WELD wheels on Drag racing Commodores

[PROPSI]

hi all, we all know the fit issue with old school 15" on commodores with PCD issues.

Has anyone been racing on these and anyone run some MPH without issue?

I have not heard of anyone having one come off or breaking studs after adding ARP studs?

any info appreciated.

cheers
Paul

[Nutter]

The thing is the studs don't hold the weight of the car the hub in the Centre does so its most likely to snap of either on launch or when braking usually from high speed. With that said it's been a long time but I have seen a rear right come off a 1 Tonner quite a few years back after the factory studs let go so even though it might not be common I know of at least one person its happened too.

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[JezzaB]

28 x 10.5" slicks, Long ARP studs, lots of 1.4x sixty foots, 9 second passe, 145mph (more to come) and i haven't broken any

[Brett SS]

I've been daily driving for over 3 years now with Weld Draglites and ARP wheel studs with no issues at all. In that time I've done like 80,000k's plus with the blower on it and done multiple 10 second passes with a best of 10.75@130mph with a 1.57 60' time.

So based on what I've seen I would say that the difference in the PCD isn't an issue. :D

[PROPSI]

thanks for the comments boys, it appear unlikely to break...famous last words....HOPE NOT!!!

Any ideas what size you where running, its for a VX the guards are rolled & arm has also been cut n shut for a bigger tyre.
15x8 w/ 5.5" BS is this the norm without too many clearance issues?
and where did you purchase them from.

cheers
Paul

[ittwgn]

hi mate the only thing i had happen is one time when i blew a cv shaft got car trailered home tried driving it just to get it into garage so was making horrible noises etc !!! went to remove wheel and had bent one of the arp long wheel studs !!! stripped thread when removing nut !!!! just cut that stud down so no real drama!!!! as for rims was running 15x 8 with 5.5 inch backspace used poly bags and was running 275/50/15 drag radials so 26 inch tall tyre is ok but tried fitting mt 28x9 full slicks and found you need more backspace like 6 inch unless you were going to run it hell raised 4wdish in the rear which i,m thinking of doing soon with a bigger slick and my widened chasers not the pro stars !!! anyway cheers

[Brett SS]

hi mate the only thing i had happen is one time when i blew a cv shaft got car trailered home tried driving it just to get it into garage so was making horrible noises etc !!! went to remove wheel and had bent one of the arp long wheel studs !!! stripped thread when removing nut !!!! just cut that stud down so no real drama!!!! as for rims was running 15x 8 with 5.5 inch backspace used poly bags and was running 275/50/15 drag radials so 26 inch tall tyre is ok but tried fitting mt 28x9 full slicks and found you need more backspace like 6 inch unless you were going to run it hell raised 4wdish in the rear which i,m thinking of doing soon with a bigger slick and my widened chasers not the pro stars !!! anyway cheers

I'm not too sure when Weld started making them but they now offer a 15x8" draglite/pro star that runs a 6.5" backspace, a 15x9" with a 7.5" backspace and even a 15x10" with an 8.5" backspace. These offsets are perfect depending on if you have the room on the inside as it will mean that your tyre will tuck in the guard and you don't need to run the rear sky high as you said. I'm currently only running 15x7" rims with a 5.5" backspace as I really wanted them to tuck up inside the guard and not stick out but I'll upgrade one day to either the 15x8's or 15x9's with the backspace I mentioned above. Below is a link to the pro stars on Weld's site so you can check out the offsets yourself.

http://weldracing.com/street-performance/sport-forge/prostar.html

[PROPSI]

I will have to do some measurements. 8 or 9" with 5.5 to 6.5 would be ideal if they fit, as the assend does stand tall......

Put the slicks on first time as the car is going in for tuning this weekend, and the slicks are too big...29.5"x 9"....
Car has the old ass end off LSX tunings car, just put in!
I have just put the custom 8" chasers with 9" slick on and does not fit. They are hitting the shock and slightly touching the inner wheel area.

Leaves me a bit concerend how many inches and BS i will actually be able to fit???

[Brett SS]

You might need to run these billet shock extensions as you can gain another inch of clearance with them by spacing out your shock absorber. As for the inner fender have you "massaged" it with a big hammer yet? ;)

http://www.shop.gforce1320.com/product.sc?productId=50&categoryId=17

[PROPSI]

nice stuff Brett, however mine is hitting very high toward top of the shock.

Not sure if these extra space will help.....
Is there anything for the top of the strut??? Cant see how?

[Brett SS]

nice stuff Brett, however mine is hitting very high toward top of the shock.

Not sure if these extra space will help.....
Is there anything for the top of the strut??? Cant see how?

Will try to find some pics for you but I think they still give half an inch clearance at the top of the tyre.

[tacka007]

The thing is the studs don't hold the weight of the car the hub in the Centre does so its most likely to snap of either on launch or when braking usually from high speed. With that said it's been a long time but I have seen a rear right come off a 1 Tonner quite a few years back after the factory studs let go so even though it might not be common I know of at least one person its happened too.

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What makes you think the this. Not how a wheel works

[Nutter]

From memory commodore should be hub centric not lug centric..... I could be wrong as I don't do much on cars anymore.

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[Nutter]

A quick search right here on these forums shows this thread

www.ls1.com.au/forum/archive/index.php/t-152591.html

I'm not the only one under the assumption the hub is used to locate and support the weight but hey I'm happy to be wrong.

