slotted rotors

[foreda]

CAD File

Yep.. I have the CAD files and was even tossing around the idea of an aluminum template to clamp on to the rotor(s) to be drilled.
Thanks to Brian for sending and sharing the drawings.

[Ken Talbot]

I'm sure by now you've found the tech article on doing your own drilled rotors....

[je2wheeler]

Years ago, when I was still an all weather rider, I tried an idea of removing the front pads that were soon needing replaced anyway, scribing lines every ¼ inch across the pad material slightly angled off the rooter sweep. Then using my calibrated eyeball and hacksaw, cut lines about an eighth inch deep. This did improve wet braking noticeably and became standard practice for me until my next bike that came with slotted rotors. Three things keep from this practice on my ’79 Special – I am now a fair weather rider – I wish to keep my XS11SF as close to stock as possible and - those swinging calipers freak me out enough already.

[crazy steve]

That used to be standard on pads for non-drilled rotors; the factory pads had a slot cut in each pad, and even aftermarket pads had that slot. But they seem to have deleted this on some newer pads, probably as a cost-cutting measure...

[fredintoon]

- - - I am now a fair weather rider – I wish to keep my XS11SF as close to stock as possible and - those swinging calipers freak me out enough already.

Hi je2,
even fair weather riders may have to ride home in the rain.
IMHO drilled rotors would be an OK upgrade.
Or if you could swap in a set of slotted rotors (or had a bro with milling machine) your '79 could pass for an '80.
Yeah, me too. But save heroic modification we are stuck with them, tapered pads and all.

[CatatonicBug]

That used to be standard on pads for non-drilled rotors; the factory pads had a slot cut in each pad, and even aftermarket pads had that slot. But they seem to have deleted this on some newer pads, probably as a cost-cutting measure...

Isn't that slot (usually vertical) designed as a "wear marker"? Once you get to the bottom of the slot, that's when you're supposed to replace the pads. I can't imagine a vertical slot having any benefit in terms of water dispersion.

[natemoen]

Isn't that slot (usually vertical) designed as a "wear marker"? Once you get to the bottom of the slot, that's when you're supposed to replace the pads. I can't imagine a vertical slot having any benefit in terms of water dispersion.

There were other grooves in them other than the wear marker groove.

[subike]

Im not sure of my information but I do recall that Mikes XS sell sets of drilled floating rotas for the XS650 that fit the XS1100 Std only.
If this is correct, then this could be just a cheque book upgrade for those of us that dont have access to machine shops or the time to do this job.
Could be worth a look into for some members, or even get conformation from somebody who has used MikesXS rotors

[crazy steve]

Isn't that slot (usually vertical) designed as a "wear marker"? Once you get to the bottom of the slot, that's when you're supposed to replace the pads. I can't imagine a vertical slot having any benefit in terms of water dispersion.

'Bug, you'll sometimes even see these slots on special caliper pads. They do zero good as wear indicators on those as you can't see them until the caliper is off.

How much good do they do? Not a lot, but something's better than nothing...

And the Mikes rotors require that you space the calipers closer to the wheels; nobody has reported if there's enough room on a XS11 to do that...

[cywelchjr]

Isn't that slot (usually vertical) designed as a "wear marker"? Once you get to the bottom of the slot, that's when you're supposed to replace the pads. I can't imagine a vertical slot having any benefit in terms of water dispersion.

Anything that gives somewhere for water and/or gases (formed under braking as the material outgases) increases braking power. One of the reasons for drilling or slotting rotors is to increase braking power by letting the gases that form from the friction and heat of stopping the vehicle. With solid rotors the gas builds up between the pad and rotor and it takes more force to hold the pad against the rotor for braking. And water on the rotor is even worse, far worse. Its not just the water per say, but that it can flash to steam under braking and the drilling or slotting lets it escape out from under the pads.

[natemoen]

And the Mikes rotors require that you space the calipers closer to the wheels; nobody has reported if there's enough room on a XS11 to do that...

Is that with all 650 rotors or just the ones from mikesxs? What about the brembo ones at 650central?

Anything that gives somewhere for water and/or gases (formed under braking as the material outgases) increases braking power. One of the reasons for drilling or slotting rotors is to increase braking power by letting the gases that form from the friction and heat of stopping the vehicle. With solid rotors the gas builds up between the pad and rotor and it takes more force to hold the pad against the rotor for braking. And water on the rotor is even worse, far worse. Its not just the water per say, but that it can flash to steam under braking and the drilling or slotting lets it escape out from under the pads.

Now from my understanding and research the gassing off from the friction is no longer an issue with asbestos free pads. It was mainly only the asbestos that caused the gas so the floating is no longer an issue. The water steam is different though.

[crazy steve]

Is that with all 650 rotors or just the ones from mikesxs? What about the brembo ones at 650central?

Well, 650 Central lists both the Brembo and the XS Performance (which Mikes sells too) rotors, and both kits mention 'longer caliper bolts and spacers' so I would have to assume that you're moving the caliper with both kits. Neither says just how much.

But for that kind of money (you'd be looking at $260+ plus for the cheaper rotors, and over $500 for the Brembos!) I would think that a caliper swap would offer a much better bang for your buck. A guy could afford some custom-machined adaptors at that price...

[natemoen]

I agree, they are not cheap!

[cywelchjr]

Now from my understanding and research the gassing off from the friction is no longer an issue with asbestos free pads. It was mainly only the asbestos that caused the gas so the floating is no longer an issue. The water steam is different though.

That may be claimed, but I watched an episode of Horsepower TV where they put drilled and slotted rotors on a Camaro Z28 and it decreased the stopping distance significantly. The only thing that could be causing that would be the gassing. It may be less of an issue, but under heat any material that is used for friction is going to be ablating, and it usually does that by turning into a gas or dust, both of which slots or holes would allow to get out from under the pads easier.

[79XS11F]

You can get a marked improvement by replacing the original brake lines with SS lines and completely rebuilding the brake system so it works as it did when the bike was new. This must include honing the MC and caliper piston bores and new rubber parts across the board. If you want added performance over and above that, then you will be wanting to look into lighter full floating rotors and they are not cheap. Full floating rotors allow for the maximum pad to rotor contact any time the brakes are applied.
Rob