FE-FC Holden Discussion Forum

Does anyone know what happens to wheel position (track width) when using commo discs instead of HQ discs, on HQ stubs?
Do they bolt straight on or is there some adapting to do?

I am under the impression it is difficult to get commo callipers to fit to the stubs also. And take it that HQ callipers wont fit over commo discs!

Yep commodore rotors are slimmer than HQ rotors just use commdore rotor HQ callipers straight on no worries.

I just did the wifes HT but i ended up using HQ cos the idiots at the parts shop sent me the wrong ones.
i machinined down the centre as HQ are bigger than commodore by a couple of mm and a commodore rim will not go over the centre unless you take off a couple of mm.
So at the end of the day just use vl or vn any of the pre VS commodore rotors.

I think that there is an issue with this for two reasons. I am happy to be corrected

1) bolt pattern on the Commodore is different to the HQ. Over time this will fatigue the wheel studs causing them to break

2) the Commodore has a lower minimum thickness to that of a HQ, this means that as the pads wear down there is a great chance of popping a caliper piston out, leading to catastrophic brake failure.

Keith

1. the stud pattern difference.

on top of that one. cheers

2. have heard this also.

I take it that using the later rotors doesn't move the mounting of the wheel in at all.!

I run 290mm Commodore discs on HZ stubs nothing special required to fit  them, with a 17'' x 7'' rim and car is lowered 2'' all works fine ....but I do run aftermarket  4 piston calipers........FC427........

Now you have me worried i have done a bit of searching and your correct.

Stock thickness and minimum thickness or a vs commodore disk break?
Stock thickness 22.8 Minmum thickness 20mm Front brakes

HQ which is 25.4mm (1") wide. The minimum legal thickness of a HQ disc is 24.5mm.
So that blows out to 4.5mm difference
My dads running this setup and a mate with a rod as well.
Would not really be a problem unless you were a tight arse and let the pads go below the indicators
but for an idiot that did it could be a disaster.
and my dads a tight arse so i will have to let him know.
Whats the difference commodore to HQ studs i bolted a set of chasers on last week without any problems?
I know the stud size is slitlghy larger but i assumed that was the only difference.



On my FC i run Commodore discs with commodore callipers usin HD drum brake stubs and castelmaine adaptors.

Pete

There is plenty written on this subject lately - this is why engineering standards were introduced.

Ken

Yep, to save some people from destroying themselves and others.

 ::) Just to clarify,

My above comment wasn't pointed at the questions and answers in this post, it was just a general reflection.

All good ;D