[nocosine]

Hey all, i've been doing immense research and reading a lot of posts in regards to wheel setup in anticipation for upcoming track day at Thunderhill in 2 weeks. This will be my absolute first time at a track and I'll be running with the novice group with an instructor. I'm in a bit of a dilemma and wondering how safe/ideal it would be to run staggered 403m w/ RFT? (Eagle F1 with < 10k miles, BUT they have a slight tire bulge when warmed up lol).

Since it is my first time is it okay to run staggered? would it be worth going to non RFT in any case for handling and safety since one of my tires are slightly bulging?
OR
Should i swallow the up front cost and find a square setup since i may go more frequently down the line?

I don't think I will be able to get the setup i want (apex 18x8.5 ec7 or sm-10) in time with rubber on them before the 14th. I could also just do a ride along but thats no fun. What are my options here?

edit: Just noticed this post should have probably been in the wheel and tire section. Apologies!

[FaRKle!]

For your first time you won't be pushing things hard and will be focusing on the line and smooth driving (smooth on/off brake and throttle), so your stock tires will be fine to run on.

Thunderhill is a great track to learn on. Can be made so things don't come up too soon after each other and lots of runoff if you're worried about that.

[nocosine]

Originally Posted by FaRKle!

For your first time you won't be pushing things hard and will be focusing on the line and smooth driving (smooth on/off brake and throttle), so your stock tires will be fine to run on.

Thunderhill is a great track to learn on. Can be made so things don't come up too soon after each other and lots of runoff if you're worried about that.

Hey Farkle thanks for the insight, hope I'll be able to go more often this year to learn the track. In this case I'm worried that my RFT's could blow since city driving probably screwed up the integrity of the sidewalls. Thinking of going with indy 500's with wider 245/35 on the front as others suggested and regular 255/35R on 403m w/ adaptive suspension m sport suspension.

[FaRKle!]

How bad is the bulge/bubble? If you're hesitant to track on it, you shouldn't be driving with it on the street either.

[nocosine]

Originally Posted by FaRKle!

How bad is the bulge/bubble? If you're hesitant to track on it, you shouldn't be driving with it on the street either.

It's actually not really noticeable so I may have exaggerated lol. In the sun it seemed like there were uneven bumps on the sidewall and at times the sidewall itself doesn't seem to be completely parallel with the rim. Perhaps my camber is too positive or tire pressure is too low.

I did some spirited driving today to try and heat up the tires but only got them up to 85F 34psi fr/36psi rear and they looked fine.

[zinner]

Hopefully your club/group will have you get the car inspected by a mechanic. They should inspect the tires/brakes along with a few other things to make sure the car isn't going to come apart on the track. If the club doesn't require it, find a decent performance shop and have them do an inspection regardless. It's between 50-100 bux here in my area. Look for a shop that maybe sponsors the track day or competes in sanctioned race events. They should flush the brakes 100%, your group might require that. If you are able to get the tires balanced and check the alignment. Hopefully that puts you around $500 depending on your location and shop rates.

[BMWILUVU]

The staggered RFT is not a problem car tends to understeer anyway. Post up a pic of the bulge and did you curb the sidewall?

[johnung]

Originally Posted by nocosine

Hey all, i've been doing immense research and reading a lot of posts in regards to wheel setup in anticipation for upcoming track day at Thunderhill in 2 weeks. This will be my absolute first time at a track and I'll be running with the novice group with an instructor. I'm in a bit of a dilemma and wondering how safe/ideal it would be to run staggered 403m w/ RFT? (Eagle F1 with < 10k miles, BUT they have a slight tire bulge when warmed up lol).

Since it is my first time is it okay to run staggered? would it be worth going to non RFT in any case for handling and safety since one of my tires are slightly bulging?
OR
Should i swallow the up front cost and find a square setup since i may go more frequently down the line?

I don't think I will be able to get the setup i want (apex 18x8.5 ec7 or sm-10) in time with rubber on them before the 14th. I could also just do a ride along but thats no fun. What are my options here?

edit: Just noticed this post should have probably been in the wheel and tire section. Apologies!

The issues have already been discussed in this thread. I just wanted to add to the conversation.

At one time I had a bulge in a runflat sidewall from hitting a pothole (that a normal tire would have handled without issue). Many people including some mechanics told me that it wasn't bad. They said to just keep an eye on it and replace it if/when the bulge got a lot bigger.

But a buddy who is BMW dealer mechanic told me to replace a bulged runflat right away. He said that he has seen bulged runflat tires hit another pothole and come apart. He said that at speed the stiff material in the runflat sidewall (maybe it's Kevlar or something similar?) does incredible damage to the metal suspension components and plastic liners. He said that he's had to replace just about everything in the wheel well.

Just a heads up.

[nocosine]

Hey all, made it back in one piece and the car did great for my first time at the track. Thank you all for your responses and tips, definitely appreciate it. I hope it helps any others who are in a similar situation down the line.

Just some context on the driving, I ran with an instructor who was in a GR Supra with 2 other novices in the group (newer STI, supercharged 86 corolla) for 2 sessions and another 2 sessions with a mixed beginner group.

