07 S2R 800 Big Brake Question

[CabbageFumes]

I picked up an 07 S2R 800 that came with 300mm brake rotors originally, but the previous owner attempted a big brake conversion and did it poorly. The rotors are 320mm, which is expected. The calipers are gold 900/750/etc as expected. I've read that this is a pretty straightforward swap, but something in this particular swap isn't right. The calipers have the mounting ears ground down about 5mm for the rotors to fit. This can't be right. I've confirmed that the calipers are the ones that are supposed to be the ones that are a plug and play fit. Is it possible that the rotors are from an incompatible model with too much offset? I can see the rotors sticking out on either side when looking at it straight on. If the rotors had half as much, or maybe no offset, it seems like the calipers would line up correctly. What am I missing here?

[Howie]

That is the problem.  Another problem is I don't remember what offset you need.

[CabbageFumes]

That is the problem.  Another problem is I don't remember what offset you need.

that is the problem meaning I have the wrong rotors? It's been a rocky road so far. I picked up a pair of original calipers and of course they were way off. I picked up a pair of original style rotors and the hub flange is larger on the wheels I have now, which means I would have to get the original style wheel with the smaller 300mm hub flange. So, unless I get new wheels, I need to get this to work. Being new to this bike and Ducati in general, does anyone know if I need 0 offset rotors, or another version of the rotor that has less offset than the ones I have now?

[stopintime]

If ( IF !!! ) the calipers are correct you'd normally need discs from one of many Ducatis. They are called 10mm offset, but if you measure they're not actually 10mm, but close enough. "Close enough" because the only alternative is 15mm offset (from 999R I think...)(or something similarly unique)

[CabbageFumes]

If ( IF !!! ) the calipers are correct you'd normally need discs from one of many Ducatis. They are called 10mm offset, but if you measure they're not actually 10mm, but close enough. "Close enough" because the only alternative is 15mm offset (from 999R I think...)(or something similarly unique)

the calipers are the standard 4 pot gold that most Monsters had around 2000. The rotors that are on the wheels I have stuck out a generous amount past the outside of the rim edge. The same as I have calipers that came in the bike had about 5mm ground off of the mounts, so it's possible that I have the 15mm style rotors that required 5mm of the caliper ears removed.

[Duck-Stew]

748R is the culprit.

Same bore to fit the wheel.
Same six bolt pattern on the same diameter.
Increased rotor offset, because ??

I borrowed a 748R rotor once to test fit something.

[Duck-Stew]

..snip.. from 999R I think ..snip..

749/999 bikes dropped a rotor bolt and went down to 5.  The R bikes may have had an increased offset though.  Don't know.

[CabbageFumes]

749/999 bikes dropped a rotor bolt and went down to 5.  The R bikes may have had an increased offset though.  Don't know.

The wheels I have are 5 bolt, larger than the S2R 800 bore. I think the center bore is 70? Anyway I measured the rotors that were on my wheels, and they are 15mm from bottom mounting surface to top surface of disc. I think I'm looking for a 759 style rotor? 320, 5 bolt, large bore(I don't know if all 5 bolt are large, compared to 6 bolt, small center bore that was original to the bike), and 10mm offset.

[Duck-Stew]

Five bolt front wheel on an S2R, well, someone's done a swapper-o.

Could be 749/999 bits.  Maybe S4RS.

[CabbageFumes]

Five bolt front wheel on an S2R, well, someone's done a swapper-o.

Could be 749/999 bits.  Maybe S4RS.

This is my dilemma. With the original forks, adding these wheels/rotors/calipers was close, but not compatible as far as rotor-caliper alignment. The prior guy just hacked away at the caliper ears until they sorta fit. I sourced a replacement set of calipers, now I just need to figure out whether a pair of 10mm offset rotors are the fix. 

[stopintime]

Not sure, but you describe a "10mm" offset. The disc is 5, so there's 10 left for offset.

[CabbageFumes]

Not sure, but you describe a "10mm" offset. The disc is 5, so there's 10 left for offset.

Most of the earlier 320MM rotors, with the exception of the Rs are supposedly 10MM offset, but that measurement isn't literal as far as the offset itself; This is measuring from the flange surface to the top of the rotor surface. Assuming that the rotor is 5MM thick, the 15MM rotor would have an actual offset of 10, but is called 15 because of the way it's being measured. My rotors stick way out from the edge of the rim, and when one of those rotors is laid on a table, a rule against the side measures 15MM, table to rotor top surface. When the wheel is fitted with these rotors, the calipers sit too far inboard, eyeball measurements say about 5MM too far. My hopes are that the other version of this 320MM rotor which people repeatedly say is an easy bolt on upgrade, will sit on the same table and measure 10MM total. From what I've read so far, there is flat, 10MM, and the 15MM "R" versions of the 320, and I'm being told those numbers come from being measured from flange to outside of rotor. I gotta tell ya, this is way more work than I think the "upgrade" is worth.

[ducpainter]

Didn't you say the calipers have already been ground down by ~ 5mm?

How can you make a decision about offset when your calipers have been butchered?

[Howie]

Didn't you say the calipers have already been ground down by ~ 5mm?

How can you make a decision about offset when your calipers have been butchered?

Yep.

[CabbageFumes]

Didn't you say the calipers have already been ground down by ~ 5mm?

How can you make a decision about offset when your calipers have been butchered?

Yep.

I guess you guys didn't read this:

This is my dilemma. With the original forks, adding these wheels/rotors/calipers was close, but not compatible as far as rotor-caliper alignment. The prior guy just hacked away at the caliper ears until they sorta fit. I sourced a replacement set of calipers, now I just need to figure out whether a pair of 10mm offset rotors are the fix.