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[tacka007]

clamping pressure between the two backing sufaces hold the wheel in place when you tighten your nuts. next time you go to the drags look at how many rims dont toutch the spigot at all ,my ute dosnt have any at all. there is alot of assumptions on alot of forums that the centre hub holds the weight but if you went to a good tyre place they would laugh at you if you told them this you carnt beleave every thing you see on the net. not in any way having ago at you either just been alot of heated theads on this topic.:yup:

[Nutter]

I've also seen the arguments and I really cbf today to be honest but on stock wheel studs even with the correct taper on the nuts time and time again people have issues getting the wheels to balance for no other reason than without the hub holding it in place the studs have enough give to cause issue's, I personally have had to repair cars were wheels have snapped off even when pcd was correct....like I say I've got nothing more to say here because the question was about pcd not hubs and I'm just not bored enough to debate. Also the OP is using Arp studs with drag wheels (lug centric setup) so it's irrelevant .

[tacka007]

This topic intrigued me, as I was interested to know what the correct answer was. Alot of you guys mention "hub centric". Looking into the word hubcentric more i found that hubcentric and lugcentric refer to a wheel, not the vehicles hubs.

The centerbore of a wheel is the size of the hole in the back of the wheel that centers it over the mounting hub of the car. Some factory wheels have a centerbore that matches exactly with the hub to reduce vibration by keeping the wheel centered. Wheels with the correct centerbore to the car they will be mounted on are known as hubcentric. Hubcentric wheels take the stress off the lug nuts, reducing the job of the lug nuts to center the wheel to the car. Wheels that are not hubcentric are known as lugcentric, as the job of centering is done by the lug nuts assuming they are properly torqued down.

Centerbore on aftermarket wheels must be equal to or greater than that of the hub, otherwise the wheel cannot be mounted on the car. Many aftermarket wheels come with "hubcentric rings" that lock or slide into the back of the wheel to adapt a wheel with a larger centerbore to a smaller hub.[3] These adapters are usually made of plastic but also in aluminum.


So using this information, ive come to the conclusion that yes, a commodore has hubcentric wheels from factory, that however does not mean that an aftermarket wheel cannot be mounted lugcentric, wheel design would be the governing factor.

Would this interpretation be correct or?

I also found a useful discussion between engineers on this site:
http://www.eng-tips.com/viewthread.cfm?qid=152939

i've always been under the train of thought that the load is taken via friction. Friction provided by a clamping force produced by torqued studs/nuts.

These guy seems to mention an interesting point:
Tmoose (Mechanical) 24 Apr 06 8:27
A 7/16 bolt torqued to 50 lb-ft exerts about 7000 lbs of clamp force. A wheel using 5 of them, with wheel-to-hub interface friction coeffecient of just 0.1 should not slip until asked to support 3500 lbs or so. Once again, friction is my friend.

Mopar93 (Automotive) 17 May 06 18:50
> the hub bears the load.

It is true that the hub is bearing the load, but not at the machined center where it protrudes into the wheel. There is no way that portion of the hub could bear the load unless there was zero clearance between the hub and the wheel.

The hub is bearing the load, not at its center protrusion, but rather at the wheel bearing locations.

Similar to what others have stated, once the wheel is "clamped" to the hub, the hub and wheel become one assembly. This is no different than a two-piece wheel being bolted together. The load isn't taken at the bolts clamping the two halves together as the wheel is essentially one unit at this point.

In most cases, the protrusion of the hub is there because the design requires a wheel bearing in this area of the hub. If the wheel bearing wasn't there, the hub protrusion wouldn't be required. In that case, there would also be no need for a hole in the center of the wheel.

[Woodchukka]

clamping pressure between the two backing sufaces hold the wheel in place when you tighten your nuts. next time you go to the drags look at how many rims dont toutch the spigot at all ,my ute dosnt have any at all. there is alot of assumptions on alot of forums that the centre hub holds the weight but if you went to a good tyre place they would laugh at you if you told them this you carnt beleave every thing you see on the net. not in any way having ago at you either just been alot of heated theads on this topic.:yup:

It is not so much an assumption. There are a lot of manufactures that run the rims with a very close tolerance to the spigot on the hub. Why would they increase costs by adding more material to a rim that was not needed? However once you start to use after market products the game can change a bit. Also can I have the name of your tyre place as I have not met any tyre fitters that I would take any sort of engineering advice from.

[ittwgn]

thanks for those links brett ss !!!! seems weld has been making the new backspace prostars since mid 2011 !!! awesome!!!! remember more room in a wagon/ute!!!!after a bit more checking i,m going for a weld 15x 9 with a 6.5 inch backspace then going to try and squeeze in a hoosier 28 x 10 slick with some standard springs and my poly airbags !!! thinking i might need the bigger slick with the new setup coming shortly!!!! cheers

[Brett SS]

thanks for those links brett ss !!!! seems weld has been making the new backspace prostars since mid 2011 !!! awesome!!!! remember more room in a wagon/ute!!!!after a bit more checking i,m going for a weld 15x 9 with a 6.5 inch backspace then going to try and squeeze in a hoosier 28 x 10 slick with some standard springs and my poly airbags !!! thinking i might need the bigger slick with the new setup coming shortly!!!! cheers

No problems, I stumbled across them recently as I didn't know they made these new backspaces either. Good luck with it, I did manage to fit my 28x9" slicks on it but would really like some 295/55 drag radials one day with the right rim. :)

[fletch86]

What rims and slicks would you be using for a vy sedan? Will have standard hieght springs in it.

Thanks Brad

[Brett SS]

What rims and slicks would you be using for a vy sedan? Will have standard hieght springs in it.

Thanks Brad

Easiest combination that will fit would be 15x7" rims with a 5.5" backspace and running Mickey Thompson 26x8.5" slicks. I ran those slicks for my pb of 10.75@130mph with a 1.57 60' time so they work well.