I am just getting into autocross, and happen to need rear tires. A lot of people have been telling me to start off with a stock car, before making any major upgrades so I decided to keep the stock rims for now (2001). Current size is 225/50/16 but a lot of people are saying to put in a 245. This seems OK, but I was looking at the Bridgestone RE-71R which tire rack does not seem to carry in the 245/50/16. Should I stick with the 225's for now? or keep looking else where for the 245s?

Thoughts?

Thank you in advance,
Eric

 

oh boy, finding a quality autocross 245 50/16 is gonna be a tall order...and its the wrong size.

what you really want is a 245 45 r16. Start with the Toyo Proxes R1R- unless you're going for some high dollar hoosiers or R888.
Unless you have a large karcepts front bar (or equivalent), you'll want to go with either stock staggered tire sizing, or Front 225, Rear 245.

welcome to the insanity.

darcy

 

I had an AP1 in the B Street for the last 2.5 years. I just sold it and bought an AP2 which I haven't gotten to an autocross yet. More importantly, 2.5 years ago, even with RE71R's in stock sizes, a guy in a pretty stock dodge neon could raw time me consistently. In a few months, with some seat time and instruction, I was able to beat the dodge neon and others. It is mostly driver until you are within a very close time to others with similar cars. The car's balance was good and was really fun on stock sizes. 16s are also significantly cheaper than 17s. This is great for focusing on seat time.

The best setup in stock class will be 225/50/16 RE71R's all around with a Karcepts front sway bar. Focus solely on improving your driving for the first year. I think good tires do give you the perspective of where you actually lie and take away the excuse/confusion of "What if I had the fast tires". As for mods, you will need a bit of driving skill to actually start feeling where you can improve the car. I'm going to be lazy and copy another post I wrote to a different question as it's late and I should go to bed.

Buy the front sway bar once you experience the problem that it attempts to solve. I believe you will learn more in the process doing it this way as opposed to throwing parts at it. Drive it stock on good tires, keep it idiot proof. Your only means of tuning are improving your driving and changing tire pressures. I did this for over a year and used known good drivers to measure my progress. Take someone who places at nationals and see how far off you are from them. They will be consistently near the top at local events and should give you a pretty good idea based on the delta between you two. Be honest with yourself. Once you are truly close and/or seriously experience and feel something about the car you want changed, consider making the change. Until then, driving is what will net you the biggest difference and most satisfaction.

If you have enough grip and drive hard enough, you will start to lift the inside rear tire. I drove my ap1 on 225 RE71's all around for a bit before truly experiencing this. I solved the problem by putting on the Karcepts big front sway bar. It was definitely oversteery but taught me a lot and was pretty fun. I think I only spun it once on that setup. I actually didn't realize how much it tended towards oversteer until I got the front bar and wasn't correcting nearly as much. That taught me what a car feels like when it is too loose.

 

+1 on this guy. If you don't have RE71R you will be at a disadvantage.

 

As you have found, not many companies produce 245 tires for 16 inch wheels. In addition, I'd imagine they'd be extremely muffin-topped on the narrow stock wheels. Start with the 225 RE71R non staggered and get the Karcepts front bar if you can drop down the cash. With this combo the car can do way more than you'd expect it to and will be much faster than you at the beginning. If they are available, go to school days to feel out your car and get some instruction from much more experienced drivers. You might initially feel like you're pushing the car when you aren't and you will need someone to show you what the car really can do. The limits are far higher than you'd think even when limited to stock classes. So much of it is driver dependent. I have a really fast buddy running a B street AP1 with the above combo and he consistently runs 1-2 seconds faster than me even though I drive an AP1 with 255 non staggered tires (though I have stock suspension so it's not fully modded out for STR). He is a far superior driver to me and gets every little drop of performance you can out of the stock class car and consistently beats the C5 corvettes even on the longer and faster courses.

 

and also weld your front upper A arm mounts to prevent pulling away from the frame rails (AP1 only).

darcy

 

Lol, welding the upper A-Arm is a bit extreme for where we are at in this thread. I totally get the point of it but I'd think you need more grip and/or a LOT of hard seat time before that is remotely a serious risk. I get that it happens to people but recommending it as a legitimate concern to someone just starting off in street class is a bit much.