sorry in advance tire wheel combo question

I know this has been discussed over and over, but honestly after reading all the post and replies on the subject myd head is about to explode from information over load.

before I shoot my wad on this setup does anybody know if fitment will be issue.

1968 Charger, current stock front end components, stock disc brakes.

what I would like to change up.
Tires

235/40R18 Fronts thinking 4.5 BS?

275/35R18 Rear 5.5 BS?

this QA1 package
https://www.summitracing.com/parts/qa1-hk01-crb1
any better ideals appreciated.
Again thanks for any input

All things on car are stock components if it makes any difference on fitment.
Hoping this can be done so I can put this to bed lol.

The rears sound short to me. That tire is just 25.6" tall (depending on brand can be a bit taller or shorter). Not sure what you are doing with the car, but most would want a taller tire like a 27" so it doesn't get lost in the wheel well. I have a '69 Super Bee that I dropped an inch or so, and I run a 295/40R18 (27.3" tall) on a 18x10 5.5BS. Fits well, but might go even taller next time... maybe a 295/45R18.


Front sounds OK, but you can certainly go wider. I run 17s on front of mine in 245/45R17 on 17x8 BS 4.75 and would easily fit 255 or wider.

What wheels and tires are on the car right now? Do you like how it looks now or do you want a big change? The tire combo that you're talking probably won't look good on that car but I'm not sure what you're trying to do. I don't think I'd use QA1 stuff on anything I build but once again, I'm not sure what you're trying to do. Do you have a copy of my book? https://www.amazon.com/Mopar-B-Body-Performance-Upgrades-1962-1979/dp/1613252501#ace-g9766277718

There are a lot of pictures in the book of different wheel and tire combinations. I'd start there before you spend a ton of money. If you don't want to read the book then find some local B body cars that you like and copy what they did. It gets really expensive really fast to just start buying wheels and tires without being 100% sure what you want. You'll spend $1000 and if you hate it when it rolls out of the tire shop you'll be super unhappy.

Thank you for info, put your book in wife's amazon cart lol.
Right now it has 15x8 torque thrust.
I want something that drives better, did the whole replacing of all wearable front end parts except the sway bar bushings. car floats really bad in curves, let alone a corner.
has new hemi torsion bars and leafs, kyb shocks, all stock stuff.

great info, glad I didn't pull trigger yet on my stuff.
Just out of curiosity, did you have issue with QA1 or know of some? not set in stone on anything, ordering Andy's book to learn some things.

Do you have an anti-sway bar on the car? If not you need to put one on there before you decide on anything else. If you do have one on there then you need to put a bigger one on. I like the Hellwig bars but Firm Feel and Hotchkis also have good bars for that car. The Hemi torsion bars are 0.920 diameter. If you step up to a 1.06 bar you'll add 33% to the spring rate. It depends on the weight of the car but a 1.06 bar should be pretty good for that car. When you put the bigger bars in the car then you'll need really good shocks. Your KYB shocks might be new but sadly they aren't any good. Best shocks that are easy to buy and install are the Bilstein shocks. I run Koni shocks on my cars but Koni has some install quirks. Hotchkis sells Fox shocks which some people really like but I have no experience with.

Try the bigger bars, bigger anti-sway bar and better shocks before you mess with the tires and see what you think. You shouldn't need to change anything else if all the bushings are new. Good luck.

It has the factory sway bar, all it says is heavy duty lol. will go with sway and TB's, see how that goes and work from there. Thanks for the help.

Factory sway bar is either 7/8, or if heavy duty, 15/16. Step that up to a 1 1/8 solid or 1 1/4 hollow bar, then drive that for a bit. You'll notice the difference. Definitely dig in the details in Andy's book.

With the bigger torsion bars you'll need better shocks so order a pair of front Bilsteins when you order the torsion bars. Or you can order front Koni shocks, the fronts install just fine. I prefer the Koni shocks since they are adjustable. Just for fun install the parts in stages. Put the big anti-sway bar on first and drive the car for a 100 miles or so. Then install the big torsion bars with your KYB shocks. Then change the shocks. You'll learn a lot more if you do it in stages since you'll be able to feel the difference from the individual parts. I wouldn't worry about the rear suspension or the tires until you get the front finished up.

275 to 295 40 18 tire on a 10" wide wheel would be ideal on the rear, 245 40 18 or 245 45 17 on the front would be a a good size. 0 offset rims fit the best on these B Bodies.
I run the full QA1 set up ,K frame and all , since last year on my Bee and was a great improvement in ride/drive quality , already had the Bilstein's ,1.12 T bars , gusseted control arms and big sways. Still made the steering feel tighter , the castor and camber went from 4deg caster to 6deg , camber from -.5 to right about -1 , so evenly on both sides all I had to do is set toe when I got done. High speed stability is great and all the parts look fantastic under there, had to get the 70 up front sway , so went tubular . that alone dropped 10 pounds .I did toss the k-frame bolts QA1 sent and used a shouldered short one in the rear position with an extra thick hardened washer that really located and centered the tubular K to the frame rails , on the front I found these stepped , machined washers ,I might have a pic ,that cam from 19 RAM 1500 steering rack mount . Fit perfectly into the front mount tubes with new hardware store grade 8 bolts . Over all very pleased with QA1 parts. Beats trying to refurbish 50 year old parts.

your right, that does look good under there. I just thought it would be a clean and easy way to get something that helped me feel more in control. Not going to autocross it or anything like that. Going to do the TB's and sway bar and shocks like Andy said, then work out from there. REALLY want to pro-street it {more my style} but cant bring myself to destroy another R/T lol.

When I was figuring out what tire/wheel combo I wanted to run on my 51 I came up with a simple way to find out if my choice would clear things.

http://www.yourolddad.com/tires

You don't have to destroy it to go Pro Street, you just have to spend money to do it right. AMD now makes wider wheel tubs that look stock. I'm working on a RoadRunner right now that is going Pro Street. It is going to be a very nice car. Costs a lot of money to do it right but it can be done. And you can build a Pro Street car that handles if you do it correctly. It won't handle like a road racer but it will handle pretty well. You aren't going to build it in your driveway though. Most likely need a professional shop to handle some of the fab work.

This car has a 275-40-18 front on a 18 x 9 wheel.
295-45-18 on the rear with an 18 x 10.

IMO... for any B-body, Frankenduster's wheel tire setup is really good.... tire/rims wide enough and tall enough... correct rim backspacing is the key to make them fit properly.

BS is for the rim not the tire, on a 2nd gen Charger a 10" wide wheel with a 5" BS for the rear works well, if it was a 9" wheel you would want 4.5 " BS, all this said not all cars are the exact same, I have 15x10 4.87 BS on the rear & a 15x 7 3.76 front

Thank you, Sir !
The outer wheel tubs in these cars is a bummer though. The design makes for clearance problems with a lowered car.

I found these pictures online. Someone had forethought while doing quarter panel replacement.

I had a less elegant fix.
This is on my second 1970 Charger

Lots more tire clearance now..

that looks sweet!

Actually, to keep the wheel/tire centered within the factory wheel well and, most importantly the on-center track width, the correct BS for a 9" rim is 5", then a 10" rim is 10.5".

Zero offset basically? I've always thought Mopar cars worked best with 1/2 inch of offset. So 5.5" BS on a 9 inch rim and 6.0" BS on a 10 inch rim. I usually start with 1/2 inch of offset on any Mopar I work on and then go from there. I keep a stack of spacers on the shelf so I can move the rim back out 0.125 or 0.250 to get things perfect.

Was done here locally by a shop in Newton, KS.