Outside temps that day were around 48-53F overcast. During the two 20 minute sessions with the instructor, I had a difficult time on the corners. Lots of understeer and had a hard time getting the tires up to temp since it was colder out. Could have been my driving but the Eagle f1 AS2 RFT had a hard time gripping. They became slightly better when up to temp. Tire pressure hot was around 36F 38R psi and that was with airing down. Which I found out later was a bit high so that could have explained my grip problem.

Flushing brake fluid with rbf 600 and swapping to stoptech sport pads prior definitely helped provide for a good day. I'm on non m sport brakes (Gray 4 piston front and 1 piston rear) and they did not give me any trouble whatsoever. I could have used my stock pads probably but didn't want to encounter any possibility of fading on a smaller tight track.

All in all, I am convinced I could have shaved a few seconds off had I put non run flats lol, but I digress. Stock adaptive m sport suspension was fairly floaty but did well for what it was. I used sport setting for 3/4 sessions and only tried sport+ on the last and to my surprise ran a slightly faster time due to less nannies kicking in at the expense of the rear kicking out. First time on a track and ran a 1:42. Lots of upgrading needed for driver mod!

tldr: exaggerated on tire bulge, RFT didn't blow up and did fine on track. Changed fluids and pads. Got passed by cars with half the power and weight :P

[casualDIYer]

Originally Posted by nocosine

. . . . BUT they have a slight tire bulge when warmed up lol).

Slight bulge? Do you mean on one tire a bump appears on the sidewall? Or do you mean when all the tires heat up they appear 'fatter'?

I get the feeling you mean all the tires get a little fatter when heated up, which is normal. But if you get a bulge in the sidewall, get rid of that tire. It is possible the entire tread could separate from the rest of the tire if the bulge fails. Happens in parking lot? Sh*t. Happens on the track? Super Sh*t. You want to avoid Super Sh*t.

Looks like you've got the right idea with pressures. When I arrive at a track day I let the car sit for bit (15-20 mins or longer) then take tire pressure. Typically these numbers are around the mid 30s for a lot of BMWs on street tires. As soon as I return to the pits after the first session, I take the pressure again. Your intuition on pressure is the same conclusion I'd make. While tires can get as high as 50 (the max), for many street tires, past 40 PSI results in reduced performance. Repetition of 'too high PSI' may result in tire-i-cide, with one or more tires 'chunking'. Seems like you've been asking around about hot and cold pressures for similar tires and vehicles so you're on the right track. Getting a before track - after track reading will help you guage the numbers you need. As an example, I run the PS4S at 35 PSI on the street but at the track, I go as low as 29-30 PSI, 1 PSI about Ford Explorer roll-over pressures. Thankfully my fat-a$$ family sedan there heats up the tires pretty good.

Staggered is fine. Even in the solo group plenty of cars run staggered with some rear tires being akin to a small steamroller in size (I think the Viper ACR runs a 330 in the rear and 260 in the front which means more than 1 metre of rubber rolling over the road). You've likely heard staggered leads to understeer, which is true, but understeer can be reduced through other tweaks to the suspension. Or, you could turn earlier.

Sounds like you had fun. Looks like a repeat customer.

[nocosine]

Originally Posted by menncars

Slight bulge? Do you mean on one tire a bump appears on the sidewall? Or do you mean when all the tires heat up they appear 'fatter'?

I get the feeling you mean all the tires get a little fatter when heated up, which is normal. But if you get a bulge in the sidewall, get rid of that tire. It is possible the entire tread could separate from the rest of the tire if the bulge fails. Happens in parking lot? Sh*t. Happens on the track? Super Sh*t. You want to avoid Super Sh*t.

Looks like you've got the right idea with pressures. When I arrive at a track day I let the car sit for bit (15-20 mins or longer) then take tire pressure. Typically these numbers are around the mid 30s for a lot of BMWs on street tires. As soon as I return to the pits after the first session, I take the pressure again. Your intuition on pressure is the same conclusion I'd make. While tires can get as high as 50 (the max), for many street tires, past 40 PSI results in reduced performance. Repetition of 'too high PSI' may result in tire-i-cide, with one or more tires 'chunking'. Seems like you've been asking around about hot and cold pressures for similar tires and vehicles so you're on the right track. Getting a before track - after track reading will help you guage the numbers you need. As an example, I run the PS4S at 35 PSI on the street but at the track, I go as low as 29-30 PSI, 1 PSI about Ford Explorer roll-over pressures. Thankfully my fat-a$$ family sedan there heats up the tires pretty good.

Staggered is fine. Even in the solo group plenty of cars run staggered with some rear tires being akin to a small steamroller in size (I think the Viper ACR runs a 330 in the rear and 260 in the front which means more than 1 metre of rubber rolling over the road). You've likely heard staggered leads to understeer, which is true, but understeer can be reduced through other tweaks to the suspension. Or, you could turn earlier.

Sounds like you had fun. Looks like a repeat customer.

Not only do the tires appear fatter but it seems uneven along the sidewalls. It's certainly not a "bulge" as I misidentified in my previous posts. I'll run around 35-36psi hot next time and see how that goes. One of the guys i ran with had an S3 and mentioned they had to run 40 psi since its low profile tires, he obviously aired down the lap after and had more grip.

I learned i could probably use the brakes a bit harder and turn in a bit sooner. The runflats feel like they're struggling hard for grip out of corners and on sweepers so I can't wait to go on something that grips more.

Hopefully the next HPDE will take place at Laguna Seca!