spectastic

I'm thinking about turning my fixie into a touring igh bike. I'm wondering if it's ok to put an igh on a track style dropout. I found this guy online, but can't tell if the dropout got messed up because he was using quick release, or if the drivetrain experienced too much torque for the frame to handle (I'm thinking the former).

https://fcdn.mtbr.com/attachments/29e...ngshotbent.jpg
https://fcdn.mtbr.com/attachments/29e...em1dropout.jpg

Anyway. rohloff has a site that specifies which dropouts are compatible, and track is not one of them. why is that?

I'm planning on a alfine 8, not rohloff. the gearing ratio is adequate on the alfine 8, and I believe when the hub is broken in, the efficiency is pretty close to the derailleur system (I think?) Please advise if you have a lot of knowledge on igh efficiency.

dabac

With an IGH, you're putting a fair bit of torque through the rear wheel axle.
The axle will try to twist in the dropouts.
And in the pic, you see that what the hub uses as a fulcrum is at the very end of the dropout slot.
With a Shimano-style Anti-rotation washer in an innermost position you'd have a better chance at pulling it off.
And maybe your dropouts are beefier than his.
Or do the half-link thing to keep the AR tab as close as possible to the bottom of the dropout slot.
Or fabricate some chain tugs to do double duty to also keep the ends of the dropouts together.
Don't think the q/r had anything to do with it.

IGH vs derailer efficiency is a debated thing. Last time I checked derailers still win in good conditions (clean, lubed, good chain line etc) while a high quality IGH has a more uniform drop. It's never as good but also never as bad.
IMO, good IGHs are good enough so that losses aren't immediately noticeable or possible to assign to a certain culprit - particularly when touring. There's the tires, the gear, the riding position etc etc, so don't worry about it.
Pretty much the only time I worry about small changes in performance is when it's fairly important one way or another that I'm able to keep up with other people who might just be fitter than I am.
If I'm gonna ride the Alps with my skinny, endurance-freak brother, I'll look both high and low for anything to make it more even.
But for my commuter bike, it's no big deal.

FastJake

Since you're willing to drop the money on an IGH setup have you thought about how appropriate your "fixie" frame will be for touring?

JohnDThompson 

I'm surprised this happened, as many IGH-equipped bikes have really cheap, stamped, mild steel dropouts and hold up just fine, while these appear to be forged or cast. The only thing that comes to mind is that the anti-rotation washer on the damaged bike appears to seat against the dropout slot at some distance from the axle, increasing the lever arm for the rotation forces. But this would be a problem for any dropout, not just rear-facing track dropouts.



Perhaps an anti-rotation washer that doesn't produce such a long lever arm would be better?



Sheldon Brown has a good discussion on anti-rotation washers here:

Sturmey-Archer Internal-Gear Hubs, Tech Tips

spectastic

good idea on the antirotation washers. and the dropouts on my fixie look a lot like the one in the pictures, except his rear triangle is weird looking.

and the alfine 8 isn't too pricey. One of the reasons of going the igh route is because my other bikes are racing types, so alfine would actually be a step back in cost. And the fixie frame is a cheap one. It's 24 lbs right now, and will probably be 26 with the new hub. But as far as I know, it's hard to find a decent steel frame that's much lighter, and I don't really want to do aluminum or carbon frames.

spectastic

have you tried using oil bath on your igh? I hear that makes everything a lot smoother, so long as it doesn't leak.

fietsbob

Track frames are 120 wide . but non track fixie, single speed frames can be MTB 135 wide , the R'off hubs are 135 wide.

use the long chainstay torque arm and the torque transfer will be away from the dropout. your yellow bike..
\
Pictured is a S-A anti rotation washer an S-A hub does not have the compound reduction gears that is the 7 low gears of a R'off hub.

it's 1:0.75 gear, low in a 3 speed is about 9th in those [0.774] 1st is 0.279

garage sale GT

This is the rear hub of a Raleigh Tourist, the bike with the full chain case and brakes operated by chrome rods. They all had dropouts that released the wheel to the rear.

I'm surprised someone with the cash for a Rohloff couldn't just have the right drops brazed in.

Shimano used to put very clear pictures and instructions on its site. On their site you may be able to find a PDF of the instructional leaflet which would show pictures of exactly what you get in terms of hardware like antirotator washers as well as a description of what it's compatible with.

I think they probably made the Alfine compatible with straight back drops because they would want to court the "dutch city bike" market and those bikes are a lot like the Raleigh tourist.

Anyway the situation with the Alfine may be quite different from the Rohloff because Alfines are not intended for MTB frames.

Dan Burkhart 

This info is correct. Too much torque to use the OEM style anti rotation system with a Rohloff. It would work fine with the torque arm option.
I have built Nexus and Sturmey hubs into track style dropouts with no issues.

garage sale GT

Actually the longer the "lever arm" the lesser the force.

Going with the Sturmey-Archer style of antirotator washer might still work because the center of the dropout is stronger than the ends.

hueyhoolihan

if the hub itself is not used for braking (coaster, roller, disk, etc), and some IGH's aren't, then it should work fine.

that pic, to me, shows a hub that was used for braking.

fietsbob

& The S-A axle is Machined Flat on the sides. the washer, shown is an extension of that fact.
Their Drum Brake Hubs all have a torque Braking force, transfer arm.

none of Rohloff's hubs are .. they're all Round axles.

spectastic

ok thanks. alfine 8 it is

dabac

OBut it also has chain tugs, which sure look like they are capping the ends of the dropouts, which would help protect them from spreading.

garage sale GT

I think they'd be deeper and the ends would be more squared if they were truly intended to protect the drops from spreading. Like the name implies, they're for controlling chain tension.

dabac

Possible, no way to tell from the pic. Wouldn't take much engagement to help prevent spreading though.

I know that's the first and foremost use.

But if track ends spreading was a common enough issue to merit attention, it'd be dead easy to make a pair whose main function would be to prevent track ends from splaying open instead, or as well.

dabac

Think the forces through. If that was brake induced deformation, it'd be on the top prong and not the bottom prong.

I'm betting on drive torque deformation. An IGH on anything but the straight-through gear will put torque on the axle. Pretty much like a hub motor.