Max tire size on E-Body??? and many more questions

[Killer_Mopar]

Heres a question for the gurus and/or people that have done it. How tall of a rim can I fit in the rear of my stock 70 Challenger without major work? (no tubbing whatsoever, and maybe spring relocation). I want to go with 18 inch Cragars and am pretty sure they will fit. However, I do not know how wide of a rim will fit.....what is the max size that will fit under a stock wheelwell? I currently have 15x10s and think 18x9s will work, but I want to be 100% sure before I spend my money on them. Also, while I'm asking, what about tire size? I am currently running stock springs with air-shocks and have the rear height where I want it, the only thing is I hate the ride quality with air-shocks so I want to change it out for new leaf springs and Eddy IAS shocks. However, this creates another dilemma, I always thought that the SS springs would give me the stance I was looking for, but recently I was told that an aftermarket re-arched spring would be better. Which is better? I know that was a lot of questions, but I want to set myself straight before I go spending the cash. I hope someone out there has done this type of swap and can give me some insight on it. Thanks

[dwc43]

15 x 10's are the max. You don't want to go more than 15 on anything. A 15" tire with a 60 series aspect ratio will give you the best handling you can get from your car. A tire has a slip angle and it is very narrow at about 5 to 8* anda tall wheel with a short profile tire will go beyound that angle and will cause handling problems. Other so called ho po cars get away with it due to a lowered center of gravity that you will never get with your car. Lower side wall tires will also reduce off the line traction since they have very little give to the side wall and on cornering they will break loose and cause a slide with very little warning to the driver.

Other things to consider is the weight factor of bigger wheels. Increasing unsprung weight will make it handle worse than it will with a lowered unsprung weight. The increased weight will take more fuel to burn to get it up to speed and it will take longer distance to stop it as well. It also stresses the braking system. Don't belive it, look over there on the truck board with all those 16 to 20 inch wheels and all the complaints about warped rotors and worn pads after only 10 to 20,000 miles on hte clock of a new truck.

The SS springs will work great and will improve traction. Get rid of those air shocks asap. Mopar has never recomended the use of those things. THey cause handling problems and bend springs and can break the shock mounts on the frame. KYB would be the best way to go. We mess with this stuff on a regular bassis in our shop building race cars and such, so if you need any help let me know.

[TL]

You have 15x10 on a stock e body? what size tire? My 275/60 on15x8 look close. If my 15x8 would go on the front, I could get 15x10 for the rear. Oh and DWC43, if you are there, what does it take to get your a arms on an e body? You said some modification was nessecary.

[70Barracuda]

Sure a 15 x 10 will fit an E car. 295 50 15 tire will fit or go on the car. Look like crap and stick out bad, plus the need for air shocks. You can bet it drives like crap.
Take your car to a good tire shop with one of those wheel measure tools that adjusts to backspace and tire size.

[Killer_Mopar]

Originally Posted by dwc43

15 x 10's are the max. You don't want to go more than 15 on anything. A 15" tire with a 60 series aspect ratio will give you the best handling you can get from your car. A tire has a slip angle and it is very narrow at about 5 to 8* anda tall wheel with a short profile tire will go beyound that angle and will cause handling problems. Other so called ho po cars get away with it due to a lowered center of gravity that you will never get with your car. Lower side wall tires will also reduce off the line traction since they have very little give to the side wall and on cornering they will break loose and cause a slide with very little warning to the driver.

Other things to consider is the weight factor of bigger wheels. Increasing unsprung weight will make it handle worse than it will with a lowered unsprung weight. The increased weight will take more fuel to burn to get it up to speed and it will take longer distance to stop it as well. It also stresses the braking system. Don't belive it, look over there on the truck board with all those 16 to 20 inch wheels and all the complaints about warped rotors and worn pads after only 10 to 20,000 miles on hte clock of a new truck.

