Balanced Tire Sizes for road racing

[rohrt]

I think I may have asked this before, but in terms of road racing what is the best combination for front to rear size with a mini tubbed 1st gen F-body? I recall being told not to go any bigger then 315 in the back. If that is the case what would be the compliment for the front? Both with 17 inch rims.

[baz67]

It depends on what you are willing to sacrafice in terms of drivability. CarlC has put 275s in the front of his 68, but had to loose some turning radius to do so. Idealy you want to get the tread width as close as you can. So 245/315 is about is close as you can get without any comprimises assuming you have minitubbed the back to be able to fit the 315s.

[rohrt]

So your saying the ideal is a 1 to 1 ratio between the front and back. I would have thought that since the front is heavier and the ideal is to have oversteer there would have been a different ratio

[sinned]

So your saying the ideal is a 1 to 1 ratio between the front and back. I would have thought that since the front is heavier and the ideal is to have oversteer there would have been a different ratio

HUH?? Who said it is ideal to have oversteer?

[rohrt]

Dennis

Educate me if i'm wrong don't you want the ass end of the car to kick out rather then the front, and isn't that oversteer?

[MrQuick]

You your really fighting for balance. You want to tune for an almost neutral feel. If your building a road racer 1:1 is best ~IMHO~ we tend to go too wide for sake of looks.

[MrQuick]

You know, your really fighting for balance. The last thing you want to do is use you tires as a tuning device. Pick your sizes and build around it. You want to tune for an almost neutral feel.

If your building a road racer 1:1 is best ~IMHO~ we tend to go too wide for sake of looks.


275's are a perfect set up cause they will fit most chassis with no problems. Remember ask 10 different people you will get 10 different answers.

[sinned]

Dennis

Educate me if i'm wrong don't you want the ass end of the car to kick out rather then the front, and isn't that oversteer?

No, you do not "want" over steer (ask me how I know ). Almost every vehicle built has under steer or push designed into and for a reason. In an over steer condition, depending on what caused it, it is almost impossible to have full control of what is going to happen next. In an understeer condition, almost every time, simply lifting out of the throttle or tapping the brakes will allow the driver to fully regain control of the vehicle. This assumes no ice, loose gravel, tec... as the cause of the condition, in which case it doesn't matter, your ****ed anyway.

[Ralph LoGrasso]

If you can fit a wide enough tire up front (275+) then there's no reason you can't run the 335 out back. A very well respected suspension company in the PT world is building their newest project car around a 315/335 combo, and the products they're developing on the car, once for sale, will give the PT crowd the ability to run some really wide tires up front (275-295-315); to balance out the wide rear tires that some people choose to run. Vince is right though, some people tend to go too wide in the rear for the sake of looks. 335s out back are useless with 235s up front, IMO.

[CarlC]

If costs are included, using a 1:1 tire ratio allows for tire rotation which will lead to a longer usable tire life. On most of our cars were going to wear the front tires faster than the rears, so being able to rotate tires will help longevity and reduce costs.

Also, just picking a size and going for it may not work in your best interest. Tire brand, size, tread type, speed ratings, and compounds may be limited in certain sizes which will reduce your options. The 275/40/17 size is about as popular as it gets, for now.

[Blown353]

If costs are included, using a 1:1 tire ratio allows for tire rotation which will lead to a longer usable tire life.

Very true and definately something to consider. While having matching sized wheels and tires all the way around may not "look as cool" as having steamrollers out back, being able to rotate the tires is a big benefit to life-- either from burnout wear out back or cornering wear up front.

I run even sizes all the way around and even though I could use a lot more tire out back for my severe forward-traction issues being able to rotate the tires has really extended the overall service life of my tires-- heck, I got almost 8,000 miles out of this set, which is a new record for me. When the fronts start showing a bit of cornering wear I toss 'em on the back and after some right foot abuse they're pretty even again. LOL. My fronts are starting to edge-wear again and could use to be rotated to the back but unfortunately my back tires have started to chunk in spots-- and I'm not taking chances putting chunked tires on the front of the car.

Keep in mind the front tires are responsible for the majority of the braking (not to mention direction changing) so there's no reason not to go as wide as you possibly can up front. If you go with 315's on the back I would try to fit at least 275's up front; a 315/35 & 275/40 combo would probably work out well and they will have the same OD or be very close in OD (depending on what wheel width you mount them on.)

