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What does this tire wear mean?

Started by triple_green, April 05, 2020, 06:51:54 PM

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triple_green

These are probably 20 years old. I have had them at 30-32 PSI the whole time I have owned them. This tire wear puzzles me. I would think the center band would wear more if the tire was over inflated...32 PSI does seem like it should be over inflated..under if anything ?? The tread also has some pretty big chunks out of it. Not what I was expecting.
68 Charger 383 HP grandma car (the orignal 3X)

Back N Black

Its usually from being over inflated, but you only at 32 PSI?

b5blue

Tire too wide for rim if not over-inflated, run 28LBS and see. The center wear indicators starting to show.

cdr

Old hard rubber driving over gravel, small rocks, the wear looks like over inflation, wrong rim width, as said already
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68 Charger 512 cid,9.7to1,Hilborn EFI,Home ported 440 source heads,small hyd roller cam,COLD A/C ,,a518 trans,Dana 60 ,4.10 gear,10.93 et,4100lbs on street tires full exhaust daily driver
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triple_green

recommended rim width 7.5-9.5" this was on a 8" rim.
68 Charger 383 HP grandma car (the orignal 3X)

Kern Dog

I'm normally not one to be over-cautious but.....D U M P those tires and get new ones. 20 years old ???  :eek2:

triple_green

Quote from: Kern Dog on April 05, 2020, 11:37:38 PM
I'm normally not one to be over-cautious but.....D U M P those tires and get new ones. 20 years old ???  :eek2:

I agree, but was wondering, if I should go a different size. I love the meaty look of the 275 60 15s. I am running a set of 265 50 15s for now on an other set of 8 inch rims. The downside of the 275 60 15s is that they take away a lot of low end grunt from the car which only has 3.23 sure grip stock.
68 Charger 383 HP grandma car (the orignal 3X)

c00nhunterjoe

275s on an 8" wheel is the problem. Thats a nearly 11 inch wide tire on an 8" wheel. It pulls the outer edges of the tread in, and runs on the center. It would hook better with a 245 on that wheel then it would with the 275.

triple_green

could this have been minimized by running a lower PSI? Like 28 or lower?
68 Charger 383 HP grandma car (the orignal 3X)

DownZero

I don't think this is a wheel width problem. I've seen a lot of tires in that condition. Besides the wear on the center rid the tread looks awfully "chunky". I would lean more to a suspension issue.

c00nhunterjoe

I was referring specifically to the uneven center wear. The chunking is from the rubber being 20 yrs old.

Running a lower air pressure will not solve the problem of an 11 inch tire on an 8 inch wheel. The sidewall is pulling the tread inwards. Less air means less stability.
3 options
1: dont worry about it as its not going to fail.
2: buy a tire better suited for the wheel
3: buy a 10 inch wheel if you want to run a 275 in more ideal circumstances.

Mike DC

  
Narrow rim width + overinflation.  

The OEMs would use more like a 235 on an 8" wide rim.  

 
The car's handling is actually better if you go the other way on rim width.  Stretching the tire on wider rim (I mean slightly, not low-rider) helps to pin down the tread so it can flex less from side-to-side.  The OEMs don't do it because it exposes the rim to curb damage a little more.     

c00nhunterjoe

Quote from: Mike DC (formerly miked) on April 07, 2020, 05:06:15 AM
 
Narrow rim width + overinflation.  

The OEMs would use more like a 235 on an 8" wide rim.  

 
The car's handling is actually better if you go the other way on rim width.  Stretching the tire on wider rim (I mean slightly, not low-rider) helps to pin down the tread so it can flex less from side-to-side.  The OEMs don't do it because it exposes the rim to curb damage a little more.     

Yup. I run a 9 inch tire on a 10 inch rim. Can cut a 1.3 60' on stock suspension in my car.

John_Kunkel

Quote from: c00nhunterjoe on April 06, 2020, 11:29:08 AM
275s on an 8" wheel is the problem. Thats a nearly 11 inch wide tire on an 8" wheel.

Pardon me but my karma just ran over your dogma.

c00nhunterjoe

Quote from: John_Kunkel on April 07, 2020, 01:16:21 PM
Quote from: c00nhunterjoe on April 06, 2020, 11:29:08 AM
275s on an 8" wheel is the problem. Thats a nearly 11 inch wide tire on an 8" wheel.



Not sure what you are trying to say quoting me john, its 10.8 inches wide, so that verifies my nearly 11 inch quote. So i am left to assume you are refering to the 7.5-9.5 width part, And that falls back to "just because you can doesnt mean you should". Same description of a part goes with torque converters that you love to point out. Just because it is advertised as a 3,000 rpm stall, doesnt mean its going to do that in your car... I also clarifed already as well that it would not hurt the tire or the car as is. But the question was answered as to what caused the center tread wear- wide tire, skinny rim.

