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Chryco's Tech Shop => Suspension, Wheels/Tires, and Brakes sponsored by THE STOP SHOP => Topic started by: HoosierCuda on May 30, 2017 - 11:24:50 am

Title: Tire Size Recommendations
Post by: HoosierCuda on May 30, 2017 - 11:24:50 am
Looking at getting new tires for my '70 'Cuda project.

I'm thinking 255/60/15 at each corner...any known rubbing issues on the front with this size?

Also considering going 275/60/15 at the rear....thoughts? or would the stance look better with equal size all around? also a factor with rotating tires...
Title: Re: Tire Size Recommendations
Post by: 1 Wild R/T on May 30, 2017 - 11:38:16 am
235/60-15 in the front... Some folks squeeze 245's but then need to be very careful... I'd rather loose the extra 10mm & be able to drive..

255 or 275 in the rear both fit... With the right wheel offset 295's fit....
Title: Re: Tire Size Recommendations
Post by: TelisSE440 on May 30, 2017 - 01:37:13 pm
235/60-15 in the front... Some folks squeeze 245's but then need to be very careful... I'd rather loose the extra 10mm & be able to drive..

255 or 275 in the rear both fit... With the right wheel offset 295's fit....

As wild RT said, i believe 235/60 front with 275/60 back is a pretty combination. You may find 235 a little small but better be safe than sorry. Both my front fenders are damaged in the inside lip, when the previous owner put 245/60, but he had the car too low and he turned it too hard.
Title: Re: Tire Size Recommendations
Post by: HoosierCuda on May 30, 2017 - 01:38:47 pm
Thank you both for saving me a mistake...I'll definitely skip 255 in the front for sure
Title: Re: Tire Size Recommendations
Post by: 72bluNblu on May 30, 2017 - 09:14:58 pm
The width isn't the problem with the 255's, it's the height. Same for the 245's. A 245/60/15 is about 26.5" tall. Usually you want to stay around 26" at the top end, especially if the car is lowered any. The 245's can be done with the right backspace but you might not like the ride height needed to pull it off. If you could find a lower profile tire in a 15" it would work, but there's really almost nothing in 245 or 255 with less than a 60 profile.

I run 275/40/17's on 17x9's with a 5" backspace on all 4 corners of my Challenger. They're 25.7" tall, and even lowered pretty significantly from stock those fit. But tire availability in the 15" rims pretty much kills running wide tires in the front with 15's. There are some competition tires out there, but pretty much nothing in DOT legal street tires.
Title: Re: Tire Size Recommendations
Post by: dodj on May 30, 2017 - 10:28:41 pm
I run 255's with room for more. Lower than stock. IMO, the bigger front tires look much better than 235's.
Title: Re: Tire Size Recommendations
Post by: 1 Wild R/T on May 30, 2017 - 10:32:21 pm
I run 255's with room for more. Lower than stock. IMO, the bigger front tires look much better than 235's.

255 what?  17's? 18's?  Cause 15's run into the steering linkage if to go bigger....
Title: Re: Tire Size Recommendations
Post by: 72bluNblu on May 30, 2017 - 11:08:05 pm
255 what?  17's? 18's?  Cause 15's run into the steering linkage if to go bigger....

