The bigger wider tires. You run less risk of overworking the right side tires, and more contact patch is always a good thing.
Chasing stagger is a waste of time in this instance where rules dictate the same size tire be on all corners. There isn't going to be a big enough difference in modern radials to bother sorting through to find which is fractionally larger. If anything I would make sure the best tire was on the right front especially if you're going with used tires as that sees the most abuse.
A low center of gravity is good for lap times but over the course of six hours you're bigger concern should be durability and drivability. As for gearing you could probably leave it in 2nd or 3rd the entire event with the larger tires. Most circle track cars never shift once underway, some only have 1-2 gears at all.
Make a car that will last six hours and not be too taxing to drive and you're ahead of 1/2+ of the people there. Then you just have to stay out of trouble, have fun, and profit?
In reply to machfive :
Do not over tire the car. That will slow it down.
Here is the trade off; cornering speed vs Acceleration. Short tires will accelerate faster than tall tires. Stagger* will help the car run in circles. ( cornering)
* stagger is the tall tire on the outside short tire on the inside. How much stagger is the difference a 28" tall tire on the outside a 23" tall tire on the inside. That's a 5" stagger.
A tall tire has more tire in contact with the track than a short tire.
The inside tire on a short circle track is not as heavily loaded as the outside tire. If you have a thermometer and take temps. You will find the outside tires much hotter than the inside tires. Which is the poor man's way of judging how effective. All 4 tires the same temps? You are perfect.
I use a cheap infrared Thermometer rather than burn my hands. I think they are around $20 on EBay
One thing. Forget speed. Racing is about time. If you bother to look at your speedometer you might miss the opportunity to make a pass or avoid an accident.
You have to feel your speed in the seat of your pants.
MotorsportsGordon said:
Peabody said:
In reply to red_stapler :
You don't shift in oval track applications
Some in 4 cylinder racing have to depending on the ratios they have and track size
I've been around oval tracks over 50 years, raced mini and street stock and only ever seen that once. And he wasn't competitive. But he could have been if he'd chosen his tire size properly
In my experience the smaller tires will work better. The car will handle better and I think the taller sidewall will fold and generate too much heat over the course of the race.
In reply to Peabody :
The whole plan was to get close to the right size tires and never need to shift.... that would not be helpful.
I appreciate everyones input and it has helped. I plan to start the first 2 hours with the taller tires and hopefully it will be close to the speed that I need around 70mph. I am not sure if other cars will be able run faster than 70mph and run much faster lap times but I suspect there will be a few and I will need to be faster? I know I can run at least 67mph in second gear by testing on the road and some easy calculating. For the first 2 hour run of this 6 hour race there will be a lot of traffic and staying alive is the goal and I will probably not be able to run full speed anyways. I can hopefully toward the end of the 1st stint be able to run a few quick laps and be able to tell if some cars are faster and if I will run out of gear and need the smaller tires and 3rd gear. This will be the testing phase since we will not have any prior testing time ... hoping not to be lapped by this time ... I will take tire temps, look at tire wear, see if I was hitting the rev limit too early and determine if I need the smaller tires ... I do think the tall tires may get hotter and roll over but I will be taking it more easy during traffic ... I expect I will need smaller tires so will have some on hand to change during the 10 minutes when refueling and driver change. But if my son and I can be very competitive running in 2nd gear and the tall tires still look decent then we will change tires to the same type if necessary and continue. I do plan to run some stagger as I believe it will help and I already have a full set of tires ( 215 60r15 ) that will be good for the inside when running the 225 65r15 on the outside front. The rear tires will have stagger also but I am still looking at sizes that I want to run there ... not a lot of info from any others that have run this track before so it will be a calculated guess.
Anyone else with any advice is helpful?
Any advice for a good place to start for stagger preference for this 3/8 mile egg shape oval with 12 degree banking can be helpful also?
The race is in 3 weeks so I am still getting last minute advice ...haha
Thanks to all.
Well looks like the track just changed the enduro event which is weird since it is three weeks away. I guess too many people did not want to run for a 6 hour endurance race even though they have had a good turn out the last 2 years. It was supposed to be three 2 hours stints where we could change drivers and fuel up and work on car for a 10 minute break between sessions.
