www.boxertrix.com

Hello all.
There now follows a stupidly intellectual discussion about brake disc material...

You see I have a new fancy front (and soon to follow fancy rear) wheel for the bike.
Not wanting to ruin a job for a 'hapeth worth of tar, I am now looking at new discs to go with my new wheels. Now it strikes me that the thousands of hours of R&D that BMW does results in as best quality item as you can get for the money - which begs the question why there are after market items. And are these said after market items actually any good.

Leaving aside carbon ceramic disc conversions at £2.5k there appears to be three options on top of the Brembo supplied OE.

Galfer wave discs.

Stealth Products wave discs.

PFM Cast iron discs.


These wave discs look good but the theory of them being better is based on them being direction specific and anyone who has looked at them will tell you they are not (not the BMW ones anyway). So they save you about 200g unsprung weight per wheel which is nice but is this weight loss at the cost of effective braking?
A quick look through the Braking/Galfer catalogue soon makes you aware that you must fit these discs with replacement pads. An idiot could tell you why - less metal means it is going to be hotter (despite the cooling fin design).
This brings us to Stealth Products who will happily take your money for a set of fancy discs - like what my mate did. And then these fancy discs warped because he wasn't using the correct rated pad (or something). Which raises this question again of messing with a good design. The results being worse then OE discs - perhaps?

Finally we come to PFM cast iron discs. Some of you may have noticed an advert for these on Ebay. They are listed for the K1200S and R - but the seller obviously is not yet aware that these discs are the same on the R1200s. This means there is a Cast Iron option.

Now I thought cast iron was the kind of thing that racers use. Salesmen will tout how much better they are. But for the man in the street who doesn't go on a race track and isn't giving it 10/10 all the time will these cast iron jobbies be any better then the OE discs? I know they look sort of cool when they rust in about 30 seconds once you get rain, but is the increased friction only in a given work/temperature range?

Brake boffins feel free to dive in...

All I can say about uprated brakes is that I tried my mates zx9 which was fitted with A.P racing brakes and they were bloody amazing. Mind you they cost him about 1300 quid i think

Blimey were to start!! lets do the simple bit first, Stealth are just shite, about on the same level as ART,and 50 quid crash helmets.

You can put what ever discs you like on with a change of pads you'll get an improvement when you've sorted out which pads do what but it isn't going to be life changeing,if it's looks your after i'd go Galfer, are they any better than stock?? certainley my 'Brakeing' on my back wheel isn't.

If you can sort a set of full floaters out then you may!! see some improvement on the sustained front as they don't fade anywhere near as much as stockers.

To be honest without a change of caliper your just talking bling,i would say of the 3 of us who made the effort,Tony Smith had the best set up,although his calipers looked crap!! as he had a full PFM setup including the discs ,PFM made several kits the last sold by Motorworks,but you needed a front Dymag wheel to go with them!!!

Look at Beringers,there is a uk importer and they are certainley very speacial i saw a set on an 1100s at the Italian GP a couple of years ago,so i see no reason that you couldn't get somthing sorted for your 1200,although when used in wet weather have a habit of welding the pads to the discs overnight,i had a moment a couple of years ago with my Tiger when i couldn't my Tiger of the ferry cuz i couldn't move the front wheel!!!

Alot depends on how serious you are,most are happy to change a cat and put Ohlins and thats it,both Boxerpan and myself along with Smithy have been on a bit of journey over the years which i guess is comeing to an end,probably 90% has never appeared on this board,it isn't easy,and it ain't cheap,but all things are possible,but has been fun,just finding out who knows who in brake manafactureing has been an eye opener.

Is it all worth it??, i've a few laughs over the years with people trying to out brake me and i've been two up!!! but cheap it ain't.

There are definately differences in brake discs and performance. Most of which is in the material used for the discs. Stainless discs don't rust and have little wear, but they brake less. Cast iron brake much better, but they rust and wear faster. And there are several steel alloys that are somewhere in between.