Brake rotor question

[Capt_Zoom]

If I were switching brake calipers, how close to the rotor sizes have to be?

Would a brake caliper meant for a 299.72 work on a an xs650 brake rotor (298mm) if the offsets were workable?

 

[XSLeo]

What caliper are you using, and what did it come from?
What rotor are you using and what did it come from?
If your building an adapter to fit a caliper to your forks then the adapter will adjust for the size of the rotor, and the offset, as long as the caliper doesn't hit the wheel.
AS long as the width of the swept area on the rotor is as wide or wider than the hieght of the pads then it should all work together ok.
On the xs1100 rotor, which works good on an XS650, has a swept area 1 3/4 inches wide. The XS650 brake pad is 1 7/16 inch tall.
If installing a caliper from something else as long as the pad is shorter than 1 3/4 inches the adapter can locate it on the rotor correctly.
If the off set and caliper+ adapter line up your good to go. If the caliper hits the wheel you need to space the caliper and adapter so it won't hit then space the rotor to match the caliper.
Leo

 

[Capt_Zoom]

My biggest worry was if the HD caliper would work with the stock xs brake rotor. Since they are only 1.72mm different I thought they should work.

Next figure that I gotta check out the offset for clearance but none of the dealers are open on Sundays here.

If that clears one would assume that it should work as long as I can make a new mount bracket and can get the right bore master cylinder.

I'm also assuming that a most multi-piston calipers are going to provide improved braking over our 30+ year old xs stockers.

Am I correct in thinking this?

 

[XSLeo]

On the Harley I have the brake rotors are flat. If you have the stock wheel in a set of forks with a rotor on it, slip the Harely caliper on the rotor to check for clearance. If it clears the wheel you just need to build the adapter to hold the caliper in the right place.
If your using an HD front end just use all HD parts, wheel, rotor, caliper.
On a multi pot caliper being better, yes, no, maybe. With the stock 77 up caliper, a more modern rotor and a 11 mm bore M/C works very well. Using a dual disc set up, the stock 14mm M/C works very well.
Once you get the brake capable of skidding the front wheel how much more is better.
Leo