Do You Have A Big Brake Kit?

[Ahl 4]

Do you have a big brake kit that utilises standard 1.9 calipers with 283mm 306 GTI-6 discs? Preferably unfitted to the car? I need your help!

 

I really need the measurements of the spacer plate that enables the standard calipers to be used with the bigger discs.

Once I have the dimensions, I'll be able to have these spacers made up by a local engineering works (for nowt!). I might even be able to have a few cheap sets made up for other 205gtidrivers!

 

Any help immensely appreciated!

[C_W 3 1 Cars]

I'm not sure if anyone has this kind of setup as most use the gti6 calipres with 283mm discs or go for the 285mm discs with standard calipers. The offset of these two discs are different.

 

Anyway, I think you could calculate it from the disc specs. From 247 to 283mm you need to space the caliper out approx. 18mm which is where it gets tricky as the thickness of the hub and caliper carrier is more than this so you can't butt them up to each other as this will space it out more (this is the reason you have to file some of the hub casting).

 

Also you need to take into account the offset of the disc which is different to the 247mm and the 285mm discs. Its 8mm further OUT (so it's a flatter disc).

 

OD WIDTH HEIGHT C. BORE

205: 247 20.5 35 66

306: 283 22.0 27 66

 

The width of the disc is also different but you would get away with filing out the caliper carrier I reckon and hope that the caliper can accept new pads over the thicker disc.

[Ahl 4]

Ah! I see what you mean C_W, cheers. I was under the deluded impression that the big brake kits used gti-6 spec discs.

 

I might try to get a gti-6 disc and work out the required spacer spec from that, but any details on the other big brake spacer would be appreciated as I believe it would help.

 

Distance between the holes, the thickness of the spacer, and whether it is simply a flat plate or 'stepped' would be handy.

Back to the drawing board...

[Pugnut 9 1 Cars]

the autofive disk is offset so that a spacer plate can be applied . if you used a gti-6 disk i understand that the offset is too close to the original meaning the spacer would be too thin or too complicated to be stong enough or worth while doing . in the long run it would be better sourcing second hand or recon gti-6 calipers.

 

the only disadvantage of using the gti6 calipers is that the increased piston size means that your brake pedal will travel further before the pads meet the disk . this can be overcome by fitting a master cylinder from the gti-6 with 2 outlets , then using tee's branch the 4 pipes into two . or there may be another (406?) mc that has 4 outlets .

 

i think if it was possible to economically fit the gti-6 disks to the standard calipers it would allready be readily avaliable as a kit or it would be common knowledge .

[Pugnut 9 1 Cars]

ahl, i just run outside and took a quick pic , whats your email addy?

[C_W 3 1 Cars]

the autofive disk is offset so that a spacer plate can be applied . if you used a gti-6 disk i understand that the offset is too close to the original meaning the spacer would be too thin or too complicated to be stong enough or worth while doing . in the long run it would be better sourcing second hand or recon gti-6 calipers.

I don't think it is like that, the disc height or offset of the original is 35mm and the Gti6 27mm so the Gti6 disc is quite a flat disc, well it has a raised "hub" part of about 5mm compared with 14mm for the 205 disc.

 

The autofive 285mm discs are somewhere inbetween (though close to the original) around 32mm. I think the lug spacers in the kit are just slightly thinner than the caliper carrier thus moving the caliper assembly outwards from the hub by a few mm to match the disc.

 

So the gti6 discs would need less thick lug spacers but it sounds like it would be very close to the wheel rim which confuses me as the autofive big disc kit is very close to the rim!!!

 

A setup using gti6 discs would be bette as they are so cheap to replace.

[Ahl 4]

Thanks for the help guys.

Ive made up this pic of how I think the spacer plate is arranged (with the spacer closer to us, and the hub/caliper bolting behind it. It doesn't say much for my art skills im afraid!

 

Spacer diagram

Can you confirm this is how the spacer fits on?

 

If this is so, then it seems to me that the spacer moves the caliper outwards (towards the wheel) and the 285mm big brake kit is offset outwards to enable the caliper still to fit. 32mm close to the hub face rather than 35mm for the standard discs.

(Sorry for basically repeating what you've already said C_W)

 

Disc offset diagram

 

If the gti-6 is 27mm offset, and closer to the hub face, then all thats required to get the standard caliper to fit is the correctly spaced spacer and larger shims. Or a stepped spacer so the caliper end is closer to the disc.

 

The only other thing is that the caliper itself is able to fit over the 1.5mm wider discs...there should be some play in the caliper to allow the pads and discs to be renewed, so hopefully this is so.

 

Do you guys agree with me, or am I missing something?

If this is all correct, then my quest for gti-6 discs can continue onwards!

