[cwebster]

Originally Posted by Trackman

That tire looks goofy in there.
Don't waste your time and money on a short tire.
You need a tall tire with some sidewall to 60'

Thanks for the opinion... I don't really care what you think of how it looks. Already tried the taller tire. Not gonna work with this car...

[JFM-jr]

Originally Posted by Trackman

That tire looks goofy in there.
Don't waste your time and money on a short tire.
You need a tall tire with some sidewall to 60'

There are already guys here that have switched from a 28" MT to a 26" Hoosier and the Hoosier knocked off about 2 tenths. One guy swapoed same track same day so they absolutley will make the A8 go faster I dont think the A10 will be any different. I agree it looks goofy but theres not a person here putting a Hoosier on for looks. This guys biggest obstacle will be ABS issues due to different tire diameters im VERY curious as to how his car reacts to this.

[DFW1LE]

It also provides a lower effective gear ratio, which for an M6 car should help.

[cwebster]

Originally Posted by JFM-jr

There are already guys here that have switched from a 28" MT to a 26" Hoosier and the Hoosier knocked off about 2 tenths. One guy swapoed same track same day so they absolutley will make the A8 go faster I dont think the A10 will be any different. I agree it looks goofy but theres not a person here putting a Hoosier on for looks. This guys biggest obstacle will be ABS issues due to different tire diameters im VERY curious as to how his car reacts to this.

As I reported in post #18, there are no negative consequences of any kind on any automated systems from using the 26" tires. Nada! If there were going to be ABS, Stabilitrak, or any other issues; they'd have shown up on my test drive.

--Cal

[cwebster]

Originally Posted by DFW1LE

It also provides a lower effective gear ratio, which for an M6 car should help.

Exactly! Plus the wide slick will offer more traction to put that additional torque to the pavement.

[cwebster]

I just got back from the track. The Hoosiers performed exactly how I predicted. My goal for their maiden voyage was to knock 2 10ths off my 60 ft and 2 or more 10ths off my ET. Accomplished both by my 2nd pass. First 2 passes had 1.8 60 ft. First 4 passes were all 11.5's with my best pass 11.5000 ET @ 125.67 with 1.92 60 ft.

Plenty of room for improvement because the car is a whole different animal with these shorter, stickier tires. There's lots more power available on the launch - much quicker through the RT/Start gates - so I've gotta tune my launch technique. Red-lighted twice before I realized I can't use the same light timing as before - gotta wait a little longer. Bogging was virtually non-existent - one pass I launched too quickly and bogged a little. It accelerates much more quickly between gears so I've gotta learn to time my shifts all over again for best effect. Still have to watch my fuel load because, as it got lighter, I had more spinning on my 2nd gear shift. Can't light these tires up too much on the burnout or they'll start hopping and bouncing. Only really did one good burnout on my first pass (2-sec line lock and rolled out). After that I just spun them to get the water off.

Posted my fastest slip to the fast list but I won't move up 'til I do 11.3 or better. Still at #8 on the Bolt-On list - maybe next time.

More later when I process the PDR, Helmet, and rooftop video...

--Cal

P.S. No intrusions from ABS or Stabilitrak in case any of you were still wondering if the 26" tires would give me trouble. Didn't do it on the test drive last week and didn't do it at the track today.

[DFW1LE]

Originally Posted by cwebster

I just got back from the track. The Hoosiers performed exactly how I predicted. My goal for their maiden voyage was to knock 2 10ths off my 60 ft and 2 or more 10ths off my ET. Accomplished both by my 2nd pass. First 2 passes had 1.8 60 ft. First 4 passes were all 11.5's with my best pass 11.5000 ET @ 125.67 with 1.92 60 ft.

Plenty of room for improvement because the car is a whole different animal with these shorter, stickier tires. There's lots more power available on the launch - much quicker through the RT/Start gates - so I've gotta tune my launch technique. Red-lighted twice before I realized I can't use the same light timing as before - gotta wait a little longer. Bogging was virtually non-existent - one pass I launched too quickly and bogged a little. It accelerates much more quickly between gears so I've gotta learn to time my shifts all over again for best effect. Still have to watch my fuel load because, as it got lighter, I had more spinning on my 2nd gear shift. Can't light these tires up too much on the burnout or they'll start hopping and bouncing. Only really did one good burnout on my first pass (2-sec line lock and rolled out). After that I just spun them to get the water off.

