Wheel and Tire size impact on performance

[T JAZ]

Hello everyone. I'm getting ready to get my truck back from some major engine upgrades and wanted to know exactly how bad do larger wheels and tires have on the overall performance of our trucks.

First, is it just the rotating mass or the size of it away from the center of the hub? My current 35x12.50r18 tires and wheels weigh 110lbs per corner. I was considering going up to 37s and going back down to 17 inch wheels which would put my weight per at 112lbs.

Ideally I want to keep my acceleration and overall horsepower intact.

Another thing I was curious about was if wheel spacers impact any performance either.

Any information or comments would be greatly appreciated, thank you!

 

[Travelin Ram]

This article explains it better than I could.

https://www.w8ji.com/rotating_mass_acceleration.htm

The diameter has a bigger effect than the mass, so going up in tire diameter without losing acceleration is practically impossible.

I am wrestling with it myself as I’d planned to upsize tires but I REALLY like the acceleration. And I got a bigger trailer, so maybe I’ll leave it alone.

 

[T JAZ]

This article explains it better than I could.

https://www.w8ji.com/rotating_mass_acceleration.htm

The diameter has a bigger effect than the mass, so going up in tire diameter without losing acceleration is practically impossible.

I am wrestling with it myself as I’d planned to upsize tires but I REALLY like the acceleration. And I got a bigger trailer, so maybe I’ll leave it alone.

Very interesting read, thank you! I wonder if I should then look into getting 35x13.5 instead for more traction?

 

[Travelin Ram]

Except in terrain where flotation is needed, a lot of serious off road operators believe narrow performs better.

The size I have my eye on is 35/10.5 like the new Ford Tremor. But that takes an 18” wheel. I’ve read some reports on here of people using the Kenda tire in 35/10.5/R17 and they like them.

It’s certainly easier to find wider tires, and that’s what most people want.

Everything in life is a compromise of one kind or another. That’s the kind of stuff that keeps me awake at night lol.

 

[Ram BB]

There goes that buzz. Only thing i can think of is Beavis and Butthead reading a book going Ahh words,words, words.

 

[Tom8]

Bigger diameter also put more stress on your brakes.

Has anyone thought of going 295 60 r20 for their 20 inch rims? Not as aggressive as 35 or 37 tires.

 

[bobeast]

Your engine has the horsepower it has regardless of the wheel-tire size. However, bigger wheels/tires have several bad things going for them.

- Increased rotating mass due to heavier wheels will rob you of performance.
- Higher friction losses from wider wheels will rob you of performance.
- taller tires, change your effective gear ratio which will rob you of performance.

I'm sure you are seeing a pattern here. I'd say the most immediate effect will be because of the effective gear ratio change which can be mitigated via an offsetting ratio change (read $$) Not a whole lot you can do about the first two, other than "don't do that".

 

[T JAZ]

Except in terrain where flotation is needed, a lot of serious off road operators believe narrow performs better.

The size I have my eye on is 35/10.5 like the new Ford Tremor. But that takes an 18” wheel. I’ve read some reports on here of people using the Kenda tire in 35/10.5/R17 and they like them.

It’s certainly easier to find wider tires, and that’s what most people want.

Everything in life is a compromise of one kind or another. That’s the kind of stuff that keeps me awake at night lol.

makes sense. I do take my truck on some trails every now and then but I am trying to find a balance between the two considering I’ve got this supercharger being installed. I just want to ensure I have enough traction as well as not lose a ton of power.

I feel you on being awake at night thinking about it. I’m doing it now! Hahaha

 

[T JAZ]

Bigger diameter also put more stress on your brakes.

Has anyone thought of going 295 60 r20 for their 20 inch rims? Not as aggressive as 35 or 37 tires.

Definitely something to consider when throwing around a heavier truck and high speeds! I ended up getting some R1 concepts rotors and pads to help out.

 

[T JAZ]

Your engine has the horsepower it has regardless of the wheel-tire size. However, bigger wheels/tires have several bad things going for them.

- Increased rotating mass due to heavier wheels will rob you of performance.
- Higher friction losses from wider wheels will rob you of performance.
- taller tires, change your effective gear ratio which will rob you of performance.

I'm sure you are seeing a pattern here. I'd say the most immediate effect will be because of the effective gear ratio change which can be mitigated via an offsetting ratio change (read $$) Not a whole lot you can do about the first two, other than "don't do that".

Very true. Guess it’s just best to find a compromise and go from there. I’m currently running 35x12.50r18 ridge grapplers with 18x9 fuel beasts. I’m not liking the wheel look so I may just swap out to a different wheel and call it a day. If I go to a 17” wheel I’d need to run spacers again. I’d be saving some weight overall on the 17” setup over the 18s but not sure if it’s worth it at this point.

 

[bobeast]

Very true. Guess it’s just best to find a compromise and go from there. I’m currently running 35x12.50r18 ridge grapplers with 18x9 fuel beasts. I’m not liking the wheel look so I may just swap out to a different wheel and call it a day. If I go to a 17” wheel I’d need to run spacers again. I’d be saving some weight overall on the 17” setup over the 18s but not sure if it’s worth it at this point.

It's a compromise for sure. I'm not sure what you meant by referencing the wheel height. Wheel height is largely irrelevant to performance (disregarding ride quality). It is the tire size that has an effect both in height and in width.


walking it backwards in terms of effectiveness.

1) shorter tire
2) narrower tire
3) lower truck
4) smoother tires

Of course, by now you are back to stock.

 

[Ludville1]

Your engine has the horsepower it has regardless of the wheel-tire size. However, bigger wheels/tires have several bad things going for them.

- Increased rotating mass due to heavier wheels will rob you of performance.
- Higher friction losses from wider wheels will rob you of performance.
- taller tires, change your effective gear ratio which will rob you of performance.

I'm sure you are seeing a pattern here. I'd say the most immediate effect will be because of the effective gear ratio change which can be mitigated via an offsetting ratio change (read $$) Not a whole lot you can do about the first two, other than "don't do that".

^^^This!

When I bought my truck 2 years ago, it had 35 12.50 20 Kumho KL 71 mud tires on the stock rims. The truck looked great. However, with these tires being 2" taller, and 15# heavier (each) than what I have on there now, 3.55 gears, and the previous owner obviously having a heavy right foot (judging by the wear on the back tires)...went a long way to taking out the transmission and rear end...both were rebuilt. That said, I think that the truck would really benefit going to 4.56 gears, even with what is on it now.

 

[RLJ10X]

When it comes to big tires, Looking cool is really expensive. It can be really, really expensive.

 

[Tom8]

When it comes to big tires, Looking cool is really expensive. It can be really, really expensive.

Amen!