Harrison builders - question on stud patterns

[sambo]

I've pretty much decided on the Harrison kit with R32 IRS. As you know this uses a Nissan (Ford?) stud pattern on the rear and VR Commodore front. When shopping for wheels does this present any problems with the mixed stud pattern? Are adapters available?

I'll be looking for replica knock-offs or similar so any offset measurements would be much appreciated. I'll probably go 16s or 17s to provide more options with high performance tyres.

Thanks,
Paul

[boxhead]

I do not have a Harrison, but my kit (Classic Revival) uses Ford rear and Jag front.
This is not an issue as the rim supplier should be able to provide the stud pattern you require.

And you will most likely be fitting different width front to rear rims so there is no point stressing about a spare that fits both front and rear.

I will be looking at getting a narrow multi fit 5 stud rim as a spare when I drive a long distance from out here at Alice.

[400TT]

Yeah, different stud patterns front and back are pretty normal on most Cobras.

Nissan stud pattern is basically the same as everything but Holden. So you can fit Nissan, Ford, Toyota & Mitsubishi 5 stud wheels.

As boxhead said, you will be ordering custom offset wheels, so getting different stud patterns will be no problem.

Best to ask Warwick Harrison about wheel offsets, he is the expert.

16" tyres really suck when it comes to tyre choices, especially wide tyre choices. Go with the 17" instead, you have endless choices. In 17", you also have some cheap wide tyres available. There is more than a couple of Harrisons rolling around with Sumitomo 315/35R17 tyres.

Plus the 17" wheels means you can upgrade your brakes down the track without worry of fouling with the wheels.

Note to Boxhead: If you are going to carry a spare make sure you can fit your rear tyre in the boot. The boot on our old Cobra would not close with the rear tyre in there, so needed to carry some tape(to stop marks) & a couple of ockey straps. It really depends how wide you go on the rear.

[07cob]

Sambo

A number of Harrison's builders (including myself) opt to get the front rotors redrilled and the studs replaced with nissan studs. This means all PCDs are the same as are the threads on the studs.

I have even gone so far as to procure a space saver wheel from a Skyline!! Although as Craig has pointed out, I am not too sure how the 10" with a flat will go in the boot!!!

I am currently in the process of purchasing wheels and the offsets I am using are 135 (rear) and 90 (front) - by advice from Warwick himself. This does not take into account the *tyre bulge* that will set these back a little further, depending on what size rim and tyre you are running. I am planning on running 225/50x16s and 255/50x16s on 8s and 10s respectively so I reckon about 10mm will be enough. Hence I have ordered offsets of 125 and 80. If you choose to run with 17 or 18s, the bulge will be less and if you want 15s, it will be a bit more I am guessing. You can run 15s on the Nissan rear end, you just need to have some mods done to move the caliper closer to the wheel centre - the recently finished Daytona has 15s all round.

Hope this helps

GeoF

[400TT]

Originally Posted by 07cob

Sambo

A number of Harrison's builders (including myself) opt to get the front rotors redrilled and the studs replaced with nissan studs. This means all PCDs are the same as are the threads on the studs.

GeoF

Geof, I didn't realise you did that. One advantage of getting same stud pattern front & rear, is that you can purchase a cheap 2nd hand set of wheels to use for racing.

On the Harrison that I built with my brother we didn't have any of these dramas. Used Skyline R32 GTR rear, with R32 Skyline aluminium uprights & hubs on the front. So run Skyline R32 rotors & calipers front & back and of course we have Nissan stud pattern front & rear. That's how we solved the problem. We also run an ABS sensor on the front and of course on the rear. Started off using oem cross-drilled GTR rotors, now using slotted DBA 4000 rotors.

[sambo]

Geoff - redrilling seems like a viable option, thanks for the info!

Craig - how much work was involved in converting Warwick's front-end to use R32 Skyline aluminium uprights & hubs? Were you using the ABS sensors for ABS, traction control, speedo...? I'd love ABS to go with a nice power steering setup.

Thanks guys

[400TT]

We did it on his previous version front suspension. Our front suspension has fabricated upper and lower "A" arms and at that stage using HQ stub axle. Warwick now uses fabricated straight lower arm with control rod(z bar) and commodore hub & upright assembly and that upright to upper "A" arm adaptor.

The advantage of Skyline uprights is:
* Less unsprung weight
* Skyline brakes fit straight on, so get 300mm rotors & 4 piston calipers. Skyline GTR V-Spec also had larger brembo brakes.
* Easier to fit abs sensor, but now with that Commodore upright, it would have abs sensor mounting, if it's a late enough model.

The disadvantage of Skyline uprights:
* Work & expense involved in fitting it.
* More difficult for parts e.g. wheel bearings etc.

For a street driven Cobra, Warwick's standard setup with Commodore brakes etc is fantastic bang for the buck.

