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cwebster · 02-04-2018, 09:07 AM

My current DRs [MT Street S/S ] are near or at the end of their life. I want to move to a street slick if possible with a shorter sidewall (lower profile) to reduce rotational mass and increase leverage to improve my 60-ft times. I've outlined my options and posed some questions below.

Here's my existing DRs. Facing the camera is the side with the most wear. The center treads are no longer visible. The opposite side has about 1/32" to 1/16" of visible tread. I've notice the same trend on my stock tires.

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Name: ZL1_ChgClnTires-0002.m.jpg
Views: 645
Size: 143.1 KB

Here's the other side of one tire with melted rubber scraped out of the groove.

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[Tire Wear]

How many more passes do these have in them? I'm thinking maybe 3 if I only do one 5-sec line-lock burnout and the other 2 rolling burnouts.

Unfortunately, tire wear has not been even. Each tire has worn pretty evenly across the tread from side-to-side but rotationally they've worn more on one side than 180 degrees away. To me this calls the wheel balancing job into question. I'm assuming that GM has balanced the rotors and I know they've worn evenly.

Where to you guys get your wheels/tires mounted and balanced? First, they have to have equipment that won't damage painted wheels. Second, they have to be able to simulate over 150 MPH on the balancer. Would you bring them to a dealer service center, local auto repair shop, or a speed shop? I'm leaning toward a speed shop, although there isn't one I trust within 50 miles.

Left side tire always wears out before the right. This seems to indicate that the eLSD is favoring the right side for power during wheel spin. It seems to me that an eLSD should be capable of tuning this bias. I doubt whether a dealership service dept. is equipped to do this, though. Even if a speed shop tech/tuner was able to do it I'm sure this type of 3rd party adjustment is a warrany buster. Dare I ask if anyone else has tuned the eLSD?

A workaround would be to rotate tires from left to right sides periodically to even out the wear. This would require unmounting the tires and swapping wheels so the inboard sidewall faces out. This way they'll rotate in the same direction. This might work with the DRs since the tread pattern is symmetrical. I doubt this would work on the stock Goodyear tires since the tread is decidedly asymmetrical.

[Tire Fitment]

I need a shorter DR that will fit on my 18x12 inch wheels and still offer good traction. The shortest MT is a Street S/S in P305/35R18. At 26.6" dia it's over an inch shorter but the tread is only 11.2" wide. I'm worried it won't have enough meat to slip and grip at the tree.

The only 18" MT Street R that fits is the P325/35R18 with 27.0" dia and 12.0" tread width. Although it is nearly an inch shorter, I'm worried the 12" wide slick tread will stick too well and not allow that minimal slip I need on the launch.

Both of the MT's are 5 lbs lighter than my current tire (P345/35R18). I'm not sure about the Hoosiers - never used them before.

Prospective MT 18" Replacements

Street S/S:
(current tire in bold type)

Code:

                                SECT.   TREAD                   APX.
TIRE SIZE /    MEAS RIM  O.D.   WIDTH   WIDTH                   WT.
EQUIV. SIZE    (+- 1")   IN.    IN.     IN.     CIRC.    COMPND LBS.   MATL #      PART #     

P305/35R18
26X12.50R18     11.0     26.6   12.2    11.2    83.6     R2     33     90000024570 3480
P345/35R18
28X13.50R18     12.0     27.8   13.5    12.4    87.3     R2     38     90000024573 3483

Street R:

Code:

                                SECT.   TREAD                   APX.
TIRE SIZE /    MEAS RIM  O.D.   WIDTH   WIDTH                   WT.
EQUIV. SIZE    (+- 1")   IN.    IN.     IN.     CIRC.    COMPND LBS.   MATL #      PART # 

P325/35R18
27X13.50R18     11.0     27.0   13.1    12.1    84.8     R2     33     90000028455 3581

Possible Hoosier 18" Candidates

Hoosier DR2 (PDF)

Code:

Item        Tire          Tread   Approx  Approx  Meas  Sec
Number      Size          Width   Dia     Circ    Rim   Width   Compound
17342DR2    P315/30R18    11.0    26.0    81.5    11    12.5    DR2
17345DR2    P335/30R18    12.2    25.9    81.3    12    13.4    DR2

I think I'm going to go with the MT Street S/S P305/35R18. This will give me the shorter, lighter tire and hopefully get rid of some of that tail wagging that's been freaking me out mid-track. I wish they made a 305 slick I could use. If I didn't have to worry about the bog I'd definitely go with the P325/35R18 slick.

I'm anxious to hear what you guys are using and what you think of my choices.

