My KTM 950sm suffers from pulsing front brakes, as if the rotors are out of true.
I could replace the rotors, but I need to feed my children: £300 per rotor buys a lot of fish fingers and beans!
I believe the issue is down to the rotors not floating properly on their bobbins. My cunning plan was to put a nut & bolt through the bobbin, then spin it up with my cordless screwdriver for a few seconds. This should loosen any corrosion off and let the disc float.
The question is: should I lubricate the bobbins with anything to stop this from happening again? Was thinking a teeny bit of penetrating oil or perhaps some silicon dry chain oil, like a drop, on a cotton bud, waved gingerly in the gerneral direction of the front brakes, of my motorbike. 🤦🏻♂️
Oh I remember reading something about this on a KTM forum, it might be (if memory serves) a poorly machined hub disk mating surface that distorts the disk slightly causing the pulsing. I think a lip has to be filed down and then the problem goes away.
No lube just do it every so often and see if it cures it 👍
Brakes and lube are not good bedfellows 😁
Make sure you do it both clockwise and counterclockwise
GT-85/WD-40 usually for me if they're getting sticky etc.
The techinque you've seen is about the best plan. However i'd say, in 99% of instances, this is not the cause. It's usually new discs. Sorry.
I (and many others) had this problem years ago with Brembo discs on an Aprilia RSVR. Doing what you suggest with the bobbins temporarily fixed the problem but it always came back. I'd certainly give it a try, at least if it helps you know where the problem is coming from. I wouldn't put any lubricant on, once your wheels get spinning where do you think the lubricant would go...
Yep they're brembo discs & completely amazing when they're working correctly. The bike is totally over braked, but in a beautifully controlled way. They're a right feker when they start doing this though. I think i'm on my third set of discs, the others all thankfully done under warranty.
Won't go near it with the lube then. The thought did make me have the heebie-geebies, but needed to check. Thanks all!
