So I have 2 sets of OEM wheels for my R53, I've been running summer tires on my 17's and snow tires on my 16's but I might not need snow tires soon (due to moving) I really enjoy the performance of my low profile sidewalls on the 17's, but they're noticeably heavier than the 16's. Has anyone tried a low profile sidewall on an OEM 16 inch wheel (I think they're s-lites, but not sure) I know it would throw off the speedo reading some, and I know I could do even better with aftermarket wheels but I'm trying to make do with what I have, and I can live with the speedo not being quite right.

 

205/50-16 is a more appropriate size.

 

I have Hankook R-S3 V2 205/45-16s on 16x7 aftermarket wheels. Rim widths of 6.5 to 7.5 are acceptable. The odometer also counts miles faster and the wheel gap (space between tire and fender) increases due to the shorter diameter. If you are having any trouble with spinning tires this size will make it worse. Sidewall height is the same as stock 205/45-17.

 

I've run that size before and didn't find it to be much different from 195/55, I'm looking to decrease sidewall height and perhaps increase tread width so that I will get less sidewall flex, and a bigger contact patch.

 

yeah, the gap doesn't bother me, shoot if money was no object, I might try and find some super light 15's with low profile sidewalls. What do you mean spinning tires? like spinning them off the line? why would it be worse? just because the wheel/tire is lighter? it seems like 205/45 - 16 would be lighter than my OEM 17's, have a similar contact patch to my 195/55 - 16, and have sidewall performance similar to 205/45 - 17 but I've never really played with tire sizes so I don't really know what I'm doing.

 

Yes, off the line or coming off corners. A smaller diameter tire changes your overall drive ratio giving you more mechanical advantage from the gearing. A smaller diameter tire also drops your car by 1/2 the reduction in diameter. Lowering the center of gravity helps handling.

205 is the section width so a 205 is going have a wider, shorter contact patch than a 195. Wider tread width is better for cornering speed but shorter is worse for acceleration and braking. The overall size (area) of a contact patch does not change much due to tire size changes alone.

If it is cornering that you are enjoying then 205 would be the preferred width (of the two being discussed). If it is steering response you are after then sidewall stiffness of the chosen tire will matter a great deal although this is typically not a concern with the available extreme summer tires in 205/45-16 as they are usually gonzo stiff.

I'm also assuming that you are not currently running on run-flat tires.