Weight Reduction
Thread Starter
Burning Brakes
Joined: Jun 2012
Posts: 1,240
Likes: 1
From: Orange County California
have been curious about that, I know track guys often run the same size tires and wheels on all four corners, how do they overcome the PCM issue requiring staggered wheel heights?
also, its hard to find wide enough rears in a good rubber compound for my power levels in a 17" rear tire, would save 12 lbs off each rear wheel to go from a 19 " runflat to a 17" 275/40/17 toyo 888 wheel setup, but I'm concerned about the dramatic loss of grip by going from a 315/30/18 setup to a 275/40/17 setup...this only saves an additional five pounds, but maybe gives up too much grip?
also, its hard to find wide enough rears in a good rubber compound for my power levels in a 17" rear tire, would save 12 lbs off each rear wheel to go from a 19 " runflat to a 17" 275/40/17 toyo 888 wheel setup, but I'm concerned about the dramatic loss of grip by going from a 315/30/18 setup to a 275/40/17 setup...this only saves an additional five pounds, but maybe gives up too much grip?
Last edited by steven31371; Nov 5, 2012 at 05:05 PM.
Thread Starter
Burning Brakes
Joined: Jun 2012
Posts: 1,240
Likes: 1
From: Orange County California
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
also, its hard to find wide enough rears in a good rubber compound for my power levels in a 17" rear tire, would save 12 lbs off each rear wheel to go from a 19 " runflat to a 17" 275/40/17 toyo 888 wheel setup, but I'm concerned about the dramatic loss of grip by going from a 315/30/18 setup to a 275/40/17 setup...this only saves an additional five pounds, but maybe gives up too much grip?
and that is 5 lbs of static weight. when you look at the rotational weight 1lb static ~ 6.5 lbs rotational. so your 5 lbs static is more like 32.5 lbs reduce PER WHEEL. x 4 wheels or 130 lbs removed.
each 100 lbs remove is ~ 1/10 quicker in the quarter, or 1 sec per lap less on a 2.5 mile circuit.
so the comprise is 18" all around.
and stop eating at Micky Ds.
Reducing our waist lines is important. ie if the driver weights more then 200 lbs, taking wt off the car wont help much.
and speaking of grip, tires have the most "grip" when that tires is slightly sliding or spinning, the melted rubber tire surface provides the most grip.
and unless you tires are under 6 months old and less then 10 heat cycles, ( a heat cycles is each time the tire is UP to operating temp or about 180* ) it wont matter. ie if you have more then 500 miles on street tires, the grip is all the same. Good but not great.
Last edited by AU N EGL; Nov 6, 2012 at 08:39 AM.
Safety Car
Joined: Apr 2007
Posts: 3,582
Likes: 137
From: SoCal CA
My car is just under 3000lbs. I deleted the ac, have lighter wheels, custom exhaust with no rear mufflers or over-axle exhaust. I still have a full interior. The power seats weight around 40lbs or close to some race seats would save a lot of weight as well.
Thread Starter
Burning Brakes
Joined: Jun 2012
Posts: 1,240
Likes: 1
From: Orange County California
took my seat out and weighed them...power sport seat are 44.9 lbs
the corbeue forza with brackets is 28 lbs
32 lbs savings, and a handling upgrade ;-)
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Safety Car
Joined: Apr 2007
Posts: 3,582
Likes: 137
From: SoCal CA
Yeah those sport power seats are sandbags in the car. I wanna swap mine out too. You cant recline or move much in the car anyway and they suck for hpde driving.
Thread Starter
Burning Brakes
Joined: Jun 2012
Posts: 1,240
Likes: 1
From: Orange County California
Yeah my car is loud with only two bullet mufflers dumping out under the car but my neighbors are cool, thank goodness. Its not my dd either.
Yeah those sport power seats are sandbags in the car. I wanna swap mine out too. You cant recline or move much in the car anyway and they suck for hpde driving.
Yeah those sport power seats are sandbags in the car. I wanna swap mine out too. You cant recline or move much in the car anyway and they suck for hpde driving.
good news is you can sell them for enough cash to get lighter better seats!
Thread Starter
Burning Brakes
Joined: Jun 2012
Posts: 1,240
Likes: 1
From: Orange County California
Turn AH/TC OFF. If you leave AH/TC ON the tire O.D. only needs to be slightly larger in the rear ( a 1/4"diff will do ), not the min of 1" difference ppl get hung up on
17x315/35
and that is 5 lbs of static weight. when you look at the rotational weight 1lb static ~ 6.5 lbs rotational. so your 5 lbs static is more like 32.5 lbs reduce PER WHEEL. x 4 wheels or 130 lbs removed.
each 100 lbs remove is ~ 1/10 quicker in the quarter, or 1 sec per lap less on a 2.5 mile circuit.
so the comprise is 18" all around.
and stop eating at Micky Ds.
Reducing our waist lines is important. ie if the driver weights more then 200 lbs, taking wt off the car wont help much.
and speaking of grip, tires have the most "grip" when that tires is slightly sliding or spinning, the melted rubber tire surface provides the most grip.
and unless you tires are under 6 months old and less then 10 heat cycles, ( a heat cycles is each time the tire is UP to operating temp or about 180* ) it wont matter. ie if you have more then 500 miles on street tires, the grip is all the same. Good but not great.
17x315/35
and that is 5 lbs of static weight. when you look at the rotational weight 1lb static ~ 6.5 lbs rotational. so your 5 lbs static is more like 32.5 lbs reduce PER WHEEL. x 4 wheels or 130 lbs removed.
each 100 lbs remove is ~ 1/10 quicker in the quarter, or 1 sec per lap less on a 2.5 mile circuit.
so the comprise is 18" all around.
and stop eating at Micky Ds.
Reducing our waist lines is important. ie if the driver weights more then 200 lbs, taking wt off the car wont help much.
and speaking of grip, tires have the most "grip" when that tires is slightly sliding or spinning, the melted rubber tire surface provides the most grip.
and unless you tires are under 6 months old and less then 10 heat cycles, ( a heat cycles is each time the tire is UP to operating temp or about 180* ) it wont matter. ie if you have more then 500 miles on street tires, the grip is all the same. Good but not great.
do you need to modify anything up front to make that work? Any rubbing anyplace?
Last edited by steven31371; Nov 7, 2012 at 12:28 AM.