Dodgecharger74

looks to me excessive wheel speed car not moving  usually produce tire smoke
74 charger se
82 dodge PU fleetside short box 440
05 magnum 5.7 Hemi
04 rumble bee hemi

triple_green

Quote from: Dodgecharger74 on April 07, 2020, 05:26:02 PM
looks to me excessive wheel speed car not moving  usually produce tire smoke
[ :2thumbs:/quote]
68 Charger 383 HP grandma car (the orignal 3X)

John_Kunkel

Quote from: c00nhunterjoe on April 07, 2020, 05:05:06 PM
Not sure what you are trying to say quoting me john

I have faith in the tire makers recommendations, they don't want their tires to get a bad rep.

From an anecdotal experience viewpoint, the 275/60 has been my personal rear tire of choice ever since they came out and always on an 8" rim. No abnormal wear pattern at 32 psi.
Pardon me but my karma just ran over your dogma.

c00nhunterjoe

Quote from: John_Kunkel on April 08, 2020, 02:45:46 PM
Quote from: c00nhunterjoe on April 07, 2020, 05:05:06 PM
Not sure what you are trying to say quoting me john

I have faith in the tire makers recommendations, they don't want their tires to get a bad rep.

From an anecdotal experience viewpoint, the 275/60 has been my personal rear tire of choice ever since they came out and always on an 8" rim. No abnormal wear pattern at 32 psi.

For what its worth, i wouldnt call the original posters photo abnormal for a muscle car. The 275/60 has fit b body mopars for years without cause for concern on 7" rims. While i agree the 8" is a much better choice, the 10" rim would be ideal. All of which will "work"

b5blue

At 20 years old the tires are pretty age overdone so be careful!  :o

c00nhunterjoe

Quote from: b5blue on April 09, 2020, 09:30:55 AM
At 20 years old the tires are pretty age overdone so be careful!  :o

Smoke off whats left and replace them! And record it for all to see.


375instroke

How's the retirement?  You got out at the right time.  The pressure on the tire is maximum.  Car manufacturers always recommend lower than that maximum.  I see a lot in the 26psi to 28psi range.  That 275 BFG has a 2149 lb. rating at max psi.  Your Charger has a lot less weight than that on that tire.  Some charts show that size tire will work on a 7" rim, which was the biggest I could find for $6 at Pick a Part back in the day.  I had to drop the pressure down to 18psi, and was still wearing in the middle.  The black R/T has 15X8 with that tire, I'm running 22psi, and wearing in the center.  The front are 245/60-15, on a 15X7, at 35psi, and wear even.  I think it's more about weight, and load rating, than anything.  Wider rims do help, though.  The cordovan Charger, with 275/60-15 in back, on 15X10 rims, wears even with 35psi, but they look like balloons, but that could be because the front tires are so tiny.  The BFG is a hard tire.  Mine chunk up like yours, too.

triple_green

Peter, thanks for the info. I was grateful to retire when I did. My brother and son are still working in Eng there.
Still love your Chargers!

Mark
68 Charger 383 HP grandma car (the orignal 3X)

375instroke

Yes, for 34 years now.  Don't think I'm going to get tired of them any time soon.  I get tired of working outside on them, though.  This confinement's putting a damper on my garage construction.  Lots of time, and no shop to work in.  The BFGs on the black R/T are worn out.  I want to try some 17" rims, but sizes are limited. 

dspaulding70

Quote from: 375instroke on April 10, 2020, 10:25:48 PM
How's the retirement?  You got out at the right time.  The pressure on the tire is maximum.  Car manufacturers always recommend lower than that maximum.  I see a lot in the 26psi to 28psi range.  That 275 BFG has a 2149 lb. rating at max psi.  Your Charger has a lot less weight than that on that tire.  Some charts show that size tire will work on a 7" rim, which was the biggest I could find for $6 at Pick a Part back in the day.  I had to drop the pressure down to 18psi, and was still wearing in the middle.  The black R/T has 15X8 with that tire, I'm running 22psi, and wearing in the center.  The front are 245/60-15, on a 15X7, at 35psi, and wear even.  I think it's more about weight, and load rating, than anything.  Wider rims do help, though.  The cordovan Charger, with 275/60-15 in back, on 15X10 rims, wears even with 35psi, but they look like balloons, but that could be because the front tires are so tiny.  The BFG is a hard tire.  Mine chunk up like yours, too.


What wheel is that on the green charger in the middle picture?

375instroke

On another thread, he says they are Magnum 500s with 4.25 backspace on the 15x7 front, and 4.5" on the 15x8 rear.