palladio

I've got a Soma rush that I've been riding fixed as a commuter for a while. I'd like to add some gears, preferably via a Shimano Alfine interal geared hub or something similar.

So is this feasible without causing major problems? I'm guessing I would have to spread the rear stays a bit to accomodate the hub, and then what about getting proper chainline?

The Rush has a rear brake mount so adding a rear brake and going freewheel won't be a problem.

Any other issues I'm not aware of?

Ex Pres 

Get a hub with the roller brake - or go caliper, your choice.
The sprocket can face inside (mines ~ 42mm that way) or outside, giving you some leeway with chainline.
If Nexus/Alpine, use the #6 silver and white axle thingys (they have a real name)
The Nexus/Alfines fit 130-135mm OLD.

I have my Nexus7 fitted to a Vassago Fistcuff.

JiveTurkey

I think the OP meant freewheeling mechanism not an actual freewheel sprocket.

palladio

So

Yes that's what I meant, sorry for the confusion.

So the Alfine is 135mm OLD with maybe an adjustment down to 130mm by removing washers? My frame is 120mm so I guess I'm going to have to cold set it no matter what. Not sure I want to attempt that myself, so need to check to see if someone local in NYC will do it.

JiveTurkey

Most bike shops should be able to do it. The Rush Hour is steel, right?

fietsbob

You could use narrower versions of 3 speeds, My brompton has a near 120 rear spacing, an AW3

Bromptons use a 28 spoke wheel 'cause they're small, but if you look at places with Sturmey parts

there are longer and shorter axles the Sun gear is attached , It's a bit of a bother to swap them .
but you could alter a 36 hole hub.

LarDasse74

I thought about readjusting the spacing on my Alfine but there are not a lot of small spacers and washers to work with.

Sturmey archer makes an 8 speed hub with 120mm over locknut dimension... the XRF8. This might be a better choice.
(https://www.sturmey-archer.com/products/hubs/cid/5/id/6)

With the Alfine the chainline is designed to work with the mid chainring on a modern mtb drivetrain, so MTb cranks or getting a longer bottom bracket will be necessary to correct it. I do not know about the S-A 8 speed hubs.

Grimlock

You'll need to add a cable-stop for the shifter down near the hub. There are versions you can bolt on that will save you some welding dollars.

canyoneagle

I'm not sure about the SA hubs, but this is not so with the alfine or Nexus, which have a cable stop built into the short armature that extends forward from the hub. The cable can be routed fully sealed from the shifter to the hub, using brazed guides, zipties or those cool adheseve/clip thingys. It is best to leave some room from the last cable guide on the chainstay (close to the BB shell) to be able to work with the cable when removing/installing the cable from the hub.

Grand Bois

The SA 8 is designed for use on bikes with 20" wheels. First gear is 1:1 and the rest are overdrive. You would have to use a ridiculously small chainwheel on a bike with 700c wheels. It's a poor choice. It's a shame because the price is right and it's a good looking hub.

Sturmey Archer makes a bunch of nice clamp on stops and guides that can be used with any brand of hub. You can also treat your shift cable like a derailer cable and run it bare using clamp on guides. That's how I did my latest one. It's a SA5-2 hub and it uses 2 shifters an 2 cables. The 5/8" clips on the stays are SA parts. The rest is Simplex.

fietsbob

if you spread the Dropouts for an Alfine as its a track sort of frame
housing from from the lever on the bars to the hub is to be expected.
Zip ties will tie the housing down just fine..

Mr IGH

Like GB says, forget about the SA 8 speed on a 26/700c/27" wheel bike.

The Alfine is hard to make less than it's 135mm OLD, the Nexus might be able to drop ~7mm if you can machine some custom spacers.

120mm to 135mm is a big move for track dropouts, I've never done it because the newer dropouts dropouts are cast, I worry about cracking them when I re-align them. Tthe older track dropouts are very thick plates and I wonder if they can be re-aligned without bending the stays by the dropouts.

I'd go for a newer SA 5 speed. 120mm OLD, lots of shifter options, you're riding a single speed now 5 speeds will be a big change.

Grand Bois

Zip ties are fine if you don't mind if your bike looks like it was built by an amateur.

palladio

Yes my frame is steel. I think it's Tange prestige.

