axr6

I am considering getting a set of light weight, forged wheels chiefly for the benefits of saving rotating weight. I think the common figure is that every single pound of weight off the wheel/tire assembly equals 4 lbs of weight removed from other places of a car. Thus, I am looking at a 40-50 lbs wheel/tire weight reduction which should have the effects of 160-200 lbs weight when it comes to acceleration and braking.

So, the question:

After switching to non-runflat tires (that also saves weight) what is the lightest list of tire repair kit you could find? I am interested in ideas/links to purchase:

1) Emergency scissor jack (hopefully aluminum)
2) Electric tire pump
3) Tire slime
4) General tire repair kit.

rothchilds

I carry a bottle of slime, compressor and a dyna plug ultralight kit. Got it all from amazon. No jack, haven't thought of a good way to store it.

axr6

That would work if I lived in suburbia :-). I tend to drive those wonderful, remote, deserted canyon roads where the nearest town or repair shop could be very far away. Don't want to be without a reasonable repair kit. If I can not come up with a kit, I'll keep the runflats.

My twin turbo 3rd gen RX-7 (recently sold) came with a super light weight scissor jack. I wish I could find one for sale. Been looking all over for one.

axr6

Thanks for the suggestion. How did you guess that those are the exact sizes I was considering?

Those are really nice wheels. Do you have the weight for them?

I would prefer the rear offset to be near the factory 79mm to make sure that there is no touching of the fenders. Do you have this setup? Is there any fender interference?

juanvaldez

Rotating mass is even more. I've seen 20 lbs thrown around.

axr6

Hmmm.... with that figure a 40 lbs rotating assembly weight saving could translate to the equivalent of 800 lbs off the car... how could anyone resist such gains?

I got the 4:1 ratio numbers last week from the owner of the very popular CA racing shop that used to sponsor me during my SCCA racing years.

Bill Dearborn

Since the Michelins on our cars only have reinforced inside sidewalls the first thing to check is how much weight can really be saved. You might save a little on the tires and cancel the savings out if you go with different wheels.

Bill

dr_gallup

I just carry 2 & 4 (plugging kit). Don't want or trust slime and the jack doesn't do you any good if you don't have a spare.

1) Emergency scissor jack (hopefully aluminum)
2) Electric tire pump
3) Tire slime
4) General tire repair kit.

axr6

Bill - When I looked up the weights of runflat vs. non-runflat tires of the same stock sizes in Michelin Super Sport I found a 16 lbs difference. From also the forum vendors advertised wheel weights I could derive an additional. close to 25-30 lbs difference using forged wheels. (More with carbon fiber wheels). I am very certain that most experienced drivers would feel the difference of the car being more responsive.

The only thing that concerns me regarding the above Pilot Sport tire exchange is that the listed tire diameters are slightly different. The non-runflat rear tire is listed on tirerack.com to be 0.2" larger. Minor difference, however, on hard compression my driver side rear tire already touches the rear wheel liner with the stock tire.

Interesting points to make regarding the jack. While I've never tried it, I would think it could be difficult trying to fix a flat tire with the weight of the car flattening it, possibly braking the bead also.

juanvaldez

Ford thought it was important enough to put $3,500 wheels (each) on the Mustang GT350R.

axr6

Yes, and here are the comparison results between the aluminum vs. the carbon wheels for the Mustang.

http://blog.caranddriver.com/tested-...-fiber-wheels/

EcoBrick Bob

On a Z51 Vette, same size non run-flat Michelin PSS will save you around 18 lbs total. Rotoforged wheels like TSW Interlagos or Cray (TSW) Spiders could save you an additional 12-16 lbs depending on size and weight.

Lighter wheels/tires really help handling and stopping distances, besides improving performance and gas mileage.

I cut over 70 lbs lf unsprung weight on my TT Flex by going with much lighter & smaller diameter wheels/tires. RPM's went up 8% but mileage didn't change due to the lower rolling resistance and weight loss. Know the PSS summer tires helped, but Flex handles like a sporty car. (Of course Megan Coilovers also help.)

xxaarraa

I get the weight savings from the non run flat tires, but doesn't the Z51 come with forged wheels from factory? Are you talking about going to even lighter aftermarket forged wheels?

GeorgeR_Zed06

I thought my factory z51 wheels were decent until I slapped on a set of TSW forged Interlagos in 18x10.5 for the rear with 315/30 MT drag radials. Talk about a HUGE weight difference, now I'm going to order the fronts. Car looks good too...

IMO, I would go to lighter aftermarket wheels for sure!!!!