17x8+45 with 8.3” tread width tires = tight spring perch to tire clearance

[Chuckable]

(Mods: This is also posted in suspension since it’s related.)

Figured I would share my experiences with this set up in case anyone wants to run the same set up so that they will know what they are in for.

Eibach pro-kit (1”lower) with KONI “yellows”
17x8+45 wheels
245/40/17 tires with 8.2” tread width per Tire Rack (Falken Azenis)
Camber bolt in bottom position at max negative camber setting

... results in about 3mm of clearance between tire and spring perch.



This is too close for comfort for me so I’m going to install a 3mm spacer which, from what I’ve read, will still allow proper fitment on the hub as well as lug nut engagement.


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[BlueWhelan]

How much camber did you end up with? Maybe run a 235 or 225 section tire?

[DJCarbine]

Ran into this issue with 17x8 +45 RPF1 wheels and 245/40/17 Continential DWS on stock struts w/Eibach Sportline springs

Installed 3mm spacers like you are thinking, 4 years no problems with hub alignment etc.

[Chuckable]

Originally Posted by BlueWhelan

How much camber did you end up with? Maybe run a 235 or 225 section tire?

I haven’t done an alignment yet but will later this week. Hoping for about -1.7°.

Thanks for the advice. I checked out 235s but the selection is pretty limited. In hindsight, to solve the issue I should’ve gone with 225s or coilovers, but a 3mm spacer should work.

Originally Posted by DJCarbine

Ran into this issue with 17x8 +45 RPF1 wheels and 245/40/17 Continential DWS on stock struts w/Eibach Sportline springs



Installed 3mm spacers like you are thinking, 4 years no problems with hub alignment etc.

Good to know, thank you! Glad to hear someone has been down this road before and made it work well.


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[ZionsWrath]

I rubbed at the track with 225/45/17 on 17x8 +45, thought it wasn't frequent I had the wheel turned that much to rub.

I usually had around 3 degrees up front. Tires at the time was AD08R

[Chuckable]

Originally Posted by ZionsWrath

I rubbed at the track with 225/45/17 on 17x8 +45, thought it wasn't frequent I had the wheel turned that much to rub.



I usually had around 3 degrees up front. Tires at the time was AD08R

Wow, even on a 225/45 huh? Were you on stock suspension with camber bolts?


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[ZionsWrath]

Camber bolt in top hole got me about 1 degree. Then I added camber plates for the rest. otherwise stock.

[wparsons]

I had about -2.3 with camber bolts/slotted upper hole on my stock struts with 17x8+45 and 225/45/17's with no rubbing on the spring perch.

[strat61caster]

Originally Posted by wparsons

I had about -2.3 with camber bolts/slotted upper hole on my stock struts with 17x8+45 and 225/45/17's with no rubbing on the spring perch.

SSC guys are getting about -3° with the yellows, 17x8 & 225/45/17 and bolts (14mm SPC bottom, small bottom bolt in the top) and I don't believe there are any rubbing issues if they max the offset to +40.

Surprised @ZionsWrath is getting rubbing at that spot with 17x8's, my 17x9+45 245/40/17 rubs at full lock in the exact same spot but that's completely fixed with a 5mm spacer (or not steering that much), I'm at about -4° of camber.

[Icecreamtruk]

3mm is plenty enough, I dont understand why you are worried. You do realise that the tire/wheel combo moves up and down "along" the coilovers and it wouldnt get any closer (or farther) when moving around?

[Chuckable]

What I’m gathering from everyone’s input is that a 245/40/17 will work with about +40 offset but anything higher gets a bit close with camber bolts, which can be mitigated with a spacer.

Alternatively, a 225/45/17 will work even with camber bolts.

I’m guessing the difference in clearance and rubbing comes down to tire brand (since tread width isn’t uniform) and wheel width (8” vs. 9”) impacting tread width.


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[Chuckable]

Originally Posted by Icecreamtruk

3mm is plenty enough, I dont understand why you are worried. You do realise that the tire/wheel combo moves up and down "along" the coilovers and it wouldnt get any closer (or farther) when moving around?

You’re probably right, but 3mm clearance is too close for comfort for me, especially since that measurement is with the tire unloaded as the car is on jack stands. Add 1 or 2 or more millimeters when the tire is loaded and another 1 or 2mm for sidewall flex during autocross or track driving and the clearance gets uncomfortably close.

For brake caliper to wheel barrel clearance the recommendation is 2-3mm to compensate for wheel and hub/bearing deflection. Since this issue is clearance between the tire and spring perch I’d want at least 12mm of clearance. For those who run less, that’s cool too.


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[Icecreamtruk]

I mean, 12mm of clearance on springs (not coilovers which have a smaller spring diamettre) is probably asking too much, you are either going to run with a lot of poke, or not enough camber. For what is worth, I have done full seasons of racing with around 2-3mm of clearance on r-compound tires and stock springs (so quite a lot of movement there). Not a single time has the tire made contact with the spring perch or the spring itself.

But like you said, if that is what gives you piece of mind, go for it, you do you

[Chuckable]

Originally Posted by Icecreamtruk

I mean, 12mm of clearance on springs (not coilovers which have a smaller spring diamettre) is probably asking too much, you are either going to run with a lot of poke, or not enough camber. For what is worth, I have done full seasons of racing with around 2-3mm of clearance on r-compound tires and stock springs (so quite a lot of movement there). Not a single time has the tire made contact with the spring perch or the spring itself.

But like you said, if that is what gives you piece of mind, go for it, you do you

If I had your level of experience I’d be more comfortable with the clearance. As it is, I’m a relative newbie (4 autocross and 4 HPDE, mostly FWD cars) so taking it slow and conservative. Maybe I’ll get there one day


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