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Pete. (l33t FS)
Pete. (l33t FS) MegaDork
2/10/21 7:19 p.m.

Detroit runs on some sites that are part gravel, part dirt, and part extremely hard packed clay.


I've got a set of Hoosier rain tires that I plan to use.  They were used, $free, and I plan on reviving them with generous application of a 8" tire scuffer and a couple cans of Track Claw.   I've used UHP summer tires before with raging success, they are much faster on the hard pack than anything else and they do not hardly give up much of anything at all.  Part of the inspiration for this was a ride along on a mixed-surface event in a 924S on Hoosier A6s, and they worked remarkably well on loose soil.  And of course they were brain-melting on the paved section.  I was driving a lower spec car with fresh Sport Comp 2s and even those gave up very little on dirt compared to snows or rally tires.  (Excuse video quality, my rig literally was a $25 VCR and a $30 security camera screwed to the roof)


captdownshift (Forum Supporter)
captdownshift (Forum Supporter) UltimaDork
2/10/21 7:36 p.m.

In reply to Pete. (l33t FS) :

Intermediates and rains are the hot ticket,  but in Florida heat, I'd question their longevity enough, at least to consider purchasing new to try out. Also 14s would unfortunately make for slim pickings to find take offs. 

ojannen Reader
2/10/21 8:00 p.m.

In reply to Pete. (l33t FS) :

I am curious about the Hoosier H2Os too. I think I want to find a set that has been heat cycled out.  Maybe it will stand up to the dirt a little better. 

My big problem is the sizing is limited.  15" tires are all miata height.  To go to a 25" tall tire, I had to bump all the way to 17" wheels.  At that size, it is about 1400 for a set including installation so I gave up.

Have you heard of anyone cutting lateral grooves for extra bite in a 200tw autocross tire?  I don't actually know which part of the tire tread is most important for loose surface acceleration.  This makes sense at first glance at least.

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
2/10/21 8:19 p.m.

I wouldn't bother with grooves.... IMO until you get to gloppy mud, tread pattern doesn't matter as much as compound.  Personal opinion.


With short runs and such, I'd be worried about getting heat INTO a tire that is meant to be run hot.  Could also be wrong there, too.  I've overheated rally tires on hard surfaces, but that's also because they don't grip "hard" all that well and it's basically doing a 60 second burnout.  Which isn't fast, in addition to being expensive.

B13Birk HalfDork
3/5/21 12:32 p.m.

Hey Friends. Just wanted to say thanks again for all of the input on the tire situation. 

Ran the first event with snow tires up front and street tires in the rear. The car handled really well. Definitely, more tuning can be done and more experimenting can be done with tire setup (and I do have some plans)  

Hopefully, this thread stays up and it can be helpful for other folks. 

If you are interested in following along on the rally car and the series we are running I started a thread for that. Thanks again for the help. Be well. 

B13 SER Rally Car


FooBag (Forum Supporter)
FooBag (Forum Supporter) Reader
3/8/21 11:45 a.m.
engiekev said:

When you're talking about Maxsports, are you talking about the non-directional RB3F, or the directional RB3D2?


While Josh (irish44j) loves the RB1F, I am of the opinion that these are not for higher horsepower FWD & AWD cars.  On our 300ish HP SRT4, the large outside lugs were gone (literally) after two events on a medium hardness surface.  They had FABULOUS turn in while the lugs lasted, but couldn't take the steering angle plus power.  I believe you are prepping a DSM, so I believe this guidance would apply to you.

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