babber

I need to buy new disks soon, and wondered what type to get? Currently got OEM disks, that I'm completely satisfied with (and I've done a few track days with them) without damaging them too much. But want to make them better, until I can afford some monster brakes

I'd be more than annoyed if they warped and vibrated, so wondered what people thought. Mate has an EVO6 and the brakes wobble like crazy once warmed up (think they are brembos) and he's on his second set now .... Grooved or X drilled, or both?

What make?

Any advise would be greatly appreciated....

Thanks Phill

Fat Boy

Not cross drilled if you're going on track as they will crack around the holes, unless they are pukka cast in holes a la Porsche.

You need grooved to allow the hot gases out and to clean pads etc.

AP racing 330m 4/6 pots are the daddies.

BlueBoy

Mine are grooved - AP 352mm 6 pots

surfer boy

EBC do a grooved and spotted disc (so no cracking) which are a good intermediate step up from the oem and not as expensive as the Brembos etc. Cost about £130 from Camsport (Super nice people)

Benno

Can recommend the EBC grooved and dimpled. Great price and service from Camsport.
Just fitted some with EBC pads, huge difference.

babber

Thanks for all the advise....

So you guys reckon the grooved and X drilled EBC disks are good then??

Thanks Phill

Jim_B

iTrader: (1)

How about the Godspeed 335 kit if you have 17'' or bigger wheels ? Groupbuy on them at the mo. It doesnt seem to me that any of the standard sized replacement discs are any better than the OEM ones [ or the ones from SAP ].

Floyd

iTrader: (9)

Try the DBA discs. They do split bell and rotor design to fit std calipers for £3-400 quid. I would go this way if I didn't already have AP's Better than Godspeed IMHO - OK!

F

Apple

as mentioned above about drilled discs - if you absolutely must have them then get them with cast holes or countersunk drillings as this reduces a lot of the stress concentration around the holes which helps with offsetting thermal fatigue / cracking

knap

Cross drilling or slotting is decreasing the overall amount of metal and decreasing the performance of the rotor to dissipate heat. Furthermore, the holes of a cross-drilled or slotted rotor decrease the area of the pad that contacts the rotor. This concentrates the heat more on certain areas of the pad, which has similar effects to that of using a smaller pad. As such the pad heats up more quickly.

It also damages the brakes structural rigidity. The iron in a brake rotor is made of a crystalline structure. By drilling holes in the surface the end grains are cut creating a situation that breeds cracks. Furthermore, even if the rotors are cut correctly to avoid cutting the end grains structural rigidity is still decreased. The temperature around the holes will be slightly less then that of the entire rotor leading to temperature stress. Moreover, the decreased mass will result in lowered rigidity.

If outgassing is an issue with pade fade then use a minimum of grooves or uprate the pad Hawk for example have a road pad for 750deg