Superstar brake adapters

paulski1966

Just fitted up the brakes on my new bike and used superstar adapters (Type 7 PM to PM for 180mm Front and Type 2 IS to PM for 160mm rear) - noticed that they seem to place the brake slightly further out then they should be so that not all of the rotor is grabbed - as can be seen in the pic. Am I missing something here?

Front




Rear

nicklouse

it does seem to be an issue with that shape of rotor. but it does look like they are really for 185 and 165mm discs.

benpinnick

I would expect that there would be some directional text on the mount facing outwards... is it on the right way round (for the front anyhow)?

paulski1966

Yeah there is text stating which way it goes up - have double checked that, even flipped it with no effect.
Not sure if its an issue with the rotor shape (the "wave" outer edge meaning it cannot sit fully in the caliper) or an issue with the adapter.

adamfo

A Shimano 180mm post mount measures 15mm thick at the top bolt hole 9mm at bottom.

XT with avid discs. Work but not optimal.

The Rookie

Look through the back of the calliper, how far from the outboard edge of the pad is the disc at it's highest point?

Kowalski675

Kind of defeats the object of the larger disc, if you're only getting pad contact on two thirds of the swept area.

The Rookie

Kowalski675 wrote:

Kind of defeats the object of the larger disc, if you're only getting pad contact on two thirds of the swept area.

Er no, not at all, only if the pads were 2 far out would it defeat the object.

Kowalski675

The Beginner wrote:

Kowalski675 wrote:

Kind of defeats the object of the larger disc, if you're only getting pad contact on two thirds of the swept area.

Er no, not at all, only if the pads were 2 far out would it defeat the object.

Not sure what you mean by that. From the OP's original pics it's clear the pads are only contacting around two thirds of the swept area of the disc, so will be giving less friction than if the caliper was sitting correctly over the disc and the pads were acting on the full width of the swept area.

The Rookie

Firstly, you can't see pad on disc, so it's not clear, secondly if the disc effective radius (from inside the braking tsic to outside) is larger tan the effective radius of the pad then you just want to match the outer section as thirdly, the actaul contact area has no effect on braking, friction being independant of area.

Kowalski675

The Beginner wrote:

Firstly, you can't see pad on disc

You can see the area of the disc that the pad's been contacting.

The Rookie

Not necesarily, it may be machining marks or differences as it's not been used barely yet.

cobba

You should be able to look in the big gap on top of the caliper where the retaining pin is and see if the braking surface on the pads is overhanging the outer edge of the rotor.

If the pads aren't overhanging the outer edge of the rotor then there isn't any problem to worry about.

Shimano pads are narrow, this is a generic rotor that wasn't made specifically for the narrow pads on Shimano brakes.

This generic Superstar rotor probably just has a wide braking track so it can accommodate other brake brands that use wider pads then what Shimano uses.

Shimano pads also have a chamfered edge on them to make it easier to put a wheel back in, as the pads wear down more of the rotor's braking track will show wear too.

XT 785 pads: http://www.chainreactioncycles.com/Models.aspx?ModelID=92721

paulski1966

adamfo wrote:

A Shimano 180mm post mount measures 15mm thick at the top bolt hole 9mm at bottom.

Thanks for the measurements. Measured the superstar adapter 15mm at the top 8mm at the bottom so pretty much identical.

paulski1966

cobba wrote:

You should be able to look in the big gap on top of the caliper where the retaining pin is and see if the braking surface on the pads is overhanging the outer edge of the rotor.

If the pads aren't overhanging the outer edge of the rotor then there isn't any problem to worry about.

Shimano pads are narrow, this is a generic rotor that wasn't made specifically for the narrow pads on Shimano brakes.

This generic Superstar rotor probably just has a wide braking track so it can accommodate other brake brands that use wider pads then what Shimano uses.

Shimano pads also have a chamfered edge on them to make it easier to put a wheel back in, as the pads wear down more of the rotor's braking track will show wear too.

XT 785 pads: http://www.chainreactioncycles.com/Models.aspx?ModelID=92721

Looking through the top of the caliper I can see that the top of the "wave" design on the rotor meets with the top of the pad - so at this point there is full contact with the rotor - the wave on the rear rotor is not as pronounced, hence why it appears as though there is more contact on the rear. Its not ideal because there is obviously less rotor in contact with the pad at the dip of each wave, however in all fairness looking at many of the other designs out there such as this -



there is probably as much rotor in contact with the pads as with mine. Have been out for a test ride and although the pads aren't bedded in yet they seem to be working fine.

dazz25

I had the exact same problem with my M666 SLX brakes when I upgraded the disc size.

I decided to just get the Shimano adaptors from chainreaction and they fitted perfectly and the pad made contact with the full swept area of the disc.

The shimano adaptors didn't actually cost too much more than the superstar ones in the end.

This is what mine looked like after fitting with the superstar adaptor:

cobba

dazz25 wrote:

This is what mine looked like after fitting with the superstar adaptor:

Where's the photo with the Shimano adapter for comparison.

The Rookie

dazz25 wrote:

I had the exact same problem with my M666 SLX brakes when I upgraded the disc size.

I decided to just get the Shimano adaptors from chainreaction and they fitted perfectly and the pad made contact with the full swept area of the disc.

The shimano adaptors didn't actually cost too much more than the superstar ones in the end.

This is what mine looked like after fitting with the superstar adaptor:

Have you got a photo with the pad in contact with the full swept area of the disc then? As the disc has a larger working radius than the pad, it's just not possible!