Front tire poke at zero toe and zero camber

Joel K

Supporter
Figure I’d throw out this issue for some comments before I contact RCR.

I just put the body on the chassis for the first time and it appears my front tires stick out too far. I chose the recommended tire sizes on the Superlite web site which is 285-30-19 for the front and 335-25-20 for the rears. The rears fit fine, but with zero toe and zero camber the front wheels stick out .75” from the top of the fender.

If my calculations are correct, if I set camber to 1 degree negative the tire should tuck in about .5” at the most leaving the top .25 to .33” of the tire poking out from the top front fender. That fitment doesn’t seem ideal to me.

The front lower control arm rod ends are in as far as they can go. Would like to know what other SLC builders think. Thanks!

Here is a pic with the top fenders on...
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A pic from behind the tire....
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Joel K

Supporter
I took some measurements with the tire on.

Tire width = 11.4”
Midpoint = 5.2”
Distance from back of tire to flange 4.625”

Backspacing = .575”or 15mm

My hunch is the run flat tires I have sit out and over the rim quite a bit.
 
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Terry Oxandale

Skinny Man
Going to a 265 will give you almost 1/2" of that back. I'm guessing the 285 size is on the high end of the recommended size for a 9.5". I've got 245 on a 9", and they fit/drive very well.
 

Joel K

Supporter
Thanks guys, When measuring from the side of the body behind the front wheel the face of the rim looks to poke out 1/2” at zero camber and the tire another 1/3” of an inch.

I’m going to play around with the camber and see how much negative camber it will take to tuck the tops of the wheels in.
 

Howard Jones

Supporter
Need picture of wheel, wheel manufacture, wheel specs, and a picture of hub with wheel off. Also how much of the inboard lower rod ends are exposed on the bottom a arm. Screw these all the way in effectively making the a arm a short as possible.

I have 285.30.18 fronts on ZO-6 GM wheels. My rain tires are 255.35.18 same wheels. Both fit very well and with no body interference.
 

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If you have space on the inside of the tire, this is an offset issue with the wheel. Offset determines how deep the hub mounting surface of the wheel. This is what drives the relation between the body and the wheel/tire. Assuming there is no interference moving the wheel inboard (check the calipers and the wheel spokes), the fix is to get a wheels with proper offset which will bring the tire inline with the body. If the tire is too far inside, sometimes a wheel spacer will work.

Also, all these suspension adjustments should be made with the car at driving weight: power plant, fuel, driver, etc. Everything changes with the weight of the car.
 

Joel K

Supporter
Need picture of wheel, wheel manufacture, wheel specs, and a picture of hub with wheel off. Also how much of the inboard lower rod ends are exposed on the bottom a arm. Screw these all the way in effectively making the a arm a short as possible.

I have 285.30.18 fronts on ZO-6 GM wheels. My rain tires are 255.35.18 same wheels. Both fit very well and with no body interference.

Thanks Howard, can’t get the wheels off at the moment but the LCAs are all the way in. Also I don’t have the rotors or calipers on the car yet, just some washers the thickness of the rotor for now. Anything else in particular you would look at?

I dialed in 1.5 degrees of negative camber which I‘ve read is the max you would want to have for a street car and it looks better. Not perfect, but acceptable. These run flats have very chunky shoulders which isn’t helping the look.

plus, the front ride height needs to be increased .25-.33 inches and that gap may help the look a little bit more.

Here are a few pics...



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RCR had no luck fitting 285 runflats on my fronts, ended up returning for 275s.
 

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The guys who mounted my tires had a real hard time and the end result was not good. Especially the front tires. I doubt I can return these at this point.

My front wheels had to get repowdercoated due to it. Don't feel bad for not being able to return them, TireRack would only refund me for one and neither were ever mounted. Said it couldn't be cleaned to sell, which is BS. Still have that stupid tire in the shop.

I also purchased the 275s from them to show "good faith" in hopes that would refund, but nada. A month or so later finally got my dirty tire. I'll never buy from them again
 

Joel K

Supporter
Del, we are in the “Wrong Tire Choice Club”. The shop did mark up the rims quite a bit as well, but I’ll just touch them up. One of the front rims may actually need to be repaired/replaced since it seems like it is losing air. Chock it up to experience I guess. This was the first bad experience I’ve had buying and mounting tires, but this was pretty much a complete disaster. Live and learn.
 

Joel K

Supporter
Need picture of wheel, wheel manufacture, wheel specs, and a picture of hub with wheel off. Also how much of the inboard lower rod ends are exposed on the bottom a arm. Screw these all the way in effectively making the a arm a short as possible.

I have 285.30.18 fronts on ZO-6 GM wheels. My rain tires are 255.35.18 same wheels. Both fit very well and with no body interference.

Howard, thanks for listing your tire sizes. Michelin makes my same tire in 255/30/19 which is almost identical to your rain tires. These are 1/2” smaller in diameter than my current fronts and agree they would fit in the front wheel wells nicely.

I think I’ll give the smaller tires a try since their width is listed at 10.2” which should fit nicely. I also think I am in luck since Michelin has a 60 day complete satisfaction guarantee and will exchange your tires for another set of Michelins for any reason. Well that is the plan, hopefully there is no fine print that will derail my hopes!

Thanks everyone for the help!
 
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Del, we are in the “Wrong Tire Choice Club”. The shop did mark up the rims quite a bit as well, but I’ll just touch them up. One of the front rims may actually need to be repaired/replaced since it seems like it is losing air. Chock it up to experience I guess. This was the first bad experience I’ve had buying and mounting tires, but this was pretty much a complete disaster. Live and learn.

Sorry to hear you had to join the club! Same here, chocking it up to experience. Or maybe our wheels are cursed??? My fronts have been powdercoated 5x so far in their life! :)

In hindsight, kinda glad I ended up with 275. I didn't realize 285s would have that much bulge to them. BTW I also have 335's out back in runflats as well, sort of wish I would have done 325 like others and would have less rubbing on my fenders. I've trimmed them 3x so far, little each time, and almost got them with min clearance. I believe with 325s I may have been good from the start, but couldn't help but go with 335s
 

Joel K

Supporter
Well, have to say I am pleasantly surprised. Was able to exchange the tires without any hassle at all. I’ll go with the smaller 255 since I want to stay with runflats all around.

Just hoping they can get the tires off and the new ones on without further drama. I am suspicious that one of the rims is damaged, but I’ll figure that out as I go along.
 

Neil

Supporter
I have no experience with "run flat" tires but I was always under the impression that they were:

1. Speed limited.

2. Heavy.

Can someone set me straight about them?
 
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