Jump to content
Sign in to follow this  

Designing a caliper relocation bracket for the SM model... Any ideas?

Recommended Posts

Howdy All....

I'm trying this topic over at SMJ with suprisingly little response...

A buddy of mine just picked up some new machining toys and I've been given the okay to use them any time I need to.... A mill, lathe, drill press and even a CNC if I ask real nice...

My first project is going to be a relocation bracket to allow the use of an aftermarket 320mm rotor and the stock caliper... I've built these brackets before for some tricked out CRF50's I've built, but never anything this "large"...

I'm looking for ideas here. What type of material? Where to position the caliper? blah blah blah.... Basically anything that you may think of to help me on my way in producing this part... Who knows... If I get the CNC dialed in maybe I'll have my "better mousetrap"...

Just thought I would add that I am a draftsman by trade and have close to 17 years experience in electro-mechanical design. I'm also skilled in AutoCAD and have my own software. It ain't Pro-E, but it'll have to do...

We've got a good "think tank" going here. Let's hear some ideas...

Share this post


Link to post
Share on other sites

Sounds like you are the best qualified person to do the design. Aluminum 6061 material. Relocate as needed to to position the pads on the outer dia of the disc. Carve out enough material so it looks cool and that is about it.

Share this post


Link to post
Share on other sites

I remember Nate mentioning fairly recently that a caliper relocation bracket for the 280mm rotor for an S model will fit as the calipers are the same as on the SM.The spacing would be enough to allow a 320mm rotor to be mounted with the bracket as the increase is about 10mm from the standard 310mm.The rim to caliper clearance would be very close I would think.I believe that the rotor would have to be mounted after bolting up the caliper because it would run extremely close to the rim of the wheel.Motomaster is the only one that makes a kit right now I think.

Share this post


Link to post
Share on other sites

depending on the loads, I would use 7075 or 6061. 7075 is stronger but will need to be anodized because it is more prone to corosion.

If you need to tap holes use some keenserts as opposed to helicoiling them. They are stronger and less likely to pull out.

Share this post


Link to post
Share on other sites

I still cant figure out why noone wants to relocate the caliper to use the SMALLER rotor for dirt wheels on the SM, im i the only one that wants the best of both worlds?

Share this post


Link to post
Share on other sites

Moosehunter,

I'm a ME, and I have some access to Pro/E, and stress analysis tools. If you get a design, I'd be happy to do some work off the company clock to make sure it wouldn't fail. PM me if you're interested.

I'm guessing that 6061 would be fine. I would position the caliper so as to make it fit with the stock brake lines.

Share this post


Link to post
Share on other sites

I personally would avoid 6061. 2024-T3 or 7075-T6 are the way to go. Both these materials are strong enough you can easily tap the base bracket and not bother with inserts of any sort. Given the tools available I can't see it as an issue.

I have had good luck with brushing the surface and hitting it with clearcoat. No corrosion to speak of on anything I have built. If you do get some surface damage it is easy to fix up. My skid plate doesn't count because it is not finished.

Share this post


Link to post
Share on other sites
I have had good luck with brushing the surface and hitting it with clearcoat. No corrosion to speak of on anything I have built. If you do get some surface damage it is easy to fix up.

Good points... cheaper and easier to fix than anodizing.

Share this post


Link to post
Share on other sites
I remember Nate mentioning fairly recently that a caliper relocation bracket for the 280mm rotor for an S model will fit as the calipers are the same as on the SM.The spacing would be enough to allow a 320mm rotor to be mounted with the bracket as the increase is about 10mm from the standard 310mm.The rim to caliper clearance would be very close I would think.I believe that the rotor would have to be mounted after bolting up the caliper because it would run extremely close to the rim of the wheel.Motomaster is the only one that makes a kit right now I think.

I converted my S to SM and used an EBC front rotor kit, it came complete with relocation bracket. In order to mount the caliper with the bracket I had to remove all but one of the screws holding the rotor on. This allowed the rotor to pivot then I mounted the caliper and then pivoted the rotor back to it's original position. Tightened everything up and it made a world of difference. Pics available upon request.

Share this post


Link to post
Share on other sites

I can't help out with the brains of this project but you could most likely count me in for purchasing one as I'd like a bolt-on wave rotor 320mm upgrade...!!!

Share this post


Link to post
Share on other sites

"avoid 6061. 2024-T3 or 7075-T6 are the way to go"

Sure 2024 and 7075 are higher strength materials but strength of the adapter plate is dependent on the design and we do not have a design yet to evaluate. In my experience as a metallurgist 6061-T6 is a better choice: less corrosion, better for anodize, less expensive, good machinability, strong enough for the application and no need for thread inserts (assuming proper design).

Share this post


Link to post
Share on other sites

6061 is great if you analyse what you are going to do. It also has good material properties for some things. If the bajabound400 puts it through pro E and you size it up accordingly cool. Conservatively and or seat of the pants I avoid the stuff. It is among the weakest aluminium alloys. It is in the range of 60% (average of) 7075-T6.

I made my bracket from 0.25 7075-T6 plate and mechanically fastened the 2 pieces. For 6061, min 0.375 and would have machined it from a single piece. that wasn't an option so...

Like you say with good design it is fine. In commercial aircraft we do not have any around, it is all 7075 or 2024. The machine shop we use doesn't even stock it. So when scrounging and making things work, go for the good stuff.

Share this post


Link to post
Share on other sites

6061 absolutely is not among the weakest of aluminum alloys. It is among the strongest, but true not in the same league as 7075 or 2024 I had a feeling you were involved with aircraft. Certainly there you are looking to reduce weight by using the strongest possible materials in the thinest sections. 7075, 2024 and 6061 (and sister alloys) are all fine materials and all have some limitations. 6061 may be one of the weakest used in aircraft but not in the larger scope of use of aluminum alloys. If I were scrounging material for a 1 off part, I would (and have) use it too. But if I were designing a part for a production application for motorcycle use, I would not use it primarily for cost and corrosion concerns. I like to avoid the use of the term "best" material just because it is strongest. There are other important properties besides tensile strength.

Share this post


Link to post
Share on other sites

So while it's fun to debate the various properties of different grades of aluminium, isn't it safe to say that all of these grades far exceed that of the porus looking casting of the fork legs that constitute the standard caliper mounts anyway? So if there were a weak link in the chain, they would be it?

Share this post


Link to post
Share on other sites

The assumption is that the final part will be waaaayy thinner than the stock casting them. So the design is really matters. I did some calculations came up with what I felt was acceptable for me. Not to mention available and free.

Were I to consider other issues that may or may not be relevent I may have done it differently. Get the geeky types discussing Aluminium alloys and see what you get. :thumbsup:

Yes the thread took a very sharp tangent. Lets leave it at that.

Now about the oil.... :ride:

Share this post


Link to post
Share on other sites

Wow, I'm impressed with the replies to this thread.

I am a draftsman also, 30+ years experience.

I want to make a rear brake bracket for a full floating caliper.

I am amazed suzuki did not use a full floater in the design.

After all the years of developement, they forgot?

Especially on an SM...which really needs it, along with a slipper clutch. :thumbsup:

I like the details about the aluminum materials.

Thanks guys.

Bob

Share this post


Link to post
Share on other sites

You know full floater brake designs come and go. Mostly now they are gone. (Remember the anti-dive forks of the 80's?) I don't even see floating brakes used in race applications. I suppose because the rear brake is so little used. Might have more application on the street. Full floater rear is going to add weight and complexity. Will be interesting to see how it works.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×