Posted my fastest slip to the fast list but I won't move up 'til I do 11.3 or better. Still at #8 on the Bolt-On list - maybe next time.

More later when I process the PDR, Helmet, and rooftop video...

--Cal

P.S. No intrusions from ABS or Stabilitrak in case any of you were still wondering if the 26" tires would give me trouble. Didn't do it on the test drive last week and didn't do it at the track today.

Thats great news Cal, thats what I was expecting to hear. Congrats!

[6spdhyperblue]

Thanks for taking the leap! Really hope the 26” rears will work similarly on the SS


Edit: and here is why it works on a zl1 and not a SS
Stock Front tire height:
ZL1: 26.8”
SS: 27.7”

[cwebster]

Originally Posted by DFW1LE

Thats great news Cal, thats what I was expecting to hear. Congrats!

Thanks. Working on the videos now. I'll probably open a new thread for it tomorrow.

Originally Posted by Nicul15

Thanks for taking the leap! Really hope the 26” rears will work similarly on the SS


Edit: and here is why it works on a zl1 and not a SS
Stock Front tire height:
ZL1: 26.8”
SS: 27.7”

I'm not following you. Are you saying that because your front tires are 9/10" taller than mine that a 26" rear with throw errors and intervene - pull power? If so, how did you come to that conclusion? I'm not saying I think they'll work but I don't think you should give up on a shorter tire without doing some math and trying to find others who have gone shorter. The SS has same size tires front and rear, right? If you think 1.8" is too much difference then maybe 27" tire would help.

These hoosiers are actually 9/10" shorter than my stock fronts. Have you done a comparison chart like the one I did in "Help selecting replacement DRs Post #20"? If you look at that chart you'll see that my stock rear tires are 1/2" taller than the front. The Mickey's were 8/10" taller and the Hoosiers are 9/10" shorter. That's nearly 1 3/4" difference between the Mickeys and Hoosiers - quite a large range.

I haven't seen any evidence that engineers built-in a non-documented booby-trap for tire sizes like they did for the torque management. I know other SS drivers have reported problems with different size tires but I haven't been able to pin anyone down to the actual cause. If there is some formula for tire size matching I haven't figured out what it is yet. Maybe someone else will try a shorter tire on their SS and let us know. Maybe you could borrow a shorter pair for 1 pass at the track just to see if they work.

Good luck!

--Cal

[6spdhyperblue]

Yeah. One option would be to run a 245/35 in the front on the SS to get the same height as the zl1. Historically GM allows approx. 1” difference from front to rear. You must be just squeaking by. I might try that size in the front, stock in the back for the street, and 275/40r17(26”) in the back for the track.

Hopefully they all play nice

[wnta1ss]

Originally Posted by cwebster

I haven't seen any evidence that engineers built-in a non-documented booby-trap for tire sizes like they did for the torque management. I know other SS drivers have reported problems with different size tires but I haven't been able to pin anyone down to the actual cause. If there is some formula for tire size matching I haven't figured out what it is yet. Maybe someone else will try a shorter tire on their SS and let us know. Maybe you could borrow a shorter pair for 1 pass at the track just to see if they work.

I've posted already in a 26" tire thread but I'll repeat it. Tried 26" rear tires on an SS (275/40-17 Mickey Thompson) with stock SS-size front tires, namely 245/40-20 Michelin PS4S. Before I even drove the car I changed the tires revs/mile in the tune to what MT said for this tire. Did not even get 1/2 mile in first drive with these tires and the car felt like it would not go, the computer was obviously mad about the difference. By disabling the nannies (the long hold on the TC button until the lights come on in the dash indicating stabilitrack is off) was able to drive the car. However on the dragstrip, I saw the 'Service Stabilitrack' message flash on the dashboard and my log showed a timing retard event that coincided with seeing the error. So turning the nannies off wasn't enough.