ColonelJLloyd 

+1
Other options include the SA S3X (3 fixed gears), S2C (2 speed kick back with coaster brake) and the good ol' AW.



I've got two semi-inconspicuous zip ties holding my dynamo headlight's wires. I did my best.

palladio

Is this the SA XRF 5? So is it more appropriately geared for 700c than the SA 8 speed?

I've been reading reviews online for IGH, and I was considering the Alfine because it seems to have great reviews. I would prefer a quiet hub and some have said the SRAM IGH models are noisier. My only experience with internal gears is on old SA equipped Raleigh 3 speeds from 30 years ago. The jump between gear ratios on those is more than I'd want. As I'm doing commuting in NYC with few hills, I probably don't need 8 speeds, but want something with a bit tighter ratios than the old SA 3 speeds.

Anyone have any experience with the newer SA 5 speed? It's tough for me to judge as I haven't found any reviews or it online. I'm not sure there is any place I can just go test drive it either.

Thanks for all the great advice so far.

fietsbob

Yea the 1:1 gear is the low in the S-A 8 speed ,
so the crank would need a tiny chain ring to keep the low from being rather tall.
the standard cogs are 23or25t on the hub ..

5 speed have the 1:1 in the middle its like a narrow ratio 3 speed
+ a wide ratio 3 speed combined. Its how you get a 5 speed 2 middle ratios are 1 redundant
https://www.sturmey-archer.com/products/hubs/cid/4/id/11
Its almost as good as a 3 speed,

NB offered in 119mm wide setup.

tcs

Ah, much like the one Sturmey offers just for use with this hub and std. sized wheels.

This is incorrect. The current production Sturmey (W) series 5-speeds have exactly the same ratios for 2nd and 4th as the three speed's 1st and 3rd. If the OP wants tighter ratios than a three-speed IGH, the S-A 5(W) isn't the way to go nor is the SRAM P5 much better.

tcs

Mr IGH

I have the older narrow range 5 speed hub, it's ~225% range, the new one is ~255%. As noted, it's not that tight. 120mm OLD maks it hard, You might call Soma and ask them if it's OK to spread the rear to 135mm. Then buy an SRAM i-Motion 9 or wait for the Alfine 11. Alfine/Nexus 8 is annoying on the road, the 5-6 jump is 26%.

I'd buy the 5 speed and suck it up. 30 years ago nobody thought anything about 26% jumps, now we all need 5% corncob steps or we can't enjoy the ride. On my commuter bike, the 5 speed is fine. Only drawback is when I go for beers with my buddies. They have derailliur bikes with tight steps, I have to set the pace if I want to be in my prefered cadence range (80~100 rpm), important after a few beers and everyone starts pushing it to the next stop.

fietsbob

fietsbob

Brompton sorted out a half step 2 cog external, 13/15 and a widely spaced 3 speed. but they engineered around their wheel size.

But like the 5 star , there's 2 levers, to sequence thru..

My mountain drive 3 + 3 speed has a range shift between 3&4, button in the middle of the crank tapped with your foot..
Big drop, low in hub followed down with high in hub but in low range.

tcs

I'd use this 120mm OLD hub with a 23T cog, this crank and this shifter on my "geared fixie" and get six nice tight, evenly spaced gears: 45, 51, 58, 66, 75 and 86 g.i. for general commuting.

But that's just me.

tcs

palladio

I see how that could be a good setup, but I really didn't want to get into replacing crankset, bb, etc. with this modification.

fietsbob

23/30 ...45" ain't much of a steep hill climbing gear, but most cities are in the flood plain anyway..

paved over farms .. Bon Appetite !

palladio

I found some comments from Sheldon Brown here https://www.trianglecycling.com/showthread.php?t=23743 , recommending the Nexus 8 as a great shifting hub that can easily be modified to fit 120mm. Maybe that's the way I should go. I'm going to try to find somewhere I can test ride this hub to see what it feels like. Either that, or talk to some shops about the feasibility of spreading the rear stays far enough to accomodate the Alfine.

Thanks for all the helpful advice. This project is a little more tricky than I would have expected! Maybe I should just buy some riser bars for my geared (derrailleur) cross bike and convert it into my commuter instead.