DWC, thanks for the imput, but I am not roadracing the car and hardly care about my 1/4 mile times. I am going with the 18s for the looks and I know about the downside of using big rims. I just want to know what type of chassis problems I will be running into. The stopping problem will be fixed with Baer brakes and the handling problem isnt that huge of a factor, considering I wont be cornering at a high speed. So, after looking over the car, I think 18x9s with SS springs and new shocks will get the car right where I want it. If anyone knows about clearence problems then please tell me. Thanks.

[Killer_Mopar]

Originally Posted by 70Barracuda

Sure a 15 x 10 will fit an E car. 295 50 15 tire will fit or go on the car. Look like crap and stick out bad, plus the need for air shocks. You can bet it drives like crap.
Take your car to a good tire shop with one of those wheel measure tools that adjusts to backspace and tire size.

He is right about the air shocks and backspacing issues, the problems that you will encounter if you go with this setup is the rear bump problem due to the airshocks. The tires do stick out of the car about 1/2 inch but they dont go pass the character line that protrudes from the side. The only other thing that did upset me with this setup was that I couldnt light the tires up as easily due to the increase of rubber.

[dwc43]

Originally Posted by TL

You have 15x10 on a stock e body? what size tire? My 275/60 on15x8 look close. If my 15x8 would go on the front, I could get 15x10 for the rear. Oh and DWC43, if you are there, what does it take to get your a arms on an e body? You said some modification was nessecary.

With proper backspacing you can get a 15 x 10 under the rear. I even have a Dart with 15 x 10's on the rear of it. but the lip is rolled and it is tight. The A arms were designed for the F,M, and J cars that we have raced in the past. They use a bolt on mount that you wont find on any other Mopars. You would have to cut off the mounts, but not the shock mount and weld on another mount that I make just for using these A arms on other cars. Give me an e mail addy and I'll see if I can send you a pic of the set up and describe the mod better.

[ChallengerChuck]

Originally Posted by dwc43

15 x 10's are the max. You don't want to go more than 15 on anything. A 15" tire with a 60 series aspect ratio will give you the best handling you can get from your car. A tire has a slip angle and it is very narrow at about 5 to 8* anda tall wheel with a short profile tire will go beyound that angle and will cause handling problems. Other so called ho po cars get away with it due to a lowered center of gravity that you will never get with your car. Lower side wall tires will also reduce off the line traction since they have very little give to the side wall and on cornering they will break loose and cause a slide with very little warning to the driver.

Other things to consider is the weight factor of bigger wheels. Increasing unsprung weight will make it handle worse than it will with a lowered unsprung weight. The increased weight will take more fuel to burn to get it up to speed and it will take longer distance to stop it as well. It also stresses the braking system. Don't belive it, look over there on the truck board with all those 16 to 20 inch wheels and all the complaints about warped rotors and worn pads after only 10 to 20,000 miles on hte clock of a new truck.

The SS springs will work great and will improve traction. Get rid of those air shocks asap. Mopar has never recomended the use of those things. THey cause handling problems and bend springs and can break the shock mounts on the frame. KYB would be the best way to go. We mess with this stuff on a regular bassis in our shop building race cars and such, so if you need any help let me know.

dwc is right on the money on all counts. (And I don't say this merely because he is a fellow Tennessean!)
Another relevant issue that dwc did not mention was that of center of gravity. When one installs extremely large tires/wheels on a car (i.e., 18+ inches), they negate the benefits of a larger contact patch by raising the center of gravity. By raising the center of gravity by using taller tires/wheels that increase unsprung weight, the gains that would normally be associated with larger tires/wheels do not materialize.
THE only circumstance under which I would recommend anything larger than 15-16 inch tires/wheels on '60s-'70s era Mopars would be if they are building a C-Body for better handling. Even then, 19 inches would be as far as I would go, and I wouldn't even do that without considerably-larger brakes (14-inch rotors with 6-piston Alcon calipers).
Merely my thoughts..................

