Greetings, I am considering taking my car to an autocross event this year. I would be running in stock H class (?) Whatever is the slowest lol. I will be using a 16x6 wheel and I'm not sure if I should use a 205/50 or 205/55 tire. It will be a Firestone Firehawk Indy 500. I'm not trying to finish at the top of the class, just trying not to finish dead last. The tire will be used for DD purposes as well so I need something not too aggressive that can handle good in wet weather. The difference between a 50 and 55 sidewall is .8", so the 50 sidewall would effectively lower the car .4" and give me a shorter gear ratio. Sort of leaning towards the 50 sidewall but I'd like to hear from some folks with experience.
What is the stock tire size on your car? Are you deadset on those tires?
For your first autocross, I wouldn’t worry about winning or where you finish. Concentrate on finding the course, driving smoothly, and having a fun time. The speed will come.
As far as the 50- or 55-series tire, it depends: The shorter tire will deliver quicker acceleration and likely better handling. But will the shorter tire also cause you to run out of second gear at a bad time?
TL;DR: Go, have fun, make new friends and report back.
In reply to camopaint0707 :
Stock tires are 195/65/15s but the car was available from the factory with 16s on 205/55s.
I have a set of OEM 16x6s.
I chose the indy 500 based on reviews, it seems to be the best compromise for a DD that would see a track day. My next choice was the Kumho Ecsta V730 but it only comes in a 55 sidewall in 205 for 16s. I don't want a tire that's going to wear in 10k miles and hydroplane in a summer thunderstorm. I live in the Midwest so it would see Temps down to the 50s in fall and spring. I have a set of Blizzaks on the oem steelies for winter.
In reply to David S. Wallens :
Don't laugh me off the boards but it's a 2006 corolla with auto trans. It weighs 2500lbs and is super flingable into corners and has exit speeds approaching my 16 Jetta Sport. I have a good feel for weight transfer and coming out of a corner so I think I'd pick things up fairly well and my competitive side thinks it would be hilarious if I didn't place dead last meaning someone lost to a Corolla lol.
Since it's an auto I have up to 70mph in 2nd gear lol so anything to shorten that would prob be good.
In reply to HalfFastRolla :
Bring it and have fun. And, yeah, sounds like the shorter tire might help.
Also, some related watching for everyone:
David S. Wallens said:
For your first autocross, I wouldn’t worry about winning or where you finish. Concentrate on finding the course, driving smoothly, and having a fun time. The speed will come.
.... make new friends and report back.
Ding! Ding! Ding! We have a winnah. Right, see if it's something you even want to do. Get there early, walk the course (twice), talk to a senior member of the Local Chapter, don't we all love talking about our stuff?
Relax. Enjoy. Bring food & water. =~ )
EDIT:
Halfast, you typed at the same time I did but I have to respond, NO ONE gets laughed off this board. EVERYONE! I mean EVERYONE from Mario Andretti to Dennis Connors to Ron Jeremy has a first time at something.
Run whatever tires are on the car for the first few events - unless they're totally dead and needing replaced beforehand.
Thanks everyone you all seem like a cool group!
I definitely plan on walking the course as much as possible and asking all sorts of questions.
I've been to different types of rodeos so to speak, so this is sort of a lateral move for me- I've done the Rusty Wallace stock car experience and I've made quarter mile passes faster than what Car and Driver reported with the equivalent car.
So I like to think I know what I'm doing- at least some of the time.
If I only had one set of wheels and spent the majority of the time daily driving I'd stick with the 205-55-16s to keep it close to the OEM diameter. If I was using a second set of wheels just for autocross I'd try a 195-45-16 as that would lower the car an inch and change the effective final drive from 2.96 to 3.23.
In reply to HalfFastRolla :
At this point I would buy stock size based on the 45,000 miles you hope to put on these tires in the next year's. Dont buy for the few minutes you plan to use them on track.
Welcome!
See my words in this thread and watch the video.
The smaller local events I've been to someone was running an automatic 2013? Corolla. Biggest hindrance for them was getting off the line and up to speed. There has also been an auto Scion TC and Buick Regal 2.0T. Run what you brung.
My first autocross car was my DD a Ford Probe 4 cylinder auto with all season tires. I ran that way for 2 years and had a blast.
We don’t care what you drive. Just be a good person.
In reply to John Welsh :
I don't expect 45k miles from a set of Indy 500s, but I don't want something that's going to wear out in 10k either.
It's definitely a dog off the line even with brake torque. My VW Alltrack leaves it behind when I short shift at 3k lol.
I'm really leaning towards the 50 sidewalls. I just have to make up my mind because the rebate is over in a few days!
John Welsh said:
In reply to HalfFastRolla :
Proof that we like Corollas with automatic...
https://grassrootsmotorsports.com/forum/grm/remeber-the-2000-challenge-corolla-with-no-springs/183885/page1/
^ This car is now a Lemons racer. I drove it at the Barber race a few months back. Still going strong! Now with ebay coilovers instead of washers. lol.
In reply to John Welsh :
Great article! Mine is more of an old lady car, it sat alot if its life, she only has 42k miles, no body rust and minimal surface rust underneath.
My auto tech friend was telling me to not use too sticky of a tire because of the low power of the car, is that a valid concern?
Ando
New Reader
3/30/23 2:25 p.m.
HalfFastRolla said:
My auto tech friend was telling me to not use too sticky of a tire because of the low power of the car, is that a valid concern?
No, the sticky-er the better-er.
To repeat what others have said...Walk the course like alot, until you can picture what comes next. Autocross definitely benefits from experience, the first couple times can be challenging. Don't worry about tires yet, you might be making all sorts of changes. If there was any prep to worry about it would be good alignment with max camber and air up your front tires a bit to prevent too much sidewall roll over.
Great advice from everyone! Thanks all, I appreciate the feedback!
If the club shares a course map ahead of time, definitely spend time with it. (I print it out and put it beneath my pillow.)
Seriously, if you don’t know what comes next, whether you’re running 50s or 55s won’t matter. Car placement is key. (Along with fun and safety, of course.) Eyes up, fast hands and think ahead. I try to walk a course at least three times.
Also, I don’t mess with my car much if at all between runs. Once at the event, I have found more speed via concentrating on my driving vs. my shock settings.
My first autox, I learned what the others are saying. I flogged several cars to the absolute limits of MY abilities, and I got out of the car after every run feeling like I had just done three lines of coke. (the good adrenaline parts, not the bloodshot eyes/insomnia/heart attack parts)
I ran a modestly competitive big RWD boat, a more modified FWD, and I also drove the fastest-lap car there. My times didn't really change with the car I was in because the limiting factor was me, not anything about the car.
Since your car is also a DD, I would focus on getting tires that are the right diameter for your speedo and odo and not stress about the little lap time difference... that it probably won't affect anyway.
I like my cars to challenge me. The day I drive my car at the same lap time as a much better driver is the day I think about upgrading it so I can be challenged more. At this point I'm just a noob driving the snot out of some cars for fun. Until then I watch a pro driver take my car around in 46 seconds while I put down a 58 second run and I realize that it's not the car, it's me.
I've driven a four cylinder automatic car on those tires. They have a sticky compound, but the sidewalls are really soft. Keep the pressures high to prevent wearing out the shoulders. 35 lbs in the front tires in this picture , not enough.
