Go Back   Rotary Car Club > All thing Racing! > AutoX Nuts!

AutoX Nuts! If you are one, post your set up, questions, etc here!

Reply
 
Thread Tools Display Modes
Old 07-28-2017, 10:04 AM   #1
project86
Can't.Make.Up.My.Mind.
 
project86's Avatar
 
Join Date: May 2009
Location: Murfreesboro, TN
iTrader: (3)
Posts: 1,370
Rep Power: 10
project86 is on a distinguished road
Default Tires, Sidewalls, Things

I'm eventually wanting to get into some auto-x and hpd so I'm trying to figure out a good wheel and tire set up. I have been considering 16" and 17" wheel options and I'm curious how side wall height will effect performance.






__________________
'90 GTUs
Stay up to date with my photography
'06 Toyota Highlander Hybrid
'10 Toyota Prius

"Initial Success or Total Failure"
project86 is offline   Reply With Quote
Old 07-28-2017, 03:42 PM   #2
GySgtFrank
Professional Stick Poker
 
GySgtFrank's Avatar
 
Join Date: Feb 2011
Location: Bozeman, Mt.
iTrader: (0)
Posts: 988
Rep Power: 7
GySgtFrank will become famous soon enough
Default

You will need to go with at least 17s if you want a good sticky tire for autocross. Anything smaller is very hard to find good performance street tires for anymore. There are race tires for the smaller sizes, but that could get expensive fast. The lower the profile of the sidewall, the more responsive the tire will be to changes of direction, downside being that the lower the profile of the sidewall the harsher the ride will be. Your choice on what balance you want to make.
__________________
1979 SA22C (parts of one anyway)
http://rotarycarclub.com/rotary_foru...ad.php?t=15585

1975 MG Midget (building)
http://rotarycarclub.com/rotary_foru...ad.php?t=18681

1988 Ford Probe look-a-like (it actually runs, so I don't fuck with it)
GySgtFrank is offline   Reply With Quote
Old 07-28-2017, 04:05 PM   #3
project86
Can't.Make.Up.My.Mind.
 
project86's Avatar
 
Join Date: May 2009
Location: Murfreesboro, TN
iTrader: (3)
Posts: 1,370
Rep Power: 10
project86 is on a distinguished road
Default

Quote:
Originally Posted by GySgtFrank View Post
You will need to go with at least 17s if you want a good sticky tire for autocross. Anything smaller is very hard to find good performance street tires for anymore. There are race tires for the smaller sizes, but that could get expensive fast. The lower the profile of the sidewall, the more responsive the tire will be to changes of direction, downside being that the lower the profile of the sidewall the harsher the ride will be. Your choice on what balance you want to make.
Ok that makes sense. What about the sidewall flexing enough that the lips of the rims get messed up? I feel like Iíve heard of that happening from hard cornering. Is that a thing?
__________________
'90 GTUs
Stay up to date with my photography
'06 Toyota Highlander Hybrid
'10 Toyota Prius

"Initial Success or Total Failure"
project86 is offline   Reply With Quote
Old 07-28-2017, 04:34 PM   #4
GySgtFrank
Professional Stick Poker
 
GySgtFrank's Avatar
 
Join Date: Feb 2011
Location: Bozeman, Mt.
iTrader: (0)
Posts: 988
Rep Power: 7
GySgtFrank will become famous soon enough
Default

Yes, it can happen with low profile sidewalls. Especially hitting rocks and curbs. Which is one of the reasons why most off road vehicles run a tire with generous amounts of sidewall.
__________________
1979 SA22C (parts of one anyway)
http://rotarycarclub.com/rotary_foru...ad.php?t=15585

1975 MG Midget (building)
http://rotarycarclub.com/rotary_foru...ad.php?t=18681

1988 Ford Probe look-a-like (it actually runs, so I don't fuck with it)
GySgtFrank is offline   Reply With Quote
Old 07-31-2017, 11:49 AM   #5
t_g_farrell
Waffles - hmmm good
 
t_g_farrell's Avatar
 
Join Date: Aug 2008
Location: Huntersville, NC
iTrader: (0)
Posts: 733
Rep Power: 0
t_g_farrell is on a distinguished road
Default

You can get good autox rubber down to 15". Anything smaller is NLA for rdot or summer performance tires. I have Dunlop Direzza *2 on my 15" Konigs on my SA and they are an excellent tire. Had to relearn to drive my car when I put them on. Tons of grip and one of the better rated autox tires out there as of 2016. Mine are 205/50x15. Keep the pressure up on autox days and you shouldn't have any issues with the rims being damaged. On the street I run ~33psi but if I'm doing any real driving I pump em up to about 38psi or so.
__________________
1980 GS stockport, Fat Nikki, RB Dual Facetfuel pumps, Holley regulator, RB Street port exhaust, 2GDFIS, MR2 MK I electric fans, 2G strut bar, relayed fans, lights and fuel pump, LEDs

