Two different tire heights - car shaking!

[sickem]

So last week one my rear 305/35/19 sport cup 2s got a nail in it. Since this tire size is backordered I mounted two 305/30/19 sport cup 2s on the back. Fronts are 295/35/19. I got out on the highway today and gave it the beans. The rear of the car started shaking badly to the point where I felt like the wheels were gonna come off! I pulled over and retorqued the lug nuts but they weren't loose.

EDIT: When I got home I did notice a pair of the tire weights on my driveway...

Would this be due to the two different height tires, or did the shop that put them on just fail miserably in balancing them??? Thanks for your help.

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[BigR4444]

I'm no tire expert, but keep this in mind..
305/35/19 and 295/35/19 are NOT the same height.
The "aspect ratio" is a percentage of the tires width... so 35% of 305mm and 35% of 295mm are not the same number... So I think you'll have slightly different heights no matter what you go with.
I don't think the small difference in sidewall height would cause a problem like that... but I could be wrong.

 

[Tony_the_Brit]

The weights likely fell off. They need to clean the rims with alcohol before sticking on weights as brake dust kills the adhesive.

 

[sickem]

I'm no tire expert, but keep this in mind..
305/35/19 and 295/35/19 are NOT the same height.
The "aspect ratio" is a percentage of the tires width... so 35% of 305mm and 35% of 295mm are not the same number... So I think you'll have slightly different heights no matter what you go with.
I don't think the small difference in sidewall height would cause a problem like that... but I could be wrong.

yes they're definitely different heights and I knew that going in. Based on an online tire height calculator they're 1.2" height difference. But that's why I swapped out both rears to the same aspect ratio. So, 30 in the back, 35 in the front.

 

[sickem]

The weights likely fell off. They need to clean the rims with alcohol before sticking on weights as brake dust kills the adhesive.

yes, i found two in my driveway (facepalm). I am flying down for Track Attack this Monday so when I get back I'll take the car back to the shop...I'm pretty pissed as I even bought them donuts LOL

 

[Postal Bob]

Sounds like your tires are no longer balanced.

 

[BigR4444]

Man... would those weights coming off really cause something so dramatic?

This is something I've thought about while considering buying a set of aftermarket wheels...

I went with a wheel and tire package from Tirerack a few years back on my Altima. Loved the look, but after a while a bunch of weights were missing off all 4.

Probly wouldn't buy from them again specifically for that reason. But would I have the same problem with fitment industries or some other site?
And if I bought everything myself and had a tire shop mount and balance them for me, would they do a half ass job as well?

Meanwhile the weights on my OEM wheels remain unfazed.

Is it common for wheel weights to fall off, or is this something that shouldn't be allowed to happen?

 

[Inthehighdesert]

The different heights front and rear matters zero. Simply losing a 1/2 ounce weight will do what your describing. It can be even more pronounced from side to side. They may not of done the balance perfectly to start either. This is one, as is convenience, the main reason I bought a tire machine and balancer.

Added: There is a difference in the adhesive on weights as well. But most often its a poorly prepped surface.

 

[shogun32]

This is one, as is convenience, the main reason I bought a tire machine and balancer.

what's the kind of rig run you?

 

[Inthehighdesert]

I purchased a chinese manufactured setup. Its pretty decent for the money. Takes some getting used to for 30 and 35 series tires. For everything else works really well.

what's the kind of rig run you?

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