JLTinsley

I'm not sure if this is the right forum for my question but tried my best guess!

So I want to convert this bike, which currently is a single speed with a coaster brake, to a bike with an internal gear hub (7 or 8 speed) and disc brakes. Here are the specs:

Frame: HandCrafted 4130 Chromoly Steel and 1x H2O boss, Rear rack mounts, rear fender mounts
Fork: Dura Forte Chromoly Unicrown with Fender Mounts, 1" threaded steerer
Stem: Aluminum alloy Threaded, 1" quill
Handlebar: Aluminum alloy Comfort Swept-back
Derailleurs: n/a
Shifters: n/a
Brakes: Rear Coaster Brake (pedal backwards for braking)
Hubs Front: Aluminum ALLOY SILVER NUTTED
R/HUB: SHIMANO COASTER CBE110
Rims: DA17, Aluminum ALLOY SILVER, 700c with 36 holes
14G STAINLESS Spokes W/BRASS NIPPLES
Crank LSC 44T Chainring, 170MM Aluminum ALLOY SILVER Arms
Cartridge Bearing Bottom bracket
Tires: Kenda 700x32C BLACK wall

And because pictures sometimes help:



My question is, what all will I need to do to convert this bike to disc brakes? I could deal with just the front being disc and the back being either a drum brake or rim, if the rear conversion would prove really difficult/expensive, but would prefer both front and back being disc.

What I think I know so far is: For the front, I will need a disc compatible fork (with a 1" threaded steerer??), disc compatible hub, and of course, the brake components themselves. However, I don't think 1" threaded steerer forks for disc exist (I can't find any, anyway) so what would I need to do to make this work? But a new stem, headset, what size, etc?

For the back, I thought I just needed a disc compatible hub (I was going to get the Sturmey Archer internal 8 speed) and the brake system. However, seeing something on the interwebz made me think I might need disc brake tabs on the rear dropouts/seat-stay/chain-stay intersection too. Is that true? Will it even be possible to use disc brakes on the back without being exorbitantly expensive? If it would be a huge hassle and cost me an arm and a leg, I'll just do a drum or rim brake in the back...so how would I convert from a coaster brake to that?

Thank you all for your help!

lz4005

The folks in the mechanics forum might have better answers for you. They'd probably know if the fork you need is available.

You're right about the rear brake. To convert to disc you'll have to have a tab welded to the frame near the rear dropout, which is a pretty precise bit of work and will end up requiring some repainting afterwards.

jsavage451

sturmey archer is not going to have a disc brake hub, nor will you probably find 1" threaded forks with disc brake mounts, you could try 1" threadless forks but they will most likely be suspension. is there a good reason you would like disc brakes? a bike like that should never need them. if its a quality thing, good rim brakes will be just as good. also, i'm making a guess here but i think a disc brake on the front without suspension forks will throw you end over!

JLTinsley

Sturmey Archer does have a disc compatible hub- their 8 speed IGH. I've changed my mind about the project and will not be adding disc brakes. I was going to convert this bike to electric, hence why I wanted powerful disc brakes, but have since decided this is not the bike I'm going to convert as it would take too much modding.

jsavage451

well kudos on finding that, i did not think sturmey archer would ever do that, good luck on your conversion!

Dan Burkhart 

Sturmey Archer also offers disc brake 3 and 5 speed hubs.
https://www.sturmey-archer.com/products/hubs/cid/4/id/60
https://www.sturmey-archer.com/products/hubs/cid/4/id/60
Although the 3 speed is for extra wide dropouts (170mm)
To the OP, drum brakes would be a much better option for that bike. No frame modification required.