22" wheels and acceleration.....

[wardog]

I remember someone said they didn't notice any decline in acceleration after installing 22" wheels.

Anyone on 22's with a different opinion?

Anyone out there have any numbers? G-tech before and after numbers would be great.

The magazines seem to be getting 0-60's of 5.3-5.8

[magnesium]

FWIW, there is no way anyone who has mounted 22" wheels on their 300C isn't taking a noticeable, if not significant, performance hit...unless of course they happened to invest in light-weight, 3-piece forged wheels at $1500 a pop.

I ran across a program some time ago that did a fair job estimating effective HP loss/gain relative to changes in unspring weight. It was very enlightening. I will try to dig it up again. It more or less convinced me that unless I'm prepared to spend big $$$ on forged modular wheels, the payoff in style has to be worth the penalty in performance.

IMHO, if you're at all concerned about your 300C's performance, look for a nice 20" single-piece, forged wheel. They'll actually weigh less than the stock setup, give you a more sporting look and unlike the high-end, forged modular approach, won't cost you 25% of your car's purchase price

Of course, if you're more of a cruiser and less of an adrenaline junky, there are plenty of nice (albeit HEAVY) cast aluminum 22s out there to roll.

[gshug]

Originally Posted by magnesium

FWIW, there is no way anyone who has mounted 22" wheels on their 300C isn't taking a noticeable, if not significant, performance hit...unless of course they happened to invest in light-weight, 3-piece forged wheels at $1500 a pop.

I ran across a program some time ago that did a fair job estimating effective HP loss/gain relative to changes in unspring weight. It was very enlightening. I will try to dig it up again. It more or less convinced me that unless I'm prepared to spend big $$$ on forged modular wheels, the payoff in style has to be worth the penalty in performance.

IMHO, if you're at all concerned about your 300C's performance, look for a nice 20" single-piece, forged wheel. They'll actually weigh less than the stock setup, give you a more sporting look and unlike the high-end, forged modular approach, won't cost you 25% of your car's purchase price

Of course, if you're more of a cruiser and less of an adrenaline junky, there are plenty of nice (albeit HEAVY) cast aluminum 22s out there to roll.

I have a noticed a big drop and i also noticed my handling on the car is very poor.going at around 60-70 mph ona turn and you hit a small bump the car fishtails. its scary

[E55 KEV]

Originally Posted by wardog

I remember someone said they didn't notice any decline in acceleration after installing 22" wheels.

I doubt anyone can tell the difference without a timed measurement of the cars performance with only a "butt in the seat" measurement when changing to heavy 22" rims.

[Tibbs]

E55KEV is right. I am certain that I did lose acceleration when I added the rims, it makes perfect sense that I would. But I can't tell that I did, this car is a bat out of hell, and when you get it on it, the pleasant rush of adrenaline and unadulterated speed is right there waiting to please. I have noticed that with the ESP off I cannot spin the tires as freely as I could with the stocks. I'm not sure of that's a weight issue or a grip issue.

[DrDeville]

Originally Posted by magnesium

FWIW, there is no way anyone who has mounted 22" wheels on their 300C isn't taking a noticeable, if not significant, performance hit...unless of course they happened to invest in light-weight, 3-piece forged wheels at $1500 a pop.

I ran across a program some time ago that did a fair job estimating effective HP loss/gain relative to changes in unspring weight. It was very enlightening. I will try to dig it up again. It more or less convinced me that unless I'm prepared to spend big $$$ on forged modular wheels, the payoff in style has to be worth the penalty in performance.

IMHO, if you're at all concerned about your 300C's performance, look for a nice 20" single-piece, forged wheel. They'll actually weigh less than the stock setup, give you a more sporting look and unlike the high-end, forged modular approach, won't cost you 25% of your car's purchase price

Of course, if you're more of a cruiser and less of an adrenaline junky, there are plenty of nice (albeit HEAVY) cast aluminum 22s out there to roll.

Thanks for the informative post Magnesium. I have read the same
thing in Road & Track, and applaud you for helping folks make an
informed decision.

If you can dig up that program, please let us know. Physics
shows wheel weight as particularly bad for acceleration,
which is why expensive alloy and modular wheels came out in the
first place. Not only do wheels have to be accelerated
forward like the rest of the car, they also have to be "spun up"
as they rotate. This is called rotational inertia, and consumes
a lot of energy, slowing acceleration.

Edit:
For example, think of the spins ice skaters do. The slow
turn with arms extended demonstrates the revs with a large rim,
the fast spin with arms at chest shows the higher revs that a
smaller rim achieves with the same amount of energy.

Best,

George Ferguson

[DrDeville]

Originally Posted by Tibbs

I have noticed that with the ESP off I cannot spin the tires as freely as I could with the stocks. I'm not sure of that's a weight issue or a grip issue.

It's a rim weight and diameter issue, specifically increased rotational inertia. Se my previous post.

Best,

George Ferguson

[magnesium]

I have to disagree, E55KEV.

I used to own a BMW M Coupe, and put a set of 18", 1-piece cast wheels on it and IMMEDIATELY could tell. It felt like I was pulling a trailer. I dumped them and bought a pair of saaaweeeeeet Kinesis 18", 3pc forged wheels and the difference was night and day.

Granted, some people may be more sensitive to these sort of things than others. However, any time you increase your unspring weight by as much as 50% (yes, some of these 22s w. tires are pushing 75lbs a corner!), you're going to notice - and not just in the accel/decel department.

But let's not belabor the point here. This is an image vehicle, not a thoroughbred.

That said, go for the look you want and be proud of what you drive, just be aware that stylin' comes at a price: Performance, handling, ride quality and yes, $$$. As usual though, the more $$$ you spend (usually), the less of the others you have to give up.

[E55 KEV]

Mag, you must have a really sensitve azz - being able to tell the difference in performance with a just a "Butt in the seat" test. He-He!

You must be one of those guys that can tell the difference between a car going 0-60 in 5.0 seconds and 4.8 seconds.

[gshug]

can someone comment on the handling of the car with 22 inch rims. I swear that i feel the car losing control on every turn tht has a bump in it