[Killer_Mopar]

Thanks for the feedback, but I didnt need to know the adverse affects big rims would have on my handling, stopping, and/or performance. I simply wanted to know what it would take to put them in. I am not drag racing, autocross racing it, or holding braking competitions. The only plans I have for my challenger is to enjoy cruising around with it and taking it to carshows to win trophies I find it amazing that people keep telling me not to do this. On the other hand, when I say I am going to build a high horsepower 400 stroker engine, nobody points out how unsafe a high horsepower car can be, its really a double standard. I guess its all go and no show for a lot of the people in this hobby.

[rumblefish360]

LOL Nothin like a cash cow of usless info on what you don't want to know no matter how well intended.

[ChallengerChuck]

Originally Posted by Killer_Mopar

The only plans I have for my challenger is to enjoy cruising around with it and taking it to carshows to win trophies. I find it amazing that people keep telling me not to do this. On the other hand, when I say I am going to build a high horsepower 400 stroker engine, nobody points out how unsafe a high horsepower car can be, its really a double standard. I guess its all go and no show for a lot of the people in this hobby.

People keep telling you not to enjoy cruising in your Challenger and take it to car shows to win trophies?! I find this very hard to believe, particularly from this chatroom.
You solicited advice from us concerning this issue. We responded, some of us giving the reasoning and logic behind our advice. One can consider said advice "useless"; that is their perogative. And ultimately, the decision on what tires/wheels you are going to install on your Challenger is you. You are a free individual that can do anything that you please (within reason, of course!).
As an aside concerning the issue of aesthetics, no E-Body looks right with 17+ inch tires/wheels. At least, that's my opinion, for what that's worth.
But if you want to run 18s, knock yourself out!

[dwc43]

400 horse power is not unsafe either. That's like saying guns kill people, they don't, some criminal pulls the trigger, just like some non drivin inexperienced kid slams the throttle instead of rolling into it and respecting what he has under the hood. I don't fear snakes, but I respect them, therfore I don't get bit, and we all live another day.

As for wheels, you said you wanted to go cruising and that alone is where the safety issues mentioned will take effect on your ride. It will never effect it while setting still, only while cruising.

[turbododge]

When one installs extremely large tires/wheels on a car (i.e., 18+ inches), they negate the benefits of a larger contact patch by raising the center of gravity. By raising the center of gravity by using taller tires/wheels that increase unsprung weight, the gains that would normally be associated with larger tires/wheels do not materialize.

I think I am missing something here. Most, if not almost all, of the larger WHEEL diameter tires are actually smaller in outside diameter than the old standard 255-60-15 rear E-body tire we all ran for years. The 255-60-15 is 27.1" tall and most of the 17"s and 18's are in the 26's" tall, so they would lower the car. The only rear I know of that is the same as the old tires is the 255-50-17 which is also 27.1. A 245-50-16 on the front will give you a 26.1 diameter which is about the same as the old 235-60-15, which was also the standard.

From what I have seen, going to lower profile/bigger wheel size improves the handling immensely, as you can get higher quality tires and the lower profiles give much less tread lift from sidewall flex. Our Challenger is noticeably better on the bigger wheels and better tires. I don't think you can even get a speed rated 15 inch tire in 255 or 235 anymore, and regular TA tires are sure not a good handling tire. I would also say (haven't weighed them) that my 16 and 17" tire and wheel combos are no heavier than the 15's I had.

[dwc43]

15 x 10's are the max. You don't want to go more than 15 on anything. A 15" tire with a 60 series aspect ratio will give you the best handling you can get from your car. A tire has a slip angle and it is very narrow at about 5 to 8* anda tall wheel with a short profile tire will go beyound that angle and will cause handling problems. Other so called ho po cars get away with it due to a lowered center of gravity that you will never get with your car. Lower side wall tires will also reduce off the line traction since they have very little give to the side wall and on cornering they will break loose and cause a slide with very little warning to the driver.

Other things to consider is the weight factor of bigger wheels. Increasing unsprung weight will make it handle worse than it will with a lowered unsprung weight. The increased weight will take more fuel to burn to get it up to speed and it will take longer distance to stop it as well. It also stresses the braking system. Don't belive it, look over there on the truck board with all those 16 to 20 inch wheels and all the complaints about warped rotors and worn pads after only 10 to 20,000 miles on hte clock of a new truck.

