Floating discs?
24 October 2002, 10:00 AM
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Hi fellas I think I read about these on this site when I owned my STI5.. does anyone know of or have any experience on using floating discs?
I have the AP 6 pot kit with grooved discs using Ferodo DS2500s which are good but I am suprised as to just how quickly they go off!
I have done Brands GP circuit (last Monday) and Goodwood (last month) plus a bit of fast road use, I am getting viabration thru the wheel and the stoppping power is obviously down.
Now I understand that the GTS catagory in the FIA GT series use floating discs/bells hence why they go for 3 hours. I know that they use a much harder complex pad material but they are using metal rotors!
If anyone can advise, it would be helpful.
..Ian
24 October 2002, 01:46 PM
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you need ds3000 pads
put in ds3000 pads
you get vibration because of use of ds2500 for track these are high performace pads and can be used for light track use but i quess youre track days are not light anymore
put the ds2500 back in for road and clean youre wheels and car when you come off track
ds2500 for road
ds3000 for track
that s how i do it
no problems so far
put in ds3000 pads
you get vibration because of use of ds2500 for track these are high performace pads and can be used for light track use but i quess youre track days are not light anymore
put the ds2500 back in for road and clean youre wheels and car when you come off track
ds2500 for road
ds3000 for track
that s how i do it
no problems so far
24 October 2002, 02:03 PM
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LOL at Croydon
As a disc gets hot, it expands.
If the discs are floating, they are less prone to warping, as there is no imposed stress from the location points that connect it to the bell. The disc is free to expand.
Any two piece disc is connected to the bell by bolts that connect to one of the two friction plates, normally the outer one. Whilst most of these are designed to allow a fraction of movement, there is a limit. A floating disc does just what you would imagine. It is losely located onto its connection points and can expand as much as necessary without collecting any stress. It is also the best design for stopping heat soak, through the bell, into the hubs.
In a solidly mounted disc, some stress is also relieved by the aluminium bell, although cooler than the disc, having a greater rate of expansion per degC temp rise.
The solid mounted version is preferable, in all but the most extreme cases. It is much quieter in use - floating discs can "clonk" when used on the road, and it is maintainance free - floating discs must be periodically cleaned to stop dirt clogging the floating connections. If they are not cleaned, the float can jam and this will wreck a disc very quickly.
Don't think I am knocking solid mounted two piece set ups, they are substantially better than one piece discs and are more than adequate for my own fast road/track day use, even with full race pads.
As a disc gets hot, it expands.
If the discs are floating, they are less prone to warping, as there is no imposed stress from the location points that connect it to the bell. The disc is free to expand.
Any two piece disc is connected to the bell by bolts that connect to one of the two friction plates, normally the outer one. Whilst most of these are designed to allow a fraction of movement, there is a limit. A floating disc does just what you would imagine. It is losely located onto its connection points and can expand as much as necessary without collecting any stress. It is also the best design for stopping heat soak, through the bell, into the hubs.
In a solidly mounted disc, some stress is also relieved by the aluminium bell, although cooler than the disc, having a greater rate of expansion per degC temp rise.
The solid mounted version is preferable, in all but the most extreme cases. It is much quieter in use - floating discs can "clonk" when used on the road, and it is maintainance free - floating discs must be periodically cleaned to stop dirt clogging the floating connections. If they are not cleaned, the float can jam and this will wreck a disc very quickly.
Don't think I am knocking solid mounted two piece set ups, they are substantially better than one piece discs and are more than adequate for my own fast road/track day use, even with full race pads.