Project Fat Nikki Budget 12A rebuild Video setup < $30.00
t_g_farrell is offline   Reply With Quote
Old 07-31-2017, 02:52 PM   #6
project86
Can't.Make.Up.My.Mind.
 
project86's Avatar
 
Join Date: May 2009
Location: Murfreesboro, TN
iTrader: (3)
Posts: 1,370
Rep Power: 10
project86 is on a distinguished road
Default

Quote:
Originally Posted by t_g_farrell View Post
You can get good autox rubber down to 15". Anything smaller is NLA for rdot or summer performance tires. I have Dunlop Direzza *2 on my 15" Konigs on my SA and they are an excellent tire. Had to relearn to drive my car when I put them on. Tons of grip and one of the better rated autox tires out there as of 2016. Mine are 205/50x15. Keep the pressure up on autox days and you shouldn't have any issues with the rims being damaged. On the street I run ~33psi but if I'm doing any real driving I pump em up to about 38psi or so.
Good advice on the pressure. I'll have to keep that in mind.
__________________
'90 GTUs
Stay up to date with my photography
'06 Toyota Highlander Hybrid
'10 Toyota Prius

"Initial Success or Total Failure"
project86 is offline   Reply With Quote
Old 08-01-2017, 08:58 AM   #7
infernosg
IT'S ALIVE!
 
infernosg's Avatar
 
Join Date: Dec 2009
Location: Richmond, VA
iTrader: (5)
Posts: 785
Rep Power: 8
infernosg is on a distinguished road
Default

Yeah, 15" wheels have good performance tire options because of the Miata guys. I can't remember if the FC's can fit 15" wheels over the front brakes though. Outside of actual race rubber, there aren't many 16" options left. I did the math once too. I compared the wheel of 16" RPF1's with 245/45R16 tires to 17" RPF1's with 255/40R17 tires. The overall weight was within a 1/2 lb or so (17" heavier) and the 16" combination puts the rotating weight slightly closer to the hub.
infernosg is offline   Reply With Quote
Old 08-01-2017, 11:08 AM   #8
project86
Can't.Make.Up.My.Mind.
 
project86's Avatar
 
Join Date: May 2009
Location: Murfreesboro, TN
iTrader: (3)
Posts: 1,370
Rep Power: 10
project86 is on a distinguished road
Default

Quote:
Originally Posted by infernosg View Post
the 16" combination puts the rotating weight slightly closer to the hub.
Is that more desirable?
__________________
'90 GTUs
Stay up to date with my photography
'06 Toyota Highlander Hybrid
'10 Toyota Prius

"Initial Success or Total Failure"
project86 is offline   Reply With Quote
Old 08-01-2017, 11:30 AM   #9
FC Zach
RCC Loves Me Not You
 
FC Zach's Avatar
 
Join Date: Mar 2008
Location: Eagleville, TN
iTrader: (2)
Posts: 2,150
Rep Power: 12
FC Zach is on a distinguished road
Default

BBS vert wheels are 15" aren't they? I could go look at my car outside but I'm too lazy at the moment.
__________________
1992 Toyota Celica Turbo AllTrac
1987 Mazda RX7 Sport
1979 Rotary Yamaha Golf Cart
1976 Hercules W2000
1975 Dolmar KMS4
FC Zach is offline   Reply With Quote
Old 08-01-2017, 01:27 PM   #10
project86
Can't.Make.Up.My.Mind.
 
project86's Avatar
 
Join Date: May 2009
Location: Murfreesboro, TN
iTrader: (3)
Posts: 1,370
Rep Power: 10
project86 is on a distinguished road
Default

Quote:
Originally Posted by FC Zach View Post
BBS vert wheels are 15" aren't they? I could go look at my car outside but I'm too lazy at the moment.
I thought they were 16"....
__________________
'90 GTUs
Stay up to date with my photography
'06 Toyota Highlander Hybrid
'10 Toyota Prius

"Initial Success or Total Failure"
project86 is offline   Reply With Quote
Old 08-01-2017, 01:37 PM   #11
Nutsid
Temporarily insane.
 
