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GT6 Brake Disc 10.25" Diameter. Sources?

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BT16 Stephen Davis
Monterey, California, USA   USA
I'm restoring a vintage race-car with GT6 vertical links, spindles, and hubs. It uses magnesium caliper brackets. It is fitted with 10.25" solid discs. Every source I check for GT6/Vitesse comes up with 9.3 to 9.75-9.80" discs.

Does anyone have a lead on where I might find these 10.25's? Or what street car they might have originally been on?

I could change out the caliper brackets and go back down to one of the 9.75" discs as a last resort.

Thanks!

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clshore Carter Shore
Beverly Hills, Florida, USA   USA
In reply to # 1419427 by BT16 I'm restoring a vintage race-car with GT6 vertical links, spindles, and hubs. It uses magnesium caliper brackets. It is fitted with 10.25" solid discs. Every source I check for GT6/Vitesse comes up with 9.3 to 9.75-9.80" discs.

Does anyone have a lead on where I might find these 10.25's? Or what street car they might have originally been on?

I could change out the caliper brackets and go back down to one of the 9.75" discs as a last resort.

Thanks!

Magnesium?
That's likely some after market mod.
You can find all kinds of discs in all kinds of sizes, but the key will be mounting to the GT6 hubs (assuming that they are also stock).
Most discs nowdays mount to the hub by sliding over the wheel studs, but GT6 disks are bolted to the hub.
So in addition to the disc diameter, you must also be concerned with the disc offset, and mounting holes.
It's likely the caliper adaptors are dimensioned to ensure that the calipers are centered on whatever discs you have.

Are the calipers anything special?
Perhaps the discs are from a TR-6 (or other Triumph car, TR-4, TR-3, etc.)

http://www.rimmerbros.co.uk/Item--i-209327

Rimmers describes them as 10-13/16", but they appear to employ the same or similar mountings to the hub.
Could have the outer rims cut down to 10-1/4" if they are otherwise suitable

HTH

Carter

BT16 Stephen Davis
Monterey, California, USA   USA
Thanks Carter.

The calipers aren't anything special. Girling 16p I believe.

I have the dimensional specs (offset, bolt circle, etc.) but haven't been able to match them yet. The magnesium brackets are after market race pieces. Links, hubs, and spindles are GT6.

In the end, I could go to the aluminum aftermarket brackets and back to a 9.75" disc but I was hoping someone would recognize the 10.25" dimension.

I've searched rimmerbros (among many others) but haven't matched them yet.

Thanks again.

Steve

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Bill Morris Avatar
Nor Cal, USA   USA
1971 MG MGB
Steve,

I have seen those alloy caliper adapters on Elva Couriers and TVR's, but they had closer spacing where the caliper mounts. The 16p has a 3.5" bolt spacing as I recall, but the alloy adapters I have seen were spaced for MGB or Healey sized calipers (less than 3.5" spacing). Maybe your calipers are 14's not 16's,
Does the car have GT6 or TR3/4 hubs. The cars I have seen with the alloy adapters had a GT6 style upright with a different stub axle hole that allows the big TR hub and either a 10.75" or 11" rotor. If that is what you have, you can cut down the rotors to 10.25" but check to see if the larger units will clear the calipers.

Bill

BT16 Stephen Davis
Monterey, California, USA   USA
Bill,

Thanks for the info. I'll look around for Elva and TVR specs. I have all the parts over being crack tested at the moment so I can't measure the brackets or the hubs.

The vertical links (uprights) are GT6. I just assumed the hubs and spindles were as well. The car weighs ~920lbs so not a lot of weight on the front.

I've seen alloy hubs and chromoly spindles for sale at some of the vendors and thought I might opt for those to lighten the unsprung weight and strengthen the spindles.

I've had a Herald, a Spitfire, and two TR3A's over the years but never had occasion to look at these parts before now. And of course now, I don't know what they're from.

Thanks,
Steve

GElliott Gerald Elliott
Enfield, Nova Scotia, Canada   CAN
1970 Ford Cortina
2004 Ford F-350 "Big Fellow"
Check out the Wilwood site. their full catalogue is there. The have both seperate rotors and hubs as well ones with an integral hat and rotor.
Gerald Elliott
Elliott Racing

clshore Carter Shore
Beverly Hills, Florida, USA   USA
Maybe this brake setup was adapted from a Formula Ford or similar?

Coleman will make them to your specification:
http://www.colemanracing.com/Integral-Hat-And-Rotor-P4809.aspx



Edited 1 time(s). Last edit at 2016-12-13 04:59 PM by clshore.

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BT16 Stephen Davis
Monterey, California, USA   USA
Thanks to all. I have a set coming from a race supply shop on the east coast. Probably from Coleman winking smiley I'll call them direct next time as I've used them for lots of Panoz parts in the past. Good experience with them. Someone else recommended them but I didn't realize they'd make to order.

BT16 Stephen Davis
Monterey, California, USA   USA
Following up.

Thanks everyone for your help.

The calipers turned out to be AR2's from an early F1 / F2 car. Still don't know what "street" cars might have run them.

Pads are "similar" in shape to the early TR3 with the "ears" on the pad, just smaller by about 1" all around.

I ordered the correct pads from Carbotech in NC (ctbrakes dot com). Ferodo also supplies them (for more $$).

The brake discs I had made by Colman. Came out perfect and on time. Have one race on them and they worked great.

Carbotech pads were also delivered promptly and worked great.


Steve

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14GPDJENGINEERING Avatar
Silver Spring, MD, USA   USA
I have 3 GT6 aluminum hubs. these were custom made for Group 44 with 1/2 inch more inset to allow using wheels with same offset on front & rear wheels.
They have the original size 3/8 studs -- one is complete with bearings, the other two just have the outer races (cups).

$150 plus shipping.



Dennis smiling smiley


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Bill Morris Avatar
Nor Cal, USA   USA
1971 MG MGB
Steve,
Do you have a spare AR2 caliper? Or know where to obtain one? I've been on the hunt for one for quite some time. Got a car with one broken off at the mounting holes and I couldn't find a mate so had to use the iron units instead. Sure would like to find another aluminum one...
Bill

BT16 Stephen Davis
Monterey, California, USA   USA
Hi Bill,

Sorry I don't have a spare. I've seen a few used ones around but probably sold by now.

If none of the below work out, PM me and I'll send out some feelers to other racers that might have them.

Good luck!
Steve

Here are some sources. Mostly reproduction calipers.

These guys have lots of used parts. Like cost-co, changes every day. e-mail them and see if they have any.

http://www.historicracing.org.uk/parts/wheels.html

AR3's and 4's maybe call for AR2s

http://www.racing-stuff.com/Girling_brake_caliper.htm

AR2's listed for 455 pounds sterling

http://race.parts/Catalogue/Braking/Calipers/Girling-Calipers

http://www.bgdevelopments.co.uk/products-sp-720548214/brake-calipers

http://www.arcalipers.com/

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