1 2 3
Dusterbd13-michael
Dusterbd13-michael MegaDork
5/5/19 10:57 a.m.

Im not convinced that the hoosier sm7 slicks i got are the right idea for my mutant miata. 

Im thinking a6/a7 would be a better choice for the challenge if i want to have a fighting chance. 

I cant personally afford a new set at 250ish each. 205/50/15.

Used may be in my wallet though. Where do i go? Ebay seems to be a bad idea here. 

Or do i spend 150ish each on re71r?

Streetwiseguy
Streetwiseguy MegaDork
5/5/19 11:37 a.m.

There is some dude in Wisconsin that buys and sells used race tires...John Berget or something like that.

imgon
imgon HalfDork
5/5/19 11:50 a.m.

I got a set of SM7 scrubs from EBay a few years ago that were  decent enough to use for a few sessions.  Try searching used A7s in the size you want and see what turns up. I would think there are enough AX guys that are  super competitive that dump them after a few runs

 

NOT A TA
NOT A TA Dork
5/5/19 11:55 a.m.

There's typically a couple places in the classifieds in the back of GRM. Grabbed a back issue off the pile and see listings by GT Racing Tires 414 350 6303 and JB racing tires 262 740 0180. Can't hurt to call and they're helping keep the mag in business!

Dave M
Dave M Reader
5/5/19 12:22 p.m.

I'll third JB tires - I've heard great things. You have to call though, as his website is like Geocities circa 1999.

Duke
Duke MegaDork
5/5/19 12:42 p.m.

I recently called JBT and he basically told me he never gets A7s in Miata sizes any more, because everyone uses them all the way up. 

He has non-DOT radial slicks available in some soft compounds, but not A7s. 

Duke
Duke MegaDork
5/5/19 12:44 p.m.
Dave M said:

I'll third JB tires - I've heard great things. You have to call though, as his website is like Geocities circa 1999.

And even if you use the online contact form, they just email back and say “Please call us to discuss. “

Boris3
Boris3 New Reader
5/5/19 6:36 p.m.

I've dealt with John (JB tires) for the past 3-4 years. Always in person since he's not that far from me. Good guy and straight up about what he's got and options for how "used" you're looking for. I've mainly bought multiple sets of SM7 take offs, and a few sets of H20s.

KyAllroad (Jeremy)
KyAllroad (Jeremy) UltimaDork
5/6/19 7:29 a.m.

I bought a set of SM7s from JB a couple years ago, and then a set of 275/35-15 R7s with something like 2 heat cycles on them for 1/4 the price of new.  They weren't A7 sticky but they wore like iron and were quicker than RE-71s.  I did a year on them with a co-driver and gave them to another autocrosser who drove them another year eeking out a couple of top 10 finishes on them. 

Justjim75
Justjim75 HalfDork
5/6/19 8:42 a.m.

My one Challenge was done on used SM7s.  I would go zig zag on the return road if my car sat any to warm them up and they seemed to do fine.  Although I've never run on As so......

enginenerd
enginenerd Reader
5/6/19 9:02 a.m.

Was going to suggest the Spec Miata facebook group but you'll mostly find SM7's there. I've had a hard time finding 205 A7's that weren't completely dead. Could you fit a 225? They seem to be more available from non-Miata people. 

GameboyRMH
GameboyRMH GRM+ Memberand MegaDork
5/6/19 9:06 a.m.

Relevant article:

https://grassrootsmotorsports.com/articles/used-rubber/

Ebay isn't necessarily a bad idea, USDRRT is on Ebay.

Dusterbd13-michael
Dusterbd13-michael MegaDork
5/6/19 9:18 a.m.

Am i overthinking it again? I have one autocross on hoosier circle track slicks, and one on sm7s that never got hot. 

Be honest. My goal is top third of autocross times.

GameboyRMH
GameboyRMH GRM+ Memberand MegaDork
5/6/19 9:53 a.m.
Dusterbd13-michael said:

Am i overthinking it again? I have one autocross on hoosier circle track slicks, and one on sm7s that never got hot. 

Be honest. My goal is top third of autocross times.

No I think you'd be much better off on a6s/a7s. I have RC1s on my Corolla right now so I know how crappy it is to autocross on tires that need heat and never get hot.

Professor_Brap
Professor_Brap GRM+ Memberand Dork
5/6/19 9:54 a.m.

There is a guy local to me that all he does is used tires/slicks. Hell my neighbor had some a7s in the size you where looking for. 

