17" front wheel brake issue

[Mustang505]

Hi All
I've been using the original 16" front wheel since owing my sport. About 2 years ago upgraded the brake callipers to the common 40mm spacing Brembo using adaptor brackets from Bevelheavan on the 280mm disc. All fitted good and worked pretty well. So far so good.
Finally got hold of a 17" Brembo front rim (it had 320mm discs - ditched) so I could go the full hog and fit floating discs and of course fit extra sticky rubber. So I bought 300mm Discs off Metalgear (standard fit to 907 and earlier 900ss) only to find that the discs don't line up with the callipers. They are approx. 10mm inboard of the callipers.
These have a 9.5 mm offset which is standard but obviously does not fit my set up. BevelHeavan sell 300mm discs identical except they have a 26.5mm offset which would be too much.
Anyone experience something similar when doing the 17" front conversion? Do I need to find other adaptor brackets?

[bmw851]

Clive, if I've read your post correctly, you should just need a 10mm spacer ring between the disc and hub on each side to offset them out enough to line up with the caliper's, fairly common problem I believe with the 17 conversion, the disc's on mine were done that way, with longer disc mount bolts etc.

Drop Dave Ward at Motoitalia a line from memory he carry's the apdators in stock usually.

info@motoitalia.com.au

Cheers

Peter

Edit: have attached this just to clear about what was done on mine, the front wheel is a Brembo 17" & 3.5" wide donated from a Monster 600 with 320 rotors fitted.

Disc Rotor Spacer Ring.jpg

(115.09 KiB) Downloaded 226 times

[Mustang505]

thanks Peter
I did think of that but wasn't too sure if that was an okay thing to do with brakes.
I send him an e-mail and see if they have.

[ducinthebay]

Not sure what you are facing here. Can you post a pic so we can see the parts you have and the offset problem you have?
I spaced my calipers inboard, but only with a single washer to move it 1.5mm inboard. Which calipers are you using?

Cheers, Phil

[Mustang505]

Thanks Peter.
yep that's exactly it. I phoned motoitalia yesterday and he has in stock 6mm spacers which might be about right. thanks for your help.

[Mc tool]

Must be the wheel Clive . My 300's have the same 9.6mm offset but my disc's are only 14mm from the inside of the fork and the wheel is 106mm wide ( from disc flange to flange )

[bmw851]

Thanks Peter.
yep that's exactly it. I phoned motoitalia yesterday and he has in stock 6mm spacers which might be about right. thanks for your help.

My pleasure Clive glad to be of help.

Dave is a damn good guy to deal with, with absolutely no BS.

Cheers

Peter

[Mustang505]

Must be the wheel Clive . My 300's have the same 9.6mm offset but my disc's are only 14mm from the inside of the fork and the wheel is 106mm wide ( from disc flange to flange )

hi Mc
not the wheel. quick measure I got 105mm wide off mine so obviously the same. it's to do with standard M1BB shock mount points for the calipers with brackets from Bevelheaven. If measure across discs on the 16" wheel with the standard 280mm discs = 142mm. Off the 17" rim with 300mm discs = 122mm. so difference = 20mm/2 = 10mm. And that's the exact problem when you try the mount the caliper once the 17" rim is in place.

[ducinthebay]

I guess I just got lucky and had more offset on the rotors that I have used. I have used the stock Yamaha 300mm rotors, and now have Brembo cast iron rotors. But looking at the picture posted, those calipers don't have as much offset as mine do.

Are the brake adapters the same on the inside as they are on the outside? If you took the adapters off and switch the fork leg they are bolted onto, does that change things? I just looked at the adapters offered by Bevel Heaven, and it doesn't look as though those can be swapped easily as the sunk the heads for the fork mounting bolts.

My brake caliper adapters are straight sided, so it doesn't matter, but I have seen some of them have some amount of offset to them. (though not much) I also didn't sink the heads on my adapters so I just swapped them around until it worked. My adaptors were made by my friend from files on the net. We scrimped on the details.

Cheers, Phil

[bmw851]

I kept thinking there just shouldn't be so much variation, then remembered we are talking about Ducati's here

The rotors on mine also have bugger all offset, very technical term that en all.

Logic doesn't seem to apply, if the wheel is centred then everything should line up, wrong.

Overall Width of Disc's fitted

IMAG0605.jpg (21.64 KiB) Viewed 11835 times

R/H has 10mm + 2mm packing spacer to get the caliper centred on the disc

IMAG0611.jpg (20.61 KiB) Viewed 11835 times

L/H has a 10mm spacer on the mounting plate.

IMAG0607.jpg (24.07 KiB) Viewed 11835 times

Looks a bit agricultural but all hangs together, and more importantly had no problems with any of the components given the type of braking that was being done from relatively high speed.

Elsewhere on the site are links to tech drawings for alternate mounting plates to suit 300 and 320 rotors, which shouldn't cost that much to have made up if worse comes to worse, will have a search and try and find the links for you.

What brand of wheels are fitted to yours Phil?

Cheers

Peter

[bmw851]

This one could be good

https://app.box.com/shared/gj6cbxn48w

[paso750]

imo those offset problems are just caused by the combination of parts. (old P08 calipers with newer discs). The P08 have a different center position than the P4.
Phil is using the black 4pot Brembo calipers and 300mm Yamaha discs which is the setup of the early 907ie therefore it all fits. Of course he could also fit 320m discs with the adapter just posted and it would still all fit.

[ducinthebay]

Yeah, the 4 piston calipers have the mounting flanges further inboard, so that the spacers you have against the fork legs won't be needed, and it all fits in tighter and neater. The 4 piston calipers also changed to threaded mounting holes, so there isn't any need for nuts. But you do need to get the mounting bolts the right length, or else they hit the rotor.

Also, confirm that your front wheel is indeed centered. If you use the speedo drive from the 17" front wheel, it will offset your front wheel to the right. The 907 fork leg had a slightly thinner fork leg where the axle goes through the left leg. I machined my fork leg to get the whole thing centered again. (not an simple set up in the mill.) I also tried the old speedo drive, which was narrower, and added washers.

I am using std. brembo wheels. I had an 748 wheel on there for a while, and now have a white front wheel from a 907. Both seem to have the same width.

Cheers, Phil