Author Topic: How Do I Make a Brake Adapter? (Read 8564 times)

Ryan856 · « **on:** May 30, 2011, 03:44:49 pm »

Hi there, I recently bought a proflex 856 from a friend and after looking around the internet I came across this little group

so where better to ask my question than here?

well, my 856 came with magura hs-22 hydraulic rim brakes which are slightly dated, so I have decided that I would like to install hydraulic disc brakes, but after flicking through a few forums I have seen various designs, but none with any instructions

I dont really know where to start when making the adapter, do I buy the brakes I want first? or is there a "universal" size to make the adapter that will let me fit many different manufacturers brakes?

If anyone has made an adapter before could you tell me what and how you did it if you have the time, or possibly scan (or post) a template that would be brilliant!

Many Thanks, Ryan Happy Riding!!

shovelon · « **Reply #1 on:** May 30, 2011, 09:29:04 pm »

Welcome.

I remember that there is a Hayes PDF that has the numerical dimensions for a weld on tab.

Here is a photo of a recent modification to an 856 swingarm.

fyrstormer · « **Reply #2 on:** May 31, 2011, 08:55:03 am »

That looks...oddly familiar...

shovelon · « **Reply #3 on:** May 31, 2011, 01:28:51 pm »

Nice Work!!!!

fyrstormer · « **Reply #4 on:** June 01, 2011, 08:15:48 am »

That's just the primer, of course. I wish I'd gotten a better match on the color coat, but it's close enough that it's only noticeable if you look at it with an eye for finding something wrong with it. Other than that, it works great.

purple gerbil · « **Reply #5 on:** June 02, 2011, 01:18:14 am »

Great job terry did there! Look's like it came from the factory like that

Colin · « **Reply #6 on:** June 02, 2011, 02:52:04 am »

Quote from: shovelon on May 30, 2011, 09:29:04 pm

Welcome.

I remember that there is a Hayes PDF that has the numerical dimensions for a weld on tab.

Here's an example with a whopping 203mm disc, that should stop even my fat ar$e! <GRIN> actually the BB7 160mm's I have on my XP-X do the job very adequately!

http://www.hayesdiscbrake.com/wp-content/uploads/2010/04/98-17887.pdf

Col.

shovelon · « **Reply #7 on:** June 02, 2011, 08:04:18 am »

Quote from: Colin on June 02, 2011, 02:52:04 am

Quote from: shovelon on May 30, 2011, 09:29:04 pm
Welcome.

I remember that there is a Hayes PDF that has the numerical dimensions for a weld on tab.

Here's an example with a whopping 203mm disc, that should stop even my fat ar$e! <GRIN> actually the BB7 160mm's I have on my XP-X do the job very adequately!

http://www.hayesdiscbrake.com/wp-content/uploads/2010/04/98-17887.pdf

Col.

Perfect. That gives all the dimensions for the mount.

w2zero · « **Reply #8 on:** June 02, 2011, 01:53:27 pm »

Sweet! Even I can carve that out on my non-cnc machine.........when the house is finished

fyrstormer · « **Reply #9 on:** June 03, 2011, 08:01:59 am »

Quote from: purple gerbil on June 02, 2011, 01:18:14 am

Great job terry did there! Look's like it came from the factory like that

It does indeed. I had to sand the edges a bit to round them off and get rid of cutter marks from whatever tool he used to shape the bracket, but it's made of aluminum so it wasn't a lot of effort. I've had people who've spent tens of thousands on fleets of bikes give me double- and triple-takes when I tell them the bike pre-dates disc brakes and I had the bracket custom-welded. It just looks that legit -- as well it should, considering it's kinda important for it to not break off.

fyrstormer · « **Reply #10 on:** June 03, 2011, 08:05:20 am »

Quote from: w2zero on June 02, 2011, 01:53:27 pm

Sweet! Even I can carve that out on my non-cnc machine.........when the house is finished

Or send it to shovelon to have it done while you work on the house. When you get it back, it'll be an evening of spray-painting and wet-sanding, and it'll be good to go.

w2zero · « **Reply #11 on:** June 03, 2011, 08:37:15 am »

Oh yeah, the HoFlex will get discs someday and shovelon will likely get the welding job. Further, the carbon fiber fork will be disc too. Meanwhile, I can't work on anything in the shop so I have to just ride the bike and clean the tires on the Fairlane....a lot.

fyrstormer · « **Reply #12 on:** June 06, 2011, 07:05:42 am »

How are you going to attach the disc adapter to the carbon fork? Won't the higher leverage applied by the disc brake pose a risk of cracking the fork leg where the adapter is attached? It's one thing to have rim brakes applying nearly the same torque to the fork legs as is being applied to the wheel, but since a disc brake is so much smaller than the wheel the torque applied to the mounting point is many times higher than what the rider feels as the bike slows down. I'm not sure I'd want to use discs on something with a default failure mode similar to shattering glass.

w2zero · « **Reply #13 on:** June 06, 2011, 08:20:52 am »

I wouldn't dream of point loading the fork leg at the mount. I still have carbon fiber stashed away and would use epoxy resin. Having 30 years of experience in composites helps a bit too. My plan would be to fab the mount from cf/epoxy and bond it with methacrylate based adhesive. It's the pits that my old shop was sold off and parted out or I could mount a fork leg on the dyno and take actual measurements of the deflection and compare with rim brakes.

Old Proflexer · « **Reply #14 on:** June 06, 2011, 12:30:37 pm »

a lotta years, a lotta miles, a lotta hills - and still going strong.

my creation below - (used to have a 'how to make' in the How Tos somewhere)

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Author Topic: How Do I Make a Brake Adapter? (Read 8564 times)