I have never seen a pattern like that. Its strange how 30-40% of the grooves run almost along the outer disc edge then actually start to run back in.
I always thought the grooves expelled the gases and dust out over the edge. With these it does not seem possible.
I always thought the grooves expelled the gases and dust out over the edge. With these it does not seem possible.
X drilled expell gases and fluid, grooves deglaze the face of the pad.
Grooves ideally shouldent penetrate the outer edge of the disc - less likely to crack that way
Grooves ideally shouldent penetrate the outer edge of the disc - less likely to crack that way
well that has just thrown some of what i thought away.
i knew the grooves were for deglazing.
Holes are for helping cool the disks (thats wot i thought) and that the help to expell gases..
but what do dimples do?
same as holes? coz i dont see how..
Holes do help keep them cool (by letting out hote gasses)
dimples theorectically do the same job has holes, the dont weaken the disc to the extent of holes drilled right through, but clog up easily
SiGainey
Guest
If you think of it, there aint gonna be litres of gas coming from a pad so a dimple will give a little more expansion space for the ags to go into, but without the cracking potential of a fully drilled hole...
I would not agree.....
Holes also deglaze and grooves also expell gases. Its just another way of doing it. Why would the top performance cars have just holes or just grooves. And a crack is far more likely to propogate from a hole. than from a groove over the edge.
Yeeeeah....... but holes dont deglaze as effectivly as grooves as they dont fully cover the swept contact patch of the pad.
The number of holes in a spiral pattern you can have on ventilated disc is guverned by the size of the disc, the depth of the contact patch, the number of spirals and the number of cooling vanes the disc has.
Some aftermarket performance discs put a substantial countersink of the holes to maximise the swept contact patch which weakens the disc even more
Also top end cars tend to have the holes cast into the disc and machined after woods - less residual stress - rather than just drill a blank
I dont use drilled discs as they more likely to crack like you say, but thats not say grooved discs dont crack as specially grooves that penetrate the outer rim like g88 types.
Horses for courses at the end of the day.
The number of holes in a spiral pattern you can have on ventilated disc is guverned by the size of the disc, the depth of the contact patch, the number of spirals and the number of cooling vanes the disc has.
Some aftermarket performance discs put a substantial countersink of the holes to maximise the swept contact patch which weakens the disc even more
Also top end cars tend to have the holes cast into the disc and machined after woods - less residual stress - rather than just drill a blank
I dont use drilled discs as they more likely to crack like you say, but thats not say grooved discs dont crack as specially grooves that penetrate the outer rim like g88 types.
Horses for courses at the end of the day.
so long as the pad cant cover the whole groove at the same time there's always a gap for gases to go
groove should be radius cut also... so no stress raisers from sharp edges (like what I do on ATE pattern machining)
Now done so miles and they are better then th OE ones but the real test will be next weeks trackday
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