ProV1

i want to upgrade from weak 16" stockers to some 19inch rims & tires, but according to the info at tirerack, the wheel/tire combo i want would weigh almost 60lb per corner!! (29lb for rim + 29lb for tire)

i'm not sure how much 16" stockers weigh but i'm sure not 58lb.

i've read of unsprung vs sprung weight and how it can affect acceleration, braking and gas mileage. is 58lb too much?

cyclerider

Why don't you jack up your car, pull a wheel off, and weigh it on your bathroom scale? I'll bet it's heavier than you think.

jangy

I'd bet you are going to gain about 10lbs at each corner. Yes, it will make your car seem less responsive. 19s are for looks and not performance. Pick your poinson and move on.

Most cast rims will be about that weight. The only difference is in the amount of metal between a 16 and a 19 AND in the radius of that weight. The farther out, the stronger the effect, so that is why 19s become less responsive.

kevinle

Prov1, yes your stock wheels will weight around that too if you try to scale them, maybe just 1 or 2 lbs diff, the reason you feel your car heavier becase the contact surface bigger or wider than to stock wheels, dont worry man.

lig

With respect to 19" wheels - if you choose a set of forged wheels instead of cast wheels you can save a good deal of weight and get wheels that are probably going to be much stronger as well.

A heavy car like the W211 + cast 19"s + moderately bad roads often = bent wheels.

I ultimately went w/ 19s for the bling factor on my audi but they are only 21lb each. (BBS RS-GT)

khaug

The OEM 225/55x16 Michelin MXV 4 tires on 16x8 cast rims on our CDI weighed 50# each (by actual measurement). The BBS forged 18x8" RS-GT wheels with Goodyear Eagle F1 GS-D3 245/40 tires I installed weigh 48# each. Not a major improvement, but at least a change in the right direction. I was amazed to find that this tire/wheel combo provides:

-A better ride
-Much better handling and braking
-No apparent loss of acceleration
-Fuel economy loss of 5 - 8% (!)

You are very wise to consider the consequences of the weight change. It appears that most folks that do an upgrade consider only appearance and clearance problems. The tire/wheel combo is both unsprung and rotating mass, and can compromise both ride and acceleration/braking if the new equipment is significantly heavier. I don't know what you have now, but the estimate of a 10# per wheel/tire sounds to be in the ballpark. This is a bunch - 20% or so!

If it were me, I'd look for something lighter. Forged wheels do, indeed, tend to weigh less and be stronger per pound than cast.

Consider: The appearance difference between 18" and 19" will be almost imperceptible, but I'll bet you can tell the difference of 10#/corner from a performance standpoint.

Good luck.

ProV1

Karl, thanks for the very insightful reply, really helps a lot. I'm curious why you are getting worse MPG ..? increased radius?

BTW, where in MI are you? i'm in A2 - GO BLUE!!

LNL

The MXV4's have a low rolling resistance, and they are on the CDI for that reason. There are a couple of perspectives on low rolling resistance tires. One is mileage, the other is handling. Here's a link to an article from Tire Rack on the subject: http://www.tirerack.com/tires/tirete....jsp?techid=29, and a link to a report on various tires (lower end) from Green Seal (often cited as a primary source in other articles): http://www.greenseal.org/resources/r...resistance.pdf

See also this link, in which the author notes that the "Bridgestone B381 ... has a measured rolling-resistance coefficient (RRC) of 0.0062 (2002)—one of the lowest on the market. The Michelin Pilot Sport A/S ... has a rolling-resistance coefficient of 0.0133 (2002)—one of the highest." http://www.hybridcars.com/blogs/hyview/tire-labels

The Goodyears must really stick to the pavement! It would be nice to find a better tire than the Michelins as far as handling characteristics that also has low rolling resistance.

Lou

khaug

Very nice post by Lou eloquently says what I was going to say.

This is a real mpg difference, not artifactual. I carefully measured the OE tires and the Goodyears, and their circumferences were within 1/4", which is trivial.

Alas, the Goodyears have become so noisy in the past several thousand miles that I'm considering replacing them with probably 70% of their original tread depth still present.

I'm in Lansing, BTW. Go Spartans!

LNL

Sorry to hear that. I have the F1 GS-D3's on my car presently, and like them a lot. Noise has never been an issue. Perhaps you got a bad set?

Please keep us informed what you decide to get, and if you extract any rolling resistance date from the manufacturer.

Lou

khaug

I suppose it could be an alignment issue, since I've never had the car aligned. Should have alignment checked before I dump a set of perfectly usable/very expensive/otherwise desirable tires, I suppose. Besides which, I don't really know where to go with replacements. My GS-D3s currently have 7-10K miles on them.

I have a strong suspicion that the lower the DOT wear rating, the higher the rolling resistance. I'd about settled on a set of Bridgestone R050 Pole Position tires, until I looked at their wear rating, which is 180 as compared to 240 for the GS-D3s! Don't want to lose still more mpg, as that's what I bought a diesel for!

Oh yeah, BTW, my Goodyears are labelled "Made in Germany", and carry a "Z" (not "Y") speed rating!

Regards,