My new cross drilled & grooved disc's

[tris]

Here are some pics of my disc's
As i know some guy's where interested will let you no what they are like when i do some miles

fitted with mintex fast road pads

Thanks to the boy's at the motorest centre canturbuy who fitted them while doing my service

Top job

 

[F2 Stu]

what make and how much for the discs?

 

[storeyd]

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.

 

[ArosaRacer]

look ok Tris, started looking at doing mine

 

[F2 Stu]

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

 

[helms]

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

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..

 

[tris]

what make and how much for the discs?

They are Maxtorq and are £103+vat a pair for 312mm

 

[badlydrawnbanan]

looking good Tris keep us posted on how they perform

 

[tris]

will do mark

 

[F2 Stu]

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]

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..

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...

 

[F2 Stu]

They are Maxtorq and are £103+vat a pair for 312mm

roughly the same as my 8 grooved discy's,

 

[storeyd]

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

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.

 

[F2 Stu]

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.

 

[ibizacupra]

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.

so long as the pad cant cover the whole groove at the same time there's always a gap for gases to go

 

[ibizacupra]

groove should be radius cut also... so no stress raisers from sharp edges (like what I do on ATE pattern machining)

 

[tris]

Now done so miles and they are better then th OE ones but the real test will be next weeks trackday