how solid is this rotor adapter setup

irk miller

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Is there a reason for that specific Tokico 4 pot caliper? They make a two pot caliper that looks nearly identical and it's on a shit ton of different model bikes, so the replacement pads are uber plentiful. SV650 and GS500 are two of many bikes that came with this caliper.

 
Caliper size is a major problem with Harley to sport bike brake conversions. Can you shave a bit off the back side of the calipers? That is the common practice on the HD conversions. The solution I used on my Evo chopper was asking the EBay sellers to measure the calipers width. EBay is full of Tokico and Nissan calipers and it didn't take long to find one that worked for my application.
How much can one shave off, though? Unlike a car caliper, it seems like even taking off 2mm would be too much on the bike ones.
 
Is there a reason for that specific Tokico 4 pot caliper? They make a two pot caliper that looks nearly identical and it's on a shit ton of different model bikes, so the replacement pads are uber plentiful. SV650 and GS500 are two of many bikes that came with this caliper.

The reason was that it would bolt right up to the GSXR forks with its 91mm bolt spacing. Nothing else, really.
The ones in the picture are flat on the inside, and definitely a better option for this wheel, but with those i'd also have to now make adapters to fit the forks.
 
You would have to measure the wall thickness.
Got any tips how to measure? With the piston out I dont have any tool that could measure accurately.
(If I assume thickness is uniform, I guess I can see if I can measure somewhere else).

It's definitely an option as well that I'm still considering. Would be the easiest, by far.
 

irk miller

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Got any tips how to measure? With the piston out I dont have any tool that could measure accurately.
(If I assume thickness is uniform, I guess I can see if I can measure somewhere else).

It's definitely an option as well that I'm still considering. Would be the easiest, by far.
How I measure, is to place the caliper on a table with mounting holes in the correct orientation that the forks are. Usually this is level, but not always. Then measure from the mounting hole to the table surface (A). Then, measure the gap (B) between the same mounting hole to the rim face (or spokes). You're usually just measuring the bottom hole, since that is the hole that aligns with the thickest part of the wheel. With single sided calipers like I posted before, you need only minimal clearance, since braking pulls the caliper away from the rim. With the type you are using, I typically give it a little bigger gap. A-B= material to remove.
 

cxman

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you can buy push back spacers for those caliper that will with an additional simple non structural angle cut on the edge of that caliper

provide ample clearance that step was missed in the cx write up

like these simple and easy

 
you can buy push back spacers for those caliper that will with an additional simple non structural angle cut on the edge of that caliper

provide ample clearance that step was missed in the cx write up

like these simple and easy

[/URL]
Hmmm, but my calipers are not radial mount. They are conventional. So adding spacers would push the caliper even MORE toward the wheel ... as they are mounted on the inside of the fork.

I think these might be used with radial mount calipers to run larger diameter rotors
 

cxman

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oops sorry that front end does not have the radial calipers i will butt out now
 
How I measure, is to place the caliper on a table with mounting holes in the correct orientation that the forks are. Usually this is level, but not always. Then measure from the mounting hole to the table surface (A). Then, measure the gap (B) between the same mounting hole to the rim face (or spokes). You're usually just measuring the bottom hole, since that is the hole that aligns with the thickest part of the wheel. With single sided calipers like I posted before, you need only minimal clearance, since braking pulls the caliper away from the rim. With the type you are using, I typically give it a little bigger gap. A-B= material to remove.
Yeah, that part is easy, I meant measuring the actual thickness of the caliper to be able to tell how much can be taken off without compromising the strength of the caliper.
 

irk miller

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Yeah, that part is easy, I meant measuring the actual thickness of the caliper to be able to tell how much can be taken off without compromising the strength of the caliper.
If you mean just for the specific calipers you posted as using, you have to take them apart and measure the depth of the bore and subtract for the easy measurement you already figured out. It's going to be an angled measurement for what you have to take of. A piece of wire or a screw driver or similar will get you close if you don't have a depth micrometer.

If your pic is any indication, I can't see how those calipers will work at all. Looks like you'll be cutting into the bore. Strength is going to be the least of your concern.
 
