Correct Rotor Offset

OverCaffeinated · February 03, 2009, 02:41:36 PM

I'm trying to figure out a few thing here. What is the correct way to measure rotor offset, then figure out what offset are the rotors I just purchased.

The first pic is from ISR brakes offset measurement.:

This is the second option, which I first would think to be correct:

There was a similar question posted on another board, but never clearly answered.

Secondly, what is the standard method of checking for warping?

TAftonomos · February 03, 2009, 03:28:54 PM

What rotors did you purchase?

I believe it's the second way as you suspect, but we can confirm it if you let me know what model they came from, or what aftermarket pieces they are.

OverCaffeinated · February 03, 2009, 03:34:49 PM

"I got it on Ebay"

Brembo off a 2002 Monster S4.

If I measure the first way I get 10mm, 5mm the second.

Even if crosschecking the model of bike can confirm what they are, I'd still like to know the correct way of measuring. Say if I found some rotors in the gutter and wanted to figure out the specs, without knowing the bike they came off of.

TAftonomos · February 03, 2009, 03:56:46 PM

They are 10mm offset then, and the first way is the correct way. By knowing what the offset is, and then measuring them, you can deduce that the first way is the correct way to measure them.

Good to know

Speeddog · February 03, 2009, 03:59:18 PM

So then S2R800/M695 rotors would be 5mm offset by that method.

TAftonomos · February 03, 2009, 04:04:11 PM

yup

.

And my 07 S4R rotors measure out to be 15mm, which they are.

It's outside to outside. Kinda strange, but it is.

Speeddog · February 03, 2009, 04:11:39 PM

OK, that's good confirmation.

TAftonomos · February 03, 2009, 04:28:28 PM

Whats kinda strange. The one guy that was selling the gsxr conversion and said he didn't need a spacer at all was using brembo HP rotors. To my knowledge, brembo HP rotors are 6 bolt, 320mm but 15mm offset like the corsa rotors and 748r/998r rotors.

Desmoworks website lists the HP rotors but with a 10mm offset, which is standard.

Everyone says you'll need the spacers (5mm correct?) to work with the 916 rotor (10mm offset)....

Something isn't adding up. What concerns me, is if I only need a 10mm offset rotor, well...mine are 15mm. So I either have to find a 5 bolt rotor (have to have a custom carrier made), or maching 5mm off the wheel.

Maybe Swift will respond with the part number or measure his HP rotors to confirm. I guess I'll know soon enough when the forks arrive, but I'd like to have a good idea (thought I did) going into the swap.

OverCaffeinated · February 03, 2009, 04:32:11 PM

And I thought my s2r800 had 0 Offset rotors? I will check when I get home.

Maybe these are questions Q-Factor can answer.

Speeddog · February 03, 2009, 05:06:53 PM

Quote from: OverCaffeinated on February 03, 2009, 04:32:11 PM
And I thought my s2r800 had 0 Offset rotors? I will check when I get home.

Maybe these are questions Q-Factor can answer.

well, they would be 0 offset by the second method in the OP.

5mm by the first method, since they're 5mm thick.

TAftonomos · February 03, 2009, 05:10:46 PM

Swift emailed me back a part number, and he was using the 10mm offset HP's.

Makes no sense to me, they are the same offset as the 916 rotor, yet people that used the 916 rotor had to use a 5mm spacer and he didn't ?

OverCaffeinated · February 03, 2009, 05:51:35 PM

Confirmed. My rotors are flat. 0 offset 5mm offset. Whatever.

I think I mentioned somewhere that swift used gsxr 600 750 forks. Maybe that's the diff.

TAftonomos · February 03, 2009, 05:56:04 PM

I just dont want to have to machine the wheel down 5mm..... because I doubt I can afford custom rotor carriers

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Correct Rotor Offset