Old tires and ride quality

[DeeVeeEight]

I have some off brand Delta tires on the back of my Buick convertible that came with the car. I get a weird wobble at speeds around 35 mph that goes away then comes back rhythmically (sp?). The tires are 255/60/15's. They look good, deep tread and no cracks in the side walls. What I am wondering is could they be contributing to the wobble? They are the only "used" component left. The 4 rims, 2 front tires, all shocks, springs, trailing arms and complete front end components are new. All tires have been balanced. Am I throwing money around unnecessarily if I replace the 2 back tires? cash is a bit tight now so another $200+ dollars has to be considered carefully, especially for non essential spending.

 

[denpo]

What about switching tires front<->back just for a test. I'm no way expert, but if you hypothesis is right you should feel the wobble through the steering wheel.
Just sayin' :noob:

 

[SmokinBBC]

As Denpo says, move front to back...if it is the tire, the wobble will follow.

I had those balancing weights fall right off because the inside of the wheel was dirty. the mounting area needs to be clean.

Perhaps a bad steel belt........btw, never heard of delta...maybe a POS brand?

 

[MYBAD79]

do you have any other wheel that fits? anything with a known good tire.... Buick??? bolt pattern 4x4.75 ?? will the the vette rims fit ??

 

[MYBAD79]

Here's an example what my old tire looked like after it suddenly "failed" ... fortunately I was only going 35mph at the time, it felt like I was riding a kangaroo, not a Vette....
these tires were on the rally wheels that were on my '79 when i bought it. Age unknown.... no warning prior to failure, no warning signs at all.... tires looked good, no cracks, properly inflated.... the inner steel belt broke....


.

.

 

[mrvette]

OLD TIRES, FUGGETABOUTIT!!!!!!!

not worth losing the car over, anything over 6 years old is suspect, HIGHLY suspect......

go to Tirerack.com and look for the date code the .gov gets put on the sidewall.....

:smash:

 

[SuperBuickGuy]

I just sold one of those (hardtop version, though) - the bolt pattern is the same between your vette and buick - swap tires. 5 x 4 3/4

That said, I had a similar problem with my Buick but the first place I started was driveline angle. Make sure you driveshaft has between a 1 and 3 degree difference front/rear. If it is the same or worse flat, you need to put adjustable upper control arms. I built some, and if that's the issue - let me know, I'll point you to the thread where I did it - it's cheap to do, simply a couple of heim joints.

 

[JPhil]

OLD TIRES, FUGGETABOUTIT!!!!!!!

not worth losing the car over, anything over 6 years old is suspect, HIGHLY suspect......

go to Tirerack.com and look for the date code the .gov gets put on the sidewall.....

:smash:

My God, I agree with Gene. Wow. Whoda ever thunk. Old tires can really mess with you.

Check the wheels for true as well. Old wheels have hit a few curbs.......& the kids at Big O have no clue about "balance" versus "true".

 

[DeeVeeEight]

Good feedback from all, and yes OMG! we can all seemingly agree with Gene at the same time (angels singing).
I suspect a belt has shifted or that there is a bulge or flat spot somewhere. As soon as $$$ allows I will get a set of Firestones to match the pair on the front. BTW - I can not swap tires back to front - I did the old school thing and put wider tires on the rear.

 

[SmokinBBC]

Good feedback from all, and yes OMG! we can all seemingly agree with Gene at the same time (angels singing).
I suspect a belt has shifted or that there is a bulge or flat spot somewhere. As soon as $$$ allows I will get a set of Firestones to match the pair on the front. BTW - I can not swap tires back to front - I did the old school thing and put wider tires on the rear.

Won't the rears fit under the front? Not even for a short ride?

 

[TimAT]

A broken belt will cause exactly what you describe. And some are nearly impossible to see. One other option is your local tire shop, they might be able to run them on a spin balance and find the bad one.

 

[mrvette]

A broken belt will cause exactly what you describe. And some are nearly impossible to see. One other option is your local tire shop, they might be able to run them on a spin balance and find the bad one.

Jack the SOB up, spin the tires by hand or drive, long as it turns SLOWLY enough you can clearly see.....if you see rough circumference, it's bad, if you let air out you will certainly see rough circumference to any defective tire..... they WILL show flat, maybe not so much full of air.....

 

[DeeVeeEight]

Good feedback from all, and yes OMG! we can all seemingly agree with Gene at the same time (angels singing).
I suspect a belt has shifted or that there is a bulge or flat spot somewhere. As soon as $$$ allows I will get a set of Firestones to match the pair on the front. BTW - I can not swap tires back to front - I did the old school thing and put wider tires on the rear.

Won't the rears fit under the front? Not even for a short ride?

It would look like a ricer. I could not show my face in public after that.

Once I get back into my house (only 3 more weeks!) I will have a full set of wheels from the Corvette (I have all 4 original rims with tires on them). I will install two on the rear of the Buick and see what gives.
Thanks again for the ideas!

 

[MYBAD79]

It would look like a ricer. I could not show my face in public after that.

haha... I've got two 15X8 rims with 295-50 tires, just in case you need more grip for your FWD..... lol

 

[JeffP1167]

Thingswith big butts always wobble

 

[DeeVeeEight]

Thingswith big butts always wobble

Sometimes that is good, sometimes not.

Makes me think of the saying "All soft and bumpy in the right places".