Warped brake disc's

[Andy XRV]

Just picked up my SD GT after a 7,000 mile, 1 year service and I've been told the front discs have warped due to heavy breaking.... I've also been told that although they shouldn't warp replacements are not covered under warranty?

The bike is marketed as "cruise missile and a "superbike slayer" so surely the discs should be able to cope with a granddads braking?

Seems piss poor to me so I'm going to peruse it with KTM.

[TimmyMallett]

No aftermarket brake levers I hope?

[Andy XRV]

Nope, standard levers. Not even tracked this one

[fredd1e]

Warped or pad deposits? Managed to get pad deposits on my old KTM1190Advs front disks, which I believe was caused by a hard stops during commute and then holding the bike on the brake, so pads cooked onto the hot disks. It was a big heavy and fast bike so it didnt take much to get the disks hot.

[Krikkit]

Sounds mental, I'd definitely pursue it with KTM.

Worst-case you might be able to get the disks machined to bring them back into spec, depends how far the runout is I suppose. I assume you can feel it when braking?

[Kevin_Birth]

fredd1e said:

Warped or pad deposits? Managed to get pad deposits on my old KTM1190Advs front disks, which I believe was caused by a hard stops during commute and then holding the bike on the brake, so pads cooked onto the hot disks. It was a big heavy and fast bike so it didnt take much to get the disks hot.

yeah id check this as well. I cant believe that the disks on a SD would warp unless you hammer round a track then dunk it in the nearest river or something.

[trickywoo]

Andy XRV said:

Just picked up my SD GT after a 7,000 mile, 1 year service and I've been told the front discs have warped due to heavy breaking.... I've also been told that although they shouldn't warp replacements are not covered under warranty?

The bike is marketed as "cruise missile and a "superbike slayer" so surely the discs should be able to cope with a granddads braking?

Seems piss poor to me so I'm going to peruse it with KTM.

Did you think they were warped?

If you can't feel a problem just carry on.

It wouldn't be the first time a dealer has tried to bend someone over on brakes.

You need to ask more questions like did they do a run out test and if so what are the readings vs spec?

If there is a problem it could be something as simple as needing to clean or replace the disc bobbin buttons.

[the cueball]

My mate has a SD and he's had 3 sets of discs replaced under warranty, maybe depends on the dealer?

[doggydog33]

SDR’s are known for it. I think it’s a bad machining/alignment problem. My SDR squeaked from new when pushing slowly/slow manoeuvres.
They weren’t warped, (nothing you could feel through the lever), but you could feel it when pushing the bike around.
Maybe this is what they are feeling when they’re pushing you bike in the workshop?

Doggydog33.

[Andy XRV]

Cheers guys, I wondered if there was a problem with SD's. Definitely some pulsing going on when gently braking from speed but not enough to worry about yet. Before I start pushing for new discs I will check for pad build up to as that's a new one to me.

[Zarco]

It's pad deposits that make the discs feel warped (they are not).

Try a series of hard stops to clean them up. It's worked for me on a car before (deposits after a track day).

[Hungrymc]

Kevin_Birth said:

fredd1e said:

Warped or pad deposits? Managed to get pad deposits on my old KTM1190Advs front disks, which I believe was caused by a hard stops during commute and then holding the bike on the brake, so pads cooked onto the hot disks. It was a big heavy and fast bike so it didnt take much to get the disks hot.

yeah id check this as well. I cant believe that the disks on a SD would warp unless you hammer round a track then dunk it in the nearest river or something.

My money is on this. I think warping is often diagnosed when it’s contamination or deposits (lots of heat and / or rain when the brakes are held on).

[Steve Bass]

If you can, measure the run out on the edge of the discs where deposits can't form. This will confirm if it's the discs or deposits.

[Andy XRV]

Not overly scientific but good enough to see it’s definitely not running true.

[Steve Bass]

Andy XRV said:

Not overly scientific but good enough to see it’s definitely not running true.

Glad to see you picked up on my brainwaves.. . 100% no need for a dial gauge you clever monkey you .

Bottom line, if the disc isn't runnuing true at it's out edge where the pads don't sweep, the disc is warped.
IOf the disc is true at the edge, it's likely to be deposits on the disc surface that can be easily taken off.

also, might not make a difference but make sure the bobbins aren't jammed up if they're floaters. WD40 and a good rattle might free them up

[Andy XRV]

Steve Bass said:

Glad to see you picked up on my brainwaves.. . 100% no need for a dial gauge you clever monkey you .

That's what I say the grandkids

I gave the bobbins a quick check and a gentle lube so I'm pretty sure they're OK so it is the discs. As it seems to be a known problem I'm going to call the dealer I bought it from tomorrow to see if their response is better than the guys in Crawley. I'll see how I get on......

Cheers for the help everyone. Top advice as always.

[Steve Bass]

Andy XRV said:

That's what I say the grandkids

I gave the bobbins a quick check and a gentle lube so I'm pretty sure they're OK so it is the discs. As it seems to be a known problem I'm going to call the dealer I bought it from tomorrow to see if their response is better than the guys in Crawley. I'll see how I get on......

Cheers for the help everyone. Top advice as always.

Good luck.

If they don't come through and you're left hanging, maybe look at a decent set of discs like Brembo T Drives. These SDR's seem to eat the standard discs!! It might be the thickness of the disc not standing up to the heat generated by the pads and caliper and a lack of heat dissipation.....

[Andy XRV]

Sounds like a proper Plan B. Might even turn that into Plan A.....

[Biker 1]

Andy XRV said:

That's what I say the grandkids

I gave the bobbins a quick check and a gentle lube so I'm pretty sure they're OK so it is the discs. As it seems to be a known problem I'm going to call the dealer I bought it from tomorrow to see if their response is better than the guys in Crawley. I'll see how I get on......

Cheers for the help everyone. Top advice as always.

I assume you are talking about P & H Motorcycles(??) I have dealt with them over many years & have always found them fair & professional. Around 5 years ago I had a leaky oil seal on a KTM which was sorted very quickly by them under warranty; if discs are shot, I think they should be replaced under warranty. Much as I like KTM, they do seem to have some strange quality control quirks.

[Steve Bass]

Out of interest, what's the nominal thickness of the standard discs?