Bad tires?

[Rich_NYS]

Tough call, and I'm afraid that I don't have a good answer for you.

If you can get a refund on the Cobras, then I'd probably just get the Toyo's. If not, and only replacement tires are offered under a warranty claim, then I'd try the replacement set of Cobras. Or, if you could get anything bearing the Cooper name under a warranty claim, then you may want to consider dropping down to a 225 in the rear and trying one of Cooper's other models.

Best luck

Thanks man....I'll go for the Toyo's if that becomes an option unless I hear that Cobra's are more prone to issues than the CS4's I have on the front.

[DMCMW Dave]

The DeLorean is VERY susceptible to imperfections especially in the front tires. This is due to a couple of things:

--it's light up there. That's why the factory pressure spec is so low, and if you run the tires slightly hard it has a much bigger impact than on a front-engine car.

--very direct steering. There is no shock-absorbing joint in the steering. The only isolation at all is the fact that the rack is mounted to the frame in rubber joints. Most cars have the rack solid mounted and then add some sort of flexible coupling.

--relatively hard bushings. Even the stock ones. Really hard on urethane bushings.

--manual steering. No damping as commonly provided by a power steering system.

One other oddity:

--alignment change - When you load up the trunk of the car, the toe in changes dramatically. This is not a problem on cars with the trunk in the rear. This itself doesn't make it more susceptible to vibration, but it is something to think about. If you have a non-lowered car, and have it aligned without weighting the front end, loading the trunk can actually move the front wheels to a toe-out position. Which is why a stock car with a fully loaded trunk handles pretty strangely on the highway. This is not a problem on a lowered DeLorean as the toe goes in on bumps when aligned correctly.


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I think one thing that leads to issues on the Coopers is age. Check the date code on the tire sidewall. Last for digits is week/year, i.e. 3212 would be week 32 of 2012. They have not made the Cobras for a couple of years, so it's likely the ones you got may have been in a warehouse for a long time and could even have been customer-returns for the same problem.

Tires also need some break-in heat cycling to stabilize. The worst thing you can do to tires is mount them on a car and then park the car for a long period of time before it's ever driven. I've seen brand new 5-year-old tires that were egg shaped from this.

[Rich_NYS]

Thanks Dave,

I'll check the date code and likely avoid the Cobras with whatever option I have. I have CS4's up front, so if I need to stick w/Coopers I'll likely get those for the rear but if possible, I'll switch to Toyo.

Uploading videos I made last night, here's the first of four I'll post from this side:

[Rich_NYS]

[Rich_NYS]

[Rich_NYS]

[NightFlyer]

Just wanted to update this thread with some valuable info:

Rich's Cobra's were made in Mexico.

I'm not sure of exactly when the transition was made, but Cooper appears to have fully transitioned the Cobra (and equivalent Hercules and Mastercraft models) over to Mexican and Chinese production facilities.

When the Cobras were made in the USA, they were a decent average tire, however, quality appears to have suffered significantly since the relocation.

I know that Dave S (DMCMW) has always said that the Cobras were difficult to balance, regardless of where they were made, but from what I've observed, the Mexican/Chinese made variants are definitely worse than the USA made variants.