Thinking of adding spacers for looks, how much will it hurt handling?

[Calum]

Hey guys, as much as it pains me, I'm considering adding 15-20mm spacers to my wheels. I'm typically a function over form kind of person but with -2.5 camber in the front, -1.5 in the rear, and at 20mm lower than stock ride height, the look is getting to me.

Obviously I could get a wider rim/tire package, but that's too much money for me to spend on appearance. I like the stock rims just fine, they're light (relatively), and with MPSS's I don't feel any need for more grip.

So, if I were to add spacers, how much would it mess up handling? Will I notice the scrub radius change? Will I lose steering feel?

Thanks for the help.

[drewbot]

There was a thread that turned to a turd about negative effects of scrub radius changes. Good luck, I am also interested in this topic.

Sent from my A0001 using Tapatalk

[wparsons]

You've already shifted the "dave point" outwards with the added camber, how much will depend on where the camber was added (knuckle or upper mount). Adding a spacer might actually bring it closer to stock.

[Calum]

Originally Posted by wparsons

You've already shifted the "dave point" outwards with the added camber, how much will depend on where the camber was added (knuckle or upper mount). Adding a spacer might actually bring it closer to stock.

I added the camber at the knuckle. How does that change things?

[wparsons]

Without a diagram it's kinda hard to explain, but just think about what defines the scrub radius, then look at how the angles were changed and what that does to the scrub radius.

Increasing SAI (adding camber at the upper mount) will move the scrub radius in the negative (outward) direction, adding camber at the knuckle will move it in the positive (inward) direction.

My last post was wrong about all camber moving the pivot point outwards, forgot what the knuckle alignment looked like when I typed it.

[Racecomp Engineering]

I posted this in the other thread. I'd say +35mm offset is about the limit and ideally +40. But there's some wiggle room.

Originally Posted by Racecomp Engineering

Yes, you can use camber plates to reduce scrub radius. There is also a very slight benefit to pushing them in...it raises your roll center a little.

However, angling the strut inwards more with camber plates and increasing your SAI has some drawbacks that IMO outweigh the scrub radius issue, namely the change in camber for the outside wheel as you increase steering angle. It's not as big of a deal if you add caster at the same time, but it's important.

In most cases I recommend getting most of your camber from the hub. The change in scrub radius is pretty small. For what it's worth, a lot of the really high end dampers will come with some neat camber adjustment at the lower mount, either specially designed bolts for a slotted lower mount or "keys" (I'm not sure what else to call them) that go in the slot. The Nurburgring Challenge STI that I saw in Japan for example simply has (roughly) center fixed location lowering top mounts and got it's camber at the lower mount. Group N rally cars get their camber at the lower mount as well. Part of it is application specific I'm sure (higher steering angles having something to do with it) and many very fast cars still do get a lot of camber from plates.

With regards to scrub radius, a very large value can feel pretty awful in terms of steering kickback, effort, and also do some funky things with toe change. A wider track width is generally a good thing, but you have to keep in mind the scrub radius issue.

I don't have any set numbers for you guys, but -10mm in offset from stock is certainly fine IMO.

- Andrew

[Calum]

Originally Posted by Racecomp Engineering

I posted this in the other thread. I'd say +35mm offset is about the limit and ideally +40. But there's some wiggle room.

So a 10mm spacer would be OK, and possibly an advantage over stock.

I can live with that.

[Racecomp Engineering]

Originally Posted by Calum

So a 10mm spacer would be OK, and possibly an advantage over stock.

I can live with that.

To clarify, when I said "ideally +40" I meant that ideally you don't go past +40. Of course, we did on our car. (and it was fine at +38)

But yes a 10mm spacer on the stock wheels is definitely OK.

- Andrew