottom gear, but that's at the cost of the maximum inefficiency being in the upper gears you mostly use. Another problem with this odd system is that it requires very small chainwheels and large rear sprockets since all the changes increase the gearing, meaning the ratios have to be reduced at the chain transmission. In fact one company now makes a Nexus mount "spider" that takes the smaller chainrings so that an adequate range of rear sprockets is available for those with larger chainwheels!

I'm a long term fan of SRAM hubs, the 3 speed being the most efficient hub gear on the market, but the 5 and 7 speed designs are very long in the tooth now and their slow gearchanging is barely acceptable now. Their new i-motion 9 speed hub gear is very much better in this respect, though still not as slick as the Nexus changing, and it's expensive.

The one to go for is probably the Nexus 8, either the premium or top of the range Alfine models, the standard one seems to have been dropped now. These are reasonably priced, efficient and reliable and probably have the widest range of dealers knowing how to service them.
.

 

[FatMog]

OK thanks flecc - to sum up, if I got a traditional bike with less-than-satisfactory hub gears and wanted to upgrade, I'd have to have the rear wheel rebuilt around the new hub with corresponding braking upgrades, roller or v-brake or whatever? An 8 speed coaster brake hub just scares me!

All sounds way beyond my very limited spanner skills and pretty pricey, so I guess I'd be better trying to find one off the peg unless I can find something second hand.

Just need to sell the other(s) first...

 

[flecc]

Yes, a new gear hub means a wheel build, but the supplying dealer will do that for round about £25, often including a new rim.

I don't rate any of the integral brakes as much good and can't stand coaster (back-pedal) brakes. Drum brakes work ok but they've nearly all vanished and Shimano push their rather weak roller brakes now. If you have rim brakes on an existing bike, I'd stick with those, particularly if you're having a new rim built onto a replacement gear hub.
.

 

[FatMog]

Thanks flecc. Plenty to think about! Gave the sprint a minor wash n brush up ready for it's ebay apperance... I'll be sad to see it go. When I sat on the push bike the other day I thought it's brakes were binding on, it seemed so much more effort!

 

[flecc]

Yes, they can come as a very big shock after an e-bike!

At least it shows just how much the motor was doing previously.
.

 

[JamesC]

Hi Fatmog
Building a little onto Flecc's replies, I am also a fan of the Shimano 8 speed hub gear, and have built up two wheels with the Nexus version.

As Flecc says, there are 2 versions:
a) The Shimano Nexus 8 speed hub, designed for the Shimano roller brake or rim brakes.
b) The Shiimano Alfine 8 speed hub, designed for a disc brake or rim brakes.

Internally, the latest models of each version are very much the same, but the Nexus is considerably cheaper.

From what you say, it is unlikely that you will pick a bike with disc brakes, so the Nexus would be a good choice. However, it is more commonly available for 36 spoke rims, where the Alfine is the one to use with a 32 spoke rim (mountain bike !)

Assuming the bike of choice has 36 spoke rims, then your local bike shop would be able to define the spoke length to suit rim and hub, and build up the wheel with a new hub gear. I can give you details for a Mavic A319 rim, which is 700C and suitable for rim brakes.

The Shimano 8 speed hub has to be matched with a Shimano 8 speed shifter. This can either be rotary (often associated with the Nexus hub) or up/down lever (often associated with the Alfine hub), but either will do.

A v large cycle outlet in Germany, Rose Versand, deal happily with the UK and happen to do a complete hub package when considering an upgrade to the Nexus 8 speed.

The package includes:
Hub gear SG-8R36 (excellent), rotary shifter & cable, cassette (where cable meets hub), 19T sprocket, non rotation washers blue/green, competitively priced at 144 euros + shipping.

Note that the blue/green pair of non-rotation washers are for vertical dropout slots in the frame. For horizontal slots, you will likely need the black/grey washers.

Unlike Flecc, I quite enjoy the Shimano roller brake such as fitted to an ezee Torq. Particularly good in wet weather. If you choose to go that route rather than rim brakes, then you would need the Nexus Roller Brake, available from Shimano outlets such as Petra cycles.

James

 

[FatMog]

Hi James, thanks for taking the time to reply. I think you're right, the shimano 8 speed does seem to be about my best choice and I too am used to roller brakes since there's one in the sprint. However I know what flecc means cos I nearly shot over the handlebars on my recent trek outing when I hauled with my sprint-esque enthusiasm on the brake levers!

Unfortunately even modern dutch bikes are still endowed with a 3 speed hub - I might find a 7 speed nexus if I'm lucky and a very few will build you one with an 8 speed but I'm talking almost as much as a new e-bike here!

For a new wheel/hub all done and fitted I guess I'd be looking at around £200, plus the cost of a new bike. Hmmm. Maybe I'd better try to love derailleurs!

 

[Phil the drill]

Hi Fat Mog

Why not look at the Specialized Globe Vienna 4? These are bikes fitted with the 8 spd Nexus hub as standard, with a nice push button shifter and built around a modern relaxed commuter style frame. I test rode one at my LBS the other day and tried it up a nearby hill of between 1:8 and !:6 in parts. I sailed up without breaking too much of a sweat. They are a nice bike and a good price (approx £490). You'll probably want to add mud guards etc., but this is easily possible given the reasonable price of the bike .
I have to admit to being a fan of Specialized bikes, my normal road steed nowadays being a Specialized Tricross Sport (a cyclocross bike - but they make great commuters, especially if you have dodgy terrain to cover on the way!).
Hope this helps.

Cheers, Phil

 

[FatMog]

Thanks for the tip Phil, but standard hybrids (nice as many are) really don't suit me. I have carpal tunnel syndrome and need to avoid carrying any weight on my wrists so when I say sit-up-and-beg, I really mean it! I will keep keep my eyes open for something second hand, I think.

Mind you, I rode the trek on my 7 mile round trip today - this is the furthest I've ridden an unpowered bike for about 30 years I reckon, and it's definitely too small. When I bought it I knew nothing about bicycles (still don't really) and was totally guided by the man in the shop - it was a proper large LBS, so he should have known what he was talking about but it's all far too long ago to worry about now.

 

[jac]

hi if you put this number in ebay you will find a german bike seller he has lots of city bikes with hub gears i bought a bike from him a couple of years ago no problems number is 400064739767

jim

 

[Phil the drill]

Hi FatMog

I understand your problem with carpal tunnel syndrome, but a standard bike like the Vienna can easily be adapted to a very 'sit-up-and-beg' riding position simply by changing the handlebars and stem. This is not that expensive or difficult to do and there are plenty of after market bars and adjustable stems out there which could easily answer for your needs.

Phil.