If you mean just for the specific calipers you posted as using, you have to take them apart and measure the depth of the bore and subtract for the easy measurement you already figured out. It's going to be an angled measurement for what you have to take of. A piece of wire or a screw driver or similar will get you close if you don't have a depth micrometer.

If your pic is any indication, I can't see how those calipers will work at all. Looks like you'll be cutting into the bore. Strength is going to be the least of your concern.
Yes, good eye. It's worth mentioning (from my previous thread about offset bearings) that my wheel is currently not centered. It needs to go another 2.5mm in the other direction, so the amount of interference you see there sould be reduced by about 2.5mm. So, it won't be quite as bad as that picture! I just worked on the side that had the least clearance for now to be in the "worst case scenario".

I will have to get my R spacer shortened by 2.5mm and get a new L spacer made up that is 2.5mm longer, then reassess.

Honestly, i think having the caliper mounting surface milled 2mm would solve my problem, but i'll have to talk to my machinist guy and see how much it would cost. Sometimes the setup for irregular shaped parts like this is where they spend most of their time.

Thanks everyone for the great advice so far. Keep it coming!! I love this forum!!
 
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Just went to the garage to look at the calipers again.... I think it's definitely easiest to just mill down the mounting surface and bring the calipers out a bit. There is more than enough meat on there to mill down a couple of mm.

It will be much easier and cleaner than doing my own adapter. I'd have to make one out of 1/8" aluminum or so. Confirm all dimensions then get it CNC'd out of 3/8 or 1/4 al aluminum.
20200514_100745.jpg
 
Took some more measurements and it looks like 4mm would have to be taken off to be safe. Call it 3mm and 1mm shaved off on the caliper itself.

What do you guys think. The mounting points of the caliper are 15mm and 12.3mm thick.

So removing 3mm is about 25%. That sounds like a lot. But 9mm of thickness left is still 0.366" which sounds plenty.

Thoughts?
 
So removing 3mm is about 25%. That sounds like a lot. But 9mm of thickness left is still 0.366" which sounds plenty.

Thoughts?
What size mounting bolts are the calipers using: 8mm or 10mm? If they’re 8mm that’d be cutting it close as you want at least a 1:1 thread engagement ratio. In other words, you would want 8mm thread engagement for a 8mm bolt, 10 for 10, etc. For critical parts, I prefer 1.5:1 so 12 for 8....

Later, Doug
 
What size mounting bolts are the calipers using: 8mm or 10mm? If they’re 8mm that’d be cutting it close as you want at least a 1:1 thread engagement ratio. In other words, you would want 8mm thread engagement for a 8mm bolt, 10 for 10, etc. For critical parts, I prefer 1.5:1 so 12 for 8....

Later, Doug
They are 10mm.
Hmm, interesting point. I suppose I could shave off 1.5mm on the caliper and 1.5mm on the fork mount to keep the caliper at 1:1 for thread engagement, but now its twice the machining cost to set up the pieces.

I guess I will have to speak to my machinist and run it by him as well and get a quote.
 

doc_rot

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Thread engegment is much more critical. Better to use 1.5x for aluminum thread engagement. I wouldn't hesitate to cut the caliper mounts. Its farily easy to do if you supply the whole front end. I did it on my KZ750 to fit a big ol 2 piston Brembos on the stock wheel. I would recommend using a ball end mill to prevent a stress raiser
 

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Thread engegment is much more critical. Better to use 1.5x for aluminum thread engagement. I wouldn't hesitate to cut the caliper mounts. Its farily easy to do if you supply the whole front end. I did it on my KZ750 to fit a big ol 2 piston Brembos on the stock wheel. I would recommend using a ball end mill to prevent a stress raiser
Very cool. Thanks for sharing! Those forks sure have a lot more meat on them than the mounting points of mine (but I dont need to take off as much).

Will update back when I have a chance to talk to the local machinist

But I think that's my only option with these calipers.

I thought about an adapter plate that goes on the outside of the fork, then space the caliper in from the inside of the adapter as necessary..... but it seems like a lot of work just to avoid a few mm of machining
 
Nice. Older style comstar .... little bit narrower and easier to make work.

Looks like a great paint job!

I will have to deal with adapters after I get calipers to clear ... then I can measure where the rotors will sit and get some adapters machined.
 

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