Why are wheel spacers bad?

[Rupert]

There was a little discussion on this a while ago, but I can't remember if they were bad or not bad, or if it was because of wear on the suspension due to effectively longer control arms or because birds.

[FlatBlackCaddy]

Are they?

I've heard some people say they are(people who don't have them and don't use them), then I hear they are fine if they are not huge(over 30MMish). I normally hear that from people who have used them for years and have them on dedicated track cars with tons of hours on them.

[hotrodalex]

A small spacer in normal conditions is fine.

A large spacer in tough track conditions can cause problems.

[FlatBlackCaddy]

What's a "large spacer", 20mm?

I'm sure the normal stuff that is 5-10MM is fine for any use.

[Rupert]

Seems like changing the offset would have almost the same effect?

[FlatBlackCaddy]

Seems like changing the offset would have almost the same effect?

I'd think it would, since the length would be measured from the center of the wheel to the pivot point. That's my uneducated guess.

[Soup DeVille]

They Can be bad. Given that they almost always accompany a wheel size change, it depends on the application. What they will do, on any given wheel, is change the scrub radius of the front wheels; which is the difference between the machanical center of the turning axis- as described by an imaginary line running through the center of both of the ball joints and touching the concrete, and the center of the contact patch of the tire- which is what the tire really wants to rotate around.

This can be good, or bad, depending on what the scrub radius was originally.

To be honest, I don't think th epeople who poo-poo them regardles really think it through- if you're going to a larger wheel you're already changing most of that anyways- you're already changing the original backspacing and in most cases, increasing the potential torque between the ball joints anyways.

[Rupert]

That makes sense-- but what would be a good scrub radius vs. a bad scrub radius/what would the effects be?

[hotrodalex]

Seems like changing the offset would have almost the same effect?

For the most part yes.

[hotrodalex]

What's a "large spacer", 20mm?

I'm sure the normal stuff that is 5-10MM is fine for any use.

I wouldn't wanna go much more than 0.5" (12 mm), but that's not a scientifically based view. If you need that large of a spacer, you should just fix the wheel fitment issue instead of trying to bandaid it.

[Soup DeVille]

That makes sense-- but what would be a good scrub radius vs. a bad scrub radius/what would the effects be?

In general, smaller is better and zero is ideal. That's not an absolute, as a small bit can help the steering to self-center, but that's generally done better by increasing caster. Too large of a scrub radius increases bump steer, brake steer and torque steer; especially on real world roads (read shitty).

For guys that track their cars, and generally aren't too concerned with road manners, the benefits of squeezing as much tire as possible outweigh the downsides.

The only time I've ever really heard of spacers causing a failure, they were installed to mount some stupid oversized wanksta wheels which were bound to break something eventually anyways.

[Rupert]

And large means the wheel is further to the outside?

[MrH]

The biggest concern is whether you get enough threads of engagement on your studs.  A lot of people put spacers on with the stock studs and they aren't long enough to get enough engagement.  You'll really stress the few threads you do get a grab on then.

[Soup DeVille]

And large means the wheel is further to the outside?

Yes.

Well, I guess theoretically it could be too far to the inside too, but that rarely ever happens, so lets pretend it doesn't.

[FlatBlackCaddy]

The biggest concern is whether you get enough threads of engagement on your studs.  A lot of people put spacers on with the stock studs and they aren't long enough to get enough engagement.  You'll really stress the few threads you do get a grab on then.

Well that isn't the spacers fault. That's a stupid people problem.

[Rupert]

Aye.

[Rupert]

Yes.

Well, I guess theoretically it could be too far to the inside too, but that rarely ever happens, so lets pretend it doesn't.

I was thinking positive vs negative, but I can see how it all works.

This is purely an aesthetic thing ATM. As H pointed out a while ago, the rear wheels are really far in in relation to the fender, and I think it looks goofy. Sort of trying to ascertain if adding ~20 mm spacers/adapters to the rear only would impact performance/longevity. The real goal is new wheels, but it looks like I can either go Turbo Twist or Cup wheels for ~$800 (still requiring spacers, I think, and not the look I like), or get the wheels I really like for $2000+, and that's not going to happen for a long while.

[Soup DeVille]

I was thinking positive vs negative, but I can see how it all works.

This is purely an aesthetic thing ATM. As H pointed out a while ago, the rear wheels are really far in in relation to the fender, and I think it looks goofy. Sort of trying to ascertain if adding ~20 mm spacers/adapters to the rear only would impact performance/longevity. The real goal is new wheels, but it looks like I can either go Turbo Twist or Cup wheels for ~$800 (still requiring spacers, I think, and not the look I like), or get the wheels I really like for $2000+, and that's not going to happen for a long while.

So, this is for the rears alone? Stop worrying about it. People have done much, much goofier things to Miatas for years, and most of them didn't break their cars.

[CJ]

Birds.

[hotrodalex]

So, this is for the rears alone? Stop worrying about it.

Rear has much less to worry about compared to front suspension geometry.

[Rupert]

Well then.

Done.

[r0tor]

Thicker spacers are almost safer because they usually have studs integrated into them.  Most of the 10-15mm spacers use the stock studs with less thread engagement

[FlatBlackCaddy]

Thicker spacers are almost safer because they usually have studs integrated into them.  Most of the 10-15mm spacers use the stock studs with less thread engagement

Unless you do the proper thing and put longer studs on. This isn't a failure of the spacer.

[Secret Chimp]

Thicker spacers are almost safer because they usually have studs integrated into them.  Most of the 10-15mm spacers use the stock studs with less thread engagement

Oh those things look scary. I'm not bolting on bolts. So many new potential failure points.

[Rupert]

Nope, no way, looks like one of those silly 95 Pathfinders with the sticky-outy wheels. My calculations should have worked!

[hotrodalex]

Pics?

[Rupert]

No way.

[MrH]

how big of spacers are we talking?  A few mm, or some stance kid monster ones?

[Rupert]

Between the two. I measured the plumb line distance from the front fender to the wheel, and then got spacers to make the back match. Apparently that was a bad strategy. :P Lesson learned.

[12,000 RPM]

I want spacers for the Z. Popular mod. Thinkin about getting G35 19s. So hellaflush. Much tire rub.

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