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Rear disc conversion
McCabe-Thiele (Ted):
--- Quote from: Oddjob on October 11, 2021, 10:09:13 PM ---Looks like an upside down mickey mouse mask
--- End quote ---
You are just being unkind as its a Yamaha Oddjob.
As you have said earlier this is an impressive rear brake engineering project by Allan - it will be interesting to see how it progresses.
allankelly1:
Hi Ted
I’m not worried as RD owners have thick skins
Back to the main subject yes a interesting project with lots of challenges but looks to be totally practical to do, and a nice one off touch to the bike.
(Plus I don’t have to take the rear wheel apart and try and repair the cracked drum brake cast iron insert)
Offered up the caliper tonight and found I needed to move the disc out by another 7mm to allow enough space between the caliper inner piston and the disc carrier as I need 28mm between the disc carrier face and the disk to allow the caliper to fit in the gap due to it being a twin piston unit rather than the original plan to use a single piston floating unit
Not a problem and that why I did a 3d print to see if there are any issues before I make the final carrier in aluminium and there is still plenty of room between the disc and swing arm even with the disc moved out by this extra 7mm
The only thing is my plan to use the original caliper hanger is a no go and will need to make up a hanger that has a dog leg to place the caliper in the correct position on the disc that I will most likely design and then print and then offer up to check my design
Still waiting for the correct disc to arrive but once that’s in I can modify the original design and print another dummy disc carrier that include this extra disc off set and will include two bearings locations in it (and a spacer tube) like the rear wheel itself as suggested by K2-K6
Lastly so you all know kick starter now sold
Catch up soon
Best wishes Al
Sent from my iPhone using Tapatalk
Laverdaroo:
Loving this!!!
Lppks mint, well done mate. :)
allankelly1:
Hi all
Ok like to ask all what they think to my idea
Now sorted out out how to control lateral “float†using an out rigger bearing that is spaced with a sleeve just like a wheel bearing assembly and I will share the final design once I have my pc repaired
Now looking on how to lock the disc carrier in place to stop rotational movement relative to the main wheel hub and have come up with this idea
I have four 30mm diameterâ€dogs†that will located in the four internal pockets of the wheel hub and under braking they will sit against the four cast bosses for the external rear sprocket bonded rubber bushes thus preventing any rotational movement
But to ensure there is no “slop†in the system (as there will be clearance in the other direction) my thoughts were to create a set up piece so the dogs are correct positioned like this
Then once I am happy I was going to make up some 90 shore polyurethane casting rubber ( like you use for custom engine mounts) and then fill each hub pocket up to the top of the ribs ( just below the original brake drum lining) so the dogs are held firmly in place and you have an inbuilt cush drive
And then to finish the assembly the disc carrier simply bolt onto the fixed dogs as shown with my second generation3d printed disc carrier
There will be no actual flex of the rubber under heavy braking as the dogs are already positioned hard up again the four internal bosses in the right direction direction but this design both solves the disc carrier to wheel hub drive connection and solves the possibility of mechanical backlash
Also access to the original wheel bearing is not an issue as you simply remove the disc and then the disc carrier
What are people thoughts please?
Best wishes Al
Sent from my iPhone using Tapatalk
SteveD CB500K0:
I've changed the name of this tread to "Rear disc conversion" (was "Rear drum conversion") as someone search for the topic would more likely choose those words.
Steve
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