19" wheels vs 20" wheels.

[m-licious]

is the ride on 19"s really that much better? i'd not heard of anyone going bigger than 40% aspect ratio on the tires on 19s so if you'll be on 35 series tires on similar width wheel, it doesn't really seem like you'll be getting any more sidewall to make the ride more comfortable on the 19 vs the 20.

so if it isn't much more comfortable, and there is still a price differential on the tires (19's more expensive than 20s). would seem like a better deal just to get 20s.

[nadzak]

My suggestion: Get the 20's. But that is me, I am sure you would get different opinions here...

[Poyzinous]

Its all about what you want. I actually like the 19" wheel design. And I rarely find aftermarket wheels that I like. Ride Also has to do with the type of tire. Michelins have soft sidewalls.

[stumbleweed]

I just did 19's in order to keep more sidewall on the tire and keep the rolling diameter of the wheel consistent with factory settings. I've been impressed with the ride quality on mine and found tires to be less expensive than expected on Tirerack. Locally, they were a little higher than 20" wheels but I made up for that with the lower cost of the rims.

There are plenty of folks on here running both set-ups so I'm looking forward to the comments here.

[m-licious]

i guess that's kinda my point, how do 19s give you "more sidewall"?if you are running probably the same width and aspect ratio then shouldn't it be the same amount of sidewall?

[07sportm35]

i guess that's kinda my point, how do 19s give you "more sidewall"?if you are running probably the same width and aspect ratio then shouldn't it be the same amount of sidewall?

Definetly not.

With the same circumfrence a 19 inch wheel has .5 inches more sidewall.

Fact:

A 18 inch wheel has 4.3 inches of sidewall (245/45/18).

A 19 inch wheel has 3.9 inches of sidewall (245/40/19).

A 20 inch wheel has 3.4 inches of sidewall (245/35/20).

Fact:

All three above sizes will yield the same speedometer readings.

As you can see you lose .4 inches of sidewall going from 18's to 19's(9.3% less). And, you lose even more going from 19's to 20's (12.8% less). This is why 19's are a happy medium in terms of loss in ride quality versus gain in handling when the same tires are used.

As always, to each their own. Just depends on ones priorities. As mentioned before, the tires will have the last word. 20's on the softest grand touring tires will have better ride quality than 18's on extreme summer performance tires.

Taste great, less filling...
Modified by 07sportm35 at 12:58 AM 11/13/2009

[m-licious]

i meant with the same aspect ratio. it seemed most of the cars with 19s i saw are running 35 series tires. perhaps i was looking at too many Gs?

[Kosmos]

The road quality is always a good factor that you should consider. If the roads where you live are good then heck get what you want. If not then maybe you would consider something other then 20's and 19's. Maybe 18's? I live in BAD roads and it's winter time here so I had to swap out my wheels for some winter tires which are 18's from my 19's summer ones. And you know it's really a big change. I was impressed that things like handling and ride quality were better. But then again I love the stock 19's and can't live without them.

Hope you pick the one you want and be happy about it for as long as you have it!

[07sportm35]

i meant with the same aspect ratio. it seemed most of the cars with 19s i saw are running 35 series tires. perhaps i was looking at too many Gs?

You would not want to run a profile of 35 unless you went to 275 width tire. That way your circumfrence and sidewall remains intact.

With 245/35's your ride quality would go to hell, noise would be worse, and it would look to small and not fill the wheelwells as good.

[Dumamei]

I have 245/35 and my ride is not terrible, the road noise is not that bad and my wheel well is filled up rather nicely..

[07sportm35]

I have 245/35 and my ride is not terrible, the road noise is not that bad and my wheel well is filled up rather nicely..

First of all you're on 20's and I'm talking about 19's.

Secondly, how many miles on your tires? If you're under 1200 miles then things will change...

BTW Your car is gorgeous!

[Dumamei]

I thought you were talking in general. I have no Idea about 19's.

I have had a 245/35 tire since Aug 07(Falken452 and Nitto Invo(since Jan(Current)).. there is nothing bad about a 245/35 tire. I have had 0 problems with that size.

Your car is hott too...

[m-licious]

i think that is my misunderstanding then. if i can get 40 series tires on a 19, i can definitely see how advantageous that would be for ride quality then. i didn't realize you could get 275s on a 20 in our car, i figured you'd need a 10 inch wide rim for that...that just sounds wide as heck.

