Topic: Brake ID please. Nothing ordered matches...

[LesterPiglet]

If it were mine I would just replace it with stainless braided hose. Prettier and better.

[crazypj]

For the caliper to be sitting that high on disc they have to be 750 forks?
Wouldn't using 750 caliper on 550 forks would move pads over the rivets?

[scottly]

The 550 arm mounts at a downward angle compared to a 750 arm, to account for the smaller rotor, 275mm Vs 295mm. Also, a 550 caliper will not bolt on to a 750 arm, due to the different bolt hole spacing. The "T" brackets are interchangeable. I believe the mounting lugs on the fork lowers are the same distance from the axle center line on both models, but I only have a 750 to measure. I found out about all these differences when trying to fit a 550 caliper to my 750; the caliper arm wouldn't clear the 750 disc. If there is about 12mm or more clearance between the outer edge of the 550 disc and the underside of the arm, the 750 disc will clear. The disc hubs on both models are exactly the same.
The arm on the left is a 550 arm, and the one on the right is a K7 750 arm (which is different than a K3-K6 arm)

[scottly]

RATS!! come to think of it no I don't because I just recently took the 750 rotor I had, cross drilled it and gave it to my kid for his 750. Oh well but if everything will interchange then I'll just pick up another rotor off ebay.

I have some cross drilled 750 rotors on hand, and would be willing to accept your rotor as a core.

[bryanj]

Scotty is right, its a long time since i worked on a 750, I know the later 750 calipers bolted on like the 500 rather than will allen screws from the back as the earlier ones

[Bailgang]

I have some cross drilled 750 rotors on hand, and would be willing to accept your rotor as a core.

I really appreciate the offer but no worries. I talked to my kid yesterday and he's planning on putting the cross drilled rotor on today and sending me back his old one so I'll still have a 750 rotor to play with.

[crazypj]

The 550 arm mounts at a downward angle compared to a 750 arm, to account for the smaller rotor, 275mm Vs 295mm. Also, a 550 caliper will not bolt on to a 750 arm, due to the different bolt hole spacing. The "T" brackets are interchangeable. I believe the mounting lugs on the fork lowers are the same distance from the axle center line on both models, but I only have a 750 to measure. I found out about all these differences when trying to fit a 550 caliper to my 750; the caliper arm wouldn't clear the 750 disc. If there is about 12mm or more clearance between the outer edge of the 550 disc and the underside of the arm, the 750 disc will clear. The disc hubs on both models are exactly the same.
The arm on the left is a 550 arm, and the one on the right is a K7 750 arm (which is different than a K3-K6 arm)

Thanks for the pic, I wish I had known that in 1978 when I did dual disc conversion, would have been a lot easier than machining 750 rotors to 550 size