Wheel size

[sewlow]

Didn't the 454SS come factory with 275/60R15s on 15X7 rims too?

Yes.
BFG & Firestone recommend an 8" width for that tire size, but if mounting on a 7" wide... "Tire pressure should be dropped to 26 psi."
Normal psi is 35-36.
26 psi equals way too squishy sidewalls for my liking. Terrible handling & kills mpgs.
Running them @ 35 psi, which I do, on a 7" rim does cause the center of the tread to wear somewhat faster than the sides.
My corner-carving antics in the twisties evens that wear out, but only on the outer shoulders.
Even still, I usually average about 35-40,000+ miles out of a set of 4.

How was the truck lowered in the front? Springs or spindles?
BellTech spindles & their derivatives, McGaughy's, Western Chassis, CMS etc. will push the wheels out approximately 1/2"-3/4" per side.
DJM spindles maintain the factory track width.
Makes a diff when considering wheel offset.

My '97 @ 2/4. 275/60's. 7" wide wheel. B/T spindles.
Rolled fender lips. Trimmed LCAs.
They do rub occasionally at the bottom rear of the fenderwell.

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454SS wheels = offset -25.
Backspacing = 4 1/8".

A backspacing of 5.25" = 0 offset.

 

[The_Family_Tahoe]

Na. The truck is lowered 2/4. The height of my current tires are good. I'd like to keep the same width but I just don't think it's possible with the AR wheel since I don't want them to stick out.

I just went through this with my tahoe. I have a 2" front spindle drop and with stock wheels the tire edges were getting caught up with the front fender lip on bumps that fully compress the suspension. The only way around this (without rolling fenders or trimming them) was to either restore to stock ride height, get a smaller tire, or get wheels with more backspace. I got wheels with more backspace. Unfortunately, this caused a whole slough of new problems:
- the new wheels are 5" backspace 15x8 and they tuck the wheel under the truck nicely
- unfortunately they also hit the brake calipers and control arms because of the additional backspace over stock (5" vs 3.75")
-this required a ton of grinding to provide clearance for them

In hindsight I should have bought 17" at a minimum diameter wheels with 5" backspace for the front using an 8" wide wheel. This would have cleared the calipers and control arms on the backside and kept the tire away from the fender lip on full suspension compression.

The takeaway for me is: if you want a 2" or more drop in the front, you can't have more than 3" of wheel front space. Said another way, if you want an 8" wide wheel you need 5" of backspace. Or 7" up front needs 4" backspace. Unfortunately, there are only a handful of wheels that fit this requirement. American racing offers the torq thrust in this arrangement. Otherwise, you'll have to roll fender lips or trim them to keep your front tires from getting chewed up.

Currently, I'm running wheel vintiques 15x8 with 5" of backspace and 235/75r15 with no clearance issues (after all the grinding). These tires were brand new when I bought the truck, and I'm a cheap skate, and thought I could make this work with 15" wheels using my already new tires and save money vs buying large diameter wheels plus new tires that would have bolted on with no additional work. Don't be like me. I'm not happy at all with this setup because of all the grinding it required, and I still need to grind more because there is wheel contact with the control arm at full turn.

In your case I would expect the AR Outlaw and 275 wide tire with a 2" drop to contact the fender lips and chew up your nice tires.

 

[sewlow]

I just went through this with my tahoe. I have a 2" front spindle drop and with stock wheels the tire edges were getting caught up with the front fender lip on bumps that fully compress the suspension. The only way around this (without rolling fenders or trimming them) was to either restore to stock ride height, get a smaller tire, or get wheels with more backspace. I got wheels with more backspace. Unfortunately, this caused a whole slough of new problems:
- the new wheels are 5" backspace 15x8 and they tuck the wheel under the truck nicely
- unfortunately they also hit the brake calipers and control arms because of the additional backspace over stock (5" vs 3.75")
-this required a ton of grinding to provide clearance for them

In hindsight I should have bought 17" at a minimum diameter wheels with 5" backspace for the front using an 8" wide wheel. This would have cleared the calipers and control arms on the backside and kept the tire away from the fender lip on full suspension compression.

The takeaway for me is: if you want a 2" or more drop in the front, you can't have more than 3" of wheel front space. Said another way, if you want an 8" wide wheel you need 5" of backspace. Or 7" up front needs 4" backspace. Unfortunately, there are only a handful of wheels that fit this requirement. American racing offers the torq thrust in this arrangement. Otherwise, you'll have to roll fender lips or trim them to keep your front tires from getting chewed up.

Currently, I'm running wheel vintiques 15x8 with 5" of backspace and 235/75r15 with no clearance issues (after all the grinding). These tires were brand new when I bought the truck, and I'm a cheap skate, and thought I could make this work with 15" wheels using my already new tires and save money vs buying large diameter wheels plus new tires that would have bolted on with no additional work. Don't be like me. I'm not happy at all with this setup because of all the grinding it required, and I still need to grind more because there is wheel contact with the control arm at full turn.

In your case I would expect the AR Outlaw and 275 wide tire with a 2" drop to contact the fender lips and chew up your nice tires.

This is one reason why I changed up to a 17" wheel.
The 275/55's were the same height-wise as the stock 235/75-15's with that additionally wider contact patch. No speedo probs.
A touch heavier than the 15's, but considerably lighter than the 20's.
Those weight differences have both good & bad points, but lighter weight = quicker cornering transitions. Better acceleration & braking, too.
Problem is...there are NO decent performance tires available in a 15". None. No R-&-D by any manufacturer for decades. Whatever is being offered is 30-40 year old dino-tech.
The best performers of that bunch were Firestone Firehawk Indy 500's & they were discontinued 6 or 7 years ago. Neither the BFGs nor the Coopers could compare in the corners, & the Firestones would just outright embarrass those two in the wet.
Especially wet corners! HeHe!
Going to the 17's, & there was a multitude of modern tech designed choices for any driving style, perceived load capacities, dominant weather conditions or mileage/longevity requirements.

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[VFJimbo]

My 92 with Eagle alloy 15s, Cooper 275/60's...

 

[Nad_Yvalhosert]

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Looks damn good with Impala SS wheels!

 

[Frank Enstein]

More wheel info.

A naked 15x8 wheel will measure 16x9 ish. Where the wheel is actually 15x8 is in the corner where the tire bead seats.

However, Backspace is measured from the lip of the wheel where wheel weights clip on. So a 8" wide wheel with 4.5" backspace would have zero offset.

Offset can be calculated. Backspace can be measured. To calculate offset you need to know the wheel width and backspace.

Offset is the difference between the center of the wheel/tread and where the mounting pad of the wheel contacts the drum or rotor.
This is how I tell people how to remember the difference between Positive and Negative offset;

Positive offset tucks the tires farther under the vehicle. That's a good thing.
Negative offset makes the tires stick out causing people to want to buy drugs from you. That's a bad thing.

This is a handy worksheet for measuring for wheel and tire assemblies.

https://help.summitracing.com/ci/fattach/get/666870/0/filename/Wheel+%26+Tire+Worksheet.pdf

 

[sewlow]

More wheel info.

So a 8" wide wheel with 4.5" backspace would have zero offset.

So, I guess I've been fed the wrong info of 5.25" = '0' offset.
I'll defer to your knowledge. You have that down way better than I do when it comes to off-sets.

 

[Frank Enstein]

So, I guess I've been fed the wrong info of 5.25" = '0' offset.
I'll defer to your knowledge. You have that down way better than I do when it comes to off-sets.

Thankyewvurrymuch!

I wrote that worksheet.