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Floating discs at last #1521049
10/01/2015 11:16
10/01/2015 11:16
Joined: Dec 2005
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Staffordshire
Nigel Offline OP
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After more than a decade of killing one piece cast discs, I've finally found some floating discs

teaser pic for now, until I can take some proper photos later....

click to enlarge

They are not meant for a Coupe, but they fit without any modification to either the disc, carrier or hub / caliper - the only element that I have to resolve is that the centre bore of the disc is 60mm, but the Coupe hub is 59mm, so I need to come up with the equivalent of a 0.5mm thick "spigot ring". They are 4 x 100, but the bolt holes are 1mm bigger than the Coupe discs, so they fit without having to open up the holes. The only element that doesn't pan out is the small securing bolt, as the PCD is a little too far out.

I'm SO chuffed - I took an expensive punt on these, as most of the dimensions were the same as the Coupe, but a couple were different enough to have caused an issue - however, I've trial-fitted them to a hub with caliper and they are fine.

Just trying to see if I can get any more


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Re: Floating discs at last [Re: Nigel] #1521065
10/01/2015 13:29
10/01/2015 13:29
Joined: Sep 2009
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szkom Offline
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I hope you find a way, they look good. My only concern would be how you're going to positively centre that disc with only a 1/2 mm thick spigot when there's a radius between the hub face/locating feature. Might be you need to go larger on the bell centre bore first.

Re: Floating discs at last [Re: Nigel] #1521077
10/01/2015 15:24
10/01/2015 15:24
Joined: Dec 2005
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Staffordshire
Nigel Offline OP
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I spoke with my friendly engineering workshop chappy this afternoon - he has also suggested that I should open out the disc centre bore and use a 5mm spigot to force a secure centring of the disc on the hub


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Re: Floating discs at last [Re: Nigel] #1521096
10/01/2015 17:47
10/01/2015 17:47
Joined: Oct 2008
Posts: 6,623
In the coupe.
magooagain Offline
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In the coupe.
On bigger machinery i have seen welds added to spigot's and the like,then machined out to the correct radius.
All though half a mm of weld may be risky?



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Re: Floating discs at last [Re: Nigel] #1521140
10/01/2015 20:04
10/01/2015 20:04
Joined: Dec 2005
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Staffordshire
Nigel Offline OP
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I'm still working on this in my head......

The disc clearly has to be centred on the hub, otherwise it'll run un-true, vibrate and cause all sorts of problems.

However, unlike the wheel, the disc won't put any weight on the "spigot" - its purely there for positioning purposes - all the force of braking is rotational, not vertical. The wheel bolts will take the force of the braking (if indeed the braking force is even sufficient to cause any disc-slip between the wheel and the face of the hub - I rather doubt it)

So - I'm going to get a 185mm long strip of 0.5mm thick metal (stainless preferably) and coil it round the hub centre, then fit the disc over it. It should be a push fit, but it MUST be centred.

I'll then test thoroughly and see if the "spigot" stays put


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Re: Floating discs at last [Re: Nigel] #1521141
10/01/2015 20:11
10/01/2015 20:11
Joined: Dec 2005
Posts: 32,269
Hemel in the Hempstead
barnacle Offline
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You've been multiplying by pi, so you have... but don't forget it's another three and a bit millimetres circumference at the outside of the hole.


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Don't get no respect! [b]Coupe Fiat 1994-2000 - an owner's guide[/b] <-- clicky!
Re: Floating discs at last [Re: Nigel] #1521145
10/01/2015 20:21
10/01/2015 20:21
Joined: Dec 2005
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Staffordshire
Nigel Offline OP
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And some more photos....

click to enlarge click to enlarge

LOTS of cooling capability...

click to enlarge

Proper floating mountings...

click to enlarge

Really can't wait to get them fitted and try them out


[Linked Image]
Re: Floating discs at last [Re: barnacle] #1521147
10/01/2015 20:24
10/01/2015 20:24
Joined: Dec 2005
Posts: 17,186
Staffordshire
Nigel Offline OP
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Originally Posted By: barnacle
You've been multiplying by pi, so you have... but don't forget it's another three and a bit millimetres circumference at the outside of the hole.