24 October 2002, 02:12 PM
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pete
you can have vibration because of pads also
i have standard discs on my evo and lot of guys have warping problems with it
i used ds2500 with standard discs on track
i had heat spots vibration all the time but know i swap ds2500 for ds3000 only for track and no vibration and no more heat spots. strange
the pads must have something to do with vibration also
andre
you can have vibration because of pads also
i have standard discs on my evo and lot of guys have warping problems with it
i used ds2500 with standard discs on track
i had heat spots vibration all the time but know i swap ds2500 for ds3000 only for track and no vibration and no more heat spots. strange
the pads must have something to do with vibration also
andre
24 October 2002, 03:19 PM
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Thank you to both Andre and Pete. I am not sure if putting 3000s in for track day use will sort it to be honest. The floating discs as you say are to high maintainance so may be thats not the correct way to go as I only do 4 or 5 track days a year.
I know that some owners are running 3000s on their cars for everyday use so I might give that a go. Is the warming temp a lot different than the 2500s?
I should have mentioned this its for a GTR 33.
Thanx again Ian Sutton.
24 October 2002, 03:43 PM
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I have AP 4 pots & grooved discs on a MY98 using Pagid blues - severe humming & vibration after just 1 or 2 stops.
Are the discs warped or are we saying that a pad change should fix it ?
Any advice appreciated.
Are the discs warped or are we saying that a pad change should fix it ?
Any advice appreciated.
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24 October 2002, 03:50 PM
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Mark T. I did 1 and 1/2 track days before my similar problem occurred I had plenty of pad material left and think it is the discs warping. I had them skimmed and they lasted again about 1 and a 1/2 track outings. In my view that is not value for money so I am searching for a solution. With regards your problem, the discs have gone off pretty quick. I must say that my AP 4 pot 330mm kit (Scooby sport) that was fitted to my STI5 (good old days) suffered no problems what so ever.
...Ian
24 October 2002, 04:27 PM
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Ian
You need to be very careful of DS3000. Prodrive supplied these in the early Alcon brake kits. The dust wrecked peoples wheels, the sides of the cars and worn the discs to minimum wear in as low as 4,000 miles. They were all sorted under warranty, but it must have cost someone a small fortune to put right.
DS3000, as good as they are, are a race ONLY pad and are really too aggresive for constant road use.
Mark, humming is caused is caused by one of two things... either its the grooves doing their job or its shock heat of the disc resulting in different rates of expansion creating a corrugated shaped surface.
You need to be very careful of DS3000. Prodrive supplied these in the early Alcon brake kits. The dust wrecked peoples wheels, the sides of the cars and worn the discs to minimum wear in as low as 4,000 miles. They were all sorted under warranty, but it must have cost someone a small fortune to put right.
DS3000, as good as they are, are a race ONLY pad and are really too aggresive for constant road use.
Mark, humming is caused is caused by one of two things... either its the grooves doing their job or its shock heat of the disc resulting in different rates of expansion creating a corrugated shaped surface.
24 October 2002, 07:28 PM
#10
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could also be "glazed" pads caused by not bedding the pad in properly (not normally a massive problem with ds2500 as it needs little bedding in).
in your stops are you having to use more pedal effort or is the brake pedal gradually going away from you (could be having problems with fluid)
mail or phone me for more specific advice 0191-4103770
alyn - as performance
in your stops are you having to use more pedal effort or is the brake pedal gradually going away from you (could be having problems with fluid)
mail or phone me for more specific advice 0191-4103770
alyn - as performance
24 October 2002, 10:11 PM
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Croydon, this should not be happening. Skyline kits are the most popular AP-Racing supply - hundreds a year, mainly to Japan. (Scoobs come second!) So they know what they're doing. And if you want floating discs, they make plenty but take Pete's comments about maintenance to heart, as he knows (eh, Pete 
).
Things to check: is it an official AP kit, with the correct discs? Skyline kits are huge, and I think the offical discs are 343x32mm with 48 vanes. Big ******* for a heavy car. Maybe check with AP?
How old are they? Max wear is 1.5mm total (ie 30.5mm) and when you get near this, it is surprising how much better your brakes are with new discs and max heat-soak available. If your brakes are going off, maybe you're getting the corrugated effect Pete mentions, probably becuase they're beyond their wear max. Skimming won't help!
