Notices
C7 Z06 Discussion General Z06 Corvette Discussion, LT4 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Sponsored by:
Sponsored by:

Hoosier A7 or R7 on a C7 Z06?

 
Old 10-30-2018, 02:41 PM
  #1  
rcgldr
CF Senior Member
Thread Starter
 
rcgldr's Avatar
 
Member Since: Sep 2018
Posts: 182
Thanks: 0
Thanked 21 Times in 15 Posts
Default Hoosier A7 or R7 on a C7 Z06?

Anyone here running these? These are DOT racing slicks (they have two "cosmetic" grooves", although there is/was some company that would cut treads into them), A7 for autocross, R7 for circuit racing. The rears are a match at 335/25/20, but the closest fronts are 295/30/19 (about 1% larger diameter, may cause the C7 to think the rears are slipping a bit). I've seen a few cars with these at some local car shows.

rcgldr is offline  
Old 10-30-2018, 02:53 PM
  #2  
lobsterroboto
CF Senior Member
Support Corvetteforum!
 
lobsterroboto's Avatar
 
Member Since: Jun 2016
Posts: 619
Thanked 81 Times in 60 Posts
Default

A7's are also really great for time trials. They give you amazing grip for a handful of laps. They'll cycle out pretty quick tho..

Be mindful that the Hoosier sizes are generally larger than normal sizes IE the section widith on a 335/25/20 A/R7 is 14.2 vs 13.5 on the pilot super sport.
Also the diameter is 27.1 hoosier vs 26.6 pss

The C7 isn't to limiting when it comes to weird size tires once you're in PTM or TC/AH off. fwiw. You can pretty much cram whatever fits on your car.

don't shop for tires based on "size" without actually looking at tire specs. you'll have a bad time.

ETA: Hoosier tire sizes
If I was gonna buy tires for the stupid OEM wheel size for a Z06 or GS I would get

Hoosier R7 305/30/20 - 27.1 13.2 vs 26.6 13.5 (PSS)

Hoosier R7 295/30/19 - 26.1 11.5 vs 25.8 11.3 (PSS)

Last edited by lobsterroboto; 10-30-2018 at 03:07 PM.
lobsterroboto is offline  
Old 10-30-2018, 03:06 PM
  #3  
rcgldr
CF Senior Member
Thread Starter
 
rcgldr's Avatar
 
Member Since: Sep 2018
Posts: 182
Thanks: 0
Thanked 21 Times in 15 Posts
Default

Originally Posted by lobsterroboto View Post
Be mindful that the Hoosier sizes are generally larger than normal sizes IE the section width on a 335/25/20 A/R7 is 14.2 vs 13.5 on the pilot super sport. Also the diameter is 27.1 hoosier vs 26.6 pss
I missed an edit. Fronts are 26.1 versus 25.8. So fronts ~+1%, rears ~+2%. I assume this isn't enough to trigger an engine braking causing the rears to slip warning, but it could interfere with the assists, or at least TC, not sure about the stability control. Is a camber change needed with these tires, or is that just an issue with the bias ply racing slicks used on the smaller cars (Caterham, Formula Ford, ... )?
rcgldr is offline  
Old 10-30-2018, 03:11 PM
  #4  
lobsterroboto
CF Senior Member
Support Corvetteforum!
 
lobsterroboto's Avatar
 
Member Since: Jun 2016
Posts: 619
Thanked 81 Times in 60 Posts
Default

Originally Posted by rcgldr View Post
I missed an edit. Fronts are 26.1 versus 25.8. So fronts ~+1%, rears ~+2%. I assume this isn't enough to trigger an engine braking causing the rears to slip warning, but it could interfere with the assists, or at least TC, not sure about the stability control. Is a camber change needed with these tires, or is that just an issue with the bias ply racing slicks used on the smaller cars (Caterham, Formula Ford, ... )?

For any slick or semi-slick I would recommend as much camber as you can get out of your car.

Not sure if you're planning on street driving on these tires but if you do you will be making a very expensive mistake.




lobsterroboto is offline  
Old 10-30-2018, 07:10 PM
  #5  
Painrace
CF Senior Member
Support Corvetteforum!
 
