Hello all, just a quick observation post. I recently swapped my AWD Lux model's stock 18x8 +45 wheels for 19x9 +35 Forgestars. Weight analysis:

Stock wheel weighs 30.5 lbs
New CF5's weigh 24 lbs.

Wheel weight removed: 26 lbs

Old 235/45R18 tires 26 lbs (new)
New 245/40R19 Continental DWS06-Plus: 24 lbs

Total rotating mass removed ~34 lbs

Observation: The car has a lot more get-up to it just shuffling through traffic and of course the handling improved substantially without killing the ride quality. I've seen folks think about tunes, exhaust systems, intakes, etc... big bucks to do mods like that for a few % gain. I recommend first installing the lightest, strongest wheels you can along with a sporty but sane tire combo in 19". if you are lowered, I'd suggest trying for a 255/35R19 in front or all around, and if stock height (especially AWD), go with 245/40R19 front or all around.

Lots of really special wheels out there square or staggered, definitely a great upgrade.

 

Real talk. I laughed out loud even pulling out of the driveway, it was immediately noticable.

 

Nothing like a 4,000lb 4-door luxury sedan trying to become a race car!

 

Felt a different. You have any idea what the gear ratio change was by changing sizes?

 

The GS is not a luxury car, it is a sport-touring luxury car. There is nothing wrong with wanting to notch up the performance (handling: noticeably better especially with wider, lower profile, lighter tires; acceleration a marginal but noticable improvement). Lighter, wider wheels also have other benefits, but I won't bother explaining, it is self-evident.

 

It is different (1.x% ish by calculation) but I can't feel it. I think it helps that the tire is lighter, not just the wheels. That's the item furthest away from the rotation centerline so it has the most "influence" on the rotating assembly.

255/35R19 would have probably been much more sporting, a good choice if lowered some and if the offset was "just right" to prevent rubbing. It's a common size that frequently costs less, too. Not a good look on a stock height AWD though.

 

You've got to get the stance right or you've got nothing!

 

Light wheels make an incremental improvement just like my friend's new Benz GLC300 48-volt mild hybrid.
Lighter wheels not only fractionally more acceleration, but also fractionally better braking, lower fuel consumption, and less skittering around corners.
My friend says she can't feel any extra power in 48-volt mild hybrid; I explained it is only an incremental 5-10% improvement at best; nothing like a proper hybrid, let alone a plug-in hybrid.

 

All of that! Steering feels lighter and front end more agile too since you arent trying to turn a heavier rotating mass.

 

A double duty car that shouldnt be taken too lightly. I daily drive it and have my fun on the weekends. This was from today, the bike gave me the point by to pass. Watch it in 4k!

 

Awesome!

That angle also showcases how a nice stiff sports tire resists rollover at the sidewall. What's your setup?

 

The gearing different will out perform on with acceleration on the bottom, or top any weight difference.

A lighter crank pulley weight rotation, yes. Put lighter wheels on a Dyno to see a difference?

 

Thanks! I just used that mount for the first time today and I'm I'm digging the angle too. Forged wheels, ps4s michelin tires, coilovers, strut tower bars, sway bars, an assortment of subframe bracing, LCA bushings, pads and SS brake lines. Also Borla mufflers, intake arm and high flow filter.

 

I'm uncertain if you are asking, or telling. But significant testing has already proven lighter wheels and tires turn quicker 0-60 and quarter mile times. It's worth a tenth or two (higher or lower, depending on which way you go.) I can't remember which motor mag did a piece on it, but back in the day when paper subscriptions were a thing, I read it then and have kept it in mind ever since.

These weren't the lightest to get but for the price paid, it was a deal to not pass up. The 5 star design also complements the GS nicely