Had also run the car with MT 305/45-17 rear tires (28.1" per MT) and stock-size fronts without having these issues. It seems the computer doesn't much care about the rear wheels spinning slower than the front wheels, but objects to them going faster.

Because of this experience, my suggestion to someone with an SS who runs tires on the rear that are shorter than the front tires to this extent, is to remove the 2 ABS fuses when they race the car. Power steering is lost and there are lights nagging on the dashboard, but that's not really such a big deal. The reason for this suggestion, of course, is that the computer won't have data on front wheel speed vs rear wheel speed when the ABS sensors are powered off.

[Chevy71]

Originally Posted by cwebster

I just got back from the track. The Hoosiers performed exactly how I predicted. My goal for their maiden voyage was to knock 2 10ths off my 60 ft and 2 or more 10ths off my ET. Accomplished both by my 2nd pass. First 2 passes had 1.8 60 ft. First 4 passes were all 11.5's with my best pass 11.5000 ET @ 125.67 with 1.92 60 ft.

Plenty of room for improvement because the car is a whole different animal with these shorter, stickier tires. There's lots more power available on the launch - much quicker through the RT/Start gates - so I've gotta tune my launch technique. Red-lighted twice before I realized I can't use the same light timing as before - gotta wait a little longer. Bogging was virtually non-existent - one pass I launched too quickly and bogged a little. It accelerates much more quickly between gears so I've gotta learn to time my shifts all over again for best effect. Still have to watch my fuel load because, as it got lighter, I had more spinning on my 2nd gear shift. Can't light these tires up too much on the burnout or they'll start hopping and bouncing. Only really did one good burnout on my first pass (2-sec line lock and rolled out). After that I just spun them to get the water off.

Posted my fastest slip to the fast list but I won't move up 'til I do 11.3 or better. Still at #8 on the Bolt-On list - maybe next time.

More later when I process the PDR, Helmet, and rooftop video...

--Cal

P.S. No intrusions from ABS or Stabilitrak in case any of you were still wondering if the 26" tires would give me trouble. Didn't do it on the test drive last week and didn't do it at the track today.

Sounds like you had a successful trial on th tires. Do you see now what I meant by driving this tire is completely different than driving a DR, lol. Your tire is more track appropriate for sure, but some like what the DR does on a road. I’m glad it went well for you, as you get use to it that tire will make you faster for sure.

[Fraxum]

Cal thanks for your threads and all the good info coming from them. You have
a really good approach to learning. We could all benefit.

I am still thinking about the switch to the ZL1 as I am starting to get bites on selling my SS. Still on the fence. I know someone will at some point figure out the bog on both v8 M6es. I am not buying it has been solved yet. My torque tables were modded and all it did was make the car hard to launch on the street in normal driving. The tip-in was too much. Pray pulled it back a little and now street driving is fine but so far no help.

[Yellow6thGen]

Let me know when your hitting the track again if you can... Are you going to,Fayetteville? It’s a couple hour drive for me but I like the track. I only have an 1/8 local in Mooresville...

I have a friend that helps me working on my car there. I’ll be heading down after the snow stops again wth

I would like to see your setup in action, I’ve done 11.40 bone stock so looking forward to test out the RotoFab and kooks exhaust and see possibly getting a set like yours in the rear and help!

Also I have a vacation planed in Aug at my condo at Atlantic Beach... looking forward to driving down to the beach.

Steve

Originally Posted by cwebster

Yup, but I didn't like it on the MT's. With just a little gust of wind it felt like it was gonna go sideways. These shorter sidewalls should minimize that, though.



Thanks man. LOL, Well maybe a little for show. At the track, however, it's the GO that's more important.


BTW,
I just found out the track is not having street drags or T&T tomorrow. They're using this weekend as the rain date for their St. Valentines Day Classic tournament. It was rained out last weekend. Daggon-it! Guess I have to wait for the next weather window then. Maybe I'll go as a spectator.

--Cal