Hoosier 25B
My tire mounter pointed out that my new rear tires were 22.5x 10.0, #43314 and that the old ones were 7.2, #43309. He said the new ones were wider(I should be so lucky). I only have my rains to compare to and they are very close to the same size. They do seem to have different shapes to the sidewalls. Any ideas or comments?
Mark
1990 Van Diemen, the Racing Machine, CM AutoX, 2016 Frontier
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
Searching the Hoosier Product spec PDF(https://www.hoosiertire.com/pdfs/speccat.pdf) I found that the 14's are spaced for 8-10 in rims and listed as 9.8 in tread while the 09's are 5.5 in and listed as 7.2 in tread. I have been using 43163 on the front for many yrs and they are spaced for 6-8 in rims. I e mailed Hoosier to ck in on this.
Mark
1990 Van Diemen, the Racing Machine, CM AutoX, 2016 Frontier
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
I missed this press release:
HOOSIER INTRODUCES NEXT GENERATION OF CLUB RACING SLICKS – NEW A2500
LAKEVILLE, IN (April 4, 2014) – In an effort to offer our valued customers improvements to our existing 13” bias-ply slicks, construction changes have been made to the following part numbers. The new A2500 construction offers the Club and Solo customers improved steering response, improved braking, and an increase in cornering stability and grip which ultimately leads to faster lap times. Enhanced performance will be provided by a new fabric and stiffer sidewall design. Tread compounds on all tires will remain the same R25B, R35A and R45B. Setup, break-in procedure, air pressure and camber settings will be the same as the previous model. Some of the following tire sizes are in stock and ready to order.
Item 43127 – 20.5 x 6.0 – 13 A2500 Item 43186 – 20.0 x 9.0 – 13 A2500 Item 43309 – 22.5 x 7.2 – 13 A2500
Item 43163 – 20.5 x 7.0 – 13 A2500 Item 43288 – 22.0 x 8.0 – 13 A2500 Item 43311 – 22.5 x 9.0 – 13 A2500 Item 43319 – 23.0 x 12.0 – 13 A3000
Item 43168 – 20.0 x 7.5 – 13 A2500 Item 43292 – 22.0 x 9.0 – 13 A2500 Item 43314 – 22.5 x 10.0 – 13 A2500
Contact your nearest Hoosier distributor or dealer with price and availability questions or visit www.hoosiertire.com for more information.
1990 Van Diemen, the Racing Machine, CM AutoX, 2016 Frontier
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
Mark, the fact is that you have the wrong tire for a 5.5 wheel.
TeamFRD-1988 Van Diemen RF88-1267 FF1600 Solo:CM#99/199 http://yspect8.weebly.com
43127 and 43309 are the proper tires for 5.5 inch wheels.
The press release is over two years old.
I talked to Hoosier West this morning. They are sending me the correct tires, 43309's and send me shipping labels for return. Ya, Hoosier!
Most of us run on 43163's for the front even though they are not the correct FF units. They are 7 in instead of 6 wide.
Mark
1990 Van Diemen, the Racing Machine, CM AutoX, 2016 Frontier
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
It did cost me about $100 to sort out the tire problem. Darn.
I noticed that all competitors in CM at Nationals used Hoosier tires. Can't just be the contingencies.
Mark
1990 Van Diemen, the Racing Machine, CM AutoX, 2016 Frontier
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
6" vs 7 " Fronts
Hi,
I've read in this thread and other places that the "go to" front tire for autox is the 7" FC tire. Are you doing this because your cars tend to understeer with the standard 6" ?
My car is a '73 Elden Mk10 with a 84" wheelbase so getting it to rotate is not generally an issue. I'm worried about going to the 7" front I'll end up with a car that will "pirouette" if I just think about it. To date I've only been using the "spec" vintage treaded Dunlops for autox that I also road race with. Next year might be more autox focused so I'm planning tire purchases.
Thanks,
Jim
This might be the better thread.Originally Posted by JGB
http://www.apexspeed.com/forums/showthread.php?t=54209
Thanks, that was one of the other places I was referring to. It mostly discusses wear/number of runs with a few vague mentions of handling.
I'm just wondering why the move to the wider front. I'm guessing is because the newer cars tend to push (understeer) so more front tire is better. My Very Old Elden definitely doesn't push, probably because the wheel base is 10-18" shorter than most modern FFs.
If I go with the same ratio of F/R tread widths the Dunlops have then I probably should get the 6" fronts.
Jim
Hey Jim,
New to autocross FF's (just a 1.5 years) so I've never tried the 6" front tire, when I asked Mark about what tire I should use, the 7" was the go to tire for autocross, I didn't ask question and just went with Mark said. Autocross is a little different then road racing in that other then hitting cones there is little concern of wrecking your car at an autocross event.
The thing is that in autocross we are trying to get Max! grip at any event we go to and because everyone else is doing it you better too (maybe not you Jim), so the extra 1/2" you may get because of roll over on a 5.5 rim is worth it. When you autocross 40 to 50 events a year (Mark, Chris, Me in the Bay area) you set your FF up for the front tire of choice
The other thing to remember is someone told me or maybe I heard it but push in a Formula car leads to over steer, I think it was push on entering a turn, over steer on the exit. For me a steep learning curve to all this and having fun.
Ben
Hi Ben,
Thanks for the reply. It's the same for me got the car in mid '15, before that autox and HPDE in my street cars. Bought a vintage Elden through this site as I wanted to do road racing, but at a somewhat relaxed level being a 60 something rookie.
It makes sense to maximize front grip then setup the car for best balance.
One of the nice things about the old historic/club FFs is that every thing is right there in front of you and easy to access for changing/tuning even potentially between runs if not sessions.
I realize that going between autox and road racing might mean I'm never optimized for one or the other. My location makes road racing very expensive due to travel costs and I like the casual atmosphere at autox events. I'll probably get another racing season (vintage) out of the Dunlops as I only do 2-3 race weekends, so this year I can spend my tire budget on purple crack. At the last event this year I was within 2-3 secs of the fast guys (Ariel Atom on A7s, S2000 on A7s, etc) even using the Dunlops which take 2 racing laps to get up to temp so there is hope for me yet.
Regards,
Jim
Jim,
Seat time is good and yes, the purple crack is lots of fun. Warms up in 2 or 3 turns.
Mark
1990 Van Diemen, the Racing Machine, CM AutoX, 2016 Frontier
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
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