Drag Radial causing uncontrollable shake

[thefinalforum]

hi friends

try and make this short (never happens) and to the point. Punctured tread on a 315/50/17 MT street R on Billet Specialty wheel which took two days to completely deflate (aka slow leak). took to local performance shop and was told tire is fine to fix, I said I have a brand new one but was told No No just fix this one. Got it back a couple days later re-balanced and good to go. Everything felt great until that 120ish mph then OMG I thought the doors were coming off the shake was so violent. Took back to same guy and he was very perplexed and balanced again....said ok it was a tad off. Put back on again same result. Was recommended to try a Dealer that uses a ROAD FORCE BALANCE that essentially does just that, applies force during balance. Thought for sure golden.... plus this was the guy that originally mounted/balanced last March but he had changed shops. Balanced both wheels and he was confident. Same damn thing. So today he is removing bad tire to see whats up, maybe shifted belt whatever that is but I also gave him the new tire just in case. Looking back maybe just put the new one on eh? Dragstrip opens tomorrow....Please be fixed

 

[coolblue]

Shouldn't have to replace a tire because of a flat. And a plug or patch will not throw it off like that. Something else going on here. Maybe when tire was full flat, the weight of car deformed something inside the carcass of tire with the soft rubber compound. Don't know how long car was sitting on full flat tire.

 

[Paladin06]

Not sure this is a cause of the effect but, what’s the top speed on those tires and what pressure are you running. I know top speed on the Nittos is 140, after that you’re on your own.

 

[thefinalforum]

Shouldn't have to replace a tire because of a flat. And a plug or patch will not throw it off like that. Something else going on here. May when tire was full flat the weight of car deformed something inside the carcass of tire with the soft rubber compound. Don't know how long car was sitting on full flat tire.

It sat on the car completely flat overnight. Then I had to roll it about 10 feet to make room for jack.

 

[thefinalforum]

Not sure this is a cause of the effect but, what’s the top speed on those tires and what pressure are you running. I know top speed on the Nittos is 140, after that you’re on your own.

Not sure on top speed rating but this exact setup has been at dragstrip numerous times trapping around 130. And on the streets it has been even higher prior to flat issue with zero vibration issue.

 

[fubar569]

When you initially installed this set how were they balanced? Static? Spin? Roadforce?

 

[thefinalforum]

Just the usual spin. Never a single concerned raised until the mishap.

 

[fubar569]

Had to have screwed up a belt or something. Sucks.

I'm just glad to hear they balanced out correctly on those wheels. Some have a lot of trouble with that.

 

[thefinalforum]

Had to have screwed up a belt or something. Sucks.

I'm just glad to hear they balanced out correctly on those wheels. Some have a lot of trouble with that.

trouble with the billet specialties?

 

[The Englishman]

I wouldnt race on a repaired tyre🥺

 

[fubar569]

trouble with the billet specialties?

Nah. They a top shelf piece. No issues there.

Referring to getting MT's to balance out on occasion. A lot just do a bubble balance or none at all.

 

[thefinalforum]

I wouldnt race on a repaired tyre🥺

I was skeptical as well....oh well the repaired one has been replaced with new new. picking up today and try a 120ish mph run...fingers crossed. track day moved to Thursday.

 

[PaVaSteeler]

Nah. They a top shelf piece. No issues there.

Referring to getting MT's to balance out on occasion. A lot just do a bubble balance or none at all.

I had a performance shop try to balance my new MT ET Street R's on Bravado Tributes, using the RoadForce machine; they said they couldn't get them to balance. Took them to another place and they balanced them fine (non-Road Force). It was puzzling.

 

[fubar569]

I had a performance shop try to balance my new MT ET Street R's on Bravado Tributes, using the RoadForce machine; they said they couldn't get them to balance. Took them to another place and they balanced them fine (non-Road Force). It was puzzling.

Most of the MT line recommends a static balance only. That's especially important on a bias tire it seems.

The ET R is still a radial but it doesnt surprise me it wouldnt roadforce.

 

[Jack_Toepfer]

That 10’ may have killed it.

 

[thefinalforum]

Went to pickup wheels/tires today. Road force balance used again. He replaced the patched tire with the new new after stating the patched tire balanced the best out of all three (not what I wanted to hear). He flipped the good old one therefore it went from passenger to driver side. I went straight home, installed and drove for 5-10 mins before punching it. I was able to do a couple hits to 125 and didn't feel a hint of vibration.
Thanks so much guys for the suggestions. Next go around I will for sure suggest the static balance. Track day set for Friday (eighth mile) and Saturday (quarter mile).

 

[thefinalforum]

Ran well at track. Trapped 131 and just the usual feel on the big end. Thanks guys. Next go around I’ll request a static balance.

 

[thefinalforum]

Well I don’t know what happened...Saturday night everything was great at track along w 30 min drive home. Car sat on radials Sunday and Monday w a quick drive Monday evening. Yup the shimmy was back and this time only at 90mph. WTF. Removed, “inspected” and put stock rears on. Shimmy disappears and butter smooth. I’ve legit had it. Taking to same guy in AM and hopefully one of the tires is way off or the problem can be identified.

 

[Hunter]

Used to have horrible shake on my 16 with (cheap) aftermarket wheels. Got good ones, and vibration went away. Not saying that's your issue, just another perspective.

 

[vortecd]

It almost sounds like the issue is with the tire that didn't go flat. You kept trying to balance the flat tire but problem went away when you moved the old tire to the driver side. Was the now driver side tire checked for balanced when you kept rebalancing the flat tire? When they flipped it from passenger to driver I would assume it was rebalanced at that point and it was fine at first but even though it didn't go flat it may be the one giving you the issues