are ventilated discs batter than solid?

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Originally Posted by rick130

and hands up those of us that do/have raced that have seen drilled discs crack and/or otherwise fail and luckily lived to tell the tale.......:eek:

Vented :thumbsup:
Slotting :thumbsup:
Drilled :thumbsdown:

as has been said, venting is very usefull to reduce fade.
If you don't hammer your brakes (I do) they may be a waste of money, although I view it as a safety issue, so would fit them, regardless if you thought they are overkill or not as you never know when you may have to tow something heavy down a mountain side.

Slotting increases initial pad bite by venting the gasses that build up between the pad and disc face and helps to keep the pads de-glazed and reduces or eliminates taper wear of the pad.
Drilling can be more effective in these endevours than slotting, at the expense of disc and pad life. Unfortunately the holes create extremely effective stress raisers that propogate thermal cracks at an alarming rate.
Yes, Porsche uses them on some models (I believe these are cast, not drilled) and some (not many) race cars use them, but they are 'lifed', ie. chucked before they start to crack too badly.

I used to keep a massively cracked race disc hanging above my desk as a reminder of my stupidity ........

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The stresses of a race car would be very unlikely replicated by a road/offroad user rick , unless you were driving;)

One of the most interesting comments I've seen on brakes was during the first London-Sydney marathon in about 1970. When the cars arrived in Perth the two leading cars were Citroen DSs - only a few points apart. During the preparation for the next leg, across Australia, one of them had the fifth set of pads fitted since London. The other had the pads replaced for the first time "even though they didn't need it". The cars were identical, over the same roads, at the same speeds - but the drivers weren't identical. Obviously drivers vary enormously.

I tend to agree with Scrambler though, and with the cost of fuel currently, those drivers who use brakes extensively should remember that you paid for the energy you are using to heat up the brakes to cause fade.
John

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Originally Posted by rick130

Now Scrambler, you're not advocating we all go back to single leading shoes, are you ?.......:p

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Definitely not, rick130.








Double leading shoes are much better kit.










But have considered trying to get some ribbed brake drums to reduce fade... :p

Steve

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Originally Posted by scrambler

:soapbox: Good enough for unlimited brake force over unlimited distances?

:rulez: Engine braking IS capable of unlimited distance and with a low range gearbox, very considerable brake force. But it's not either/or - brakes compliment the engine braking and vise versa. All brakes eventually fade. That's why our ancestors decreed engine braking for descents. Better brakes means it takes longer before the fade happens, but the principle is the same. :soapbox:

I'll take a blue pill and lie down now. :angel:

Steve

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I love youse. :D

No not unlimited force over unlimited distance, but I'm not sure where that hill is. The brakes do have a pretty good capacity to disipate heat though with increased sizes, ventilation and improved heat ranges in the pad materials.

I agree that engine braking and brakes compliment each other, but our ancestors decreed engine braking for decents because they only knew single circuit drum all round brakes that were unbalanced, low temperature, low heat dispersant with poor fluids and a lot of weight. Much like even the modern truck. Still underbraked for the load they carry and the air drive in them while making them very effective probably also induces overheating to a certain extent.

:wasntme:

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Originally Posted by rick130

Interesting you fellas are using the EBC pads.
When I upgraded the brakes on the 'fender, I wanted to use the Greenstuff pads, and bounced it off one of the engineers at DBA and he recommended Ferodo.
DBA do a lot of on car testing with different pads and compounds and he felt at the time that EBC were too inconsistent batch to batch and he really didn't like that.
He reckoned that Bendix were behind the game with Asbestos free compounds and that Ferodo were probably pick of the crop.

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Thats interesting. I've had 3 sets of EBC greenstuff now, and they have all performed differently, even 1 set of brake pads were different to look at, containing a bed in material on the pad. Perhaps the factory rotors are the go over the EBC rotors???? I wouldn't mind trying the dba rotors, but am unsure of how well the Kangaroo Paw ventilation will clear the mud.

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Originally Posted by Yabbie

http://www.dba.com.au/images/shop_ca...BAgold_lrg.jpg


I fitted these to my 93 Rangie both Front and Back. Best investment I ever made. Rangie stops on a dime. No noise no fading Nothing just stops when I want it too.
Check out their web site: www.dba.com.au
Had to wait a few weeks for them to be made though. And don't forget to sit down before he tells you the price:twisted:

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I put DBA Gold cross drilled and slotted rotors on my Rangie about 3 years ago as the price was no that much dearer than solids. At the time I got the 4 rotors and 2 x sets of front and back bendix 4wd pads for about $700 delivered to my door and spent a day fitting them. Local garage loved them and said it would normally cost about $2k if I got a mechanic to do the job. The Rangie pulled up slightly quicker, braking was effective, firmer and pulled up a lot better towing a trailer and had no brake fade. When I bought them I was told there were some issues with cross drilled types developing little cracks near the holes if run extremely hot and then dipped in cold water (mud). The cracks that had been noted were tiny and should not affect braking performance, also that if large cracks did develop they would replace them. My Dad has the Rangie now and there have been no problems. When it comes time to change the Fender units, this is what I will be replacing them with. The most benefit comes from replacing the front ones. I have to say I did not notice any increased pad wear with these.
:D :D

When DBA first brought out the slotteds, they said they wouldn't do cross drilled for 4wds, the pad wear rate was too high in mud.

There must have been some demand for them then.

Regards
Max P

Does anyone know if you can get larger than standard disks and calipers to suit a Defender. Dont think it brakes to great overall and want to move from 33's to 35's which will makes this worse again. Would hate to be towing something on top of this!!

My brother changed his disc on his D2 to vented and cross drilled and found them huge better, But best to put EBC brake pads a well. as these are alot better and add to the complement of the new disc's

My current Kingswood ute has front crossdrilled and slotted DBA rotors (100 000km approx) and my previous Kingswood ute had them front and rear (probably nearer 200 000km now) and I never had any problems with them at all. The wear rate on the discs was/is almost zero, no noticeable increase in pad wear and the braking is definately less fade prone compared to the standard vented rotors.

I have just gone through the whole deal with the front rotors on my D2. I have scored the rotor running out of pads and there was a massive lip on it as well. I decided they were a bin job and I have'nt measured them up.

So I decided to go with the DBA slotted only as it is most likely I will not need the cross drilled. So the usual story is...none at the store, ring you during the week.

They sure did :mad::mad::mad::mad:

None in Australia and wait 6 weeks before they are on the production line again :censored::censored::censored::censored:

So it looks like I am chopping out a new set of front pads with a scored disk for 6 weeks.