15 replies to this topic

[Advmoto18]

Wheel sizes...

As others have posted, the smaller the wheel, the more sidewall the tire caucus will have thus allowing you to air down to a lower psi without damaging the sidewall as long as you pay attention to gross weight.

 

Why are we seeing 20" wheels on trucks?

Easy/quick answer-less rolling mass thus better fuel economy.  All truck manufacturers are trying to get the last .1 of a mile in fuel ratings.

 

20" wheel are not optimum in the least for overland and work pickup trucks.  Why we still see 18" wheels the norm except in the more expensive submodels.

 

I have 16" wheels on my 1988 Toyota Land Cruiser.  I can air down to less than 1 Bar and get a super comfortable ride on the harshest terrain.

 

Axle hub/drum, brake rotor/caliper will determine the minimum size wheel your truck can accommodate.

 

Generally, you want to stick to even numbers, 16, 18, 20 as these tire diameters are more common with greatest offerings.

 

Start with the smallest wheel your truck can accommodate, then work through the tires.  You will want to set the spare up the same way if you change tire diameters.  Using a spare of different outside diameter will put stress on your axle bearings, cause the gears to overheat and created problems for a limited slip rear end if you have to travel more than a few miles to a shop.  This doesn't mean you must use the same wheel diameter for a spare, but rather, you must select a spare tire with the same outside diameter as your other 4 tires.

 

If you're stuck more then ~25 miles from a repair shop, and using a dissimilar diameter spare, put the spare up front.  Front end parts will be cheaper and easier to replace/repair than the rear.

 

Having a spare set up identical to the other 4 wheels/tires gives you the ability to perform a 5 tire rotation which adds longevity to all 5 tires.

Edited by Advmoto18, 18 January 2019 - 02:13 PM.

[Mighty Dodge Ram]

This: “Axle hub/drum, brake rotor/caliper will determine the minimum size wheel your truck can accommodate.” Also, if you use tire chains on a larger than stock tire, be sure they will clear brake lines, etc. Here in CA, I carry them by law but never use them. If I ever had to...

I ran KO2s E rated on my Dodge. Great tire offroad, nothing stopped them. But I found that the treadwear was very low compared to others. YMMV

[klahanie]

Thanks for the replies. My camper is only on the truck for 4-6 weeks a year and they are high mileage trips. I'll have to see what I can get for my tires and rims , that will help make my decision easier. Have a good day. 

 

Sounds like our road trips. Lots of highway. We usually do a good bit of gravel on those trips too. I read you also use yours as a DD. Don't really need an aggressive tire for any of that.

 

FWIW we ran the oem Continental AT tire for 3 years and it did everything we asked of it off highway and on, prob helped by our vehicle weight. Think tread pattern was like this

 

 

I reckon you can find a quality tire with more of a highway tread that would noticeably improve your pavement ride over current and might be quieter, last longer and use less fuel. I'd talk to a few tire shops too, so many choices available and I know they get customer feedback. Not sure why you want to buy different wheels tho ...lower tire cost maybe ?

 

True, 55 is low profile and 17" would be better for airing down off highway but that might be moot for you, IDK. I like to air down for gravel, but our truck has extra stiff spring rates and I tend to drive faster than some, so I want all the cushion I can get. Good Luck !

[penner]

The reason I was thinking of the 17" rims is that I thought the extra sidewall might smooth the ride a bit. Also the extra sidewall might handle the HUGE potholes I I tried to avoid in Baja and Nfld last year. 

[klahanie]

 Also the extra sidewall might handle the HUGE potholes I I tried to avoid in Baja and Nfld last year. 

 

In this case, for sure. Another benefit could be reduced inflation pressures required even before "airing down" with a different tire size. eg. using LT275/55R20 (~31.9" OD) as a base, a LT265/70R17 (~31.7) is rated to a max load of ~8% higher for a given PSI and a LT275/70R17 (~32.2) is rated ~13% higher.

 

So if you had been running at 35PSI (1750# max load rating at that PSI x 2 tires = 3400# for an axle wt) you could safely do the same at ~32 and ~30.5 PSI respectively with the tire size listed above. Per the TRA Load and Inflation Tables.

 

Might not sound like a lot but coupled with the taller sidewall it will make a difference in ride quality when on irregular road surfaces.

[Advmoto18]

The reason I was thinking of the 17" rims is that I thought the extra sidewall might smooth the ride a bit. Also the extra sidewall might handle the HUGE potholes I I tried to avoid in Baja and Nfld last year. 

If 17" is as small as you can go, and you can find the tires to suit your needs, then such is a worthy consideration.

Just realize those 17" tires you find and like may not always be available due to low demand.

 

Personally, if 17" was the smallest my truck could handle, I would step up to 18".  Yes, the 18" sidewall is not as tall and the ride many be a bit harsher when aired down, but, the sheer number of tires available in 18" would make the decision easy for me.

 

Indeed the roads in Baja can be rough in places.  Yet, plenty of RVs, truck/campers, even towed travel trailers, head up and down MEX 1 all the time without much of an issue.   Don't get distracted while driving and never drive at night and I think you will be fine regardless if wheel/tire choice.