Ride not as smooth after putting on new wheels
 

I recently put on a set of new wheels\tires (XXR 527 w\ Michelin Pilot Super Sports). When driving at highway speeds, the car doesnt feel as smooth. There's not quite a vibration but it feels like minor rapid bumps almost, it's hard to explain, it's just not as smooth as when I had my stock setup. I started to think that maybe the balance was wrong. I checked each wheel and no weights have fallen off, but I did notice that one of the rear wheels has no weights on the inside surface while all of the other 3 wheels do. Is there a chance that one of the tires was perfectly balanced from the factory? Should I go back to the shop and ask them to re-check the balance on all wheels. I went to a GoodYear tire shop that has great reviews on the web and my family has gone to them for years. I don't want to be that a-hole customer going back and doubting their work but I just want to be sure it's done right. I also need an alignment since I recently installed springs so I thought about going back and asking them to double check the balance and give me an alignment.

Is this normal for these tires or is there likely a balance\alignment issue? I expected to see no difference in ride quality since I didn't go cheap with tires, but if it's the price to pay for better performance then thats ok with me.

You went from a 215/45 to a what size tire?

Anytime you decrease tire sidewall ratio, you potentially harshen the ride to some degree.

Edit: re-reading, it does sound like balancing.

Get your wheels balanced again.

225/40/18

Sounds like a balancing issue. Get them balanced.

Yeah I agree with the other posts , you should probably get your wheels balanced again !

And there's the reason, bigger wheel and tire setup with less sidewall.

I'd expect to feel more bumps as a result of that. Not an imperfect ride on a smooth surface.

I'll just leave this here. I had a set of adjustable coils and was showing my cousin what "adjustable" meant. I set it to full stiff and drove on a fairly flat road. His response? I didn't know there were bumps on this road.

That is the kind of thing that happens when you increase your wheel size, decrease your aspect ratio, AND get a tire with a stiffer sidewall. All those variables at the same time and BOOM, something you never noticed is there.

If your steering wheel isn't vibrating I doubt you have a tire balance issue and it is just you went further than you thought with your wheel and tire mod.

From what I've read, a shakiness in the steering wheel would indicate front wheel(s) are off-balanced, while shakiness in the seat would be rear wheel(s).

Idk, on my first highway stretch this morning I didn't experience it at all and I though all was well, then on the 2nd highway I started to feel it (after driving for about 20 minutes). Maybe it's the surface of the 2nd highway? I'll see what happens on my way home today. Maybe I'll rotate my wheels tonight and see how my drive is tomorrow.

This probably won't offer you much help as like others have said - it sounds like it may be a balancing issue, but I'm someone that likes to start at the bottom with the most basic (do we really need to check this?) issues.

Two or three times I've experienced a ride-doesn't-feel-as-smooth issue, and even felt (like you mentioned) sort of like I was rolling over something super small, but definitely noticeable on a flat road like the freeway.

It turns out each of these times I had a good-sized pebble wedged firmly between one of the grooves of a tire, and it was poking out a bit. After removing it, it was clearly the source of the problem.

Again - might not be the case with your issue, but figured I'd mention it.

Have you re-torqued the lug nuts?