Disc Brake Gurus?....Sprocket Adapter

[Demosthenese]

there was a really cool motorbike built for discovery's motorcycle mania i think, anyway, this guy engineered a combined rear sprocket/disk brake. if only you could make ur own caliper lol...

also, the bolts i were using, don't know what they were, but i went to the local mtb store and told them about it then asked for the strongest bolts available. they cost like 3 bucks each, so i know they were strong and i did use lock washers too.

 

[Bogaurd]

Hi Andy,
I'll get some pics for you tonight.

However, regarding the caliper mounting, I don't believe mounting the caliper on the outside of the frame will be a feasible solution to the problem - the frame mount is often such that the tubing etc will prevent the caliper from being mounted on the wrong side.

Seeing as you have access to a machine shop, I would think a better option would be to look at designing a dual purpose adapter - that is a disc which acts as both the braking surface & has the appropriate drilling to accommodate the drive sprocket. In this way it would be a painless conversion, and would suit more bikes. Infact, there's at least one user on the forums who has successfully mounted his drive sprocket to the disk brake.

 

[andyinchville1]

Hmmm....Mounting a sprocket off a disc...now that is thinking out of the box.....I'll have to look into that idea too....

Andrew

 

[Bogaurd]

Andy,
Sorry for the long time in taking the pics, but I've now put a few shots up at www.bogaurd.net/brake/

 

[andyinchville1]

Thanks for the Pics Bogaurd....Great close ups!

Andrew

 

[married_n_macon]

souloution

ok first off discs come in 120, 140, 160, 165, 180, 185, 186, 203, 205, 225, 230, and 256 mm sizes w/ many manufactures making theirs afew mm off from the standards of 140, 160, 185, 203
second there is a 4.5 mm difference in offset from a front or rear post mount adapter and one size rotor too. Hence a you can use a adapter for a front 185 mm rotor for a rear 160

 

[andyinchville1]

HI,

Thanks for the added info....I think we have "solved" the problem with the Top Hat Sprocket Adapter....;-)

Andrew

PS - I ha no idea there were so many different size discs out there! WOW

 

[married_n_macon]

for the record andy I run a 20t cog sandwhiched between 2 160 rotors so that they act as chain guides. this is extremely effective and allows me to run some slack in the chain so it is not strining such massive side load on out put shaft and wneel. the wheel itself as it suported on both sides isn't such a issue but it can strain the outp9ut shaft considerably when it is sitting dormant in one position. now what I would like to know is what is the smallest you can make your cogs that fit your hat?

 

[andyinchville1]

HI Married,

I am not 100% sure of the smallest sprocket that can be run with the Top Hat Sprocket Adapter but I think a 27T would be close. (Maybe a 25 or 26 would work BUT at some point the chain will start to ride the bolt heads of the 9 hole adapter mount....I haven't tried to verify for sure though)....FWIW I am pretty sure we can make a 18T to fit to the disc hub itself! ;-)

Hope this helps you.

Andrew

PS - I like your idea of your chain guides!

 

[Bonboy87]

souloution

ok first off discs come in 120, 140, 160, 165, 180, 185, 186, 203, 205, 225, 230, and 256 mm sizes w/ many manufactures making theirs afew mm off from the standards of 140, 160, 185, 203
second there is a 4.5 mm difference in offset from a front or rear post mount adapter and one size rotor too. Hence a you can use a adapter for a front 185 mm rotor for a rear 160

Just wondering what companies did u find 230 and 256mm disc brakes from i need discs that big to get my caliper out of the way of my sprocket and chain