Warped discs ?

[sedge]

OK, here's the story...

I take a bike out for a test ride, the brakes are shite, juddering at high sppeds and grabbing at low speeds as it's coming to a stop. I like the bike apart from that and its quietness.

So... I say, I'll buy the bike at sticker price, but I want the brakes fixed and an extra set of loud pipes coz it sounds apologetic.

Deal done.

The shop tells me the brakes are not warped and it must just be me coz they can't feel anything on their test rides. OK.

I take the bike to another shop for a second opinion (well, this is incidental, I just wanted it checked over in general for bad stuff) They put the dial on the discs and it says they are warped.

I go back to shop A and they say OK, we'll replace the discs and pads (awesome of them) and they do.

Unfortunately, after 200ks of gentle braking the brakes still feel like poo, grabbing at low speeds and juddering braking down through 80-60.

I take the bike in for a full service to my normal shop, valve clearances, new tyre on the front to match the rear etc (just in case it was the tyre) and get them to check the discs while they are there... Dial says "Discs are a bit warped" ? WTF ?

What do I do now ? How could both discs be warped from new ? I've been using them like a nana for 100s of Ks like they asked, but they are still shite.

I ring shop A and they say talk to shop B and get them to deal with where shop A bought the discs.

What else can cause these symptoms ? I don't want to bug shop A as they are still trying to find me a set of exhausts and if I annoy them I'll get shite ones. Shop B costs me money, what else can I tell them to narrow the search ?

I definitely don't think I'd get a set of discs both warped from new... Can shite fitting cause this ? How can I work out what's wrong for myself ? Do bent forks / bad bearings / bent axle show up on a disc dial guage ?

Tell me quick coz my warantee runs out soon.

Cheers,

Sedge.

[number33]

Junk the obviously modern plastic jap sportbike shite and buy an old dunger with proper discs that never warp.

[.produKt]

As a suggestion , take it back, and get them to put a entirely different wheel on the front with its brakes still on.

Doing this will at least assertain if theres anything wrong with the wheel

[Sketchy_Racer]

where the disk bolts onto the wheel in six palces ( or close enough)
one of the bolt points may be lower than the other so that when the disk is tightened up it trys to warp it, then when it gets a bit of heat into it from riding the metal bends....

all just a theory....