Atl3128

I decided to replace the factory 17's on my Q40 in favor of some 19's off a 2011 Maxima. I got a great deal on a full set in hyper silver with michelin tires.. I really like the look of them on my car.. The problem is immediately felt a very noticeable dip in performance, handling and mpg( by like 15%) Did a little research and and from what I can find that these wheels were 40lbs each and the tires were around 28lbs so 68lbs per wheel. So if my research is right that's a 22lb per wheel gain over stock.

My question is will adding this much weight per wheel make that big of a difference in performance and handling?
What are my options for some lighter wheels that have a stock look for reasonable cost?

Lego_Maniac

iTrader: (3)

There is a link in this thread:

Fast Ford's Lightweight Wheel Test

To an article from Fast Ford on lightweight wheels testing acceleration-braking-handling. Basically, lighter weight wheels improved everything, although they were more likely to spin from a standing start. It stands to reason that adding 22 lbs per corner will impact performance. Up to you if a few tenths of a second, or a few extra feet braking matters.

Atl3128

Thanks for the response but I didn't see the link in the thread anywhere?

Entcee

iTrader: (3)

In the first post.

http://www.focusst.org/forum/attachm...wheel-test.pdf

Black Betty

iTrader: (60)

In a word, yes. Adding 22 lbs. per corner and pushing the mass out 2 inches from the axis of rotation will cause you to suffer a huge performance and fuel economy deficit, as you have already discovered.

Atl3128

The loss of performance and mpg is not something I'm OK with but l really don't like the look of the 17's will some light weight 19" wheels and tires make a difference or should I drop down to 18"

Lego_Maniac

iTrader: (3)

The 17's aren't exactly attractive.

18 or 19 OE wheels are pretty common in the classifieds and are a good upgrade.

slartibartfast

iTrader: (7)

The sedan S 18" Duckfeet and coupe S 19" wheels are a good upgrade. While heavier than the 17s, they fit and you can get some good-sized tires for them. Keep an eye on our Classifieds forum and your local Craig's list. For aftermarket wheel ideas, look in the Media Share forum, there are sub forums for different sizes.

Black Betty

iTrader: (60)

19s are fine, but ones that are lighter or the same weight will be expensive. Slightly heavier, say 3-5 lbs, might not be very noticeable. Also remember that 19" tires are heavier as well. You'll have an easier time and spend less if you find lighter 18" wheels. Going to bigger wheels and tires almost always comes with some sort of sacrifice - performance, economy, or expense.

Lego_Maniac

iTrader: (3)

Some tires are lighter than others though, like PSS and the PS4. Might be able to offset some weight in that regard

bPChaos

It's the difference between unsprung rotational and sprung weight. Think of your wheels/tires as 4 gyros on each of the corners of your car. A heavier gyro that's spinning will resist movement more than a lighter one - resulting in a car that feels less nimble and is requires more force to react, reflected in the overall performance of the car. It's really one of those things you can feel.

My 18x9.5 and 275/40R18 wheel/tire combo weighs about 50lbs. It's also surprisingly more comfortable, too. The lower wheel weight means it cycles more gently and isn't as jarring.

Atl3128

OK so decided call the local Nissan dealership and ask for the weight of the rims they quoted me 25lbs. Of course I didn't believe them so I decided to take one of my rims off and weigh the tire/rim the subtracted the weight of the tires from tire rack specifications and to my surprise they weigh a whopping 25.2lbs each... So tires and rims weigh 4lbs more than stock.

slartibartfast

iTrader: (7)

Yessssss! I just couldn't believe that open design weighed forty pounds.

Surfnazi

Iirc for every 1 lb of rotational mass from wheels and brakes its 10lbs loss or gained inside. So if you drop 4lbs per corner it's like losing 40lbs inside

hexotic

What was that rule of thumb again? Unsprung mass = 10 x weight. So 25 lbs at every corner is like adding 250lbs to the car. Then, with rim sizes, you're also looking at the rotational force which is exponential the larger the diameter gets.

From personal experience running 28lb 20" wheels and now using 22lb 18" wheels ... its like I'm driving a different car all together. It accelerates faster, stops easier, feels more agile.