35 series in 19in and 35 series in 20in same same?

[o2sys]

But different?

If both tires are same section width ie. 275 with 35 aspect ration but one is 19" and the other 20" they will both have the same sidewall height but will both ride the same as well? As in ride quality?

 

[stkjock]

the 20" will be a 1" taller tire


they should ride similarly

 

[WJBertrand]

Sidewall heights will be the same in your example. It's calculated by multiplying the width of the tread, in this case 275mm by the aspect ratio which is a percentage of the tread width, in this case 35% or 0.35. Therefore 275 x 0.35 = 96.25 mm sidewall height.

As noted above however, the 20" version will be 1" larger (taller) in overall diameter. I suspect the heavier 20" wheel and smaller relative portion of the diameter contributed by the tire, the 19" will probably ride a little better.

 

[o2sys]

I get that 20" will be overall taller but if the "cushioning" or sidewall height is the same not considering weight and rotational mass trying to wrap around my head how and why 19" would have a better ride quality.

 

[WJBertrand]

I get that 20" will be overall taller but if the "cushioning" or sidewall height is the same not considering weight and rotational mass trying to wrap around my head how and why 19" would have a better ride quality.

Besides the flexing of the side wall, ride quality also depends on unsprung weight which is basically anything not supported by the suspension, i.e. wheels, tires, brakes, etc.. Generally the less unsprung weight the better for both suspension performance and ride quality. Assuming the same wheel style/design, between the two, the 20" will be heavier than the 19". Don't forget that the tire itself will be heavier too. That's not to say you couldn't find a 20" tire/wheel combo of a different design that is the same weight or maybe even lighter than another 19" tire/wheel design though. In that case I'd be surprised if you could tell any difference in ride quality.

 

[Norm Peterson]

But different?

If both tires are same section width ie. 275 with 35 aspect ration but one is 19" and the other 20" they will both have the same sidewall height but will both ride the same as well? As in ride quality?

I'm betting that it would come down to the difference in tire pressures that you could (or actually would) run with either of those sizes. Based only on load capacity, you can run a 275/35-20 about 2 psi softer than a 275/35-19 on the same car (the 20 is a slightly bigger tire, and load capacity is mostly a function of the air volume inside it). Handling preferences and other considerations are separate.


Norm