If you could find a 255 in the right height you could run it on a 15x8 with 4.5" of backspace. 17" rims still don't clear the outer tie rods. I don't think you could run a 15x9" because you can't go much past 4.5" of backspace so 275's would be out, but a 15x8" with 4.5" will get you to a 255. You just can't use a 255/60/15 because it's 27" tall. Ideally you'd need a 255/55/15, but you're not going to find that size.
Title: Re: Tire Size Recommendations
Post by: dodj on May 30, 2017 - 11:12:26 pm
17's, sorry, should have included that detail.  :grinyes:  255ZR4017
You can't buy a decent tire in 15" anymore.  :2cents:
Title: Re: Tire Size Recommendations
Post by: 1 Wild R/T on May 30, 2017 - 11:16:05 pm
I run a 235/60-15  (26.1" tall) my rims have enough backspacing that I run a 1/8" spacer so my rim clears the tie rod end & if I'm not careful my tires will rub turning into a driveway..... So tell me were your gonna put the extra 3/4" of tire....  Yes only 3/8" is to the outside but still where's it gonna fit inside the fender.....
Title: Re: Tire Size Recommendations
Post by: TelisSE440 on May 31, 2017 - 01:03:38 am
I was under the impression that HoosierCuda liked tires with big sidewalls (suggesting 60s wide sidewalls). Getting 17s or 18s is a out of the ''stockish'' look and you have to get new wheels of course. But dodj is right, 15s tires, due to their rare size, are of average quality technologically.
Title: Re: Tire Size Recommendations
Post by: 72bluNblu on May 31, 2017 - 01:09:14 am
I run a 235/60-15  (26.1" tall) my rims have enough backspacing that I run a 1/8" spacer so my rim clears the tie rod end & if I'm not careful my tires will rub turning into a driveway..... So tell me were your gonna put the extra 3/4" of tire....  Yes only 3/8" is to the outside but still where's it gonna fit inside the fender.....


Well, you haven't told us your rim width or backspacing, so I really couldn't tell you why you can't fit more tire on your car.

But you can put 255/60/15's up front on 15x8's. Mopar Mitch did it on his car. 15x8's with 4.375" of backspace, 255/60/15's. And that's a 27" tall tire!!!! Not sure what he did to make it work, I wouldn't think a tire that tall would work well up front. But it can be done. You do have to keep in mind that ride height, alignment specs, and even rim design can make a big difference when you get down to squeezing the last 1/4" of tire under there. With tie rod clearance I've seen rim design account for as much as 3/8" of additional clearance from one rim to another in the same width and diameter, just the shape of the lip of the rim being different. 

I currently have 255-60-15 T/As front, mounted on 15x8 minilte rims (and 275-60 15 rear on same 15x8 rims).   These same tires will also mount and work fine on factory 15x7 rims.  You can tuck the lips in for added peace of mind if you want (my car is already lowered).

(http://www.cuda-challenger.com/cc/index.php?action=dlattach;topic=19470.0;attach=184244;image)
Title: Re: Tire Size Recommendations
Post by: HoosierCuda on May 31, 2017 - 09:03:23 am
17's, sorry, should have included that detail.  :grinyes:  255ZR4017
You can't buy a decent tire in 15" anymore.  :2cents:

Sadly true...14"s and 15"s are getting harder to find in a variety of sizes

I was under the impression that HoosierCuda liked tires with big sidewalls (suggesting 60s wide sidewalls). Getting 17s or 18s is a out of the ''stockish'' look and you have to get new wheels of course. But dodj is right, 15s tires, due to their rare size, are of average quality technologically.

Correct...I am trying to keep as close to stock in appearance as possible and prefer 15"s
Title: Re: Tire Size Recommendations
Post by: HP2 on May 31, 2017 - 09:51:16 am
I run a 26x10x15 on the front of my Challenger. This is close to a 255/50 metric tire. Rim is a 15x8 with 4.5" backspace. It also is a competition style rim and not stock, so its backside clearance for tie rods and calipers is improved over stock. Clearance is close to outer fender lip and I had to roll the edge to ensure it doesn't cut the tire, but they do fit. Inner fender clearance seems fine.

To get more than 4.75" of backspace requires stepping up to a larger diameter rim to allow tie rod ends to fit inside wheel.
Title: Re: Tire Size Recommendations
Post by: 1 Wild R/T on May 31, 2017 - 10:43:37 am
Well, you haven't told us your rim width or backspacing, so I really couldn't tell you why you can't fit more tire on your car.

