Need Some Help

Discussion on wheel & tire issues
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offutt0311
Posts: 60
Joined: Tue Jul 21, 2015 2:44 pm

Need Some Help

Post by offutt0311 »

Anyone have any opinion as far as fitment on these wheels?

Description:
Set of 4 NEW Ultra 431 Series Hustler Muscle Wheels. Anthracite Grey with Diamond Cut Accents and Clear Coat finish. 18x9-1/2" , 5 on 120mm bolt pattern , +35mm offset , 6.63" of backspacing , 74.1mm center hub diameter. 5 spoke design, slightly concave dished profile.
smwalker
Administration Staff
Posts: 2201
Joined: Mon Jul 29, 2013 1:44 am
Location: Azusa,CA

Re: Need Some Help

Post by smwalker »

offutt0311 wrote:Anyone have any opinion as far as fitment on these wheels?

Description:
Set of 4 NEW Ultra 431 Series Hustler Muscle Wheels. Anthracite Grey with Diamond Cut Accents and Clear Coat finish. 18x9-1/2" , 5 on 120mm bolt pattern , +35mm offset , 6.63" of backspacing , 74.1mm center hub diameter. 5 spoke design, slightly concave dished profile.
Bill Wrote in another thread:
Camaro - 20's
F is +35 (Offset) (8")
R is +40 (offset) (9") - the result is usually tire contact with wheel opening, requiring the rolling of the fender (inner) lip


So if you had a 9 1/2 wide rim I would think that would make it even closer to the fender. I think. I am still trying to wrap my head around this stuff.. Need a visual to make sense of it.
Steve Walker
Azusa, CA
'11 PPV 9C3 Huron White
Navy Lifer
Administration Staff
Posts: 1724
Joined: Tue Mar 19, 2013 6:30 pm
Location: Canton GA

Re: Need Some Help

Post by Navy Lifer »

Let's put this in perspective.

Camaro SS uses 20" wheels:
8" front with +35mm offset
9" rear with +40mm offset

SS Sedan uses 19" wheels:
8.5" front with +48mm offset
9.0" rear with +57mm offset

Your Ultra 431 9.5" wheel with +35mm offset is going to be positioned considerably further outboard on the hub compared to the above wheels.

You will need to use a tire that is able to properly mount on the wider wheel--do you have a size in mind? For example (Continental DWS, just for reference) a 255/45-18 tire is at it's limit on a 9.5" wheel, but it still close to OE (PPV) diameter at 27".

Most everything else that might be OK (in 18”) is shorter, with a few exceptions....and those are mostly MUCH taller. This would make it more likely that the car would be lowered, which is where I think you will begin to have issues with the 9.5” width UNLESS you intend to massage the rear fenders for clearance.

A wheel with more offset, say +42mm to +45mm (to move the wheel outer edge inboard) would be necessary to run the 9.5” wheel without some extra work, especially if a larger/wider tire (vs 255/45-18) is going to be used.

I am unable to predict what may happen if you run the Ultra 9.5" wheel on the front of the PPV. With lowering, I think there will be issues, assuming you run a tire sized correctly for that width, unless you plan to go with significantly shorter than stock (PPV) tire diameters.

Depending on whether you plan to run the car at stock ride height, you'll find that even the Camaro 9" +40 wheel is going to have an issue with fender rub under high load or bump (compression) conditions. A lowered PPV with Camaro SS wheels, running a 275/30-20 tire, will contact the lip of the rear wheel opening.

Stock PPV wheels are +47.6mm, which rounds up to 48mm, same as SS sedan front wheel (but SS wheel is 8.5”, not 8.0)

The math looks like this for the PPV wheel:
- Backspace is 6.375
- Wheel width (bead edge to bead edge) is 9.0, so wheel lateral center is 4.5”
- Subtract 4.5 from 6.375 = 1.875
- “Offset” is +1.875” x 25.4 (metric conversion) = +47.6mm >>> = +48mm

All comparisons below are based on dimensions for the PPV stock wheel & tire

9.5" +35 offset (18” Ultra wheel) + 255/45-18 tire (27" OD)
outer rim bead is 32.1mm closer to edge of wheel opening
- that's a full 1.25"
http://www.willtheyfit.com/index.php?wi ... 35#content" onclick="window.open(this.href);return false;

9" +57 offset (19” SS sedan rear wheel) + 255/40-19 tire (27” OD)
outer rim bead is 3.7mm closer to edge of wheel opening and inner bead is further inboard 21.7mm (closer to suspension)

http://www.willtheyfit.com/index.php?wi ... 57#content" onclick="window.open(this.href);return false;

9" +40 offset (20” Camaro rear wheel) + 255/35-20 tire (27” OD)
outer rim bead is 20.7mm closer to edge of wheel opening

http://www.willtheyfit.com/index.php?wi ... 40#content" onclick="window.open(this.href);return false;

285/30-20 (compare tire profile with 255/35-20)
http://www.willtheyfit.com/index.php?wi ... 40#content" onclick="window.open(this.href);return false;

Other considerations include load range & load rating, and whether tires are summer-use only or all-season. You may find there are a limited number of tire choices that meet the recommended bead width range in appropriate sizes (diameter OR width), not to mention the load range recommendations.

And don't forget the hub-centric rings!!!
smwalker wrote:I am still trying to wrap my head around this stuff.. Need a visual to make sense of it.
Steve, just take a look at the willtheyfit.com links I've used--good visuals there
offutt0311
Posts: 60
Joined: Tue Jul 21, 2015 2:44 pm

Re: Need Some Help

Post by offutt0311 »

You guys are awesome.... he wanted too much for them for my pockets. Found a couple of sets of Camaro wheels that I'm trying to get him to come down on.
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