Tire Size?

[ThankfulLutheran]

I currently have stock 275X70X18 Firestone tires on my truck. I would like to put a 295X70X18 tires on the stock rims. Will they fit safely and without rubbing? Thanks for any feedback you may give me!

 

[johanh13]

Should fit just fine, I ran a 35x12.50r18 on my stock wheels on my previous Ram. I only rubbed on the radius arms at full lock. However the 295/70r18 is a bit shorter (maybe 1/4 to 1/2") and the tread is at least 1/2" narrower. I my humble opinion, should work just fine...

 

[MADDOG95]

I did a tire, wheel & level kit upgrade last year and went with 285/75R18 tires. I chose those as they gave me the height I wanted on the front.

Here are a few pictures showing the differences between a stock 275/70, a 295/70 & the 285/75 size I used. The comparisons provide dimensions and speedometer errors that may be useful to you.

I don't know if you'd see rub with either of the larger sizes without a level kit, but I suspect you won't.

275/70 vs. 295/70:



275/70 vs. 285/75:



Here is my truck stock, then with the tire, wheel & level kit upgrade.

Before:



After:

 

[ThankfulLutheran]

I did a tire, wheel & level kit upgrade last year and went with 285/75R18 tires. I chose those as they gave me the height I wanted on the front.

Here are a few pictures showing the differences between a stock 275/70, a 295/70 & the 285/75 size I used. The comparisons provide dimensions and speedometer errors that may be useful to you.

I don't know if you'd see rub with either of the larger sizes without a level kit, but I suspect you won't.

275/70 vs. 295/70:

View attachment 95391

275/70 vs. 285/75:

View attachment 95392

Here is my truck stock, then with the tire, wheel & level kit upgrade.

Before:

View attachment 95394

After:

View attachment 95396

Thanks so much for taking the time to post the diagram. It was a big help!

 

[ErikTheRed]

285/75R18 here too, I like the look a lot better than the 295/70 and they fit fine without any rubbing. I did a 1" front spring lift to level the truck, but even without it no rubbing.

 

[EGT75]

I currently have stock 275X70X18 Firestone tires on my truck. I would like to put a 295X70X18 tires on the stock rims. Will they fit safely and without rubbing? Thanks for any feedback you may give me!

Yes. I just mounted 295/70R18 Bridgestone Dueler A/T Ascent on my 2025 Ram 2500. No rubbing at all.

 

[EGT75]

Yes. I just mounted 295/70R18 Bridgestone Dueler A/T Ascent on my 2025 Ram 2500. No rubbing at all.
View attachment 95449View attachment 95452View attachment 95451

The taller 75 profile tires will make your odometer a read 7% difference from actual.

 

[Ritchie_Rich]

The taller 75 profile tires will make your odometer a read 7% difference from actual.

Even wider 70 series tires will affect speedometer readings.

 

[johanh13]

On my truck I fixed the speedometer accuracy by updating the Revs per mile of the new tire and converting that into millimeters of circumference. For example, my tires are listed as 596 revs per mile; 5280 divide by 596, multiply by 12 and by 25.4 = 2700mm. I used alfaOBD to input the new tire size of 2700 and my speedo is 100% accurate, verified by my TomTom GPS...

In case you need more info; 5,280' per mile, 596 revs per mile for my new tire, multiply by 12 to get inches, multiply by 25.4 to get millimeters.

 

[EGT75]

I am not sure what you are trying to say.
When comparing the effects on the speedometer reading, the differences in the circumference of the tires is the only thing that affects the speedometer.
According to wheel-size.com:
- 275/70R18 tire has a circumference of 2646mm - 0% difference from stock 2500 tire so the speedometer reading should match actual speed.
- 275/75R18 tire has a circumference of 2826mm - 7% larger circumference meaning when the speedometer reads 60mph the actual speed will be ~64mph.
- 295/70R18 tire has a circumference of 2734mm - 3% larger circumference meaning when the speedometer reads 60mph the actual speed will be ~62mph.
- 295/65R18 tire has a circumference of 2641mm - 0.2% smaller circumference than stock so when the speedometer reads 60mph the actual speed will be ~59.9mph.

 

[dieselscout80]

Yes. I just mounted 295/70R18 Bridgestone Dueler A/T Ascent on my 2025 Ram 2500. No rubbing at all.
View attachment 95449View attachment 95452View attachment 95451

Let us know how you like the Ascent’s.

 

[johanh13]

I am not sure what you are trying to say.
When comparing the effects on the speedometer reading, the differences in the circumference of the tires is the only thing that affects the speedometer.
According to wheel-size.com:
- 275/70R18 tire has a circumference of 2646mm - 0% difference from stock 2500 tire so the speedometer reading should match actual speed.
- 275/75R18 tire has a circumference of 2826mm - 7% larger circumference meaning when the speedometer reads 60mph the actual speed will be ~64mph.
- 295/70R18 tire has a circumference of 2734mm - 3% larger circumference meaning when the speedometer reads 60mph the actual speed will be ~62mph.
- 295/65R18 tire has a circumference of 2641mm - 0.2% smaller circumference than stock so when the speedometer reads 60mph the actual speed will be ~59.9mph.

What I am saying is you have to use the manufactures revs per mile of your new tire to calculate the circumference in millimeters. The actual circumference (theoretical) is more than the revs per mile listed by the manufacturers. I am speaking from experience, I have tried it, for 100% accuracy, I used the revs per mile calc, which is smaller than actual.

For example, if you use your 2826mm for the 285/75r18 tire, your speedo will be showing about 4% FASTER than you are driving. You should use the calculated circumference of 2713 for accuracy. See the screenshot below that shows the revs per mile for said tire.

If you doubt my calculations, just tell me if the revs per mile below, match your calculations based on a 35.1" diameter tire? The actual 'theoretical' revs should be closer to 574, which is close to your 2826mm....