But you can put 255/60/15's up front on 15x8's. Mopar Mitch did it on his car. 15x8's with 4.375" of backspace, 255/60/15's. And that's a 27" tall tire!!!! Not sure what he did to make it work, I wouldn't think a tire that tall would work well up front. But it can be done. You do have to keep in mind that ride height, alignment specs, and even rim design can make a big difference when you get down to squeezing the last 1/4" of tire under there. With tie rod clearance I've seen rim design account for as much as 3/8" of additional clearance from one rim to another in the same width and diameter, just the shape of the lip of the rim being different. 
([url]http://www.cuda-challenger.com/cc/index.php?action=dlattach;topic=19470.0;attach=184244;image[/url])



So you haven't done it, your not sure what needs to be done to accomplish it but you would suggest someone who doesn't what to have to modify his car to bolt them on goes ahead & spends his $$$ on them anyway? Brilliant!!  Knowing Mitch uses his car for competition road course events I'd first assume he's running more camber than you would want on a street car, it helps with handling as the cost of tread wear... a high camber number will pull the top of the tire in 1/2"-3/4" But the inside edge of the tire will be gone in 5000 miles.... Next I'm certain he's rolled the fender lip for clearance & possibly even did a subtle bulge which would gain him another 3/8'-3/4"... Not really the hot ticket for a bolt on scenario....

Like I was saying 235/60-15 up front... :2cents:
Title: Re: Tire Size Recommendations
Post by: HoosierCuda on May 31, 2017 - 11:17:15 am
Like I was saying 235/60-15 up front... :2cents:

Sounds like that's where I'm leaning...maybe do the 255/60/15 in rear...?
Title: Re: Tire Size Recommendations
Post by: TelisSE440 on May 31, 2017 - 12:09:37 pm
Sounds like that's where I'm leaning...maybe do the 255/60/15 in rear...?

You could see a comparison between 255 and 275/60/15 in rear. I have 255, i thought it was big enough, but a 275 seemed to me far better. (but you need 15x8 wheels). If you have 15x7 wheels then 255.
Title: Re: Tire Size Recommendations
Post by: 1 Wild R/T on May 31, 2017 - 12:26:35 pm
275's work, I've used them but they are 28" tall & while it fits fine I like somewhat similar height tires front to back.... Currently I have the 255's in the back, they fit great, never rub & look "nice"  27.1" tall 10.2" wide .... Honestly I prefer 295/50-15's they don't look "nice" they look "aggressive".....  26.7 tall 12.2" wide.....  However they need the wheel backspacing just right & honestly moving the springs inboard a little makes it much easier to fit....  Back in the late 80's I built my own shackles to mount a B body housing, these days you can buy parts to just bolt in a 68-70 B body housing..... 
http://www.doctordiff.com/e-body-offset-spring-hanger-shackle-kit.html (http://www.doctordiff.com/e-body-offset-spring-hanger-shackle-kit.html)
Title: Re: Tire Size Recommendations
Post by: 72bluNblu on May 31, 2017 - 10:02:07 pm

So you haven't done it, your not sure what needs to be done to accomplish it but you would suggest someone who doesn't what to have to modify his car to bolt them on goes ahead & spends his $$$ on them anyway? Brilliant!!  Knowing Mitch uses his car for competition road course events I'd first assume he's running more camber than you would want on a street car, it helps with handling as the cost of tread wear... a high camber number will pull the top of the tire in 1/2"-3/4" But the inside edge of the tire will be gone in 5000 miles.... Next I'm certain he's rolled the fender lip for clearance & possibly even did a subtle bulge which would gain him another 3/8'-3/4"... Not really the hot ticket for a bolt on scenario....

Like I was saying 235/60-15 up front... :2cents:

Let's get a few things straight.

First, I didn't recommend anyone run 255/60/15's up front. Go back and check my posts, never happened. I said a 255 wide tire would work just fine if you could find a shorter one (different profile) and run it on a 15x8 with up to around 4.5" of backspace. I also said you wouldn't be able to find a shorter tire, and that the height would be a problem. That's not a recommendation. I did say 245's will fit, and they will, and I know exactly what that would take. 