Troy

[rohrt]

Carl I refer to your web site quit often and I see you you run 275 all the way around without the mini tubb. How has your car performed and what events have you been in?

Just curious what the thrasher and red witch have front and back for tire sizes? I couldn't find the info.

Also MrQuick I understand what your saying about

"You know, your really fighting for balance. The last thing you want to do is use your tires as a tuning device. Pick your sizes and build around it. You want to tune for an almost neutral feel."

I want function B-4 looks and to learn from you guys that are out there being competitive to find out what trick parts to use use and what is a wast of money.

Thanks for the replys

[CarlC]

The car is mostly a street car but makes it to track days 2-3 times per year. It's a rolling laboratory for me, and is getting progressively better.

[sinned]

Also MrQuick I understand what your saying about
"You know, your really fighting for balance. The last thing you want to do is use your tires as a tuning device. Pick your sizes and build around it. You want to tune for an almost neutral feel."
That being said I wonder why....

I want function B-4 looks and to learn from you guys that are out there being competitive to find out what trick parts to use use and what is a wast of money.
So we realize that you need to have some kind of balance and NOT buy tires based on what looks good but rather what works; and then we go here...

Just curious what the thrasher and red witch have front and back for tire sizes? I couldn't find the info.
What possible difference could that make as to what tires YOU need?

Not looking to start an argument or erk you but it doesn't sound like you are nearly as interested in running the best tires as you are the best looking tires.

[Ralph LoGrasso]

What possible difference could that make as to what tires YOU need?

Perhaps he's looking for past examples of what similar, well sorted out cars have run?

[MrQuick]

yeah Dennis, will you quit questioning his questions with questions and answer his questions with an actual answer...CC made you abrasive man! ok now im confused.

Looks aren't bad right? You ran 315's that rub and really didn't help keep you on the track...if I remember correctly?? Hey hows the rain out there? Pretty nasty hu?

I think Ralph is right with his hypothosis. Seems Rohrt has a mini tubbed 69 and doesn't want to waste the space,but in the same breath wants a nice handling car...my advice, go with 315's in the rear and MAKE 275's fit up front. Then make the car work with that tire arrangement.

[sinned]

Looks aren't bad right? You ran 315's that rub and really didn't help keep you on the track...if I remember correctly?? Hey hows the rain out there? Pretty nasty hu?

Nope, 315's were on for a month or so before the 285's went back on. Rain sucks, especially working outside.

Agreed looks are not bad, just don't claim you are a function over fashion type person while trying squeeze maximum rubber.

[rohrt]

No offense taken Dennis. I have two 68s F bodys. One vert one hard top. I'm still finishing the vert right now(non PT car). The Hard top is a Southern Cal car that I would like to drive to and put in some races. I have most of it planed out with exception to the entire suspension system and wheel tire combo.

It is not yet mini tubbed or any work as of yet, but I had planned to do that mainly for the fact of what Ralph had stated "Perhaps he's looking for past examples of what similar, well sorted out cars have run"

So yeah I will forgo the mini tub idea if its not beneficial. Also I apologize that I only know of a few of you guys that race their cars on this forum. Being a PHR reader I have read the article of Stielows lap of america (wish I still had that), I have read Mike Pozzi web site, looked at what Detroit speed is doing, seen hundreds of web sites of others that have built cars and have seen the never ending supply of aftermarket parts that have come out. Its enough to make my head spin.

I would like to see maybe 4 cars that are competitive and what they did to achieve that?

I do admit I'm at a loss when it comes to the what types of races there are out there I would like to compete in. The Silver state classic is one that I read the rules on but I don't consider it a true competition in the sense that your racing against a clock and not another driver.
This Forum is my education and thank you to thoses that teach.

[MrQuick]

Agreed looks are not bad, just don't claim you are a function over fashion type person while trying squeeze maximum rubber.

I go both ways...depends on the car, plus you know me...I like BIG looking rears. LOL
OUTSIDE?!?! My you went up didn't you!
Rohrt, mini tubbing is not necassary. You can achive very good traction with a 10inch wide tire. 285/275 combo works real well. I don't know your background but if your new to the race scene try a few autoX events,maybe hit the drags or maybe an open track day and see what your into. You can't really know till you try.

Silver state is a big race to jump into.

[rohrt]

I have been to the 1/4 mile drags plenty of times. I just googled the autoX events and they look pretty cool.

http://www.fbody-event.org/bin/autox.cgi

I'm finding lots of stuff out there. I will keep looking to see what is close to me.

Thank you