Tiger 800 / 900 - Main Discussion Section > Brakes and ABS

Galfer Rotors

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Originally Posted by Paulhere Race bikes had full floating discs & some Ducati's in years gone by, they rattled like hell.
Normal road bikes were fitted with semi-floaters with some side clearance but with the wavey washers to stop them rattling about, Triumph fitted this type to the 900 Sprint in '94 to replace the previous solid discs, they worked well, similar on the 955 Sprint.
On the 2005 onwards 1050 Sprint they did away with the wavey washers & tightened up the side play but they had a much greater clearance in the bobbins, this allowed approx. 2mm radial movement in the disc on a new bike, notable by the knock while manoeuvring. This play & knock made them wear quickly giving MOT testers cause for concern at relatively low mileage. Aprilia had gone the same way with similar problem. My 955 Sprint discs were still sound at 60k miles while I had this issue with a brand new 1050.
The Triumph discs now fitted on the 1050 & 800 Tigers have virtually zilch side movement, the bobbins are a good close fit, simply allowing for diametric heat expansion of the disc.

This spinning the bobbins idea is imo a load of bollux. I clean my discs occasionally with a scotchbrite pad to remove the transfer of pad to disc. Each to their own on that, it works for me.

I do not have PHD on bobbins, but I have 5 bikes with them, 3 semi-floating, and 2 full-floating.  In none of them, bobbins move around (not a single bobbin) not even if I try to force them with plyers. 

as someone mentioned here correctly, it is about heat expansion, not about bobbins moving around or sideways in a way that you can actually feel the movement with your fingers.  I would say, if a bobbin is moving, the rotor is damaged.  and indeed, not to offend that guy (as he has some good ideas in his videos), he is certainly not an expert on anything, and regarding moving the bobbins around - it is just idiotic.

as to cleaning the bobbins around with brake cleaner and stuff, I am not sure if it makes any difference.  I cannot see how some dirt entering them can prevent basic heat expansion.  but I am not sure here. 

from the manufactures, Galfer and EBC, they just said that there is no need to do anything in terms of maintenance.  I did fit Galfer disc rotors (in UK and USA they call them differently), but just because of their design and superior quality of metal....

I personally prefer the old style disc rotors.  the simpler the better, unless you are racing, riding on the edge of survival...

generally speaking with monoblock callipers, floating rotors make more sense, as the disc pads lack flexibility.  with floating callipers, which are more flexible, I see no need to use any bobbins.  it is a general agreement that floating callipers should be used with fixed or (semi-floating) rotors, and vice versa.  But I have full-floating rotors with floating callipers on my tiger and the combination seems to work just fine.  maybe because the actual difference between semi and full floating is not so big?  if the bobbins are rattling (you can see this on some youtube clips), they are not 'full-floating' - they are simply damaged!


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