Second, I have a pretty good idea of what it would take to run a 255/60/15 like Mitch does on one of these cars. My point with Mitch's car isn't that he modified his car, I'm sure he did. My point was that it can be done, and can be done with a tire I originally said I wouldn't use or recommend. Heck I flat out said it wouldn't work, and yet it does. The fact of the matter is that a 255/60/15 on a 15x8 with a 4.375" backspace has significantly more outboard clearance to the fender than the 275's I run on my Challenger. The 275/40/17's I run on 17x9's with a 5" backspace stick out a 1/4" further outboard than Mitch's tires do. The height is the issue, not the width or even the backspace/suspension clearance in that setting. You could run less backspace and still not have to modify anything if you could find a shorter 255. As for camber, you can run as much as -1.5* on the street with no issues. I do, and I have tens of thousands of miles on my cars like that with no abnormal wear. I do spend some time driving on winding roads though, I suppose if all I did was drive back and forth to the Dairy Queen it might cause a little more wear on the inner tread.

Third, tire recommendations are difficult. All of these cars are a little different because of the fairly loose body tolerances. Ride height, alignment specs, tire manufacturer and even individual models of tires from the same manufacturer can make a big difference when you start maxing out tire sizes. I'm well aware of what it takes to start making adjustments like that, I run 275/40/17's on my Challenger up front after all. So what it takes to fit a wide tire on one car may not be the same as on another, what works on my car might not work on another one without modifications. Just the way it goes. If someone isn't willing to make any adjustments at all, they shouldn't try to max out their tire size, they should just run something easy that will have a mile of clearance just in case.

And finally, if you'd bother to provide the specs on your own rims, I could probably tell you why you can't fit more than a 235/60/15 on there. But since you can't or won't, well, can't help you.

I run a 26x10x15 on the front of my Challenger. This is close to a 255/50 metric tire. Rim is a 15x8 with 4.5" backspace. It also is a competition style rim and not stock, so its backside clearance for tie rods and calipers is improved over stock. Clearance is close to outer fender lip and I had to roll the edge to ensure it doesn't cut the tire, but they do fit. Inner fender clearance seems fine.

To get more than 4.75" of backspace requires stepping up to a larger diameter rim to allow tie rod ends to fit inside wheel.

Exactly. The width isn't the biggest issue, the height is.  If someone made a 255/55/15 or a 255/50/15 running 255's on the front would be pretty easy. But there's pretty much nothing out there in those sizes for street legal tires.

Also, running 17's still doesn't get the outer tie rod ends to fit inside the wheel. At least not on all 17's. Mine don't fit inside, which is why I was limited to about 5" of backspace with the 17x9's. Better than a 15", but still not unlimited like you get if you go up to an 18" rim and the tie rod ends fit entirely inside the wheel. On E-bodies it isn't as important though because the track width means that the clearance to the frame rails starts to come up pretty close to the same place as you run out of tie rod end clearance with the 17's. 18's might buy another 1/4" of backspace, but with tires close to 26" tall you'd run out of clearance to the frame when turning at that point anyway. Not like on an A-body where you can run 6" of backspace before the frame starts to be an issue, I run 275/35/18's on 18x9's on the front of my Duster with a 6.1" backspace. With a 15" on those cars you can only run about 4.75", so to max out you have to run an 18".

My next set up with my Challenger will probably be 285/35/18's on 18x9.5's with around 5.25 to 5.5" of backspace. I'll have to roll the fenders for that one though, and I suspect I'll have to do the last bit of fine tuning with some spacers. It'll be close. I'll just lean on the fender roller a little harder to give the fenders some push if I have to.

Title: Re: Tire Size Recommendations
Post by: Mopar Mitch on June 05, 2017 - 12:35:05 am
Hi everyone... sorry I haven't been on the site lately... travelling, etc.

To play it safe, a 245-60-15 on 15x7 with 4" bs (as a factory rim) will fit a-ok on any e-body, f/r... ok 99% of all e-bodies; if you go to an 8" rim, then you need 4.5" bs; 9" rim needs 5" bs; 10" rim needs 5.5" bs.... all this so to keep the original factory centerline of the tire sames a the factory designed it.