[loystock]

Ride quality is subjective. Some drivers would like to 'feel' the road while others don't. Low profile tires will always give you a good feedback about road condition. I love the looks of the 19" wheels on our M35 Sports but not the ride, given the road condition in NorCal.

If the road condition in your area is good, then larger wheels should be Ok. If the roads are bad, and you want a comfortable ride, then stick to 18" wheels. Even NASCAR cars ride on 15" wheels while F1 race cars are still on 13" wheels.

[rocastro71]

Pardon me if I'm asking a dumb question but I'm totally ignorant about tires. On 19" wheels, would a 245/45/19 fit on our Sport M's and would the ride quality be better going slightly bigger in aspect ratio? What would be the disadvantage of going to a 45% aspect ratio?

[loystock]

The standard wheel size on an M35/45 is 245/45-18 while for the Sports model is 245/40-19. The lower aspect ratio on the 19" wheel allows the overall diameter of the tire to be the same as that on an 18" wheel.

The first number (245) indicates the width of the tire in millimeter, the 2nd number is for the aspect ratio in % while the 3rd one is for the diameter of the wheel in inches.

If you use a higher aspect ratio (245/45-19) tire in the Sports, the overall tire height in the wheel well will increase by @ 1". I'm not sure how it will affect the VDC but your speedometer will be out of calibration. And if my calculation is correct, at speed of 65MPH, with the higher aspect ratio tire, your actual speed will be @ 68MPH.

[mjgspr95]

I just went to 20s last week. 255/35/20 Nexens on Fusion wheels. 8.5" front 9.5 in rear. Ride is awsome and looks great. Less than one mph speedometer difference. Feels the wheel well without lowering and tires will be a lot less expensive next time. I made the switch because replacement 19" tires were over a thousand bucks.

[abrahams600]

Let me chime in on this, i.e staggered 225/40/19 and 255/35/19 have the same sidewall height. What you are doing when you go to a bigger rim size is called up sizing. You keep the same overall diameter of the tire while making the inside diameter bigger with a larger wheel. Ride quality also depends on the tire and thread pattern. 19" tires are not as expensive as you think and are coming down in prices specially since there are now a lot of OEM manufactures that are using 19" rims.

Visit this calculator and you'll have a better understanding of tire sizes...

http://www.bigcustomwheels.com/rt_specs.jsp

[mjdknico]

I use Sumitomo HTR Z III's 245/45/19 on my M35 Sport. The ride is comfortable, but I have no basis for comparison as I have had the 45's since buying the car.

[07sportm35]

I use Sumitomo HTR Z III's 245/45/19 on my M35 Sport. The ride is comfortable, but I have no basis for comparison as I have had the 45's since buying the car.

A picture is worth a thousand words. Show us a detailed side shot explicit showing the sidewall of the tires...

[abrahams600]

Your odometer should be off by going taller than stock. ^^ like he said, show some pictures because a 245/45 is a pretty tall tire. You can also throw off traction control systems by going with taller tires or staggered on most awd cars like the m35x.

[NBP45]

I have 245/45/19 winter tires on right now...they fit the wheel well really nice and to me look more aggressive than the 245/40/19's, so far no problems with them. I can post pics later.

[fooitm35x]

I have 245/45/19 winter tires on right now...they fit the wheel well really nice and to me look more aggressive than the 245/40/19's, so far no problems with them. I can post pics later.

I guess you know that when speedometer reads 60mph (96.6km/h) actual speed will be 62.1mph (100km/h) - 3.5% faster.Info take from http://www.bigcustomwheels.com/rt_specs.jsp

[NBP45]

yeah that doesn't bother me...i'll just remember to add 2mph. are there any other issues with going over OEM spec, such as VDC issues???

[NBP45]

here are some pics...the car is on an incline so the front wheels have more wheel gap than usual...










Modified by NBP45 at 1:18 PM 11/20/2009

[rocastro71]

Any issues with rubbing when you have 5 adult passengers in the car?

[abrahams600]

They won't rub but the rear looks a little big don't you think? or you need to lower the front.

[NBP45]

The cars on an incline and uneven pavement on the other side, thus making the front wheel gap look worse than it really is. Although I do agree the car still needs a drop at the front. And there is no rubbing at all with 5 people in the car...there is plenty of clearance.