The SS springs will work great and will improve traction. Get rid of those air shocks asap. Mopar has never recomended the use of those things. THey cause handling problems and bend springs and can break the shock mounts on the frame. KYB would be the best way to go. We mess with this stuff on a regular bassis in our shop building race cars and such, so if you need any help let me know.

[ChallengerChuck]

Originally Posted by turbododge

I think I am missing something here. Most, if not almost all, of the larger WHEEL diameter tires are actually smaller in outside diameter than the old standard 255-60-15 rear E-body tire we all ran for years. The 255-60-15 is 27.1" tall and most of the 17"s and 18's are in the 26's" tall, so they would lower the car. The only rear I know of that is the same as the old tires is the 255-50-17 which is also 27.1. A 245-50-16 on the front will give you a 26.1 diameter which is about the same as the old 235-60-15, which was also the standard.

From what I have seen, going to lower profile/bigger wheel size improves the handling immensely, as you can get higher quality tires and the lower profiles give much less tread lift from sidewall flex. Our Challenger is noticeably better on the bigger wheels and better tires. I don't think you can even get a speed rated 15 inch tire in 255 or 235 anymore, and regular TA tires are sure not a good handling tire. I would also say (haven't weighed them) that my 16 and 17" tire and wheel combos are no heavier than the 15's I had.

No, you didn't miss anything here. In essence, you are correct up to a point. Yes, installing 16 or 17 inch tires/wheels WILL improve the handling capabilities of an E-Body because, as you said, most 16 or 17 inch tires are in fact shorter than most 15-inch tires.

I was directing my comments concerning center of gravity and weight more specifically to tire/wheel combos that are 18 inches and larger. Here, you do run into issues of weight and center of gravity. These reasons here are why one has premature brake failure, as was mentioned by dwc.

Personally, I would stick with 15 inch tires on any E-Body, simply because anything larger just doesn't look right. But then again, that's just me.

[turbododge]

So.. If you repeat it, it must be fact. I have never seen any information that says higher profile tires handle better (at the same tire OD). In fact I have many times seen the opposite. Slip angle is tire and profile related, and is a very complicated item, but in general, a shorter stiffer, sidewall takes more cornering force to get to the critical slip angle range and thus gives more lateral cornering ability. The only time it will be a problem is if your suspension can't handle the higher forces and lays over too far.

Reread what I said about weight and diameters.

Tell me what 15" tire you can put on a 10" rim that is speed (Z or better) and DOT rated. We are not talking road racing slicks here, this for street applications, with real world driving.

[ChallengerChuck]

Originally Posted by turbododge

The only time it will be a problem is if your suspension can't handle the higher forces and lays over too far.

My point precisely !!!
All too often, many people (ricers being most prominent in this group) slap 19-22 inch tires/wheels on their cars, and that is the extent of their suspension mods. Consequently, these very same people have problems with premature brake failure.
Again, I agree with you concerning 16 and 17 inch tires/wheels!

[Killer_Mopar]

Originally Posted by turbododge

Our Challenger is noticeably better on the bigger wheels and better tires.

Turbododge, maybe you can answer my questions without throwing in personal preferences like other people.......

I just want to know if 18s will fit in the rear without major problems and if so, what is the max width that can be run. I have no concerns whatsoever on ride quaility and/or ride height. Basically, If I buy a set of 18x9s and put low profile tires on them, will they fit under the stock wheel wells? If you have any tips on making this setup work, please feel free to share. Thanks

[turbododge]

Chuck-we crossed paths as typing-I wasn't addressing your reply. I haven't looked specifically at 18" and bigger for Mopars, as I agree they look wrong. That is why I stayed at 50 ratio and 16 and 17" wheels, as well as the same outside tire diameters as the 15" I had before. They look very close to the 15" but allow you to get some good tires. I also agree that if you go to a bigger tire OD, either by bigger wheel or higher ratio, you will put a higher mechanical advantage to the brakes, which means higher pad pressure at lower rotating speed, and can really generate heat. Center of gravity raising will also happen and effect handling. The goal in going to bigger wheel, lower aspect ration is to have the OD come out the same as it was. My only issue is with the arguement (not yours) that higher aspect ratios and thus more sidewall flex will actually be better handling because of slip angle. Lower aspect ratios, with other things staying equal (tire diameter, width, quality) will almost always be a big improvement. As you said, the 16 and 17 will improve the handling of an E-body, if you can live with the look.

