Change to 16" rims to improve ride?
 

I have a 2004 C70 HT with 225/45/17 on factory rims. Nice sporty, grippy, harsh ride. We are in Mid-Missouri and the back roads we like to explore are a little hard on our backs and the car.
My wife and I prefer a more GT style ride. Sporty but a little more plush.

I am looking to go to 16" rims and was wondering do I go to a 225/50/16 or a 225/55/16?

I know the 55 profile will throw off my speedo but will the extra height add any additional comfort.

Never owned a Volvo or any "sporty" style car so I have no experience with performance tires

Thanks in adavance

Stick with the OEM tire size of you will confuse the engine computer.

It will mess up your abs esp and speedo
 

Abs esp will go wrong!

if you go to a different wheel size, you will want to find the proper width/aspect ratio equivalent for your OEM size. Wheel-size.com and tirerack are two good resources to figure that out. With that said, I think you will be disappointed by lack of difference in ride quality. I've done plus sizes and run different rims for winter tires on my cars over the years and find that tire pressure and tire model factor more than going plus 1 or minus 1. Usually when people complain about ride quality its because they went from a 195/60 -15 to a 205/35-18 or something similarly far from the orginal suspension's design. I have 235/45-17s on my daily driver and don't find them particularly harsh (I keep 36 PSI). I'd say before you invest $1000 in wheels and tires to shop brands/reviews and adjust the tire pressure back to OEM recommendations.

I too was sick of the 17" on my C70, so I went to 15x6.5 and 195/65 Michelin tires that end up the exact same diameter. It's far better with the 15" rims, much less bone jarring. True the 17" handle better, but given that I've spent probably 45 seconds in 14 years flying around corners, I think I'll be ok. The 15s handle very well anyway. I got the Musca rims, mostly as they were all I could find.

not all models can drop down to 15s - need to check the brake disk size.

Yes, mine has the 280mm disks, and the 15" rims just clear the caliper. I don't think it would clear the 302mm. My C70 is the most hi-perf version and has 280mm...