Good wheel/tire size for 70 Challenger?

All,

I've been so used to upgrading the steering and suspension on my 71 B bodies that I realized I'm at a loss when it comes to E bodies. It's time for me to replace the wheels and tires on my 70 Challenger. I've never had to do this before, and thought the Moparts crowd might have some suggestions as to what I can squeeze into those wheel wells. I currently have 15" rallyes with 235/60 in front and 275/60 in back.

Any recommendations?

Also - would you know if the backspace/offset would be the same as a 71 B body?

Thank you!!

Rylis-Pro has a '70 Barracuda and used to post here. He had 315-35-18s on his car.

Here's how I sorted out how ti fit 17" rims and fatter tires on my 51.

http://www.yourolddad.com/tires

Ewen if you just hare a 15" rim for test purposes you can still use this method. All you need is over all height and width of the tore in question and you can mimic it.

Depends on what you want.. styling? function/purpose? comfort/handling????

The YearOne 17x9 have a perfect backspacing and will easily accommodate tires 275-40-17 front and rear... no fender problems at all.... but they are a rather small diameter... but good for upgraded appearance and functioning.

RylissPro runs 315-30-18... but with special offset/backspacing rims.. AND he has aftermarket non-stock front and rear suspensions... another ball game.

Your 71-B-body rims should easily swap with the E-body.

Short sidewall tires are stiffer; offer better transient handling response, but also welcome damaged rims when low tire PSI vs pot-holes eventually come into the mix.

Taller sidewalls offer softer rides, but with less handling transitions.

For my street/hwy driving, I run 15x8 minilites (Superlite brand, 4.3/8: backspace); BFG T/A 255-60-15 front. 275-60-15 rear... nice ride, good cruising tires. No problems with fender clearance.

For track events, I run 18x11 minilites (ET brand, 5.5" backspace), Yokohama AO52 200TW 295-30-18, F/R... lips flushed as needed (done many years ago).

Just go ahead and put the biggest tire/wheel you can “squeeze” in there that looks cool without looking at the car’s total suspension set up. That is what everyone does…even when told that the tire size is not proper for the car. Then come back and complain that it rides like a dump truck and does not handle well.
Want real advice? try a pm

AAAaaaaand Tom chimes in with the usual cynical, pessimistic type of response.
Why doesn't everyone just call YOU directly for everything instead of using an open forum? Think of all the money and time that could be saved if we all just did what YOU say!
Short sidewalls don't always result in a poor ride. If you know anything, you'd admit that shocks and spring rates also factor in greatly.
These cars are not always used for competition or as daily drivers. In many cases, they are merely toys that we play with and enjoy. Because of that, they don't have to be the fastest or the most comfortable. Styling plays a major role in how the car will be set up.

Come on Kern Dog, put up or shut up...bring it on!

I know what works well, i have 22 years or more of results and lap times - with multiple vehicles....5 or 6 or 7 maybe 8... i lost count.....you have an opinion.
One size does not fit all, it's custom fit due to the combination of parts.

Show me a better tire rim combination that will knock another 3 or more seconds off the proper measurement of the car’s performance – that is called lap times - that does not compromise it’s street manners. You can’t. kma

I will put the Charger R/T up against your thing on Watkins Glen International Racetrack any time...come on - let's go!!!!!
You have no clue how much fun it would to be behind you on the Glenn with my faster car and you would have to let me pass....yeeehaaa...track rules ...and btw Black n Blue is way more badass than your thing....ahhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh

Nice looking car.... we know that the car is NOT yours.....You've admitted as much before here. I can brag about other people's cars too but what would be the point?
My car isn't specifically set up for racing but it could be if I wanted. Who knows...maybe I'll set up my other Charger for road race fun. My red car has A/C, extensive sound deadening, a stereo and other things to bring it to almost 4000 lbs. That would make it less likely to be a good performer. It does handle and ride pretty good for me despite not following what experts like you might demand.
This topic wasn't about racing or comfort was it? You tried to make it that way. Your abrasive and pushy personality may be appropriate in some instances but it wasn't requested here.

Thanks all so far.

For additional context - I have been racing my 71 Satellite Sebring for over 30 years. SCCA Solo II, Willow Springs, etc. I'm very familiar with what a 71 Satellite/RR can accommodate because I've been under those fender wells since 1987. The Challenger is new for me and while the back wheel wells look roomy, the fronts don't. I just picked up a set of the Year One 17x9 Rallyes for my RR, which so far I like very much. I am sticking with 17's for now.

I'm just not sure if the Challenger has the same offset, etc, that my 71 B body has. Based on the above responses it sounds like it does, which is great because then I can swap wheels among all my cars.

Where has that post gone to?

