Truck Wheel Size

ppine wrote:
The wheel size affects the final drive ratio. More power with smaller wheels unless the rear axle ratio is changed.

I don't get the appeal of big wheels but I am old school. My one ton Ford has the original 16 inch wheels and does fine. What tends to happen is that larger wheels require tires with a lower aspect ratio ie 60 series instead of 70 series.

not really. on my 2015 duramax, the 17, 18 and 20 inch tires all have the same overall diameter, just different aspect ratios.

In fact, they use a 18 inch spare on ALL 3/4 ton duramax and it has the same overall diameter as my 20" tires, and the same for 17".

ScottG wrote:
I wonder if 20's are used on some trucks to provide brake clearance..?
That's the reason they went to 17's back in the day.

As of current models of all US pickups and I suspect the imports too, 17s are still all that’s needed to clear brakes that I’m aware of.
I can’t think of a model that isn’t offered with 17s, typically on base model or low option trucks.

ppine wrote:
The wheel size affects the final drive ratio. More power with smaller wheels unless the rear axle ratio is changed.

I don't get the appeal of big wheels but I am old school. My one ton Ford has the original 16 inch wheels and does fine. What tends to happen is that larger wheels require tires with a lower aspect ratio ie 60 series instead of 70 series.

Wheel size has exactly 0 to do with final drive ratio. If you meant tire diameter you would be correct though.

Flashman wrote:
20 inch wheels are for show. They are stupid for trucks that really do any real work.

Lol. I was wondering how long before the peanut gallery would show up!

The wheel size affects the final drive ratio. More power with smaller wheels unless the rear axle ratio is changed.

I don't get the appeal of big wheels but I am old school. My one ton Ford has the original 16 inch wheels and does fine. What tends to happen is that larger wheels require tires with a lower aspect ratio ie 60 series instead of 70 series.

I wonder if 20's are used on some trucks to provide brake clearance..?
That's the reason they went to 17's back in the day.

Flashman wrote:
20 inch wheels are for show. They are stupid for trucks that really do any real work.

Agree - my 2012 Silverado was factory built with 20" tires and although they do IMO improve the look of the truck I'd be far better off with 17" or 18" for towing as the engine would rev just a bit quicker and therefore a bit closer to it's optimum torque range.



At highway speeds I tow in 5th but even the slightest upgrade and/or headwind will cause the truck to downshift to 4th but if I were running 17" tires the truck would be less likely to downshift under these conditions. If the truck was equipped with a 3.73 axle ratio instead of the 3.42 it does have then the 20s would be less of an issue but as it is they're a poor match for towing with a 3.42 axle ratio.

20 inch wheels are for show. They are stupid for trucks that really do any real work.

if you are talking 250/2500/350/3500 SRW then 17" are not good, as they all have low weight ratings now. 20" are still very expensive. So 18" are the best.

well, my truck came with 20". Upside is the shorter stiffer sidewall seems to give better stability than the 16's on my older truck. Downside it number of available tires. not much to choose from. And NO true winter studdless snowflake LRE tires available. To do that I had to go down to 17" on another set of wheels.

Upside of 17 or 18 is more tire choices.

Price wise, 17 or 20's of similar tires seems to be pretty close. but the price RANGE of tires in the 17 and 18 has lots more low end tires.

for my 3/4 ton 17, 18, 20 are all factory option tire sizes with very close to the same load rating and same overall diameter. aspect ratio just changes with tire size.