I have Sumitumo's and they definitely are stiff. But I also have FRPP suspension.

 

The shop put 42psi in my tires when installing them. it road like ****.

 

Damn, you could probably feel dirt on the road!

 

it's all about tire pressure and type.

I can honestly say that my Toyo Proxes tires on my 20" wheels ride a heck of a lot gentler than the Goodyear F1 SuperCar tires that were on my stock 19" Brembo wheels.

 

I daily drove through 2 sets of Sumitomo's on my '02 GT convertible. I think the tires are just a lot more firm than others out there. Relative to some others out there the Sumitomo's are cheapest and that is probably why they ride harsh. Whether that be cheaper rubber, thinner plies, or the like I don't know. I bought them b/c of the price and for my use the stiffness didn't bother me.

Higher air pressure definitely changes the ride. Try to lower air pressure, but if that still doesn't help I think the best option is new tires from a different brand or maybe new shocks/struts.

 

I posted the question over in the AM section of the forum and they responded that they purposefully over-inflate the tires when shipping them and they need to be deflated a bit when they arrive.

 

Continental ExtremeContact DW is a really nice quiet and comfortable riding summer tire.

I put them on my 18's a couple years ago and it was like night and day compared to F1's. Still running the Conti's today.

 

That was EASY! lol

 

You didn't know that? LOL! Says with the paperwork they come with or a sticker on them, I can't recall.

 

Lol, I was joking when I said to let some air out of your tires. I didn't actually think they were overinflated... Yay for easy fixes.