Drilling stock brake discs.

[AMMO]

Has anyone drilled the stock brake discs to save a bit of weight? Any problems?

 

If you have a I wouldn't mind a template. Alternatively a worn-out commercially available drilled disc to use as a pattern.

 

Many thanks

 

 

AMMO

[oilyhands]

I've done 10 or so sets of disks for various people. Usually drilling is done to allow gases to escape when the pads get hot.. but.. drilling is OK, provided it is symmetrical(to keep the balance near) and that the holes are slightly chamfered to avoid stress risers and excessive noise, pad life will be shorter and the brakes noiser, the pads will be effectively de-glazed though. If the disks are vented it may be a problem to get a symmetrical pattern since the number of supporting bosses is often an odd number and sometimes a prime, this rather knackers you for symmetry. if you want to avoid drilling through a supporting boss.

 

You can make a simple pattern for the drilling in Autosketch or Autocad using the (er-umph) 'ring-array' function to draw the holes on a full sized drawing of ths disk surface. Make sure you draw the bosses too to avoid drilling them. This can then be taped to the disk and used as a drilling pattern.

 

Oily

[AMMO]

Thanks for that Oily.

 

I'm aware of the necessity to chamfer holes. I'm drilling standard (Triumph Herald / Spitfire?) solid discs.

 

I don't have Autocad. Do you have a template for these discs?

 

 

 

AMMO

[oilyhands]

Believe it or not you are the fourth person to ask about disk drilling this week, send em the disk outer diameter and the inner diameter at the bell and I'll draw you a loose spiral pattern, if you give me a mailing address I'll mail the pattern to you.

 

Oily

[AMMO]

Oily

 

You are a gentleman. I'll measure the disc swept area today and email you.

 

Thanks very much

 

AMMO

[Westfield]

On this subject I once drilled the solid discs on my Lancia Montecarlo with a pattern I took off a motor cycle disc. There was a lot of debate with fellow club members as to what, if any effect this had. In an effort to prove things one way or another one of the club members purchased 2 new discs and pads and asked me to drill just one of them. He then put them on his car, drilled one side, un-drilled the other.

 

The results were quite interesting. The car pulled to one side immediately , (the side with the drilled disc) and continued to do so even after bedding in. this was particularly noticeable in the wet. From this it was deduced that the efficiency of the drilled disc was improved, particularly in the wet over the un-drilled disc. Convinced we drilled the other disc. I still have the Lancia with all four discs drilled and have never noticed a significant effect on pad life. Most motorbikes have drilled discs which may be to improve the wet weather braking where the discs are more exposed to water than those shrouded in a car wheel.

 

It would be interesting to compare drilled versus groved………..

 

[AMMO]

Tony

 

That's interesting. I used to drill Brembo solid motorcycle discs when the drilled ones were not available from stock. Just used to clamp an old drilled disc to a solid one and use it as a pattern.

 

I measured my front Caterham discs today. 232 mm diameter. Same as a Brembo motorcycle rear from a few years ago. If I hadn't have put those old worn out Brembos in a skip some time ago I would have had a pattern without having to get Oily to go out of his way to help me out.

 

Used to like the look of the Lancia Montecarlos. Never did get a go in one. Did have a ride in a Lancia Stratos belonging to racer Vittorio Brambilla in the early eighties. On Italian cobbled streets.

Very quick for those days.

 

AMMO

[Westfield]

AMMO

 

I used to do the same thing with the Brembo disks on my Laverda Jota! I am back on solid discs now in the interests of originality (and the fact I never ride in the wet!)

 

I still have the Monte Carlo. I have owned it for over 20 years. It has been a great car and still turns heads. Its not getting much use since I brought a W*******d a couple of years ago so I am thinking of selling it and the W*******d to fund a Caterham. We will have to see…..

 

have a look at

 

http://www.jtccc.freeserve.co.uk

 

[Phil]

all the time at work I am asked for drilled disk for road car application and they are a waste of time. If the car is used on the track and raced the team will check the disk after every race for cracking and replace on a regular basis, on a road car when would they be checked? the addvantage of drilled disk is as you have said to get rid of gases and cool things down but when in a road situation do you generate that sort of heat. The better alternative in most cases is a quality grooved and vented disk and posible with dimples, they also have the advantage of being a lot cheaper, ie EBC disks and green stuff pads.