Dusterbd13-michael
Dusterbd13-michael MegaDork
5/6/19 10:10 a.m.

In reply to Professor_Brap :

Talk to them. Please. Im also looking for 22-24x7-9×15 drag slicks.....

Patrick
Patrick GRM+ Memberand MegaDork
5/6/19 10:14 a.m.
Professor_Brap said:

There is a guy local to me that all he does is used tires/slicks. Hell my neighbor had some a7s in the size you where looking for. 

I need some 315 a7’s for $10 each for budget reasons cheeky

 

you have a highish powered miata, you can top third on sm7’s.  I did 7th on s80 compound road race tires in a car way more suited to drag racing.  

Professor_Brap
Professor_Brap GRM+ Memberand Dork
5/6/19 10:37 a.m.

In reply to Dusterbd13-michael : In reply to Patrick :

can do, ill be talking to him tonight

In reply to Patrick :

KyAllroad (Jeremy)
KyAllroad (Jeremy) UltimaDork
5/6/19 10:49 a.m.

In reply to Dusterbd13-michael :

Beside the tire compound, what are your alignment settings?  What size wheels are you running?  What brakes? Suspension?

 

My old CSPish car was running SM suspension, 15x9 wheels and 275/35 A7s, -3.5 camber front and rear (0 toe), and HPS/HP+ pads.  One of the biggest things I discovered was to get the tire pressure low.  No, lower than that.  On a 2100 lb car I had the tires down to 21/19 psi.  It loses a bit of "precision" in the handling but the outright grip makes up for it.

TLDR: if your camber supports it, use less pressure.

Dusterbd13-michael
Dusterbd13-michael MegaDork
5/6/19 10:54 a.m.

I have -3 camber front, -1 rear, zero toe all around. Fully seam welded and braced chassis. Gm 3400v6 from a Buick rendezvous swapped in. Subframe connectors 4 point roll bar. Butterfly brace. 1 1/4 front bar, none rear. Hard s bilstiens and 450/350 springs. Stock nb miata 15s (15×6 i think)

Robbie
Robbie GRM+ Memberand UltimaDork
5/6/19 10:58 a.m.

You can occasionally find good deals here: (new but discontinued) the f40s that you ran on the spirit are $75 each NEW. 

https://shop.hoosiertire.com/index.php/discontinued-tires.html

Also, check out the hoosier spec sheets:

https://www.hoosiertire.com/assets/Circuit4.pdf

I've read that R25B compound is either the same as A7 or as close as you can get (but if someone can elaborate, i'm listening). If you look at the spec series they run those tires on, you can look for series with really light cars that run sprint races. It's much easier to talk to the used tire guys when you know exactly which tire you are looking for. 

Dusterbd13-michael
Dusterbd13-michael MegaDork
5/6/19 11:01 a.m.

In reply to Robbie :

Can you explain that again? Apparently i haven't had enough coffee. Its not making sense. And didn't we all decide circle track slicks on the autocross dont work that well?

Robbie
Robbie GRM+ Memberand UltimaDork
5/6/19 11:10 a.m.

If you look on the hoosier spec sheet it tells you the compound that each race tire is available in. Then at the bottom of each section it gives a little diagram that gives relative "hard - soft" ratings for the compounds listed. R25B is the 'softest' compound listed for circuit track tires in the spec sheet. 

Circle track tires I think yes don't work that well for autox, but if you think about it, this makes sense since circle track cars are heavy and run longer races. So the tires would need to be harder (and giant) for longevity. 

But 'circle track' isn't the only type of circuit tire! Tires for small cars like formula Vs or spec racer fords, etc, could work really well for autox cars. 

am I even making sense here?

Dusterbd13-michael
Dusterbd13-michael MegaDork
5/6/19 11:12 a.m.

Ah! Yes. Any idea where i can find the breakdown of what the abbreviations stand for on the spec list?

Robbie
Robbie GRM+ Memberand UltimaDork
5/6/19 11:19 a.m.
Dusterbd13-michael said:

Ah! Yes. Any idea where i can find the breakdown of what the abbreviations stand for on the spec list?

I wish! Someone familiar with SCCA and NASA classes could probably name them off the top of their head. Here are most of them I think:

https://www.scca.com/pages/car-classifications-and-groups

 

1 2 3
Our Preferred Partners
0T0T1nUuDFNLY7IuwLVljm2ApVwVqtcV7oU9sXx4aqx8dCXvGOglfP6BCnsDm8nm