Trouble fitting 203mm rear disc, Elixir R

sambasams

hi,

I recently bought some new Elixir Rs, with 203mm rotors front and back.

I fitted the front a few weeks back, went on fine, taking only a few goes to properly center the caliper and get rid of any rubbing.

I came to fit the rear last week, and had a nightmare trying to stop the bloody thing rubbing. I must have spent hours trying to set it up over 2 days, and in the end I had to give up and fit the 160mm rotor I'd just removed, as I was off on a ride in the morning.

I have the correct IS mount for the 203 rotor, so that's not the problem. The Elixirs work perfectly with the 160mm rotor, but I want to get the 203 on.

When I fit the 203, it's very hard to see quite how they can fit without rubbing. I've tried aligning the caliper by hand, with business cards, with credit cards, and it's as if they're just not compatible. The disc also rubs the uppermost CPS washer when they're torqued down. I can get clearance between pad and disc on the inner side, but found it impossible to get clearance between pad and disc on the outer side. It's like the caliper needs to be mounted further outboard...


anyone got any tips?!

nicklouse

so set it up as best then go ride.

it should sort its self as it beds in.

You are not over tightening the bolts.

YeehaaMcgee

The frame IS mounts might be slightly bent, misaligned, or need facing - so that when you extend the mount along it's axix, it throws the calliper out of alignment.
With a smaller rotor, the difference would be less noticeable.

.blitz

Probably no help at all but the Elixir/IS 203 combo on the back of my Voltage works very well. The inside face of the adaptor clears the rotor by the thickness of a credit card but otherwise it all works

May be worth visually centering the caliper with the rotor (disregard the pad position) and go ride. Sometimes there is a minor imbalance in the pistons which is self-correcting if the caliper and rotor are correctly aligned.

Seems odd that the rotor is touching the cps washers can you post some pics?

Chris`I

What discs are they? When I ran Hope 183mm rotors on my old Elixir CRs I had to put a washer to space out the caliper from the disc slightly to stop the contact. This is widely known as incompatability between the older Elixirs and Hope 2 piece discs. My new Elixir 9's fit straight on without the washer, cleared it just fine.

supersonic

If the 160mm works 'perfectly' then I see little reason to change!

sambasams

cheers for all the replies so far...

supersonic wrote:

If the 160mm works 'perfectly' then I see little reason to change!

probably should've been clearer - I'd prefer the extra power! I went out for a ride with the 203 rubbing away and the power was noticeably more awesomer.

Chris`I wrote:

What discs are they?

Avid G3CS... good idea though

.blitz wrote:

Probably no help at all but the Elixir/IS 203 combo on the back of my Voltage works very well.

May be worth visually centering the caliper with the rotor (disregard the pad position) and go ride. Sometimes there is a minor imbalance in the pistons which is self-correcting if the caliper and rotor are correctly aligned.

Seems odd that the rotor is touching the cps washers can you post some pics?

no that is very helpful. I did go out for 5 minutes, gave the brakes a bit of a seeing to, and no change. Didn't try centering the caliper with no regard to the pads though - I'll definitely give that a go.

I will try to have a fiddle, and take photos as well, as soon as I can, but I'm a bit hectic with work at the mo and with a big interview coming up, the missus will give me a right ear bashing if I spend time fiddling with the bike rather than preparing for that.

YeehaaMcgee wrote:

The frame IS mounts might be slightly bent, misaligned, or need facing - so that when you extend the mount along it's axix, it throws the calliper out of alignment.
With a smaller rotor, the difference would be less noticeable.

definitely something to check. cheers.

The Rookie

How does a 203 give more power as surely you can lock the wheel with a 160?

A mate has gone back to a 160 after what was nearly a nasty fall on a steep decent as with a 203 he was either off the brake or locked, he couldn't modulate it well enough. (this was very steep)

YeehaaMcgee

The Beginner wrote:

How does a 203 give more power as surely you can lock the wheel with a 160?

Because you can lock it with less finger effort.
The ability to lock it doesn't mean it has equal power.

The Rookie

So the braking power is the same (limit of tyre grip) then! Yes the brake can give more, but as you can't use it, it doesn't give it!

YeehaaMcgee

The Beginner wrote:

So the braking power is the same (limit of tyre grip) then! Yes the brake can give more, but as you can't use it, it doesn't give it!

I see where you're coming from. However, you can lock up the wheels on a Ford Focus. And you can also lock up the wheels on an F1 car.
That doesn't mean the Focus brakes are just as powerful.

Ultimately, the maximum deceleration is determined by tyre traction, and I agree that it's almost useless having such a powerful rear brake.

sambasams

I might not have tested them in identical conditions but I much preferred the 203, even when it was rubbing like mad.

Also, it was the disc that came with the brakes... I'd have been happy with a smaller disc, but seeing as I've got it now I'm going to want it fitted, aren't I....

bennett_346

Some people like to just tap the rear brake and lock it up, which is fine if it suits your riding style. Personally i like to have to put a bit more effort into locking it because i use the rear brake for both slowing down and for locking the rear to steer down steep slopes (anyone else do this, almost like steering with a rudder?).

.blitz

The 203 is a fine brake if you are a serial brake dragger like me

Compared to a smaller rotor the modulation is not that bad tbh it scrubs off speed in pretty much the same way but when you really need to slow down there's the same power for less effort or more power for the same effort. Of course ultimate stopping is limited by tyre traction but in the meantime a 203 rotor is much more subtle than the stick-through-the-spokes some people think it is.

Works quite well on a big heavy barge like my Voltage esp with me on board