Different tire pairs on front and rear with a 4x4 Ram

[Harry Paratestes]

I have 2 different sets of tires on my winter rig for the summer. Ive been told both ways about different sizes and types of tires on a 4x4 but have gotten conflicting information on it.
All 4 are 275 60 20. The front 2 are the same brand and model and the rear 2 are the same brand and model. Both sets have roughly the same tread depth.
Is this an issue? I would think its fine to drive like this and Ive put on several hundred miles already so I hope so. I had these tires sitting around and dont want to burn up my bfg ko2s on the hot pavement this summer if I dont have to. The current tires are ... front 2 are starfire ht's and the rear are cooper discoverer atp's
Thanks for reading my thread

 

[tron67j]

There are a lot of views in this, and the answer I would give is: "it depends".

Are you doing a fair amount of highway driving on less than ideal pavement/concrete with rain getting heavy at times. Your truck will not be as sure footed as if it had matching tires. Are one set more worn than the other? Put those on the front. Are you off-road at all? I would imagine you notice one set gripping while the other may slip more. In the end, mismatched tires like your's aren't going to be the primary cause of anything but can be the difference in an unexpected situation.

 

[Harry Paratestes]

There are a lot of views in this, and the answer I would give is: "it depends".

Are you doing a fair amount of highway driving on less than ideal pavement/concrete with rain getting heavy at times. Your truck will not be as sure footed as if it had matching tires. Are one set more worn than the other? Put those on the front. Are you off-road at all? I would imagine you notice one set gripping while the other may slip more. In the end, mismatched tires like your's aren't going to be the primary cause of anything but can be the difference in an unexpected situation.

Mostly in town driving with occasional drives at about 55 mph to parents lake cabin. All 4 are fairly close in tread depth.
My biggest concern is hurting the anti spin rear or 4x4 by running 2 different sets. I know awd vehicles are picky about that and didnt really know how picky these trucks are.
I agree with what your saying about having matching tires for best traction in rain etc, it makes sense. I wont really be going 70mph+ for long distances in rain etc. Good post thanks i appreciate it

 

[rzr6-4]

If you are in 2wd, a small size difference makes no difference at all. Even a large difference (.5" or more) wouldn't really hurt anything, although your wheel speed sensors having different read outs might make it throw a code.

If they are 1/8" different or so I wouldn't want to go down a dry highway in 4wd but you shouldn't be doing that anyway. If you are in mud or snow, the slick surface will have enough give to prevent any binding.

TLDR: You'll be fine.

 

[Hagar1]

IA small difference isn't much of a deal. At one time, manufacturers intentionally had a "slight" difference from front to rear, with the front being slightly faster. They claimed it improved handling.
I once encountered a real problem though, I worked on a Ramcharger back in the day that clearly was a "miss build" 2.87:1 in the front and a 2.94:! in the rear. On dry roads, in 4WD, every 3/10s of a kilometer, you would think you had been rear ended by a bus! You could hear the entire drive train "loading up" and then there was the bang. Put the proper gears in the front, problem solved.

 

[Recoil]

As long as the tire size and wear is the same, you are fine. My question is though, are you driving around in 4x4 on dry pavement? If so, why?

 

[David Tree]

Mostly in town driving with occasional drives at about 55 mph to parents lake cabin. All 4 are fairly close in tread depth.
My biggest concern is hurting the anti spin rear or 4x4 by running 2 different sets. I know awd vehicles are picky about that and didnt really know how picky these trucks are.
I agree with what your saying about having matching tires for best traction in rain etc, it makes sense. I wont really be going 70mph+ for long distances in rain etc. Good post thanks i appreciate it

Your fine because the tires are in good shape.

 

[RamDiver]

Instead of using our magic 8-ball, how about we examine the physical properties a bit closer and then make a judgment call? This is a good learning moment for somebody.
Plus, this is assisting me with procrastination, which is important.

As a rule, I tend to avoid using AI for anything technical, but after an unproductive traditional type search for the Starfire HT specs, screw it. AI rocks today.

These specs are based on new. It would be impossible to account for size changes due to wear.

The rear - Cooper Discoverer ATP 275/60/20 has a revolutions-per-mile rpm spec of 630.





The front - Starfire HT 275/60/20 has a revolutions-per-mile rpm spec of 637.




So the difference we are concerned with is approximately 7 revolutions per mile.
The front tires are turning faster, therefore smaller than the rear tires.


That doesn't sound very significant. Nobody should be driving on dry pavement with 4WD, so who cares about 1.1% difference in wheel speed?

Most tire manufacturers will list the rpm spec of their tires.

.

 

[Recoil]

Nobody should be driving on dry pavement with 4WD, so who cares about 1.0% difference in tire speed?

Overall, this was my point.

 

[Harry Paratestes]

As long as the tire size and wear is the same, you are fine. My question is though, are you driving around in 4x4 on dry pavement? If so, why?

I never do that. Im just asking for when i drive in 2x4. I only use 4x4 on slippery surfaces, never on pavement unless its icy and im going straight

 

[Harry Paratestes]

I checked with my depth tool today. Both driver side are at 10/32 and both passanger tires are at 8/32. Is this a big enough difference that it is a problem?

 

[Recoil]

I checked with my depth tool today. Both driver side are at 10/32 and both passanger tires are at 8/32. Is this a big enough difference that it is a problem?

A problem with what? You've already been told you can run them. 1/16 of an inch is not a big difference.

 

[jws123]

trucks not AWD so it doesnt matter just dont drive it in 4x4 on dry pavement lol.

 

[Dean2]

I checked with my depth tool today. Both driver side are at 10/32 and both passanger tires are at 8/32. Is this a big enough difference that it is a problem?

Just drive them. Even in 4x4 it would hardly matter, in 2 wheel it makes no difference at all.