Nutsid's Avatar
 
Join Date: Feb 2008
Location: Changing constantly.
iTrader: (1)
Posts: 283
Rep Power: 10
Nutsid is on a distinguished road
Default

I heart 15s on my Miata with Bridgestone RE71-R's. I had a ton of choices for tires, too. I don't know the FC size, though, but it may be worth dealing with a speedo being off.
__________________
Quote:
Originally Posted by Industrial Records
Leaders are not essential, we are TAUGHT to believe we need them, that we are not able to assume responsibility for ourselves. Lies created leaders, lies perpetuate leaders, lies destroy joy and creativity and hope
Quote:
Originally Posted by chibikougan View Post
Did you just call us Penis Wrinkles?
For my music blog: dustinsmusicblog.blogspot.com

For my collection of short stories:
Kindle
Nook
Nutsid is offline   Reply With Quote
Old 08-01-2017, 01:39 PM   #12
Nutsid
Temporarily insane.
 
Nutsid's Avatar
 
Join Date: Feb 2008
Location: Changing constantly.
iTrader: (1)
Posts: 283
Rep Power: 10
Nutsid is on a distinguished road
Default

Also the very wheels are 15x6.5
__________________
Quote:
Originally Posted by Industrial Records
Leaders are not essential, we are TAUGHT to believe we need them, that we are not able to assume responsibility for ourselves. Lies created leaders, lies perpetuate leaders, lies destroy joy and creativity and hope
Quote:
Originally Posted by chibikougan View Post
Did you just call us Penis Wrinkles?
For my music blog: dustinsmusicblog.blogspot.com

For my collection of short stories:
Kindle
Nook
Nutsid is offline   Reply With Quote
Old 08-01-2017, 11:29 PM   #13
FC Zach
RCC Loves Me Not You
 
FC Zach's Avatar
 
Join Date: Mar 2008
Location: Eagleville, TN
iTrader: (2)
Posts: 2,150
Rep Power: 12
FC Zach is on a distinguished road
Default

Quote:
Originally Posted by Nutsid View Post
Also the very wheels are 15x6.5
(vert?) I thought so. . I run a ~225/50/15 on mine (i think). They work well for me. There are still performance tires for the fifteen inch wheel but some are very expensive depending on the exact size. . for example, a Pirelli P Zero in my size is ~$300 per tire so with that said I currently have some much cheaper Kumho tires mounted. Considering how little I drive the car, I may try the more expensive alternatives once these wear. .
__________________
1992 Toyota Celica Turbo AllTrac
1987 Mazda RX7 Sport
1979 Rotary Yamaha Golf Cart
1976 Hercules W2000
1975 Dolmar KMS4
FC Zach is offline   Reply With Quote
Old 08-01-2017, 11:33 PM   #14
Nutsid
Temporarily insane.
 
Nutsid's Avatar
 
Join Date: Feb 2008
Location: Changing constantly.
iTrader: (1)
Posts: 283
Rep Power: 10
Nutsid is on a distinguished road
Default

Yeah, vert. My phone autocorrected.
__________________
Quote:
Originally Posted by Industrial Records
Leaders are not essential, we are TAUGHT to believe we need them, that we are not able to assume responsibility for ourselves. Lies created leaders, lies perpetuate leaders, lies destroy joy and creativity and hope
Quote:
Originally Posted by chibikougan View Post
Did you just call us Penis Wrinkles?
For my music blog: dustinsmusicblog.blogspot.com

For my collection of short stories:
Kindle
Nook
Nutsid is offline   Reply With Quote
Old 08-02-2017, 07:24 AM   #15
infernosg
IT'S ALIVE!
 
infernosg's Avatar
 
Join Date: Dec 2009
Location: Richmond, VA
iTrader: (5)
Posts: 785
Rep Power: 8
infernosg is on a distinguished road
Default

Quote:
Originally Posted by project86 View Post
Is that more desirable?
Without going into too much detail the closer the center of mass is to the point of rotation the less inertia it has. Basically, it's easier to accelerate/decelerate. It's why racers use small diameter, ultra-lightweight flywheels.

Quote:
Originally Posted by FC Zach View Post
BBS vert wheels are 15" aren't they? I could go look at my car outside but I'm too lazy at the moment.
That's a good point. I completely forgot about those. I never calculated the weight of a 15" wheel and tire combination. I was looking at RPF1's and they don't come in a 15" wheel with our 5x114.3 bolt pattern. Depending on the wheel and tire widths and tire sidewall I'm sure it could be even lighter than the 16" combination but at some point you're trading weight for contact area and sidewall flex.
infernosg is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 03:31 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Hosted by www.GotPlacement.com
Ad Management by RedTyger