Warped disks?

[MacLean]

On the bike heavy braking feels great.

The issue is when I get down to say less than 20mph and very gently apply front brakes, i can feel a fast pulsing as if an imperfection is going round and round the disks.

Results in a very stuttery braking sensation, when im being gentle.

So I read somewhere that if you dont feel it when braking hard and only when gentle as in my case, then it could be just some surface shite that will wear itself away after some usage for a while.

It also lets out a good squeel just as you come to a hault.

I've had a look and there is some expected scratches on the disc in the usual pattern, but nothing obvious. Is this likely warped discs? Or should i say disc thickness variation?

The bike has these wavey discs which came on it when I bought it, which if replacing I will probabbly just put normal ones back on.

[Guest Hodgy]

When I had a warped disc, I could feel a pulsing sensation at all speeds, it was just faster when going fast, so hopefully just something on a part of the disc surface that the pads are passing over, it maybe worth giving them a good clean with some brake cleaner?

[Boothy]

On the bike heavy braking feels great.

The issue is when I get down to say less than 20mph and very gently apply front brakes, i can feel a fast pulsing as if an imperfection is going round and round the disks.

Results in a very stuttery braking sensation, when im being gentle.

So I read somewhere that if you dont feel it when braking hard and only when gentle as in my case, then it could be just some surface shite that will wear itself away after some usage for a while.

It also lets out a good squeel just as you come to a hault.

I've had a look and there is some expected scratches on the disc in the usual pattern, but nothing obvious. Is this likely warped discs? Or should i say disc thickness variation?

The bike has these wavey discs which came on it when I bought it, which if replacing I will probabbly just put normal ones back on.

 

I'd start with the calipers, clean them out and check that the pistons are all moving freely.

[MacLean]

Thanks guys,

Yeh I get the feeling it isn't as straightforward as warped discs, as i should be feeling a vibration at all speeds.

I think I will take it all appart and get stuck in with brake cleaner and give the whole lot a good scrub....

Would it also be a reasonable idea to give the pads and discs a light sanding do you rekkon?

If still not right after a good scrub up then I guess i'll just have to deduce that something aint right with the discs.

[Guest Hodgy]

placing a piece of sandpaper on some glass (to make sure its flat) is a good way to remove anything from the surface of the pads.

Another thing to have a look at if your bike has 'floating' discs, is all of the little spring loaded rivets that fasten the friction surface of the disc to the carrier are all loose and not stuck full of rust or crud, making the disc stick in places

[MacLean]

placing a piece of sandpaper on some glass (to make sure its flat) is a good way to remove anything from the surface of the pads.

Another thing to have a look at if your bike has 'floating' discs, is all of the little spring loaded rivets that fasten the friction surface of the disc to the carrier are all loose and not stuck full of rust or crud, making the disc stick in places

 

Ah I get what you mean... yes they are floating discs so I will check that out as well thanks!

[klingelton]

Get a nut and bolt that will fit through the circular rivet doohickeys. Tighten it up until it rotates. If it binds, spray copious amounts of brake cleaner in there while rotating. It should rotate smoothly with little effort.

Repeat for all rivets.

[MacLean]

Sorted -

Clean up with loads of brake cleaner and a scrub with a toothbrush in the crevices done the job. Some new copper grease on the back of the pads and the vibration and squealing is gone.

Thank feck for that, was not in the mood for buying discs for a bike I've had for about 2 months.

[klingelton]

good stuff. i will be having a look at my brakes this weekend i think. but i will treat myself to new pads. Mine's a daily ride and needs to be just so.

[MacLean]

good stuff. i will be having a look at my brakes this weekend i think. but i will treat myself to new pads. Mine's a daily ride and needs to be just so.

 

Yeh brakes and tires, most important things to have tip top before anything else aey

[Stu]

good stuff. i will be having a look at my brakes this weekend i think. but i will treat myself to new pads. Mine's a daily ride and needs to be just so.

 

Yeh brakes and tires, most important things to have tip top before anything else aey

 

apart from your brain you mean

[Lumor_uk]

Don't use wd 40 to clean it, I sprayed some on my push bike discs to stop them rusting. Oh dear.