As 72 blunblu says, the DIAMETER is the biggest factor.     I also run 275-45-16 (~25.7" dia) Hoosier A6 DOT autocross tires (ok, race only..) on 16x10 rims f/r... having only a 5" bs... for competition autocross events.... and yes, for THOSE tires, I've slightly modified my fender lips... flushed/pulled... but they still appear stockish (best friend owns a body shop and he's great at body work!).... also, my suspension is lowered and very stiff (still ok for street/hwy driving.

I used to run 245-60-15 f, 275-60-15 r, both on factory 15x7 rims (4" bs)... and they fit a-ok.   i recently changed to the 255-60-15 f for a touch more ground clearance for my headers for street sake.

I love my current setup... suspension, choices of rims/tires, etc.... I also have a set of 16x8 f/r minilite rims (4.5" bs) with 255-50-16 BFG G-Force T/As f/r.... hwy and HSAX, etc)

At the very least, IMO... don't be afraid to tuck your lips... its worth it... enjoy the ride... its YOUR car.
Title: Re: Tire Size Recommendations
Post by: Mopar Mitch on June 05, 2017 - 12:47:43 am
Here's another picture... to share...
Title: Re: Tire Size Recommendations
Post by: HoosierCuda on July 15, 2017 - 11:57:24 am
Me again...almost ready to order tires and I appreciate everyone's input thus far.

I "believe" I'm leaning towards 235/60/15 front and 275/60/15 rear.
Does anyone have a picture of an E-body with this combo?

I realize I'm looking at approximately 26" tall tires in the front and 28" tall in the rear...or would a 255/60/15 (27" tall) in the rear be a better blend?
Title: Re: Tire Size Recommendations
Post by: dodj on July 17, 2017 - 07:33:41 pm
Me again...almost ready to order tires and I appreciate everyone's input thus far.

I "believe" I'm leaning towards 235/60/15 front and 275/60/15 rear.
Does anyone have a picture of an E-body with this combo?

I realize I'm looking at approximately 26" tall tires in the front and 28" tall in the rear...or would a 255/60/15 (27" tall) in the rear be a better blend?
No pics, but that combination looks good and fits available room in a stock ebody.......IMO.
Title: Re: Tire Size Recommendations
Post by: HoosierCuda on July 17, 2017 - 07:57:44 pm
I'm glad you agree because I placed my order this morning haha
235 front and 275 rear...should be a good vintage muscle look IMO

Thank you
Title: Re: Tire Size Recommendations
Post by: jimynick on July 17, 2017 - 10:33:05 pm
Lots of good feedback on 15" wheels here, but I'm leaning toward 17's and can someone give me their thoughts on tire sizing for that diameter? Thx.!  :cheers:
Title: Re: Tire Size Recommendations
Post by: burdar on July 17, 2017 - 10:44:58 pm
I saved this pic for reference years ago and finally found it.  This is the ultimate 15" tire combo IMO.
235-60-15 front
275-60-15 rear with 4.5" backspace
Title: Re: Tire Size Recommendations
Post by: HoosierCuda on July 17, 2017 - 10:50:45 pm
  This is the ultimate 15" tire combo IMO.
235-60-15 front
275-60-15 rear with 4.5" backspace

If it's the "ultimate combo", then I'm sure I'll be happy with my choice :)
Thanks all for your help and advice.
Title: Re: Tire Size Recommendations
Post by: dodj on July 18, 2017 - 12:24:04 pm
Lots of good feedback on 15" wheels here, but I'm leaning toward 17's and can someone give me their thoughts on tire sizing for that diameter? Thx.!  :cheers:
Original size wheel wells or are you moving the rear springs in?
I'm running 255-40-17 on the front and 315-35-17 on the back. But I moved in the rear springs with the Dr.Diff 1.5" offset kit. December 2016 and 2014 calendar for pics.
Depending on what wheel you are going with, the hub register is important to keep an eye on. You need 72mm to fit the stock rotors/axles.
Title: Re: Tire Size Recommendations
Post by: jimynick on July 18, 2017 - 11:25:26 pm
So far, the springs are in the original position. Thx for the heads-up about the centre hole! I'm not really trying to cram the absolute largest tire in the hole, but I do want a decent size nonetheless.  :cheers: