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wheel sizes

16K views 22 replies 9 participants last post by  cschieck2002 
#1 ·
I had a chance to get a Terrain today with the specs I wanted except for it had a 6cyl and 19" wheels. I really wanted the 4cyl for the gas milage. The reason I didn't want 19" wheels is because EVERY article and review I've read on the Nox and Terrain said stay away from the 19" wheels because the produce a very hard ride.
Does anyone have the 19" wheels and what do you think?
 
#2 ·
The wheels - themselves - have nothing to do with the ride, only to hold the tires.

Reason the larger wheels seem to ride differently is that the sidewalls on the tires are generally shorter (less high - stiffer) to keep the overall circumference the same between all the wheel sizes offered on the same vehicle.

This allows them to have one setting for Speedo and all other things that operate off the rpm of the wheels the same.
 
#3 ·
I took the only Terrain on the lot and it had the V6 and 19" wheels. I have since purchased a set of 18" Terrain wheels and tires on E-bay so I have experience with both sizes. The 19" wheels ride fine. Most people do not realize that the 19" tires have a higher profile than the 18" tires (If you research the Terrain specs you will see that the 19" wheel vehicles have a different axle ratio to adjust for the higher profile tires). When using the 18" wheels/tires on my Terrain the speedometer is off by 2 MPH when driving 60MPH due to the difference in tire height. One big downside to the 19" wheels is that they come with Hancook tires (made in China) versus the Michelins (made in USA) that come with the 18" wheels.
 
#4 ·
Thanks guys. I had the feeling that there was less flex due to the shorter sidewall, but thought maybe the new technology in tires would give a softer ride. I don't know how those "Tuners" can take the ride comfort from those 1" low profile tires they use.
The other thing about the 19" tires/wheels is the $900 extra cost and the higher price for replacement tires. I guess I'll just wait for a SLT-2 w/ 18" units.
 
#5 ·
The wheels have EVERYTHING to do with the ride. And more...

I'd gauge the purchase more on the roads in your area, or where you intend to drive the vehicle. Short wall tires are a problem where I live due to very poor roads. We traded in a vehicle with large wheels and short side-wall tires, and was very pleased to do so. We had to pay once for replacement of the suspension, wheel and new tire on that old vehicle because of a pot hole. Hitting the hole at only 15 MPH caused damage to the tire, wheel and suspension. The repair guy said if we had the normal wheels and tires then we would not have had this problem.

And, yes, the ride is different. Much smoother and more forgiving with smaller wheels and normal side walls. Personally I like the looks of the larger wheels, but I've come to the conclusion the ride quality loss and risk of damage is not worth it.

If you don't mind a rougher ride (and better cornering BTW..) and your roads are good, then go with the larger rims.
 
#6 ·
sactruck said:
I took the only Terrain on the lot and it had the V6 and 19" wheels. I have since purchased a set of 18" Terrain wheels and tires on E-bay so I have experience with both sizes. The 19" wheels ride fine. Most people do not realize that the 19" tires have a higher profile than the 18" tires (If you research the Terrain specs you will see that the 19" wheel vehicles have a different axle ratio to adjust for the higher profile tires). When using the 18" wheels/tires on my Terrain the speedometer is off by 2 MPH when driving 60MPH due to the difference in tire height. One big downside to the 19" wheels is that they come with Hancook tires (made in China) versus the Michelins (made in USA) that come with the 18" wheels.
The different axle ratio is only there for the different engine, not the wheels. To change your speedometer you simply install a different ratio measurement gear in the speedometer (on older cars) or adjust the computer at the dealership. Most modern cars have settings in their computer to match the size tires so that engine and speedometer changes are done to meet the difference in torque needed and speed expected.
 
#7 ·
Well, I still maintain that the wheels - in themselves - have nothing to do with the ride. The tires are what affects the ride. For the purpose of this little discussion, we'll disregard suspension & shock absorber differences and just consider the wheels and tires involved.

Agree on the various differential ratios, only change is from I4 to V6.
 
#10 ·
Lets try this again (hitting the tab button sends the reply)

I have done some research and both the 18" and 19" tires have the same sidewall (used a tire calculator you can find with a google search)
tire size sidewall diameter revs/mi
235/60R18 5.6" 29.1" 693
235/60R19 5.6" 30.1" 670

Also the axle ratio for the 19" wheels is different than the 18" wheels to make up for the higher tires (If you go to the GMC site to features and specs/engines & mechanicals/transmision/than roll mouse over the 'A's it will give the detail for the optional ratios that I have listed below)

3.23-4 cyl FWD
3.53-4 cyl AWD
2.77-V6 18"
3.39-V6 19"
 
#11 ·
sactruck said:
Lets try this again (hitting the tab button sends the reply)

I have done some research and both the 18" and 19" tires have the same sidewall (used a tire calculator you can find with a google search)
tire size sidewall diameter revs/mi
235/60R18 5.6" 29.1" 693
235/60R19 5.6" 30.1" 670

Also the axle ratio for the 19" wheels is different than the 18" wheels to make up for the higher tires (If you go to the GMC site to features and specs/engines & mechanicals/transmision/than roll mouse over the 'A's it will give the detail for the optional ratios that I have listed below)

3.23-4 cyl FWD
3.53-4 cyl AWD
2.77-V6 18"
3.39-V6 19"
I'm not really following this thread but I thought I'd point out that the 18s and 19s come with 55-series tires, not 60s, in case it makes a difference.
 
#13 ·
That is an important fact, also consider that the wheels may weigh the same and any difference could be in the tires. ;D I still maintain that the difference in sidewall heights - and therefore stiffness - has more to do with the ride quality than the diameter of the wheel itself.

It's interesting that the specs for the Terrain show 4 different differential (ring gear and pinion) ratios and the Equinox just shows two - one for the V6 and one for the I4.

Maybe General Motors feels that Chevy owners are less technically minded than GMC owners ??
 
#14 ·
In many cases, sidewall height makes a big difference, on the Terrain:
The 18" wheels come with rubber that has a sidewall height that it 55% of the 235mm treadwidth(235/55R18)
The 19" wheels come with rubber that has a sidewall height that is 55% of the 235mm treadwidth(235/55R19)

As those tires have the exact same sidewall height, I think we can safely rule out that factor as being the reason for the difference in preceived ride quality.
I think a difference in sidewall stiffness could still be a contributing factor but I would tend to suspect the make & model of the supplied tire as being the reason for the difference in stiffness.
 
#16 ·
Steve A said:
I'd agree with that !! Don't think they have different shocks, springs or sway bars so I agree that it's probably all in the tires in this case.
Why are you so ready to discount the effect an increase in unsprung weight could have on ride & handleing?
The 19" wheels will weigh more then the 18" ones, of this I have no doubt and a 235/55R19 tire is larger and likely heavier the 235/55R18 tire that would accompany the smaller wheel, it seems inconceivable to me that the 19s could be anything but heavier.
 
#17 ·
Gee, I'm not attempting that in any fashion - other than - without any pertinent information, like what are the weights of the 18" vs 19" wheels in question ?? What are the weights of the various tires in question ?? Sometimes a larger diameter wheel may be lighter than a smaller diameter wheel. Ditto for tires, especially now that some mfrs have "better gas mileage tires" which in some examples I've seen in tire charts may weigh less.

With that information a reasonably good case might be made for the difference in ride due to a weight differential !!

Usually - and for sure not always - a change in ride quality - and cornering ability - may be tied to a difference in sidewall height. Evidently this isn't the case here, if the sidewall height is the same, which it appears to be from previous posts.

Also, some of the owners have said that they don't notice a reduction in ride quality with the 19" wheels ???
This is presumably a subjective judgement. I say that because they don't say whether or not they have tried the same vehicle with both sizes.
 
#19 ·
GARYD said:
Thanks guys. I had the feeling that there was less flex due to the shorter sidewall, but thought maybe the new technology in tires would give a softer ride. I don't know how those "Tuners" can take the ride comfort from those 1" low profile tires they use.
The other thing about the 19" tires/wheels is the $900 extra cost and the higher price for replacement tires. I guess I'll just wait for a SLT-2 w/ 18" units.
I can tell you there is def a noticable dif in ride from 19" to 18". I was researching the terrain and nox since last April. I read all the Same articles. So when out test driving I was sure to drive both. The 18" had a noticble Softer feel. The 19" was not so nice on even slight road imperfection. Much harder!

I decided on terrain for overall look and ordered the slt2 and made it clear I wanted the 18". At the time gmc build your own online automatically added the 19" when selecting the slt2. The dealer corrected it on his side and ordered my 18"

side note ... In my opinion gmc 19" style are also ugly. The nox def has the nicer chrome 19". Just my opinion! We all have to like what we buy!
 
#20 ·
SnowItch said:
I didn't even realize they were different. I have the Nox 19 and like them. I'll have to go find a picture of the Terrain 19s.
Here's the wheel gallery for the GM Terrain:
http://www.gm.ca/gm/english/vehicles/gmc/terrain/gallery-wheels01
And here's the gallery for Chevy:
http://www.gm.ca/gm/english/vehicles/chevrolet/equinox/gallery-wheels01

I like the 17s that Chevy offers better then GMC's 17s but I like GMC's 18s better(my favorite infact) and could take or leave either of the 19s equally. I like the looks of either of them but not enough to pay extra for them. Of course, these are just my personal subjective opinions.
 
#22 ·
Steve A said:
Well, I still maintain that the wheels - in themselves - have nothing to do with the ride. The tires are what affects the ride.
agree.

But the 'judgement' depends a lot on personal perspective. Having driven cars with very stiff suspension in the past (porsche, camaro), my Nox w/ 18" wheels is smooth very cushy. But someone used to driving a mercedes might find it harsh.
 
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