20" wheels...reducing tow capacity?

VintageRacer wrote:
20" wheels are the stock wheel and so will not impact load capacity or towing capacity at all. None, zero, ziltch. Aftermarket 20" aluminium wheels that didn't have an acceptable load rating might have, but stock is stock, so stock ratings apply. Tire size is a totally different subject from wheel size. Overall rolling diameter of the stock tire would have to be compared to the overall rolling diameter of what you put on. If you are within say 5%, probably no impact to towing capacity that you would really notice. A taller tire will reduce the overall gear ratio and reduce torque delivered to the road by the ratio of the tire diameters.

Brian

Brian gave you the CORRECT answer......Stock 20", like mine, No impact at all. After market "may" but you need to see what the load rating for that wheel is.

From the tire's perspective, it doesn't matter if the vehicle is towing or just loaded up. The tire doesn't know the difference.

Replacing a tire with one that has less load carrying capacity is directionally unsafe. Better to replace with larger load carrying capacity.

So pay attention to load carrying capacity (Load Index)

20" wheels are the stock wheel and so will not impact load capacity or towing capacity at all. None, zero, ziltch. Aftermarket 20" aluminium wheels that didn't have an acceptable load rating might have, but stock is stock, so stock ratings apply. Tire size is a totally different subject from wheel size. Overall rolling diameter of the stock tire would have to be compared to the overall rolling diameter of what you put on. If you are within say 5%, probably no impact to towing capacity that you would really notice. A taller tire will reduce the overall gear ratio and reduce torque delivered to the road by the ratio of the tire diameters.

Brian

What is the diameter difference between the two? I can get smaller diameter tires on a 20 than a 18 if I want and so can you. Then you can just plug in the two in a free online final ratio calculator.

To give you an example, there is not much difference between the two stock Ford wheels.

This is just what I have noticed in the Ford pickup brochure. The heavy duty package wheels are 17" and 7 lug. All the other wheels are 18" and 20" and 6 lug. The decreased diameter essentially increased your torque. If you think about it to the extreme a very large diameter wheel needs more energy to turn 1 revolution than a very small one.

In conclusion, to answer your question, yes, the wheel diameter does make a difference.