We use one of the rear Skyline ABS sensors for speedo and use the front and rear sensors for traction control. Well that was the plan, but the version of Autronic SM2 ecu we have is buggy, traction control doesn't react. We can see the ecu detecting the wheel speed difference between front & rear, but ecu does not try to correct it be retarding the ignition etc. Didn't bother with abs, but people have done it.

[sambo]

Craig, sounds like the Commodore discs will be fine after a redrill, for my needs anyway. I might even save another 57g from the extra drilled out stud holes.

I'm hoping to visit the Harrison shop next Friday 9th so I'll quiz Warwick on the ABS setup - along with 100 other things.

[macloft]

Sambo
As Geof says Warwick will redrill your front Commodore hubs and replace with the Nissan studs (stud price $50). He currently has a car he is building right now with this change incorporated plus many other refinements to his standard package
I have just recieved Harrison Chassis 72. I am extremely happy with Warwicks
proffesionalism. There are many car options you can explore with him and yes talk to him directly as he is very approachable.

[400TT]

Originally Posted by sambo

I'm hoping to visit the Harrison shop next Friday 9th so I'll quiz Warwick on the ABS setup - along with 100 other things.

Yep, make sure you write a list, that's what we used to do.

[Aussie Mike]

Why not re drill the rears to the Holden pattern? There are heaps of wheels available for the Holden pattern as it's the same as BMW.

Cheers

Michael

[sambo]

Thanks Macloft - and yes, I've had half a dozen emails with Warwick and will be getting the 50mm lowered floor. The revised stud pattern and extra camber are also on the cards. So many things to think about aren't there? Part of the fun I guess...

[sambo]

I hadn't thought of that Mike. I guess if I just go with the mixed pattern for now (since it'll come on donor wheels) then when I choose the 'final' wheels I can redrill whichever end is necessary. Fingers crossed I can find someone to do it for a reasonable price. $50 sounds unbeatable (plus labour?)

[400TT]

Originally Posted by Aussie Mike

There are heaps of wheels available for the Holden pattern as it's the same as BMW.

Cheers

Michael

Yeah, but if you have Nissan pattern, you are also the same as Ford, Mitsubishi & Toyota. Commodore is prolific, but can it beat these four.

Plus if you are thinking second hand, in my opinion the best vehicles to get wheels from are Skylines & Supra's...both came standard with 8" on front and 9" on the rear. Also not unusual to see 9" and 10" rims on these.

We bought 2 x sets of rims for our Harrison. Both 2nd hand. Nissan 17x8,17x9 & Toyota 16x8,16x9(standard Supra).

Mike, wouldn't Nissan pattern be the better choice?

Also keep in mind, that even though the stud pattern is the same, the wheel stud threads are not. So you've got to get the right wheel nuts. e.g. Ford wheel nuts do not fit Nissan.

[07cob]

Originally Posted by Aussie Mike

Why not re drill the rears to the Holden pattern?

Mike

I queried Warwick about this as well. When I did, his eyes rolled back in his head, his head spun 360 degrees a bunch of times and smoke poured out his ears. He finally stopped and said that it would be much more problematic redrilling the R32 rear compared to the front rotors. I accepted his advice with little further question! I think (from memory) that the issue would be the *real estate* around the hub where the studs are slotted into. The R32 would be difficult to find somewhere to drill for the studs, while the fronts only need the rotors to be redrilled and the studs replaced in the original holes in the hub.

Geof

[07cob]

Originally Posted by sambo

Fingers crossed I can find someone to do it for a reasonable price.

sambo

Are you Melbourne based? As I understand it, Doug Pearce Engineering does a bunch of work on Harrison's Cobras, I am sure he could sort you out. One of our Southern counterparts might be able to offer more detail.

GeoF

[sambo]

Yes I'm in Melbourne and I've been to see Doug and he will certainly get some work out of me. I'm ok with assembly, disassembly etc but NFI when it comes to fabrication and other tricky bits.

[Aussie Mike]

Holden Commodore stud pattern is 120mm PCD (Pitch Circle Diameter). This is basically a nearest metric whole number to the old Holden ie HQ and Chev stud pattern which is 4 3/4" PCD (120.65mm). The Ford pattern is 4 1/2" PCD (114.3mm) so it will fit on a smaller hub. I reckon the nissan rear hubs musn't be much larger than this diameter so that spacing the pattern out another 6mm might put the studs off the sides of the hub. This must be the issue Warwick is refering to.

With his price of $50 is that what he's asking per stud? I bought a set of new studs for the front of mine when I made the new hubs and the studs were about $15 each from memory. These were 1/2" studs the same as the Ford rears. There may be some other studs available from another car in the same thread pitch that work out a bit cheaper.

Cheers

[macloft]

Mike
Warwick said to me $50 for the Nissan studs to convert Commodore hub to Nissan stud PCD pattern plus labour /machining on top if I got it done through him. Yes you are right spacing the rear studs out further (ala Commodore PCD) would be difficult on the Nissan rear.
Cheers

[Aussie Mike]

Sounds like a good price for the studs. Go for it.

Cheers