Wheel spacers

T

Tiger tamer

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Has anyone used or would trust the safety of a wheel spacer to widen the rear track and fill in the rear wheel arch. I am not talking the cheap multi fit spacers like these
http://www.trademe.co.nz/motors/car-parts-accessories/wheels-tyres/other/auction-614054280.htm
but ones like these with the hub-centric ring http://www.trademe.co.nz/motors/car-parts-accessories/wheels-tyres/other/auction-614054280.htm
They say they can custom make them so some made to the same 108mm to 108mm would be needed.

Wheel spaced out 15mm


The other side with no spacer
 
General Cautions

For the general public out there, be careful of spacers because they limit the amount of bite a lug nut has on the bolt. I recently dismantled a Tiger for resto that had 1/2" spacers on the rears. There were only 4 turns per lug nut remaining to hold things together !!:eek:
 
I looked into doing something like this a couple of years ago but have yet to do anything.

Keep in mind that the Tiger has 7/16 studs, while most wheels and adapters today are made for 1/2 inch studs or a metric size somewhat close to that. You would want the spacer-adapter to be able to attach properly, and center on, 7/16 studs. And of course the tiger stock lug nuts cannot be used on the adapter because they have a non-standard taper that will not seat properly in most adapter holes.

While it precludes being able to rotate the tires front to back, you can get the same effect by having different wheels for the front and back with different back-side dimensions. Less back-side will cause the rear wheels to sit further out.

I do like the idea of finally having a hub-centric mounting for the wheels.

As for the number of turns, I believe the minimum for a 7/16 stud is 7 full turns. Someone please post the formula, I forget what it is. I think it has to do with the thickness of the stud and how many turns it takes to equal the same distance of engagement.

Gene
 
There are two types of spacers commonly available.

The first, used to make relatively small adjustments in wheel spacing is essentially a metal disc with holes to fit over the wheel studs. It is sandwiched between the wheel and hub, and retained by the wheel and its lug nuts. These are only safe if the studs are long enough to maintain full thread engagement in the lug nuts, as Oneoffive noted.

The second, used for larger adjustments and bolt pattern adaptation, attaches directly to the hub with its own set of nuts, and had it's own set of studs, to which the wheel attaches.

In both of the above cases, better quality spacers are hubcentric, which is to say they locate using machined features on the hub and wheel to maintain concentricity of the wheel relative to the hub. Non-hubcentric spacers rely only on the studs, which is an inferior method, due to the necessary clearance between the studs and holes in mating parts.

There has been a flood of cheaply made spacers and adapters that have given the concept of spacers a bad reputation. But well-made, hubcentric spacers, properly installed and torqued, are quite safe. I used H&R spacers on the rear of my Cobra for over ten years. The car made 325 hp, and all of them were used quite frequently. I had no issues whatsoever with vibration, loosening of wheels, spontaneous combustion, or any other maladies commonly attributed to wheel spacers.

The OP's intent was to install spacers on the rear axle. But be aware that using them on the front will cause issues. It will change the wheel scrub radius, and can dramatically increase the wheel bearing loads, due to cantilevering the tire contact patch further outboard from them. Expect bumpsteer, tramlining, rapid tire wear and other issues, which are hard to eliminate.
 
cadreamn67 said:
I looked into doing something like this a couple of years ago but have yet to do anything.

Keep in mind that the Tiger has 7/16 studs, while most wheels and adapters today are made for 1/2 inch studs or a metric size somewhat close to that. You would want the spacer-adapter to be able to attach properly, and center on, 7/16 studs. And of course the tiger stock lug nuts cannot be used on the adapter because they have a non-standard taper that will not seat properly in most adapter holes.

While it precludes being able to rotate the tires front to back, you can get the same effect by having different wheels for the front and back with different back-side dimensions. Less back-side will cause the rear wheels to sit further out.

I do like the idea of finally having a hub-centric mounting for the wheels.

As for the number of turns, I believe the minimum for a 7/16 stud is 7 full turns. Someone please post the formula, I forget what it is. I think it has to do with the thickness of the stud and how many turns it takes to equal the same distance of engagement.

Gene
Click to expand...

Gene

Good point on the stud dia. I will discuss this with them Monday morning. The studs will need to be 7/16" and so will the holes and special nuts to locate the spacer to the original studs. They say they can do custom so we shall see.

I agree with you and the tool man about the hub-centric mount but the rear wheels on the Tiger are stud centred only. Though if the spacer is hub centred it makes it part of the wheel which I feel is better than if it was not.

Cheers Mal
 
Mal,

I think you will also find the front hubs are also lug-centric mounts. Even though there is a lip that fits into the hole in a stock wheel, it is not machined to be a centering device.

If you were to mount a stock wheel and center it on the lugs, you will see that the center hole in the wheel goes over that lip, but the space between its edge and the wheel hole is not perfectly equidistant all around. So any spacer needs to have its center hole at least as large as the stock wheel hole. That would be bigger than the diameter of the lip on the hub.

Cheers, Gene
 
Moroso used to sell extended studs you could use on the rear.. or you can always call you local rootes dealer and ask for the hillman hunter safari rear studs :p
 
cadreamn67 said:
As for the number of turns, I believe the minimum for a 7/16 stud is 7 full turns. Someone please post the formula, I forget what it is. I think it has to do with the thickness of the stud and how many turns it takes to equal the same distance of engagement.

Gene
Click to expand...

A good rule of thumb is to have a depth of thread engagement equal to or greater than the diameter of the fastener, assuming both stud and nut are made of materials with similar strength and stiffness. Number of turns is then calculated knowing the number of threads per inch:

No. Turns = Threads per Inch * Stud Diameter
 
One other thing to be aware of regarding the type of spacers that attach using their own nuts. You need to make sure the mounting flange of the wheel has clearance for the studs to protrude between the wheel mounting holes. If the mounting flange is solid, that means the spacer must be at least as thick as the studs are long or the wheel won't mount properly.
 
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