Of course, I'm only guessing but I'd take a close look at your discs, and get the vernier gauge out.
Final comment is really a question on DS2500 pads. I had some vibration problems but they were clearly related to wheel balance. Fixed that, but still vibration under braking (new discs). I couldn't believe they were warped so gave them a 20 minute workout to clean any pad deposits off the discs. Problem solved. Never had this before with a variety of different pad compounds. Any thoughts out there?
Cheers,
Richard.
PS Edited to add, I think the brakes that I saw fitted to the official Mercedes CLK55-AMG F1 pace car at the last AutoSport show should stop a Skyline
Yep, six-pot APs.
[Edited by Hoppy - 10/24/2002 10:15:44 PM]
).Things to check: is it an official AP kit, with the correct discs? Skyline kits are huge, and I think the offical discs are 343x32mm with 48 vanes. Big ******* for a heavy car. Maybe check with AP?
How old are they? Max wear is 1.5mm total (ie 30.5mm) and when you get near this, it is surprising how much better your brakes are with new discs and max heat-soak available. If your brakes are going off, maybe you're getting the corrugated effect Pete mentions, probably becuase they're beyond their wear max. Skimming won't help!
Of course, I'm only guessing but I'd take a close look at your discs, and get the vernier gauge out.
Final comment is really a question on DS2500 pads. I had some vibration problems but they were clearly related to wheel balance. Fixed that, but still vibration under braking (new discs). I couldn't believe they were warped so gave them a 20 minute workout to clean any pad deposits off the discs. Problem solved. Never had this before with a variety of different pad compounds. Any thoughts out there?
Cheers,
Richard.
PS Edited to add, I think the brakes that I saw fitted to the official Mercedes CLK55-AMG F1 pace car at the last AutoSport show should stop a Skyline
Yep, six-pot APs.[Edited by Hoppy - 10/24/2002 10:15:44 PM]
25 October 2002, 07:36 AM
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Thx again for your comments chaps.
DS 3000s are obviously a wheel ruiner in the long run.
The AP 343mm kit I have is the real thing. A while back I was pushed in to trying some Carbon metalic pads (Performance Friction), these were to harder compound and basically shagged the discs in a week of road driving. So I purchased new rotors and had the originals skimmed. the new ones were fitted the whole kit checked and the fauthful DS2500s bunged on. I did Goodwood shortly afterwards and they were fine up until the last session where I felt the viabration.
It would seem that either I have been unlucky with the discs (bad batch)or with my track day driving getting better/faster I am just experiencing brakes as a consumable!
Hoppy how do you clean the pad deposits off the disc orvwere you referring to sharp braking?
And could the way the brakes viabrate be due to wheel balance and suspension set up?
..Ian
25 October 2002, 01:53 PM
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Ian, I'd call AP and speak to their tech dept - Pete Collin if you can get him. Very helpful peeps.
I guess a Skyline on track is going to give any brakes major grief and you may be into the 'consumable' area. What does the vernier gauge say?
Are you sure it's the front brakes, ie steering wheel vibrates? If not, it's the rears. No wheel balance problems? Are the discs clean? To be sure, just find some quiet road and warm them up gently and then give 'em some grief, ie half a dozen 120-5mph full on-stops. Don't come to a standstill until you've given the brakes a few minutes to cool or you'll recreate the problem all over again. Vibration should disappear after the 3rd or 4th run.
Hope it works
Richard.
I guess a Skyline on track is going to give any brakes major grief and you may be into the 'consumable' area. What does the vernier gauge say?
Are you sure it's the front brakes, ie steering wheel vibrates? If not, it's the rears. No wheel balance problems? Are the discs clean? To be sure, just find some quiet road and warm them up gently and then give 'em some grief, ie half a dozen 120-5mph full on-stops. Don't come to a standstill until you've given the brakes a few minutes to cool or you'll recreate the problem all over again. Vibration should disappear after the 3rd or 4th run.
Hope it works
Richard.
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