Befitter

Hello, Hope you all had a good Easter.


Would an internally gear hub work on a single-speed bicycle?

I would not want to add a shifter, cable, or switch to 3/32". I like 1/8" for my gear setup.

GamblerGORD53

SS bikes most likely have a 120 dropout. So only a 3 sp will fit. I wouldn't trust the no cable ones, prone to fail I hear.
You can put the shifter on the TT like I do. No cable flopping or clutter there.
While you are at it, get the DRUM brake too. SA X RD3 is what I bought 3 years ago. It has the old style pull rod shift chain.

My only problem was the cable stop moving. Otherwise it has 3,000 easy miles. These brakes will never fail or wear out. Better than calipers for sure. Any dust gets ground up and falls out. When you take it apart and oil the inside, it runs even better. Waiting a year or 2 is fine.
Mine is 46/19T with 1/8" chain. 49.3/ 65.8/ 87.7 GI. I shift at 10 mph with this combo. I ride this on the highway just fine. Even do 10% hills at 20 RPM. LOL
If you only ride in the city then maybe 46/ 21T would lower 1st to 44.5 GI.

FiftySix

This past summer, I bought an SRAM Automatix 2-speed hub for my single speed bike. It requires no cables of any kind as it shifts to second gear by an internal centrifugal weight.

Here's an old article of what was a single speed bike with a Automatix hub installed. https://eklitzke.org/mission-bicycles-automatix
Another link: https://forum.cyclinguk.org/viewtopic.php?t=62320
And another how to adjust, if needed: https://bikesfornoreason.blogspot.com...peed-hack.html

My single speed bike frame has room for a 110mm rear hub width, while the Automatix I have can only go down to 120mm. So, some frame spreading will be likely. I should get off my keister and build a wheel with this hub, but I really like riding my single speed as is. Except for this morning when I was riding its 66 gear inches into a stiff head wind.

Maybe, just maybe, the source I got my hub from in Asia will have some more SRAM Automatix in the coming months. If so, keep an eye out here and on eBay for a used one.

Okay, I found some on the Bay, but it's over triple the price I paid this past summer coming from Asia. Looks like a USA seller might have bought up the Asian inventory.

Otherwise, look into 2 speed kickback hubs from Sturmey Archer. Their 2-speed hubs don't require cables to shift, but you do have to backpedal to shift. Pick a 1/8" rear sprocket to go with it. Sturmey-Archer | Products

Moe Zhoost

I have a 2 speed Sturmey S2 hub and like it very much. It's not automatic but requires a slight backpedal to shift. It takes a few days to teach your muscles to remember just how much to back pedal (the angle depends on your gearing) and, also, you need to develop a strategy for being in the right gear when stopping and starting. It doesn't take long to become adept, though.

FiftySix

I like that S.A. has coaster brakes in their 2 speed hubs. The SRAM I mentioned hasn't been available with a coaster brake for some time, it would appear.

adlai

I second the automatix sram. Very impressed with it.

Only hard part is getting the gearing right. Probably the best front crank size for that hub is like 38t

FiftySix

Interesting, why is that?

The bike I have in mind for the SRAM happens to have a 38 tooth front sprocket and the SRAM came with an 18 tooth cog. With the tires I have (700x42) that would put that bike at about 58.8 and 80.1 gear inches.

Due to that, I have a 21 tooth cog I plan to use which would give about 50.4 and 68.7 gear inches.

Befitter

Merci, gracias, thank you everyone

Trevtassie

Another option would be the ATS speed drive. Set it up so the 1:1 is in your climbing gear and 1:1.65 is your cruising gear. They don't look too bad either. I ordered mine and hired the fitting tool from the supplier. Welcome to ATS I run mine with a Rohloff so I have something 830% gear range!
Like most geared drives it's a bit noisy at the start until the gears wear in.

FiftySix

Interesting indeed. I've never seen that before.

grizzly59

Crank back to 1968 or so, Schwinn made Typhoons with a 2-speed coaster brake. Heavy 26" wheel gaspipe bike. Took a licking and kept on ticking.

dedhed

You can find an old Bendix 2 speed kickback

adlai

most single speed bikes have a front crank of like 44 or 46. The SRAM actually is an overdrive hub eg the cog setup has to be able to climb hills.

ups

I had a Nexus 8 built that I put on a single speed Kona. Worked like a charm.