Now they say they are going to do a 500 lap race ... with a break at 250 laps to fuel and change driver which throws a wrench in being able to adjust tires sizes and be ready to go quick on the third leg.
I also just got some more info and a few fast guys say they 'think' they were getting to 75mph or more down the straights so that will not work for 2nd gear ... tires not tall enough so I am looking at running the smaller tires in 3rd gear now ... which is where I thought I was going to need to go to after the first 2 hours ... but now since its a shorter race with one pit stop I guess I need to be capable of going faster than I planned right from the start.
Now just need to calculate how much stagger to run? I believe a little will help.
I have not decided yet whether to run 195/55 outsides and 185/55 on insides but that is ball park right now. Car will not be able to have any camber .... all stock ... so any others that want to chime in with advice? ... it is still appreciated.
In reply to machfive :
I agree with Wally on the stagger - it might be tough to get a noticeable difference between the two sides with radials of the same exact size, with just changing air pressures.
Another thought - FWD or RWD?
machfive said:
In reply to Peabody :
The whole plan was to get close to the right size tires and never need to shift.... that would not be helpful.
I have no idea what that comment means. You asked for opinions on two different tire sizes and I told you which one I thought would work based on a lot of experience racing 4 cylinder cars on tracks like that
Suspension has to be stock parts, but that doesn't necessarily mean stock adjustment range, right? Can you do some out of the box stuff, like bending a control arm or drilling new holes in the strut tower to mount the strut further inboard and back to get camber and caster? The right side tires are going to take a pounding.
My hunch is that the guys up front are going to go hard flag-to-flag without breaking or getting taken out. Can you make 2 hours on fuel?
In reply to J.A. Ackley :
Stagger will be done with different size like 195/15 on outsides and 185/55 on insides so about 1.3 inches of stagger is what I am figuring so far ... still asking for recommendations?
This is for FRONT wheel drive.
In reply to Peabody :
Comment was because someone said that I would not want to be shifting gears and I agreed with them and you said you don't shift which is right. I want the correct size to stay in one gear.
Your recommendation is spot on thanks.
In reply to Tyler H :
Unfortunately rules are "bone stock" and no adjustment other than tires so yes tires will be beaten up.
We can make it 2 hours on fuel just barely but should be okay. We will run hard the entire race.
i would say 14" because the wheels will be lighter and the tires will be lighter and the car will be lower so there will be less weight transferred from inside to outside.
Tyler H said:
Suspension has to be stock parts, but that doesn't necessarily mean stock adjustment range, right? Can you do some out of the box stuff, like bending a control arm or drilling new holes in the strut tower to mount the strut further inboard and back to get camber and caster? The right side tires are going to take a pounding.
My hunch is that the guys up front are going to go hard flag-to-flag without breaking or getting taken out. Can you make 2 hours on fuel?
What about gray areas? Stock shocks right? But fluid? Drill a hole in the weld on a shock abosorber, drain out the thinner fluid, fill it with thicker fluid, Re weld and maybe smear some grease over the weld area?
Slice off the rubber bushings leaving the outside visible. Put a nylon bushing in with an offset in it to get better geometry. Super glue the rubber bushings back in place, hidding the alteration.
In reply to machfive :
Do not run hard the first 1/2 of the race. Maybe even 3/4 of the race. Because a lot of the guys will be dropping out. No sense in racing those. Especially if racing hard causes you to drop out.
I'm not saying coast or go slow. I'm saying find a comfortable pace you can maintain without hurting your car.
The guy flying around st the very edge of control will either blow up or make a mistake. Why waste your chance on him?
In reply to AngryCorvair (Forum Supporter) :
Yes thank you that is what I have been looking at today ... nice to be reminded ... I looked at 15 inch for a bit and said no I think I want it lower.
In reply to frenchyd :
Yes stock shocks
Something to consider but I have brand new kyb shocks (can not have any type of performance) that are for this car and would not want to mess with them yet ... hopefully others will not be cornering much different than me... I suspect half the cars will just have old junk and mine will be new so I should have an edge.
In reply to frenchyd :
I believe patience will win this race and then flying at the end.
