Hubcentric spacers and big bhp

I'm doing a bit of research and have some questions for all the knowledgable people on here. I may be looking to fitting a wider bodykit for the car. It will increase rear width by 50mm each side. I really like the current wheels on the car and, if fitting the kit, would have to fit 45/50mm hubcentric spacers on the rear to fill the new arches out.

Is anyone running these with 600+bhp...? The car is not used on track but is driven "spiritedly" sometimes (in a straight line). As said I am not going to change the wheels of the car (10.5j on the rear).

Any advice appreciated

If you want to go to that sort of extreme I would probably look to have the spacer welded to the wheel rather than just assembling it.

50mm is on the large side but if you use ARP studs on the spacer and car they should be fine, no alloy wheel nuts either.

If you want to go to that sort of extreme I would probably look to have the spacer welded to the wheel rather than just assembling it.

Ive done that with my front drag wheels but its only a 15mm spacer and i have extended studs, to do it with a 50mm spacer you would need super long studs, sounds dodgy to me.

50mm is on the large side but if you use ARP studs on the spacer and car they should be fine, no alloy wheel nuts either.

 

 

 

Ive done that with my front drag wheels but its only a 15mm spacer and i have extended studs, to do it with a 50mm spacer you would need super long studs, sounds dodgy to me.

Not really sure on the maths of it all but I'm guessing the main worry would be twisting due to the extra power being put through the wheels. The shear strength of the studs will be the same regardless of the length so in theory it should be OK. The only issue I can think of is the extended load, but that's always going to be the same with oversized offset and narrow wheels.

The best solution would be to additionally band the wheels to spread the load a little more evenly.

If i was to do any sort of wide body transformation, then i would buy the rims for the job. Especially when your going that big of a spacer, i think its asking for trouble.

I dont even know if you could get ARP wheel studs that long, banding is only done on the inside of the rim on alloys, they would be wider but he he would still need spacer to push them out.

Not worth the risk IMO.

I would always use a dedicated spacer with captive studs rather than use long studs through (too much shear force on them), better to use purpose made wheels, but its not the BHP that is the problem, its the torque which will usually be less than the BHP anyway.

Not really sure on the maths of it all but I'm guessing the main worry would be twisting due to the extra power being put through the wheels. The shear strength of the studs will be the same regardless of the length so in theory it should be OK. The only issue I can think of is the extended load, but that's always going to be the same with oversized offset and narrow wheels.

Wheels (and any properly designed face-clamped rotating joint, including crankshaft pulleys, cam sprockets and flywheels) never ever transmit torque via shear through the studs.

The studs are there to provide a purely axial clamping force to hold the wheel to the hub. The amount of torque that can be transmitted is then a function of the dimensions of the mating faces, the clamping load, and the coefficient of friction between the two faces. This also why you should never put copper grease on the mating faces, as I have seen some tyre centres do.

So, provided the effective mean diameter of the mating faces (largest inner diameter + smallest outer diameter divided by two) is roughly the same as standard through both the hub-spacer and the spacer-wheel joints, then you should be OK.

However, as you mention, if something goes wrong with the clamping for whatever reason, allowing the faces to slip, the studs are going to be subjected to some pretty large alternating bending loads. If it happens at speed I wouls think you could fatigue through a stud fairly fast. If the spacers spigot into the hub and the wheel then you will be better protected agianst this kind of failure.

Wheels (and any properly designed face-clamped rotating joint, including crankshaft pulleys, cam sprockets and flywheels) never ever transmit torque via shear through the studs.

 

The studs are there to provide a purely axial clamping force to hold the wheel to the hub. The amount of torque that can be transmitted is then a function of the dimensions of the mating faces, the clamping load, and the coefficient of friction between the two faces. This also why you should never put copper grease on the mating faces, as I have seen some tyre centres do.

 

So, provided the effective mean diameter of the mating faces (largest inner diameter + smallest outer diameter divided by two) is roughly the same as standard through both the hub-spacer and the spacer-wheel joints, then you should be OK.

 

However, as you mention, if something goes wrong with the clamping for whatever reason, allowing the faces to slip, the studs are going to be subjected to some pretty large alternating bending loads. If it happens at speed I wouls think you could fatigue through a stud fairly fast. If the spacers spigot into the hub and the wheel then you will be better protected agianst this kind of failure.

Yeah, totally agree. Although I think it's only you and I that think along those lines

if the 50mm spacers had a new centre made out of solid alloy so they fitted snuggley over the hub lip and still solid going into the wheel would that make them better.

50mm is on the large side but if you use ARP studs on the spacer and car they should be fine, no alloy wheel nuts either.

 

 

 

Ive done that with my front drag wheels but its only a 15mm spacer and i have extended studs, to do it with a 50mm spacer you would need super long studs, sounds dodgy to me.

i noticed you'd replaced your alloy wheel nuts with steal ones,can i ask why?

i noticed you'd replaced your alloy wheel nuts with steal ones,can i ask why?

I never had alloy nuts mate, had some titanium ones but they started to show signs of wear after a year so i replaced them.

I'm doing a bit of research and have some questions for all the knowledgable people on here. I may be looking to fitting a wider bodykit for the car. It will increase rear width by 50mm each side. I really like the current wheels on the car and, if fitting the kit, would have to fit 45/50mm hubcentric spacers on the rear to fill the new arches out.

 

Is anyone running these with 600+bhp...? The car is not used on track but is driven "spiritedly" sometimes (in a straight line). As said I am not going to change the wheels of the car (10.5j on the rear).

 

Any advice appreciated

HI Add,

I was in the same boat as you when I bought my Top Secret Supra from Japan via Jurgen. The TS Evo kit is 50mm wider than the conventional Supra so the guys in Japan removed the original wheels to sell for extra money and instead left me with normal fitting Supra wheels but with a 50mm Spacer to fill the gap. It was imported with 265 rubber.

The short of the story is that when I accelerated hard the Supra's back end went all over the place so Michelle Lane recommended to me that I replace the bodged ones with correctly fitting kit. This led to me buying the Veilsides which are now on the car (-8 offset with an 11-inch wheel and 305 rubber). They fit like a glove but the tail wiggling issue just vanished which was the important thing to me.

I never had alloy nuts mate, had some titanium ones but they started to show signs of wear after a year so i replaced them.

oh ok,i thought you had the alloy d1 spec nuts.