Need help going fast...

[JaxS550]

Ok so I've gone thru some mods and caused some issues, got rid of them and now this...

I was down in Mexico and was racing some random guy on the highway. When I got up top 110-120 my car started moderate to severely rocking left to right until I slowed down. Like to the point of it were any worse I might have lost control. I'll list all the mods/specs below.
Please let me know if you have ideas on what's wrong or needs tweaking.

16 GT PP
vogtland sport plus springs, stock PP shocks
Billet vertical links
Steeda rear subframe alignment kit
Steeda subframe support bushings
Steeda diff bushings (red)
Steeda mt82 bushing
I also have 25mm/20mm spacers front/rear

Unrelated: mbrp street CB, corsa CAI

Also had the alignment done about 2 weeks ago.

@steeda any ideas? You guys always have good ones.

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[LETHAL]

Tires?

 

[jbailer]

Tires?

That would be my guess. Especially if they are under inflated and/or too wide for the wheel.

 

[West TX GT]

What brand of spacers? Did you torque them to spec? When I first installed mine the hub lugs looked like the poked out a bit too far to my eye. I hand tightened it (pretty tight like I have always done) before a test drive to see if it would leave wear marks on the back side of the rims. When I got to around 60 mph it started to rock back and forth wildly. Pretty scary, it felt like the whole bottom of the car was about to fall apart. I slowed to a crawl and the wobbling stopped. After seeing there wasn't scratches on the rims, I decided to torque it as I should have and give it another try. Worked perfectly fine and have never had any problems since.

 

[West TX GT]

Have you gone that fast before the mods and did you have any issues?

 

[jbailer]

How did you do your rear spacers? Did you cut 3+ mm off the rear studs, replace the studs with shorter studs or drill out the pockets on the back of the wheels?

My measurements showed anything less than a 23mm spacer and the studs would be hitting the back of the wheel. That would definitely be bad.

 

[Rebellion]

What brand of spacers? Did you torque them to spec? When I first installed mine the hub lugs looked like the poked out a bit too far to my eye. I hand tightened it (pretty tight like I have always done) before a test drive to see if it would leave wear marks on the back side of the rims. When I got to around 60 mph it started to rock back and forth wildly. Pretty scary, it felt like the whole bottom of the car was about to fall apart. I slowed to a crawl and the wobbling stopped. After seeing there wasn't scratches on the rims, I decided to torque it as I should have and give it another try. Worked perfectly fine and have never had any problems since.

[MENTION=21067]West TX GT[/MENTION] How much did you torque them...150ftlbs on the hub side and 150ftlbs on the wheel side? I happened to be waiting for mine to be delivered.

 

[West TX GT]

I did 150 on the spacer to the hub and just did 100 on the wheel to the spacer. I was worried about doing any more than that on the spacers lugs.

 

[jbailer]

I did 150 on the spacer to the hub and just did 100 on the wheel to the spacer. I was worried about doing any more than that on the spacers lugs.

This is correct, the torque goes with the lugs. Follow the torque rating for the vehicle (150 lb ft.) to bolt the adapter to the hub. Then follow the torque rating for the spacer (should be about 90-100 lb ft) to bolt the wheel to the spacer.

 

[JaxS550]

Front studs don't hit so I didn't trim those down. Rear studs we trimmed down so they wouldn't hit the inside of the rim.

I'm running the stock PP rims and pirelli tires. I know they aren't the best, but I've never heard anything like this from them. I've kept them bc I got a tire warranty too good to pass up on. I'll eventually swap them for better tires later on.

I torqued down the spacers and wheels to spec. And I actually just rechecked them all when I put new lug nuts on this week. (Replaced those stupid chrome lugs from Ford with black ones to match the PP rims)

 

[jbailer]

Front studs don't hit so I didn't trim those down. Rear studs we trimmed down so they wouldn't hit the inside of the rim.

I'm running the stock PP rims and pirelli tires. I know they aren't the best, but I've never heard anything like this from them. I've kept them bc I got a tire warranty too good to pass up on. I'll eventually swap them for better tires later on.

I torqued down the spacers and wheels to spec. And I actually just rechecked them all when I put new lug nuts on this week. (Replaced those stupid chrome lugs from Ford with black ones to match the PP rims)

The only other thing I can think of is the tire pressure, that wasn't low was it?

 

[Dsquared]

Front studs don't hit so I didn't trim those down. Rear studs we trimmed down so they wouldn't hit the inside of the rim.

I'm running the stock PP rims and pirelli tires. I know they aren't the best, but I've never heard anything like this from them. I've kept them bc I got a tire warranty too good to pass up on. I'll eventually swap them for better tires later on.

I torqued down the spacers and wheels to spec. And I actually just rechecked them all when I put new lug nuts on this week. (Replaced those stupid chrome lugs from Ford with black ones to match the PP rims)

What size spacers are you using that you had to trim the studs? I'm about to bolt on some Eibach 20mm's and have the stock PP rims.

 

[jbailer]

What size spacers are you using that you had to trim the studs? I'm about to bolt on some Eibach 20mm's and have the stock PP rims.

He listed having the 20mm spacers in the rear. Anything less than 23mm, the studs will hit the wheel when mounted if you don't modify by like trimming the studs.

 

[JaxS550]

25mm up front - no trim on studs
20mm rear - I had to trim the studs on the rear. they were sinking maybe half a mm into the rear face of the PP rims. Just enough to not make it safe.

We took off the rear spacers, put the nuts all the way on the studs, marked them where to cut, then took off the nuts to help clean up the threads as we backed them off the studs. Then we hit the newly exposed tips of the studs with a little black paint to prevent rust.

 

[Dsquared]

25mm up front - no trim on studs
20mm rear - I had to trim the studs on the rear. they were sinking maybe half a mm into the rear face of the PP rims. Just enough to not make it safe.

We took off the rear spacers, put the nuts all the way on the studs, marked them where to cut, then took off the nuts to help clean up the threads as we backed them off the studs. Then we hit the newly exposed tips of the studs with a little black paint to prevent rust.

Hey John, that's good information. About how much did you take off the studs if they were 1/2 mm too long? Did you grind or use cutoff wheel? Just want to make sure I do it right and without error. Thanks!
Edit: Ok , reading back over the posts jbailer says to cut 3mm off. Man, I should have just gone with the 25's.

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