Edited June 25, 2003 by Ahl

[C_W 3 1 Cars]

I drew this, I think this is a fairly accurate picture of what is going on;

 

[Pugnut 9 1 Cars]

Chris , you're just showing off now !

 

do you realise if you include an arrow showing the point you need to file to allow the spacer to fit , you've drawn a descent set of instructions for fitting autofive's big brakes .

[Ahl 4]

Ah!

Are you sure the lug spacers go between the spacer and hub and not the caliper carrier? Pugnut?

[Pugnut 9 1 Cars]

the thing is , the autofive disks are 285mm and the gti-6 are 283 ? (am i right?).

 

with the 285 disks the pads are already running right on the edge of the disk . take 2mm of disk away and the pads are off the disk . adjusting the spacer plate to accomodate this means you would have to file off too much from the original lugs on the hub carrier.

 

is there another way of adjusting the caliper to allow a 283mm disk?

 

so can enough metal be removed from the caliper itself to allow for the wider disk ?

the yokes will need to be filed out so the wider disk fits in .

[Pugnut 9 1 Cars]

just been out with my calipers ,

 

right , the spacer is as CW says between the spacer and the hub carrier. allowing for a small amount of error (rust) the "lug" spacer is 14.0mm wide and the spacer is 10.0mm wide

[Ahl 4]

I think I see what you mean pugnut. Bugger.

Thanks for measuring them up.

I think I'll try to get a gti-6 disc cheap and experiment with that.

Edited June 25, 2003 by Ahl

[C_W 3 1 Cars]

the thing is , the autofive disks are 285mm and the gti-6 are 283 ? (am i right?).

 

with the 285 disks the pads are already running right on the edge of the disk . take 2mm of disk away and the pads are off the disk . adjusting the spacer plate to accomodate this means you would have to file off too much from the original lugs on the hub carrier.

 

is there another way of adjusting the caliper to allow a 283mm disk?

 

so can enough metal be removed from the caliper itself to allow for the wider disk ?

the yokes will need to be filed out so the wider disk fits in .

I reckon y ou'd get away with 283mm discs with this autofive spacer size as it would only be 1mm smaller in radius, but it's jsut the offset that has me worried because its a lot flatter than either standard or autofive so I don't know how wheels clear it enough, but they must do.

[Ahl 4]

When you talk of the wheels clearing the gti-6 discs C_W, do you mean the 1.9 caliper, or the disc itself?

As the whole GTI-6 setup sits under the 15" speedlines just fine, then it must fit. That is unless the gti-6 calipers arent quite as 'thick' as the 1.9 ones.

 

I still reckon the gti-6 disc conversion is possible. Just need to get a gti-6 disc so I can start measuring a potential spacer plate.

However, If anyone can give me dimensions of the hispec/autofive spacer plate, it would help a lot

 

The offset of the gti-6 won't cause any great problems, just the manufacture of the correctly sized and shaped spacer.

Edited June 27, 2003 by Ahl

[Guest mrswampy]

ahl if you get this all done and working any chance you can get me a set of the spacers made up and supply me a spec of what other parts i need

 

cheers

[Ahl 4]

Yeah, I'll keep everyone informed at what stage im at and with any potential blueprints or spacers etc.

[C_W 3 1 Cars]

Update: For anyone with an Autofive 285mm kit, I've just fitted a pair of R21 discs @ £20+vat each (plus whatever it costs to have them machined to fit). Replacement discs for the Autofive Kit are £150+vat from Autofive or around £125 for plain discs from Rallye Design.

 

The main differences are the PCD (100 vd 108) and the centre bore (61mm vs 66mm). I got a local engineering firm to modify the discs to match the peugeot specs and fitted them today.

 

At first the offset appeared slightly different and I was worried I might have to pull the carrires out by thinning down the spacer lugs which I really didn't want to do as with the Fondmetal wheels it alread catched the caliper with new pads. But then I notice it wasn't sitting on the hub flat as the 205 hub has a very large bevel and the R21 doesn't have one as big so it wasn't sitting flat on the hub by a few mm. I thought I would have to have a bevel machined on the inside of the disc but I managed to do it OK with a curved file.

 

Once that was done the discs sit nicely on the hub, the grub screws don't quite line up but that isn't a problem as the discs can't fall off when the caliper etc is on. I still wasn't totally sure if when I bolted up the carrier and spacer where the disc was going to sit inside the carrier but its almost exactly the same as the autofive disc.

 

So it all bolts up as normal just that you don't have the grub screws.

 

Total cost was £45 (discs) plus £25 machining, so £70 compared with £125 for the plain 285mm discs from Rallye Design. Just need to see if they stand up to track days or not!!