Painrace's Avatar
 
Member Since: May 2003
Location: Mt. Juliet Tennessee
Posts: 8,054
Thanked 24 Times in 20 Posts
Default

A7s for all!
Painrace is offline  
Old 10-30-2018, 07:34 PM
  #6  
rcgldr
CF Senior Member
Thread Starter
 
rcgldr's Avatar
 
Member Since: Sep 2018
Posts: 182
Thanks: 0
Thanked 21 Times in 15 Posts
Default

Originally Posted by lobsterroboto View Post
For any slick or semi-slick I would recommend as much camber as you can get out of your car.
Not sure if you're planning on street driving on these tires but if you do you will be making a very expensive mistake.
I was asking for one of the guys at a local weekly car show, who has a 2016 C7 Z06 A8 Z07. I don't plan on tracking my car (2015 C7 Z06 M7 3LZ (without Z07)) at either a drag strip or road course, so I will only be using the Super Sport tires. One of the other guys that used to go to the car show tracked a Caterham, using the R7's with the softer compound on 13" rims, pulling lateral 1.5g, which is good for a non-downforce car, which is why I remembered the A7 / R7 tires, and asked here about them before I mention them to that guy at the car show. Thanks for the replies.

Last edited by rcgldr; 10-30-2018 at 07:34 PM.
rcgldr is offline  
Old 10-30-2018, 09:46 PM
  #7  
Newb73
Junior Member
 
Member Since: May 2018
Posts: 43
Thanks: 0
Thanked 6 Times in 5 Posts
Default

All the fast Mile guys seem to run the Hoosiers. Cars up to 250mph.....
Newb73 is offline  
Old 10-31-2018, 01:32 AM
  #8  
Bill Dearborn
Tech Contributor
 
Bill Dearborn's Avatar
 
Member Since: Oct 1999
Location: Charlotte (formerly Endicott, NY) NC
Posts: 32,858
Thanked 3,356 Times in 2,245 Posts
Default

Originally Posted by rcgldr View Post
Anyone here running these? These are DOT racing slicks (they have two "cosmetic" grooves", although there is/was some company that would cut treads into them), A7 for autocross, R7 for circuit racing. The rears are a match at 335/25/20, but the closest fronts are 295/30/19 (about 1% larger diameter, may cause the C7 to think the rears are slipping a bit). I've seen a few cars with these at some local car shows.
I run either the A7 or R7 in 18 inch diameter sizes. Front 315/30/18 on 18x11 wheels and Rear 345/35/18 on 18x13 wheels. That combo works very well. Diameters are close to stock and a limited number of tires are available as scuffs Vs new so you can save some money on tire purchases.

Bill
Bill Dearborn is offline  
Old 10-31-2018, 04:53 AM
  #9  
X25
Sr.Random input generator
Support Corvetteforum!
 
X25's Avatar
 
Member Since: Jan 2008
Location: Sammamish, WA
Posts: 4,020
Thanked 416 Times in 337 Posts
Default

Originally Posted by lobsterroboto View Post
A7's are also really great for time trials. They give you amazing grip for a handful of laps. They'll cycle out pretty quick tho..

Be mindful that the Hoosier sizes are generally larger than normal sizes IE the section widith on a 335/25/20 A/R7 is 14.2 vs 13.5 on the pilot super sport.
Also the diameter is 27.1 hoosier vs 26.6 pss

The C7 isn't to limiting when it comes to weird size tires once you're in PTM or TC/AH off. fwiw. You can pretty much cram whatever fits on your car.

don't shop for tires based on "size" without actually looking at tire specs. you'll have a bad time.

ETA: Hoosier tire sizes
If I was gonna buy tires for the stupid OEM wheel size for a Z06 or GS I would get

Hoosier R7 305/30/20 - 27.1 13.2 vs 26.6 13.5 (PSS)

Hoosier R7 295/30/19 - 26.1 11.5 vs 25.8 11.3 (PSS)
If I understand it correctly, I think you should focus on tread width, not sectional width. The tread width will be measured as mounted on a rim. If the measured rim (listed in the spec) is different size than what you're using, you can also add/substract 0.2" for every 0.5" wheel size increment/decrement to reach your specific wheel size as an approximation.

PSS ZP actually runs incredibly wide. Some of the sizes (like the TPC spec Corvette sizes) actually run wider than the corresponding Hoosier tires. I realized this when I put my Miata tires (R7 285/30/18) next to PSS ZP 285/30/19; PSS ZP was wider.


The tire at the bottom left is 285/30/19 PSS ZP. The tire at the right is Hoosier R7 285/30/18. Per manufacturers' specs, PSS ZP has 11.3" tread width, while R7 has 10.6" tread width, which clearly shows in the pic (they are both not mounted).