Aye - I twigged that, but I'd prefer there to be a small gap in the ring, rather than it being a perfect circumferential length - will allow for a bit of expansion due to heat


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Re: Floating discs at last [Re: Nigel] #1521150
10/01/2015 20:43
10/01/2015 20:43
Joined: Jun 2006
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Peterborough, UK
jas_racing Offline
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Abarth Punto Evo EsseEsse discs?


[Linked Image]
She's BACK!
Re: Floating discs at last [Re: jas_racing] #1521154
10/01/2015 21:16
10/01/2015 21:16
Joined: Dec 2005
Posts: 17,186
Staffordshire
Nigel Offline OP
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Originally Posted By: jas_racing
Abarth Punto Evo EsseEsse discs?


thumb

You have PM


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Re: Floating discs at last [Re: Nigel] #1521156
10/01/2015 21:20
10/01/2015 21:20
Joined: Aug 2009
Posts: 4,807
Oakworth
Big_Muzzie Offline
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I thought only the 695 carried floating discs as standard?


Less torque, more thrust!!
Re: Floating discs at last [Re: Nigel] #1521179
11/01/2015 07:49
11/01/2015 07:49
Joined: Oct 2006
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kidderminster
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368bhp @ 1.5 bar
Re: Floating discs at last [Re: Nigel] #1521182
11/01/2015 08:48
11/01/2015 08:48
Joined: Dec 2005
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Hemel in the Hempstead
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Originally Posted By: Nigel
Originally Posted By: barnacle
You've been multiplying by pi, so you have... but don't forget it's another three and a bit millimetres circumference at the outside of the hole.


Aye - I twigged that, but I'd prefer there to be a small gap in the ring, rather than it being a perfect circumferential length - will allow for a bit of expansion due to heat


A fair point, but I'm concerned that if you don't get an exact match you could effectively have a flat spot where the gap is. Shouldn't be a lot, though; don't forget that you will stretch the outside of the strip when you curve it.

Also, the hole will expand when the brakes are hot; with cast iron centres and stainless steel rings you'll have a similar expansion ratio difference as you have with piston rings/cylinder bore, and they get away with about ten thou.

What's the advantage of floating discs?


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Don't get no respect! [b]Coupe Fiat 1994-2000 - an owner's guide[/b] <-- clicky!
Re: Floating discs at last [Re: Nigel] #1521186
11/01/2015 09:14
11/01/2015 09:14
Joined: Aug 2011
Posts: 2,595
angus, scotland
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angus, scotland
As I understand it, the advantage is that it allows the disc to effectively self centre, which reduces drag and allows the disc to go through its thermal cycle unimpeded. Helps reduce the risk of the disc warping. But I may well be waffling bull poop....


[Linked Image]
Re: Floating discs at last [Re: Nigel] #1521192
11/01/2015 09:50
11/01/2015 09:50
Joined: Sep 2009
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szkom Offline
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Nigel, I think you'll struggle to build the car with your solution. IMHO, not enough depth to the bell centre bore owing to the chamfer/radius interface you'll encounter at the hub face; I don't think it'd ever run true.

For my money I'd create a spigot that's an interference fit to the hub, then machine that assembly to a tight clearance fit for the bell. You'd need to measure the various radii to make sure the spigot starts life with sufficient diameter to transpose the radii. Then open open the bell to suit.

Re: Floating discs at last [Re: Nigel] #1521221
11/01/2015 14:08
11/01/2015 14:08
Joined: Jun 2008
Posts: 912
Kent, South East
Cooperman Offline
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Pardon me for asking but would it not be easier to change the hubs?

Re: Floating discs at last [Re: Nigel] #1521228
11/01/2015 15:44
11/01/2015 15:44
Joined: Aug 2000
Posts: 9,701
Zele, Belgium
Kayjey Offline
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Zele, Belgium
Can't you have someone CNC a new center for the discs to sit on?


- Kayjey -

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Re: Floating discs at last [Re: Nigel] #1521253
11/01/2015 18:51
11/01/2015 18:51
Joined: Aug 2009
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Oakworth
Big_Muzzie Offline
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Personally I'd machine out the disc, including a key, and go and see your local wire erosion firm and get them to make some inserts. They work to 0.5 microns (usually) so I am sure they'd get an OE fit for you.


Less torque, more thrust!!
Re: Floating discs at last [Re: Nigel] #1521257
11/01/2015 19:20
11/01/2015 19:20
Joined: Dec 2007
Posts: 2,248
Windsor/ Reading
knight7660 Offline
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These are looking good Nigel shame I'm moving onto 330mm smile


LE53 (452BHp & 389ftlb's with Quaife)
Wine red VIS FOOFY
Audi RS4 B7
Re: Floating discs at last [Re: Nigel] #1521260
11/01/2015 19:40
11/01/2015 19:40
Joined: Jan 2006
Posts: 3,033
Sweden
Per Offline
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Looks good Nigel!
Knight 7660: I got some response from Compbrake for split 330mm disc's before my Coupe was destroyed, just in case you're on the hunt!
Check them out, I asked for Alfa 147 GTA 330mm replacement discs with 98x4 holes so it would fit straight on. Lucky me I never got to pay!

Re: Floating discs at last [Re: Nigel] #1521280
11/01/2015 21:37
11/01/2015 21:37
Joined: Dec 2005
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Staffordshire
Nigel Offline OP
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I suggest you do some research on Compbrake before buying - they don't have a very good reputation


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Re: Floating discs at last [Re: Nigel] #1521299
11/01/2015 23:58
11/01/2015 23:58
Joined: Jan 2006
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Sweden
Per Offline
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Aha. Good riddance then..

Re: Floating discs at last [Re: Nigel] #1521404
12/01/2015 19:16
12/01/2015 19:16
Joined: Mar 2010
Posts: 288
ireland
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jonofitzer Offline
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A machine shop should be able to bore them out in a couple minutes and make you the spacer rings also. Another option is to build the gap with weld and machine it to desired bore.

I converted my hubs to 5 stud which involved machining the disks and hubs and a custom alloy spacer. Have not had a single problem yet

Re: Floating discs at last [Re: Nigel] #1524812
08/02/2015 20:55
08/02/2015 20:55
Joined: Dec 2005
Posts: 1,192
Pontefract, West Yorkshire
andyps Offline
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Any update on these Nigel?


Andy

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Re: Floating discs at last [Re: Nigel] #1524848
09/02/2015 10:05
09/02/2015 10:05
Joined: Dec 2005
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Staffordshire
Nigel Offline OP
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Not yet....

I've sourced some 0.5mm stainless sheet, in order to make up a spacer - just need to work out how to cut it without distorting it - I guess a guillotine would be best


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Re: Floating discs at last [Re: Nigel] #1524929
09/02/2015 15:45
09/02/2015 15:45
Joined: Dec 2005
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Pontefract, West Yorkshire
andyps Offline
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Thanks - good luck and look forward to hearing more.


Andy

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Re: Floating discs at last [Re: Nigel] #1531034
23/03/2015 11:04
23/03/2015 11:04
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Staffordshire
Nigel Offline OP
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Damn....

I wonder if 20vt front hub flanges come in different sizes....

When I trial-fitted one of the floating discs to a loose hub, it seemed to fit just fine (along with the Brembo caliper). However, then I came to fit the discs to my car on Saturday, the flange is very slightly too big for the disc centre - it'll need a bit of machining

The project continues....


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Re: Floating discs at last [Re: Nigel] #1531038
23/03/2015 11:22
23/03/2015 11:22
Joined: Aug 2013
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North Italy
Gimmo Offline
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Good luck Nigel.
A friend of mine in Italy has got Brembo Abarth EsseEsse floating discs.
They are expensive, but great!

Good work!


Supporting member of FCCUK
Re: Floating discs at last [Re: Nigel] #1531043
23/03/2015 12:01
23/03/2015 12:01
Joined: Dec 2005
Posts: 9,706
Gone
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Jimbo Offline
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Was the hub hot on the car Nigel? Im just wondering why it would fit on a spare hub but not one on the car. Thermal expansion could be a reason if the car had been used.
Maybe heat the disc centre up too and see if it fits then, so long as both expand then youre safe.

Re: Floating discs at last [Re: Gimmo] #1531049
23/03/2015 12:33
23/03/2015 12:33
Joined: Dec 2005
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Staffordshire
Nigel Offline OP
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Originally Posted By: Gimmo
Good luck Nigel.
A friend of mine in Italy has got Brembo Abarth EsseEsse floating discs.
They are expensive, but great!

Good work!


On a 20VT? - If so, could you ask him to contact me to let me know what modifications were needed


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