Killer: We are running 255-50-17 in the rear. The actual tire width and height are the same as a 255-60-15. If you go to an 18" wheel, the car won't care, if you get the right tire. The tire is what will hit things. We could easily fit a 28" tall tire in ours, maybe a bit more. So, if you can find a 255 or 265 wide 18" tire that has a diameter less than 28", it should be an easy fit.

[Killer_Mopar]

Originally Posted by turbododge

.
Killer: We are running 255-50-17 in the rear. The actual tire width and height are the same as a 255-60-15. If you go to an 18" wheel, the car won't care, if you get the right tire. The tire is what will hit things. We could easily fit a 28" tall tire in ours, maybe a bit more. So, if you can find a 255 or 265 wide 18" tire that has a diameter less than 28", it should be an easy fit.

Turbododge, Thankyou for the clear concise answer. I was going to go with 17s, but 17s are becoming more common now so I figured 18s would be a little different. I could always go with 24s like this guy.....

[dwc43]

Man, that sucks. Wont handle, wont stop, and will smoke the tires for ten miles or more ... LOL! Some people have a lot of time and money on hand to waste. Wished they had not done it to a classic.

[70Barracuda]

That Challenger looks like shit!

You can never have enough HP. Same with stopping and handling, you need that too.
These car's dont look good with 17 and 18 inch wheels on them.
But it's your car so go purple!

[ChallengerChuck]

Originally Posted by dwc43

Man, that sucks. Wont handle, wont stop, and will smoke the tires for ten miles or more ... LOL! Some people have a lot of time and money on hand to waste. Wished they had not done it to a classic.

Yeah, I would hate to imagine what kind of a ride this Challenger has, ESPECIALLY with the ride height being lowered to that degree!
You couldn't pay me all of the gold in Fort Knox to ride in that car!
THE largest wheel that I would install on a Challenger would be a nice American Racing Torq-Thrust "D" 15 X 8 1/2.
But that's just me...................

[turbododge]

Attached are some pics of our Challenger with 16" fronts and 17" rears. Tires are 245-50-16 and 255-50-17 which fill the wells (diameter wise) almost exactly like 235-60-15 and 255-60-15. I appologize for the crappy pics, but I had to pic them off my wallpaper as photoisland is gone and I haven't uploaded to a new host yet.

I understand you logic and desire to keep the nostalgic look (and I think ours is not far off), but I also hear a lot of talk of performance. Like I asked before, what tires would you run in a 15" that would give you any kind of decent street handling and speed rating. I was not even able to find an "H" rating when I looked, and that is why the upsizing was needed.

[TL]

Turbododge, what size rim on the fronts with 245/50-16 tires? Does anything rub?

[dwc43]

Originally Posted by turbododge

Attached are some pics of our Challenger with 16" fronts and 17" rears. Tires are 245-50-16 and 255-50-17 which fill the wells (diameter wise) almost exactly like 235-60-15 and 255-60-15. I appologize for the crappy pics, but I had to pic them off my wallpaper as photoisland is gone and I haven't uploaded to a new host yet.

I understand you logic and desire to keep the nostalgic look (and I think ours is not far off), but I also hear a lot of talk of performance. Like I asked before, what tires would you run in a 15" that would give you any kind of decent street handling and speed rating. I was not even able to find an "H" rating when I looked, and that is why the upsizing was needed.