If you compared sectional widths, however, you'd see 11.5" vs. 11.4", and think that they're about same width. Sectional width is very much dependent on radial belt design, and doesn't even change much with different wheel widths. As such, it might not be as helpful : )

Last edited by X25; 10-31-2018 at 04:59 AM.
X25 is offline  
The Following User Says Thank You to X25 For This Useful Post:
lobsterroboto (10-31-2018)
Old 10-31-2018, 08:37 AM
  #10  
lobsterroboto
CF Senior Member
Support Corvetteforum!
 
lobsterroboto's Avatar
 
Member Since: Jun 2016
Posts: 619
Thanked 81 Times in 60 Posts
Default

Originally Posted by X25 View Post
If I understand it correctly, I think you should focus on tread width, not sectional width. The tread width will be measured as mounted on a rim. If the measured rim (listed in the spec) is different size than what you're using, you can also add/substract 0.2" for every 0.5" wheel size increment/decrement to reach your specific wheel size as an approximation.

PSS ZP actually runs incredibly wide. Some of the sizes (like the TPC spec Corvette sizes) actually run wider than the corresponding Hoosier tires. I realized this when I put my Miata tires (R7 285/30/18) next to PSS ZP 285/30/19; PSS ZP was wider.


The tire at the bottom left is 285/30/19 PSS ZP. The tire at the right is Hoosier R7 285/30/18. Per manufacturers' specs, PSS ZP has 11.3" tread width, while R7 has 10.6" tread width, which clearly shows in the pic (they are both not mounted).


If you compared sectional widths, however, you'd see 11.5" vs. 11.4", and think that they're about same width. Sectional width is very much dependent on radial belt design, and doesn't even change much with different wheel widths. As such, it might not be as helpful : )

oohh yah you’re right i know this tread width would be the more important measurement

great post
lobsterroboto is offline  
Old 02-02-2019, 09:48 PM
  #11  
z8ra
Junior Member
 
Member Since: Apr 2018
Posts: 24
Thanked 12 Times in 7 Posts
Default

for autocross i would like to use these hoosier A7 sizes on my 2016 C7 Z07:

P315/30/ZR19
P335/25/ZR20

The rears are the exact size of the stock tires, so I assume that is the best tire.
The front A7s are the ones I am worried about. They are 30mm too wide. Would this even fit? If so I assume this would be the best performing combo for the c7 z06 right?

Last edited by z8ra; 02-02-2019 at 09:48 PM.
z8ra is offline  
Old 02-02-2019, 10:50 PM
  #12  
BLK06ZO6
CF Member
 
Member Since: Mar 2011
Posts: 92
Thanked 12 Times in 10 Posts
Default

A7’s get up to sticky temp faster than R7’s. The grip at optimal temp is pretty much the same. Race teams like to use A7’s to qualify and then pull the tires off and either trash them or sell them as scrubs like Bill was alluding to. I have a friend who buys A7’s from Pheonix this way. R7’s are the way to go for HPDE guys if you’re buying new tires. They typically last as long as Cup2’s and they’re easier to mount because they aren’t run flat.
BLK06ZO6 is offline  
Old 02-08-2019, 06:49 PM
  #13  
Dabigsnake
CF Senior Member
Support Corvetteforum!
 
Member Since: Nov 2014
Posts: 741
Thanked 104 Times in 62 Posts
Default

As Jed Clampert would say..."My brain hurts from all this ciphering"! I want the best tire for the track while retaining my current wheels on my '17 Z07-7 CCB.(I have two sets) Seems Hoosier or Toyo is my choice? I hate the Cup2's as they wear out to quickly, with no big grip benefit over the pilot SS(which I really like). So, is there anybody actually running these off sizes that are available? obviously not? Why? Probably because we 07 CCB guys are caught in a whirlpool, while the other racer guys have zeroed in on the choices available with Steel brakes and differing wheel sizes? Seems at competitionmotorsports.com they have the 335/25/20 R888RN listed and the N denotes a narrower tire than usual? What Da? No actual details on their site, w full specs? Would it make any sense to run R7 on front with A7 on rear? Why not? I would also think that a Hoosier A7 rear would also be best for drag strip action, as the work better/quicker on cooler temps? and the A7 should never get greasy hot on a road course, as my car will run hot/limp before the that happens. Three hard laps is all I'll get running 9/10ths.

