[T32803]

A co-worker with a 2017 V6 with 18" stock wheels wanted to try my 2018 V6 with 20" stock wheels. I was curious to see how 18" wheels felt so we swapped cars to try each others car out.

Florida roads are boring straight without curves or hills so you can't test handling at the limit unless you go to a track.

We both liked his 18s better. His car with the 18s was more agile feeling, changed lanes much smoother, were insanely quieter, and felt like they had less drag. The ride seemed better in every way. My 20's in comparison generated a lot more road noise, the ride was harsher, more vibration, and driving in general did not seem as smooth or fluid as the 18s. Yes, the 20s do look nicer.

Anyone else have this impression? I am tempted to look for a set of OEM 18" wheels. (and keep my stock 20s for when I sell the car some day)

[arpad_m]

Try some quality non-runflat tires and you'll be surprised how much of this is due to the tires (I'd say 100%, but then I might be partial towards my Michelin PS4S set). I had those 18" wheels with the stock all season GY tires on my previous V6 and they didn't feel more agile at all than my stock 20" wheels on the SS.

[HCI2000SS]

I have both 18 and 20 inch factory wheels for my 2018 V6. To be honest I noticed very little difference, but my scale says there is about a 5 lb difference between the two. 55 lbs vs 60lbs

[T32803]

Originally Posted by arpad_m

Try some quality non-runflat tires and you'll be surprised how much of this is due to the tires (I'd say 100%, but then I might be partial towards my Michelin PS4S set). I had those 18" wheels with the stock all season GY tires on my previous V6 and they didn't feel more agile at all than my stock 20" wheels on the SS.

Thank you very much for replying arpad_m..

I suspected the runflats were hurting the ride but I know from trying many cars over the years that 18s and 19s always felt like a quieter, more agile, and better quality(less vibration) ride than stiffer low profile 20 inch setups. It must be the feel of a wider sidewall that I prefer. I tried a Cayman at the dealer with 20s then tried one with the same tire model on a 19 inch rim and the 20s were too much road punishment for me. I liked the 19s much more. I suspect I would like a Cayman on 18s even more but never tried one.

The recent test drive on the R18 GoodYear Eagle Sports made quite an impression on me so I looked online to see if I could get them in 20s but they don't come in 245/40R20. Closest size is 245/35R20. They would fit but it would throw off my speedometer because of the 26.8" diameter vs 27.7". Also, the even smaller side wall of the 245/35 might make the ride harsher still even though I switched to smoother tires like the Eagle sport.

Changing tires is a very expensive deal so it's hard to know what to do and not risk blowing $1,000+ and not getting the effect you are after. I'd be very happy with the R18 GoodYear Eagle Sport ride. My question is whether that ride is possible with a 20" rim. For me it's more than just being agile. It's the absolute quietness, less feeling of tire drag, less vibration from the road, less jarring on the bumps. Steering with my current 20s feels heavy compared to the quick steering 18s I recently tried out.

I got the 20s because they look way better. But now looks matter less than the ride for me. Comments welcome. Save me from making a costly mistake.

[T32803]

Originally Posted by HCI2000SS

I have both 18 and 20 inch factory wheels for my 2018 V6. To be honest I noticed very little difference, but my scale says there is about a 5 lb difference between the two. 55 lbs vs 60lbs

Thanks HCI for the comment. For me the weight difference isn't a factor. I just responded above to flesh out my dilemma better. There are several ride characteristics that I would like to improve. I don't track the car so I'm looking for a better ride.

[Scargoes]

Originally Posted by T32803

Thanks HCI for the comment. For me the weight difference isn't a factor. I just responded above to flesh out my dilemma better. There are several ride characteristics that I would like to improve. I don't track the car so I'm looking for a better ride.

But the weight difference is a factor. Less weight will start rolling with less effort. It will make the sispension feel more crisp because there is less weight to try to control. The 18's also aid in ride quality because of the taller sidewall. Little bits here and there add up. But the 18's wont perform as well at an autocross or road course.

[JT58]

I was also worried about this- mainly the weight- as I have the 18's on my V6 and was looking to upgrade to 19"s or 20's. Main reason is I want black wheels versus the silver color wheels. I am happy with the ride, handling and performance of the 18's but the 20's do look a lot better. I have been looking aftermarket but it's been so difficult as Tire Rack gives great specs including the weight of the wheels but they do not have hardly any that I like. I see nice 19" and 20" wheels on Carid and other sites but they do not give the weight. I do not want to go heavier and there are more 20" available than 19". I do like the stock GM 20" black wheels but outrageous prices to buy them new. So I may end up with settling with the 18" unless someone near my area sells their stock black GM wheels.

[T32803]

Originally Posted by Scargoes

But the weight difference is a factor. Less weight will start rolling with less effort. It will make the sispension feel more crisp because there is less weight to try to control. The 18's also aid in ride quality because of the taller sidewall. Little bits here and there add up. But the 18's wont perform as well at an autocross or road course.

Interesting that 5 lbs makes a difference. I would have thought that 55 lbs vs 60 lbs would make no difference since the whole car weighs about 3,400 lbs.
Maybe it does.

[T32803]

Originally Posted by JT58

I was also worried about this- mainly the weight- as I have the 18's on my V6 and was looking to upgrade to 19"s or 20's.

You should go to a dealer and test drive a camaro with 20s to see what you think. For me the ride difference is huge and I am not sure it's all due to the GoodYear runflats they put on the 20s.

[arpad_m]

Originally Posted by T32803

Thank you very much for replying arpad_m..

I suspected the runflats were hurting the ride but I know from trying many cars over the years that 18s and 19s always felt like a quieter, more agile, and better quality(less vibration) ride than stiffer low profile 20 inch setups. It must be the feel of a wider sidewall that I prefer. I tried a Cayman at the dealer with 20s then tried one with the same tire model on a 19 inch rim and the 20s were too much road punishment for me. I liked the 19s much more. I suspect I would like a Cayman on 18s even more but never tried one.

The recent test drive on the R18 GoodYear Eagle Sports made quite an impression on me so I looked online to see if I could get them in 20s but they don't come in 245/40R20. Closest size is 245/35R20. They would fit but it would throw off my speedometer because of the 26.8" diameter vs 27.7". Also, the even smaller side wall of the 245/35 might make the ride harsher still even though I switched to smoother tires like the Eagle sport.

Changing tires is a very expensive deal so it's hard to know what to do and not risk blowing $1,000+ and not getting the effect you are after. I'd be very happy with the R18 GoodYear Eagle Sport ride. My question is whether that ride is possible with a 20" rim. For me it's more than just being agile. It's the absolute quietness, less feeling of tire drag, less vibration from the road, less jarring on the bumps. Steering with my current 20s feels heavy compared to the quick steering 18s I recently tried out.

I got the 20s because they look way better. But now looks matter less than the ride for me. Comments welcome. Save me from making a costly mistake.

I hear you loud and clear. At the end of the day, the call is yours to make, and if you want the same or close enough ride quality from a 20" wheel/tire combo as the 18" you tested, you probably have to bite the bullet. I don't think there are any giant gotchas here that someone could help you steer clear of. Heck, even my earlier comparison of 18" vs 20" is scientifically invalid, because the entire car (engine, suspension, extra weight) changed underneath me, not just the wheels and tires.

What I do know, however, is how night and day of a difference runflat vs quality non-runflat makes, because I have a direct comparison of the OEM runflats to the Michelin PS4S set on my current car, and the difference is absolutely astounding. I don't think I'd be able to recognize a ride quality impact caused by a 5 lbs delta in wheel weight.

Here's an idea, though, how about trying to get 18" wheels, maybe even tires, real cheap from someone who upgraded to 20" wheels for the look, and then you have both sets without forking out over a grand? You can post a WTB in the wheels/tires section of the members classified subforum to test the waters. Or are you turned off completely by the look of the 18" wheels?

[Scargoes]

Originally Posted by T32803

Interesting that 5 lbs makes a difference. I would have thought that 55 lbs vs 60 lbs would make no difference since the whole car weighs about 3,400 lbs.
Maybe it does.

I have a set of stock 1LE sized wheels that are 6.5lbs lighter each than the stock wheels. It made a huge difference. The car takes off easier from a start, transitions when turning feel crisper but the down side is that NVH is greater. There isn't the mass in the wheel to help quell road noise and road imperfections.

[asthmamax11]

18's will give u gearing advantage and significant unsprung weight advantage. (Assuming they are lighter than your 20's)
Go for it

[T32803]

Originally Posted by asthmamax11

18's will give u gearing advantage

Could you explain this to me? The gearing ratios are fixed and the diameter of the entire wheel should be the same between 245/40R20 and 245/50R18. Thanks..

[KirkH]

I acquired a brand new set of unused wheels and tires off a 2016 1LT . They are 18" with the OEM Eagle Sport tires.

Can I use these on my SS? Are there any rubbing issues, etc?

Thanks!