Just looked through todays delievery of MotorTrend. All sorts of H and V rated tries in 15 inch sizes. From BFG to Perille (sp) Yokahomas and Proxies that the SCCA swear by and all sorts of other brands. There's all sorts of speed rated 15 inch tires. Heck, just to prove a point, look at any police cruiser. Everone I have seen is on 15 inch speed rated tires. They need it for high speed handling.

[Killer_Mopar]

I was just wondering, if 15s were so good at handling, stopping, and still maintain top speed, then why do all the current high performance cars come with 17+ rear rims? The viper has 19s in the rear and is capable of 180+ MPH, stops on a dime, and handles like a dream, not to mention its amazing stopping power. The Ram SRT-10 has 22s and handles, turns, and stops better than most cars, including just about every muscle car. Corvettes, Camaros, Mustangs, Lambos, Porsches, hell even SRT-4s have bigger rims than any stock muscle cars, I just understand why every major car company would put 17+ inch rims on their high performance cars if they are so "inferior" to 15s.

[JoeGrapes]

WOW Killer! What a good discussion. I've been going thru the same thing the past few weeks. I have a 70 440 Cuda with 15" Cragars on it and I was thinking about going to 17" Torq Thrust wheels for a little more updated look. I've been measuring for backspacing and tire diamaters until I drive myself nuts. I look at all the pics I can find on other peoples rides and asking opinions from all my car buddies. One minute I like the look and the next I don't. It's funny, most car guys I talk to don't like the look of the bigger wheels on a Cuda but none has ever mentioned any possible handling problems. Anyway, I'm so undesided about it I 'm going to put the idea on the back burner for a few months and see how I feel then.

[dwc43]

Two reasons really. The performance cars have a lower center of gravity which aids handling and that cannot be achieved with a 15 inch 60 series tire. The lower cg is where they are getting the vast majority of there handling. It's a trade off just like a small cam for more torque or a big cam for real top end hp.
Secondly, because the idiotic unimformed public will buy them. The only one you mentioned that does not take into effect of the first reason is the truck. The truck can get by with it cause effectivly you have a 15 60 series if you do the numbers, but you still have ride height that a truck will need if you tow anything with it and ground clearance. The viper truck will handle ten times better if you lower the cg and go to a 15" 60 series tire.

Seondly almost all performance cars use a tire that is pretty much a 15" 60 series. Such as any police cruiser. Race cars also use them. NASCAR, Bush, and Trucks all use a 15 x 9 tire that pretty much measure out to a 15 " 60 series. ARCA and lots of other series uses them too.

[turbododge]

Front rims are 16 X 8 and rears are 17 X 8, I think the backspace is 4.5 on both,but I don't recall for sure. I have an aftermarket gear in my steering that doesn't have stops, so I can turn just far enough for the tires to touch the inner fender.

Of course there are lots of speed rated 15" tieres, but not in our sizes. Just did a quick search on tire rack. One mfg has started making a 255-60-15 --Pirelli Scorpio-good speed rating at VR. There is no matching 235 or 245-60-15 however and you have to go to a P600 to get a front. I could find no 245,265,or 275-60-15 on their search, so you are extremely limited and wouldn't be able to match a set of tires.

Even in 16 and 17" it is tough to find tires that will fill the wheel wells, we are just lucky that the Impalla SS used the 255-50-17 so they are available.

I wouldn't get concerned that going to bigger wheels is going to hurt handling and braking. As was said, if you go lower profile, you will get better grip and higher cornering forces, so you would may need to upgrade suspension and bars a bit to take advantage of the grip, but it is not going to make the car handle worse, unless you go to a bigger diameter tire and change your center of gravity. As far as braking goes, you will not put any more load on the brakes unless you go to a larger OD tire. The brakes don't care how big the wheel is, only the radius from the hub to road (1/2 the tire diameter).

If you are still concerned, get some books, or do some searches on handling, suspension, tires, and wheels to get more information from folks other than us. Let us know what you find out.

I can tell you flat out that our Challenger is much better with the bigger wheels and lower aspect tires than it ever was with 15" tires and wheels.

Just a little edit here--just looked at a web site that said the new Magnum cop car will come with 18" V rated tires.