What ya'll think?
Dabigsnake is offline  
Old 02-08-2019, 07:01 PM
  #14  
malexand123
CF Senior Member
 
Member Since: Jul 2017
Posts: 174
Thanked 19 Times in 16 Posts
Default

Subbed
malexand123 is offline  
Old 02-08-2019, 07:27 PM
  #15  
BLK06ZO6
CF Member
 
Member Since: Mar 2011
Posts: 92
Thanked 12 Times in 10 Posts
Default

Originally Posted by Dabigsnake View Post
As Jed Clampert would say..."My brain hurts from all this ciphering"! I want the best tire for the track while retaining my current wheels on my '17 Z07-7 CCB.(I have two sets) Seems Hoosier or Toyo is my choice? I hate the Cup2's as they wear out to quickly, with no big grip benefit over the pilot SS(which I really like). So, is there anybody actually running these off sizes that are available? obviously not? Why? Probably because we 07 CCB guys are caught in a whirlpool, while the other racer guys have zeroed in on the choices available with Steel brakes and differing wheel sizes? Seems at competitionmotorsports.com they have the 335/25/20 R888RN listed and the N denotes a narrower tire than usual? What Da? No actual details on their site, w full specs? Would it make any sense to run R7 on front with A7 on rear? Why not? I would also think that a Hoosier A7 rear would also be best for drag strip action, as the work better/quicker on cooler temps? and the A7 should never get greasy hot on a road course, as my car will run hot/limp before the that happens. Three hard laps is all I'll get running 9/10ths.

What ya'll think?
Call Competition Motorsport and ask their advice. They’re great guys and they’re racers who know their stuff. They won’t lead you wrong.
BLK06ZO6 is offline  
The Following User Says Thank You to BLK06ZO6 For This Useful Post:
Dabigsnake (02-09-2019)
Old 02-08-2019, 11:56 PM
  #16  
Bill Dearborn
Tech Contributor
 
Bill Dearborn's Avatar
 
Member Since: Oct 1999
Location: Charlotte (formerly Endicott, NY) NC
Posts: 32,858
Thanked 3,356 Times in 2,245 Posts
Default

Originally Posted by Dabigsnake View Post
As Jed Clampert would say..."My brain hurts from all this ciphering"! I want the best tire for the track while retaining my current wheels on my '17 Z07-7 CCB.(I have two sets) Seems Hoosier or Toyo is my choice? I hate the Cup2's as they wear out to quickly, with no big grip benefit over the pilot SS(which I really like). So, is there anybody actually running these off sizes that are available? obviously not? Why? Probably because we 07 CCB guys are caught in a whirlpool, while the other racer guys have zeroed in on the choices available with Steel brakes and differing wheel sizes? Seems at competitionmotorsports.com they have the 335/25/20 R888RN listed and the N denotes a narrower tire than usual? What Da? No actual details on their site, w full specs? Would it make any sense to run R7 on front with A7 on rear? Why not? I would also think that a Hoosier A7 rear would also be best for drag strip action, as the work better/quicker on cooler temps? and the A7 should never get greasy hot on a road course, as my car will run hot/limp before the that happens. Three hard laps is all I'll get running 9/10ths.

What ya'll think?
Given new tires the Hoosier will perform better than the Toyos.

Bill



Bill Dearborn is offline  
The Following User Says Thank You to Bill Dearborn For This Useful Post:
Dabigsnake (02-09-2019)
Old 02-11-2019, 12:18 PM
  #17  
Dabigsnake
CF Senior Member
Support Corvetteforum!
 
Member Since: Nov 2014
Posts: 741
Thanked 104 Times in 62 Posts
Default

Just ordered my set of R7 from competitionmotorsport.com. They were even $200 cheaper than tirerack.com.
Now, how about some skinnies for the front that will clear my CCB's for drag racing? any recommendations? I'm thinking my R7 Hossier rears will launch well, after a decent burnout?
Dabigsnake is offline  
Old 02-11-2019, 01:43 PM
  #18  
X25
Sr.Random input generator
Support Corvetteforum!
 
X25's Avatar
 
Member Since: Jan 2008
Location: Sammamish, WA
Posts: 4,020
Thanked 416 Times in 337 Posts
Default

Originally Posted by Dabigsnake View Post
Just ordered my set of R7 from competitionmotorsport.com. They were even $200 cheaper than tirerack.com.
Now, how about some skinnies for the front that will clear my CCB's for drag racing? any recommendations? I'm thinking my R7 Hossier rears will launch well, after a decent burnout?
Try trackdaytire.com with a coupon code (like msrvip).
X25 is offline  
 


Thread Tools
Search this Thread
Quick Reply: Hoosier A7 or R7 on a C7 Z06?


Sponsored Ads
Vendor Directory

Contact Us - About Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: