Brake Disc Grooves.
Discussion
I'm currently renovating the whole of my suspension and brakes on my Griff 500 and as there isn't much wear on the brake discs I'm just going to have them re-faced. Whilst they are in the machine shop, I'm tempted to get them either cross drilled or grooved. Does anyone on here have any technical knowledge on the ideal amount, shape, depth and profile the groove's should be ?? Or does anyone know of a site where I can find this detail out ??
Thanks in advance.
Thanks in advance.
If they're in reasonable condition I'd be inclined to leave well alone. If they're worn, new discs are relatively cheap so it may not be worth the cost and hassle of resurfacing the old ones. Obviously, the more material you take off to resurface them, the less thickness you have left for your grooves/holes etc.
If you decide to do it any way, I advise you not to cross drill them under any circumstances. Even new discs suffer from mechanical weakness and stress raisers afer cross drilling. There doesn't seem to be any hard and fast rule about grooves except that they should be angled at about 45 degrees (rather than radial) to prevent pad chatter. Doesn't matter which way they are angled. Grooves are typically about 5mm wide and 2.5mm deep. Don't run the grooves right out to the edge of the disc, and make sure you don't leave any sharp corners at the bottom or ends of the grooves. Four or eight grooves per face are ample. However, my advise would be to leave them alone unless you're confident you know what you are doing.
If you decide to do it any way, I advise you not to cross drill them under any circumstances. Even new discs suffer from mechanical weakness and stress raisers afer cross drilling. There doesn't seem to be any hard and fast rule about grooves except that they should be angled at about 45 degrees (rather than radial) to prevent pad chatter. Doesn't matter which way they are angled. Grooves are typically about 5mm wide and 2.5mm deep. Don't run the grooves right out to the edge of the disc, and make sure you don't leave any sharp corners at the bottom or ends of the grooves. Four or eight grooves per face are ample. However, my advise would be to leave them alone unless you're confident you know what you are doing.
Which way is preferable for the grooves in rotational terms .... swept backwards or swept forwards .... if you know what I mean.
I have just got 300mm bells and rotors with AP 4 pots and unfortunately they are drilled as well as grooved, would have preferred grooved only as have cracked disks historically, although there are many manufacturers ( Porsche ) seem to swear by them ...
I think some of the issue is how there are drilled. They should be a counter sunk hole, as this seems to be better than straight drilled holes ...
I have just got 300mm bells and rotors with AP 4 pots and unfortunately they are drilled as well as grooved, would have preferred grooved only as have cracked disks historically, although there are many manufacturers ( Porsche ) seem to swear by them ...
I think some of the issue is how there are drilled. They should be a counter sunk hole, as this seems to be better than straight drilled holes ...
I agree with the countersuck. I had and inch bigger in the front of my last Chim500 - and asked for no holes or grooves for that reason - but have gone for both this time (but hole sunk to disipate likelihoos of cracking.
http://photos.fotango.com/p/eba00195316f00000038.jpg
http://photos.fotango.com/p/eba00195316f00000038.jpg
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