--Cal

02-04-2018, 09:07 AM	#1
cwebster Cal Drives: 2017 6th Gen Camaro ZL1 Coupe M6 Join Date: Sep 2013 Location: Newport, NC Posts: 779 View My Garage	Help selecting replacement DRs My current DRs [MT Street S/S ] are near or at the end of their life. I want to move to a street slick if possible with a shorter sidewall (lower profile) to reduce rotational mass and increase leverage to improve my 60-ft times. I've outlined my options and posed some questions below. Here's my existing DRs. Facing the camera is the side with the most wear. The center treads are no longer visible. The opposite side has about 1/32" to 1/16" of visible tread. I've notice the same trend on my stock tires. Here's the other side of one tire with melted rubber scraped out of the groove. [Tire Wear] How many more passes do these have in them? I'm thinking maybe 3 if I only do one 5-sec line-lock burnout and the other 2 rolling burnouts. Unfortunately, tire wear has not been even. Each tire has worn pretty evenly across the tread from side-to-side but rotationally they've worn more on one side than 180 degrees away. To me this calls the wheel balancing job into question. I'm assuming that GM has balanced the rotors and I know they've worn evenly. Where to you guys get your wheels/tires mounted and balanced? First, they have to have equipment that won't damage painted wheels. Second, they have to be able to simulate over 150 MPH on the balancer. Would you bring them to a dealer service center, local auto repair shop, or a speed shop? I'm leaning toward a speed shop, although there isn't one I trust within 50 miles. Left side tire always wears out before the right. This seems to indicate that the eLSD is favoring the right side for power during wheel spin. It seems to me that an eLSD should be capable of tuning this bias. I doubt whether a dealership service dept. is equipped to do this, though. Even if a speed shop tech/tuner was able to do it I'm sure this type of 3rd party adjustment is a warrany buster. Dare I ask if anyone else has tuned the eLSD? A workaround would be to rotate tires from left to right sides periodically to even out the wear. This would require unmounting the tires and swapping wheels so the inboard sidewall faces out. This way they'll rotate in the same direction. This might work with the DRs since the tread pattern is symmetrical. I doubt this would work on the stock Goodyear tires since the tread is decidedly asymmetrical. [Tire Fitment] I need a shorter DR that will fit on my 18x12 inch wheels and still offer good traction. The shortest MT is a Street S/S in P305/35R18. At 26.6" dia it's over an inch shorter but the tread is only 11.2" wide. I'm worried it won't have enough meat to slip and grip at the tree. The only 18" MT Street R that fits is the P325/35R18 with 27.0" dia and 12.0" tread width. Although it is nearly an inch shorter, I'm worried the 12" wide slick tread will stick too well and not allow that minimal slip I need on the launch. Both of the MT's are 5 lbs lighter than my current tire (P345/35R18). I'm not sure about the Hoosiers - never used them before. Prospective MT 18" Replacements Street S/S: (current tire in bold type) Code: SECT. TREAD APX. TIRE SIZE / MEAS RIM O.D. WIDTH WIDTH WT. EQUIV. SIZE (+- 1") IN. IN. IN. CIRC. COMPND LBS. MATL # PART # P305/35R18 26X12.50R18 11.0 26.6 12.2 11.2 83.6 R2 33 90000024570 3480 P345/35R18 28X13.50R18 12.0 27.8 13.5 12.4 87.3 R2 38 90000024573 3483 Street R: Code: SECT. TREAD APX. TIRE SIZE / MEAS RIM O.D. WIDTH WIDTH WT. EQUIV. SIZE (+- 1") IN. IN. IN. CIRC. COMPND LBS. MATL # PART # P325/35R18 27X13.50R18 11.0 27.0 13.1 12.1 84.8 R2 33 90000028455 3581 Possible Hoosier 18" Candidates Hoosier DR2 (PDF) Code: Item Tire Tread Approx Approx Meas Sec Number Size Width Dia Circ Rim Width Compound 17342DR2 P315/30R18 11.0 26.0 81.5 11 12.5 DR2 17345DR2 P335/30R18 12.2 25.9 81.3 12 13.4 DR2 I think I'm going to go with the MT Street S/S P305/35R18. This will give me the shorter, lighter tire and hopefully get rid of some of that tail wagging that's been freaking me out mid-track. I wish they made a 305 slick I could use. If I didn't have to worry about the bog I'd definitely go with the P325/35R18 slick. I'm anxious to hear what you guys are using and what you think of my choices. --Cal Last edited by cwebster; 02-04-2018 at 12:34 PM.