44T Sprocket with disc brakes

[scandisnoc56]

As the title says, I'm wondering if this is possible? I believe it is, but you would need a pretty big disc to make it work. for a 44t, would a 203mm disc be good or you need to go bigger? i was thinking using spacers to try and get as much room out as possible so the caliper could hopefully clear, I would have to see. any help would be greatly appreciated!

 

[ImpulseRocket]

As the title says, I'm wondering if this is possible? I believe it is, but you would need a pretty big disc to make it work. for a 44t, would a 203mm disc be good or you need to go bigger? i was thinking using spacers to try and get as much room out as possible so the caliper could hopefully clear, I would have to see. any help would be greatly appreciated!

I had to figure this mess out myself, and unfortunately there is no single correct answer, but for the majority of frames a 44 tooth sprocket with a 203mm disc will not work with one exception. A frame that has the disc brake mounts between the two rear dropout tubes (inside the V ahead of the axle. This is because on most frames the caliper is mounted above the axle outside of the upper dropout tube, and what causes the interference is the chain hitting the caliper. With the sprocket on the inside of the tubes, there is no chain on the sprocket in that location and it buys enough room that it can work.

I was able to figure out a 40 tooth sprocket with a 203mm disc on my bike with some clever spacing, and the chain gap to the caliper can be measured with a feeler gauge.

Example of what I am talking about.

 

[Sidewinder Jerry]

I had to figure this mess out myself, and unfortunately there is no single correct answer, but for the majority of frames a 44 tooth sprocket with a 203mm disc will not work with one exception. A frame that has the disc brake mounts between the two rear dropout tubes (inside the V ahead of the axle. This is because on most frames the caliper is mounted above the axle outside of the upper dropout tube, and what causes the interference is the chain hitting the caliper. With the sprocket on the inside of the tubes, there is no chain on the sprocket in that location and it buys enough room that it can work.

I was able to figure out a 40 tooth sprocket with a 203mm disc on my bike with some clever spacing, and the chain gap to the caliper can be measured with a feeler gauge.

Example of what I am talking about.
View attachment 213601

With a steel frame, welder, and some ingenuity many things can become possible. One could have a selection of frames to weld mounting bosses to the stays in places that'll work.

I had to weld on flat bars to my frame in order to do a rear rack mount and keep the rear disc brake.

The LandRider had rim brakes and rear bosses for mounting a rear bicycle rack. I used those for mounting a rear engine rack. The Sidewinder had front/rear disc but no rear rack bosses.

 

[Deleted member 33057]

I run 203’s and a 36T is close in my application. No way I could even run a 38T.
If you run a 415 chain and don’t have the space between the dropouts to space the caliper out, the caliper has to be on top of the chain. The hub width and space from hub to dropout… not there in my case. My rotor is very close to the seat/chain stays.
I already pushed both stays out to close to the bottom bracket to clear the 2.5” tires.
There are 220mm rotors but they’re not as common as 203’s and cost a bit more.
Pedal assist on a 36T is minimal..usually from a dead stop only.

 

[ImpulseRocket]

220mm rotors will only buy 8.5mm more clearance., an that may well be just enough to pull it off. They are expensive, but SRAM rotors are only about $40 for a 220mm rotor. I think the hard part would be finding the caliper adapter bracket for the rear. I haven't really tried myself, so I could be entirely wrong.

 

[robe]

Here is one with a 40T sprocket and a 203 mm disc. Very close fit, I had to file a bit of extra meat of the caliper to gain a couple mm of clearance.

 

[scandisnoc56]

Thanks for your responses guys! its all been very helpful, and im still pretty fresh to all of this. ive been trying to get this bike to start for the past couple of months, but those coaster brakes man...ended up just caving and bought magwheels. im gonna try to start it today, but if the 44t doesnt allow clearance, then ill just throw on a 36t which should come in tomorrow...i just really wanna ride this thing atp lol

 

[DAMIEN1307]

if the 44t doesnt allow clearance, then ill just throw on a 36t which should come in tomorrow

I have been using the 36 tooth sprocket with the 203mm sprocket for years and love it, I am using a Phantom motor with mine though as it is a very torquey motor...lol.

 

[Gordy]

You will need some clearance. If you can get the axle replaced with a longer one and space the rotor out, you might be able to stretch the dropouts enough to run the rotor and sprocket side by side with space between them.

 

[Deleted member 33057]

I’ve been looking at pitbike hydraulic brakes. It can be set up with the same dual brake from the right lever.
There’s bias valve to adjust the bite for front and rear.
It’s really not much more costly than the line pull hydro calipers but the stopping power is much stronger.
The hydraulic calipers have dual pistons.

I stop fairly well but if I ever really need a super hard stop it’s not there. No locking up my wheels at speed.
I also go through pads a good bit too. Been buying 10 sets at a time.