Author Topic: Tire Size Recommendations  (Read 2270 times)

Offline 70HoosierCuda

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Tire Size Recommendations
« 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...
Jeff
1978 Trans Am
1970 Camaro
1970 'Cuda




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Re: Tire Size Recommendations
« Reply #1 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....
JS27N0B 70 Challenger R/T Convertible  FJ5 Sublime, Show Poodle w/90,000 miles since resto
WS27L8G 68 Coronet R/T Convertible  PP1 Bright Red, Project
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Offline TelisSE440

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Re: Tire Size Recommendations
« Reply #2 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.

Offline 70HoosierCuda

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Re: Tire Size Recommendations
« Reply #3 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
Jeff
1978 Trans Am
1970 Camaro
1970 'Cuda

Offline 72bluNblu

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Re: Tire Size Recommendations
« Reply #4 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.
« Last Edit: May 30, 2017 - 09:16:55 pm by 72bluNblu »

Offline dodj

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Re: Tire Size Recommendations
« Reply #5 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.
Scott
1973 Challenger  440 4 spd 
2007.5 3500 6.7 Cummins Diesel, Anarchy tuned.
Good friends don't let friends do stupid things. ........alone.

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Re: Tire Size Recommendations
« Reply #6 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....
JS27N0B 70 Challenger R/T Convertible  FJ5 Sublime, Show Poodle w/90,000 miles since resto
WS27L8G 68 Coronet R/T Convertible  PP1 Bright Red, Project
RM21H9E 69 Road Runner Coupe R4 Performance Red, Sold...
5H21C  65 Falcon 2 dr Wagon... Dog Hauler...

Offline 72bluNblu

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Re: Tire Size Recommendations
« Reply #7 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.

Offline dodj

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Re: Tire Size Recommendations
« Reply #8 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:
Scott
1973 Challenger  440 4 spd 
2007.5 3500 6.7 Cummins Diesel, Anarchy tuned.
Good friends don't let friends do stupid things. ........alone.

Online 1 Wild R/T

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Re: Tire Size Recommendations
« Reply #9 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.....
JS27N0B 70 Challenger R/T Convertible  FJ5 Sublime, Show Poodle w/90,000 miles since resto
WS27L8G 68 Coronet R/T Convertible  PP1 Bright Red, Project
RM21H9E 69 Road Runner Coupe R4 Performance Red, Sold...
5H21C  65 Falcon 2 dr Wagon... Dog Hauler...

Offline TelisSE440

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Re: Tire Size Recommendations
« Reply #10 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.

Offline 72bluNblu

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Re: Tire Size Recommendations
« Reply #11 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).


« Last Edit: May 31, 2017 - 01:11:38 am by 72bluNblu »

Offline 70HoosierCuda

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Re: Tire Size Recommendations
« Reply #12 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
Jeff
1978 Trans Am
1970 Camaro
1970 'Cuda

Offline HP2

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Re: Tire Size Recommendations
« Reply #13 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.

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Re: Tire Size Recommendations
« Reply #14 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. 




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:
JS27N0B 70 Challenger R/T Convertible  FJ5 Sublime, Show Poodle w/90,000 miles since resto
WS27L8G 68 Coronet R/T Convertible  PP1 Bright Red, Project
RM21H9E 69 Road Runner Coupe R4 Performance Red, Sold...
5H21C  65 Falcon 2 dr Wagon... Dog Hauler...