290/70/17 or 285/75/17

[JT_Nighthawk]

I'm probably overthinking this but with 3.73 gears, I assume both sizes will perform about the same. Im not considering 315/70 as I dont plan to regear. What route would you go and why?

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[Firingpin1977]

I’m not a tire expert, but after suffering on 3.73 gears on my 4Runner before my last two Jeeps (JL/JT), my only suggestion is to go with the lightest of the two that you’re looking at if you don’t plan on regearing.
I get that we have an 8-speed trans on these to help compensate , but when I made the jump from 265/70 to 285/70 on my 3.73 gears, my mpg died (17 down to 12.9) and my vehicle became very sluggish through the mountain passes.
I know my experience is not apples to apples in comparison, but I would stick with the lighter of the two sizes.

 

[Dave D]

I think the diameter will be about the same around 33 inches.
Check the manufacturers site.
I am thinking about going to 33s as well wiith the 3.73 gears.
Would like to hear any feed back.

 

[Bantam]

The difference in width is .2” so that’s pretty marginal.

The 285/75/17 are going to be about an inch taller, 33.83” vs. 32.98”.

I’m currently running 285/75/17 and have been pretty happy with them, but I think I’m going to try and find a skinnier tire with about the same diameter next time. There’s some light signs of rubbing underneath from the extra width but I think it takes a good bit of flexing to get there.

 

[Dave D]

The difference in width is .2” so that’s pretty marginal.

The 285/75/17 are going to be about an inch taller, 33.83” vs. 32.98”.

I’m currently running 285/75/17 and have been pretty happy with them, but I think I’m going to try and find a skinnier tire with about the same diameter next time. There’s some light signs of rubbing underneath from the extra width but I think it takes a good bit of flexing to get there.

Are you running 3.73 gears.
If so how is the performance with the bigger tires

 

[Bantam]

Are you running 3.73 gears.
If so how is the performance with the bigger tires

I am. The stock size was 245/70/17 (if I remember right). I took a slight hit with on gas mileage, but it was marginal. I think I had gotten 18-19, and am closer to 17-18 now. I refer to my commute as uphill both ways; anything outside of work-home drive shows an increase in mpg.

I lost some peppiness with the bigger and heavier tires, but I still tow my camper and various utility trailers around without issue. Not a mountainous area by any means but quite hilly and nothing is really flat.

 

[Dave D]

I am. The stock size was 245/70/17 (if I remember right). I took a slight hit with on gas mileage, but it was marginal. I think I had gotten 18-19, and am closer to 17-18 now. I refer to my commute as uphill both ways; anything outside of work-home drive shows an increase in mpg.

I lost some peppiness with the bigger and heavier tires, but I still tow my camper and various utility trailers around without issue. Not a mountainous area by any means but quite hilly and nothing is really flat.

 

[Dave D]

Thanks for the input. I dont tow so I think the change would be accepable. I have a Willys with 255/75 at 32 inches so moving to 285/75 isnt a big change .

 

[Bantam]

Thanks for the input. I dont tow so I think the change would be accepable. I have a Willys with 255/75 at 32 inches so moving to 285/75 isnt a big change .

If it helps, here’s the (quite worn) Willys takeoffs vs 285/75/17

 

[Sandman 4x4]

I’m not a tire expert, but after suffering on 3.73 gears on my 4Runner before my last two Jeeps (JL/JT), my only suggestion is to go with the lightest of the two that you’re looking at if you don’t plan on regearing.
I get that we have an 8-speed trans on these to help compensate , but when I made the jump from 265/70 to 285/70 on my 3.73 gears, my mpg died (17 down to 12.9) and my vehicle became very sluggish through the mountain passes.
I know my experience is not apples to apples in comparison, but I would stick with the lighter of the two sizes.

Absolutely weight is the enemy. The most weight with the same overall diameter tire, say a moderate 32” tire, the wider tire on the biggest wheel will weigh the most! That goes all the way up to a 40” tire. For overall performance and daily driving I suggest a 235/85-17, that’s 32.7”, that with alloy wheels will be the lightest in the 32-33” range. Will drive the best in rain and snow, will expand in size of footprints aired down as low as 15 psi, for sand floatation and off road traction. But being a pizza cutter won’t look as tough as say a 305/65-17 at the same 32.7”, but will hydroplane easily in rain, have a lower per sq inch ground pressure, while not expanding its footprint aired down. But depending upon brands will weigh more than the pizza cutter and rob more power and efficiency.

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