Internally geared hubs confusion.

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Internally geared hubs confusion.

18 posts & 11 voices | Started 2 years ago by Saccades | Latest reply from Mister P

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Saccades - Member

I have an alfine, which I like very much - so much so that I was going to get one for my SS pompino so I can use that as the tug for the child trailer.

Which is where I get confused, I don't have disc mounts so I don't need the disc brake ability of the alfine, right?

So I'm now looking at nexus, what's a coaster brake? Some hubs have them and some don't, then I'm confused over the red band nexus (Although I have managed to work out there is also a 3 speed version I don't want).

Then there is the SRAM version, which I know nothing about.

Can anyone clarify and if possible point me in the direction of a shop that sells 700cc wheels pre-built.

Ta muchly.

Posted 2 years ago #
simonfbarnes - Member

if you pedal backwards it activates a drum brake inside the hub

Posted 2 years ago #
Saccades - Member

ah, a pedal back brake like i had as a kid...

Worth having do you think as opposed to a rim brake? one less cable I guess.

Posted 2 years ago #
mk1fan - Member

I doubt you'll find a bike shop with a stock of pre built wheels with Alfine hub and a 700 rim.

Just buy the Alfine and get it built up onto your choice of rim. You don't have to use the disc rotor mount.

If you're so offended by having an un-utilised disc rotor mount on the hub then order a normal Nexus without coaster brake and get it built up onto the rim of your choice.

Shimano and Sram have product details on their websites. Bear in mind that although the Sram item has 9-gears it is heavier than the Alfine.

Posted 2 years ago #
StirlingCrispin - Member

The coaster brakes on my Nexus hubs are cable-activated from a brake lever, just like a normal brake. They also need a braze-on below the left chainstay to hold the torsion arm.

Posted 2 years ago #
Saccades - Member

I've found 2-3 places with an alfine hub built onto a 700cc wheel, I just didn't see the point in spending the extra cash for having the ability to run a disc that I can't on the frame I have.

Yeah, that Sram appears to be impressively heavy, not too much of a problem if the shifting/range is good.

edit - humm, if it needs a lever (unlike the pedal back thing I had as a kid) I'd rather rim brakes I think.

Posted 2 years ago #
Mister P - Member

Striling you don't have a coaster brake then, you have a roller brake.

To the OP, I would stick with the Alfine hub if you plan to use the bike off road. The Nexus hub is really a commuter part and might not last as long off road.

Posted 2 years ago #
PhilO - Member

The coaster brakes on my Nexus hubs are cable-activated from a brake lever, just like a normal brake.

That's not a coaster brake, then. There are three options: Unbraked, for use with normal rim brakes; "Coaster" brake - back-pedal activated, as stated above; and "Roller" brake - a cable actuated hub brake. You have the third.

Posted 2 years ago #
rootes1 - Member

3 speed sturmy or sram instead if you are using it on the pompino?

what is your drop out width on your pomp?

Posted 2 years ago #
cynic-al - Member

*hijacks*

Do any provide road-style close ratios?

Posted 2 years ago #
Saccades - Member

I use the pompino as a pub/commuter bike it doesn't go off road as such.

My main sticking point appears to be that nexus is 132mm rear spacing, alfine is 135mm which is what fits my pompino. But the pre-built wheels are all on disc only rims which I can't use.

It does look like I'm going to have to get an alfine built up for me which is a pain in the bum, last time the lbs got very shirty supplying the rim and spokes because the hub is not on any spoke calculators.

Posted 2 years ago #
epicyclo - Member

I think On-One still have 1 built up Alfine wheel.

Posted 2 years ago #
bikewhisperer - Member

last time the lbs got very shirty supplying the rim and spokes because the hub is not on any spoke calculators.

Aw. Poor things. They didn't know how to use a measuring stick.

Don't worry about the hub spacing. It'll bend to accommodate that much. You could always add some spacers in-between the lock nuts if you want it perfect.

Posted 2 years ago #
Del - Member

the lbs got shirty? build it yourself, or at least, measure it yourself and do the spoke calculations for them. if you google 'spocalc', then there is a guide on how to use the spreadsheet and how to measure your hub. if you don't have excel download openoffice ( free ) and use that.
it'll fit a pomp fine. thinking about fitting one myself.

Posted 2 years ago #
Mister P - Member

I have checked the 2010 Shimano product spec folder that bike manufacturers use and for some reason they don't give the centre to flange measurements, just the distance between the flanges. When I get a few minutes I will get the calipers out and report back.

Posted 2 years ago #
rootes1 - Member

It does look like I'm going to have to get an alfine built up for me which is a pain in the bum, last time the lbs got very shirty supplying the rim and spokes because the hub is not on any spoke calculators.

jes sounds like a lazy shop - if they can not be bothered to measure the hub and work out the spoke length don't think i would use them to supply the wheel...

shimano list a prebuilt nexus 700c wheel 24 spoke:

WH-8R25 - perhaps madison dealers can get it?

techdocs

Techdoc part 2

also this place lists nexus builds:
http://www.byercycles.co.uk/29R0809.html

Posted 2 years ago #
Mister P - Member

That wheel is not available from Madison, it is an old line now.

Posted 2 years ago #
Mister P - Member

From a quick look I reckon the centre to flange measurements are 29.3 non-drive and 22.4 drive side.

Posted 2 years ago #

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