I want to improve the rear brake on my Multistrada. Motul rbf660 or Castrol react srf? There’s a difference in the range of temperatures that the two work within. As I understand it they’re a significant improvement on the standard brake fluid. There’s a big difference in the cost of these two. Will I be happy enough changing Motul 660 a bit more regularly than the much more expensive Castrol? Has anyone tried either or both?
I've tried both but not on the rear brake as I don't use it. They both work really well at high temperatures on track but I now only use the 660 because of the cost. I never noticed any difference in performance between the two.
Thanks, that’s good to know. The problem on the Multi is it’s proximity to the Catalytic Converter. The heat radiated from it effects the useable length of life of the fluid. Motul is good to 600 degrees and Castrol to 590. BUT in wet climates the Castrol is much better....apparently.
Wet climate? Are you referring to the wet boiling point? There’s two figures quoted for the fluids. The dry is for brand new fluid. The fluids will absorb moisture over time and the wet figures refers to this. I think it’s about 4% water content. Moisture content affects performance drastically. I don’t use Castrol but Motul suggest the 660 is changed annually vs. changing regular fluid at 2 years for instance. Most high performance fluids absorb moisture faster than regular DOT 4 or 5.1
To be honest I’d be amazed if you’re getting that much heat in your rear brake ? srf is the king but it’s overkill to be honest.
Gulf racing rbf in my 500hp elise. It needs brakes and the gulf fluid is superb. Change it every spring or more often if you live in damp parts or store the bike outside..
it's it's high "wet" boiling point ability that will hopefully help cancel out the inherent problem with constant heatsoak on the rear system that's makes it desirable rather than the on-track performance. If it works then it could mean you could have a working rear brake for longer between bleeds.
Yes I was referring to the wet boiling point. Just couldn’t remember the exact term. Thanks for the feedback. Something makes the Multistrada rear brake famously useless. I might as well start with a decent fluid. Then bleed it with the rear calliper unbolted and suspended high in order to get all the air out. I have to say, after all these years it is something that Ducati should have sorted out. Along with the ridiculous slop in the throttle’s.
Apparently the Motul has a wet boiling point of 400 degrees. Whereas the Castrol has a wet boiling point of 520 degrees. Given that they have dry boiling points of 600 & 590 degrees respectively the Castrol should give better performance for longer but at a huge price difference. Maybe it’s cheaper and just as effective to bleed the system every year with the Motul. Presuming you’re doing it yourself. It’s not difficult with the right kit is it. Motul also comes in a smaller bottle which is good unless you can share a 1ltr bottle of Castrol between various bikes you own or share with various mates.
RF1000 617f dry........£15.95 for 500ml...did I mention I use this in my 500hp Lotus on track days etc..and in my 1299S..buy it from OPIE...it works.
Unfortunately, it is a bit of a pain, removing the whole caliper and suspending it up high while you bleed, this being the only way to guarantee the best pedal. You must have done yours once or twice by now though i’m guessing?
I’ve bled brakes before but not this one. It was done in the service earlier this year but it isn’t as good as my Panigale rear brake or my Monster rear brake. So I thought I’d start with the fluid and see. Hopefully more frequent replacement should do the trick. The next stages would be different pads then onto to replacing the disc. One step at a time though.
I’m a rear brake user, the bike is on its second rear disc and third set of pads in 35000 miles. I started to use Motul 660 in the Multistrada because that is what I have used for every incarnation of track bike over recent years and had a bottle when I needed it. Did the whole 9 yards with removing the caliper and then weighting the pedal overnight. I’ve not had a problem since and have only bled the system again once since. The rear brake suits me now but I did manage to cook it during a spirited descent out of the Picos. Pleased to say after letting it cool, the pedal came back and was fine for the rest of the 2000 mile journey. That was why I subsequently bled the brake on my return. Andy