Maybe I've got a brain cramp, but trying to search his name and the site tells me he doesn't exist.

It really depends on what you're trying to do, what kind of look you want and how big the budget is. I've found that the 235/55-17 is a good tire size for a B/E body street car with decent performance capability . It should fit in all corners on all cars, should be fairly easy to find and shouldn't be too expensive. Fits a 17x8 wheel really well although you can use it on slightly narrower or wider rims.

Its RylisPro, Last posted here 4/23/23?, last "seen" 9/1/23 whatever that means. last time he mentioned his 315's, I believe he was trying to "squeeze" in bigger?
A couple of other notes, the abrasiveness is indeed predictable, and for me easy to overlook, while I will always try to squeeze in the largest/widest set of tires, with one caveat, in a track/handling application, I always try to seek a '"square" set-up, for those unfamiliar with the term, get used to being passed.
In my world, everything else on a car non engine wise is there to help the tires do their task.

Thank you, that found him no problem.

I'd imagine the "last seen" is a log in without a posting. Since he sells the AAR/TA spoilers, he may need to communicate with buyers without needing to post.

Back in the days when a broad range of varying performance tires were available in 15" sizes, it was easy to find a very grippy tire in a narrow width that would perform better than a wider, harder, pure street tire. I think we would all agree that a narrower racing slick will grab better than a significantly wider street tire. Sadly, the even limited number of speed rated 15" tires that were available a couple of years ago has slimmed down even further. I think we are opening the door of it will either be hard cruiser tires and racing slicks only, unless you use a smaller sport compact size and those guys aren't too interested in sticking with 15".

It is amusing in revisiting Rylispro's 315 thread from 2017 that the range of available performance tires in 17" diameters has significantly changed and 18s are now a better diameter for a broader choice as the OEMS have moved up to 20s. I've long advocated using OEM sizes in a car to ensure tire availability. Viper, Vette and Cobra sizes in 17" always seemed to yield a good selection. These days, you get maybe a single UHP summer tire around 350 wear rate and all out race tires. My idea of sticking to those sizes has now become a limitation. We seem to be an such a rapidly advancing tire tech place now, that it can become prohibitively expensive with wheel purchases (especially if you use a high quality forged or spun form wheel) chasing whatever less expensive OEM boutique tire size is the latest go fast goody with a broad range of tread, wear choices and potentially (at least for a short time) lower prices.

Various sanctioning bodies with their 200 treadwear requirement is starting to create a nitch of wider, better performing handling tires in a small range of select sizes that can be applied to vintage wheel well sizes with some carful work. As is often the first question we see here, what are you intending to do with the car must still be the first question asked when seeking to understand options.

BTW, the "last seen" comment is a tongue and cheek reference to a thread months back about members thought to be deceased years ago being "last seen" only months ago, and attributed likely to another person surfing on the decease's computer.

And to the rest of your spot-on reply, it is rather difficult to solve any problem if one can't define it first.

I do love road racing, but have never built any of my muscle cars for road racing. Depends what you (the o.p.) has planned for the car. I have always built mine for street/strip cruisers. I have 315/60/15's on the back of my 70 Challenger with -1" lowering Springs.

My only reply. is a 236-60-15 front on 15x7s and a 295-50-15 on 15x8 rallyes looks killer and ride isnt bad .

IMO any shorter sidewall and ride is gonna get harsh .

Just my 2cents

Years ago, I had a dead-stock, low-mileage 318 '70 Barracuda and put 15" Rallyes on it.
Ran 275/60s on 15x8s in back - the standard 4.5" BS from I think Wheel Vintiques.
With a couple people in the car, the rears would rub in the wheelhouses over bumps.
That was a surprise, since the same sizes have plenty of clearance on my '68-up B bodies.
IIRC, it was the 4.5 BS, and 4.25 would have prevented it.

As for 50 vs 60 profile, I've run both on B-bodies, and the 60s look more "proper" to me.
Ride quality 50 vs 60 wasn't different enough that I noticed it.

I've been using a 235/55-17 tire on my Coronet for the last 30 years. The ride isn't soft, but it isn't any harsher than any typical grocery getter made in the last 20 years. 235/55-17 was an OEM fitment on a bunch of cars so the size has generally been easy to find.

I already had the tires I planned on running but I purchased this tool to determine near exact back spacing.


https://www.speedwaymotors.com/Wheel-Fitment-Tool-for-Tire-Fit-Testing-Size-Measuring-Mockup,485869.html?utm_medium=CSEGoogle&utm_source=CSE&utm_campaign=CSEGOOGLE&gad_source=1&gclid=EAIaIQobChMIz_vSmumWgwMVDjmtBh0eTQnSEAQYASABEgKNBvD_BwE