Stiffer ride with 18" wheels vs 17in?

[Brian76]

Looking for custom wheels and have not found much to choose from in 17in. There are plenty 18in offerings, but I was wondering if this will make the ride stiffer? My build will be IRS with standard coil over suspension. I want to enjoy driving this car and hopefully my wife will enjoy taking rides in it as well. Don't want something that punishes you over every bump.

[rsw81]

Subscribing with similar concerns. I'm also having a hard time finding reasonable tire options in 17's as well.

[NAZ]

Stiffer ride? Perhaps, but not unreasonably so. Many imported and domestic luxury performance cars run larger wheels and short sidewall tires that are stiffer than those found on a soccer mom minivan but these give a firm not harsh ride. I wouldn't sweat the small difference between rim sizes -- go with the size that allows you to run the tire you want.

While the tire is part of the suspension system and can make a difference in ride (and handling) the suspension design, spring rates, and shock damping will usually have a bigger impact on ride quality once your tire pressures are optimized. Remember, you have a much lighter car with typically a much larger tire footprint. If you inflate the tire to the max air pressure moulded into the tire sidewall you are most assuredly running too much pressure and that will impact grip and ride harshness. I usually use tire temps across the tread to establish proper inflation for a custom application. Too much pressure and the center of the tread will be hotter than the sides.

[CraigS]

There is a fairly obvious difference between 15s and 17s but much less between 17s and 18s.

[edwardb]

I've had both. Mk4 (#7750) with 17's/Nitto 555, and Mk4 (#8674) with 18's/BF Goodrich Rival S. There is nothing about the 18-inch setup to be concerned about IMO. It rides great. Not harsh at all, even on our far less than ideal Michigan roads. My wife cruises with me all the time. Now to be fair, #7750 was a solid axle build, #8674 is IRS. That alone in my experience makes a big difference. Based on what you're describing, you'll be fine with the 18's. In the end it's more about appearance IMO. Can't say the 17's looked a lot different than the 18's. But some like the more traditional appearance of 15's. But even then the ride quality is also highly dependent on the suspension setup.