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Discussion Starter · #1 ·
My 78 2+2 eats rear tires. I never realized how badly until I recently installed different size rear tires and thus don't rotate. I have some Dunlop z rated tires and after about 3,000 miles of hard cornering, very limited tire spinning, The fronts are still like new, but the rears are almost gone.
$225 ouch!

Is this normal? This is the only z I've had so I have nothing to compare to.

It takes the bumps pretty hard in the rear. I thought this was bad struts, so about a year ago, I replaced the rear struts. No change.

Could my springs be gone?

And if my springs are wasted, did I blow those crappy Gabriels within the first few miles?

Any feedback or ideas would be appreciated.

Thanks,

Matt

BTW, these Dunlops are the best performing tires I've ever run. Well worth the money even if it cost me $225 for rears every six months.
 

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> My 78 2+2 eats rear tires. I never realized
> how badly until I recently installed
> different size rear tires and thus don't
> rotate. I have some Dunlop z rated tires and
> after about 3,000 miles of hard cornering,
> very limited tire spinning, The fronts are
> still like new, but the rears are almost
> gone.
> $225 ouch!

> Is this normal? This is the only z I've had
> so I have nothing to compare to.

> It takes the bumps pretty hard in the rear.
> I thought this was bad struts, so about a
> year ago, I replaced the rear struts. No
> change.

> Could my springs be gone?

> And if my springs are wasted, did I blow
> those crappy Gabriels within the first few
> miles?

> Any feedback or ideas would be appreciated.

> Thanks,

> Matt

> BTW, these Dunlops are the best performing
> tires I've ever run. Well worth the money
> even if it cost me $225 for rears every six
> months.

where on the tire do you have wear? if the springs are bad, you will have a low ride height, which results in negative camber and toe in. the tires will be worn on the inside and be scuffed. run your hand across the tread, if you feel the bite of the tread as you pull your hand out, you have bad toe in. this will eat the tires. check the ride height. the car should be level or slightly higher in the rear. you may have ruined the struts, but more than likely their okay. check them for an oil leak.

-casper
 

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Most definetely

> My 78 2+2 eats rear tires. I never realized
> how badly until I recently installed
> different size rear tires and thus don't
> rotate. I have some Dunlop z rated tires and
> after about 3,000 miles of hard cornering,
> very limited tire spinning, The fronts are
> still like new, but the rears are almost
> gone.
> $225 ouch!

> Is this normal? This is the only z I've had
> so I have nothing to compare to.

I have the same problem. This is typical of high performance rear-wheel drive cars. Especially when they're driven hard. Accelerating out of turns (onramps, etc...)causes the most wear IMO. Imagine a tire trying to put power to the ground, at the same time it is being flexed from the turn?? That's pretty hard on any tire. The reason these probably wear out faster, is for several reasons. First of all, they are a performance tire, which means they grip good, but the compound is quite soft, which makes them wear fast. Secondly, is the way you drive. Hard acceleration and/or turning will wear them out faster than usual. Not to mention any burnouts.

I'm running 225/50/15 Dunlop D40-M2's, at all four and the grip is phenomenal. BUT, after just a little over 1 year (8000mi), the rears were almost bald. They looked like slicks!! If yours wore out at 3000mi, I would say something isn't right, or maybe you drive the car really hard. If it's even wearing, then it would indicate a normal condition. If there is uneven wear, then that would be cause for investigation. I would guess that these tires should at least last @8000-10,000mi. I've come to accept this tire wearing phenomenon, much as Porsche owners do, for they have the same exact problem. Frankly, I don't mind wearing out tires, if it keeps giving me this kind of grip. I guess it all comes down to how you drive.

240Dave
 

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Discussion Starter · #4 ·
Re: Most definetely

> I have the same problem. This is typical of
> high performance rear-wheel drive cars.
> Especially when they're driven hard.
> Accelerating out of turns (onramps,
> etc...)causes the most wear IMO. Imagine a
> tire trying to put power to the ground, at
> the same time it is being flexed from the
> turn?? That's pretty hard on any tire. The
> reason these probably wear out faster, is
> for several reasons. First of all, they are
> a performance tire, which means they grip
> good, but the compound is quite soft, which
> makes them wear fast. Secondly, is the way
> you drive. Hard acceleration and/or turning
> will wear them out faster than usual. Not to
> mention any burnouts.

> I'm running 225/50/15 Dunlop D40-M2's, at
> all four and the grip is phenomenal. BUT,
> after just a little over 1 year (8000mi),
> the rears were almost bald. They looked like
> slicks!! If yours wore out at 3000mi, I
> would say something isn't right, or maybe
> you drive the car really hard. If it's even
> wearing, then it would indicate a normal
> condition. If there is uneven wear, then
> that would be cause for investigation. I
> would guess that these tires should at least
> last @8000-10,000mi. I've come to accept
> this tire wearing phenomenon, much as
> Porsche owners do, for they have the same
> exact problem. Frankly, I don't mind wearing
> out tires, if it keeps giving me this kind
> of grip. I guess it all comes down to how
> you drive.

> 240Dave

I have the D 40 M2 as well. 225 50 15 rears 205 55 15 fronts. I couldn't find four tires of either size in town. Yes they are awsome. And yes I do drive them hard. I live four miles up a twisty (slightly bumpy) canyon road and that pretty much says it all.

I might get 6,000 miles on them before they are bald. So if that's normal, so be it.

As for casper's question about negative camber and ride height:

I think if anything it appears to be positive camber. That would be looking at it from the rear , the wheels are angled as they would if you jacked the car up, just not nearly as much.

About the toe in. I guess I could put a tape measure between the two wheels and see if there is a difference between front of tire and rear of tire.

I'll let you know.

Thanks

Matt
 

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Re: Most definetely

i have a 78 2+2 and the outsides of the tires are wearing faster than the insides.....the insides still have 1000 or so mioe sleft but the outsides are completely bald.....

they're not the best tires yokohama radial 388 but are of stack sze....could theis be a result of wornn bushings? if so how much would all new bushings (polyurethane preferably) run for the entire suspension (front and back)?

thanks in advance.
 

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Other possibilities

> I have the D 40 M2 as well. 225 50 15 rears
> 205 55 15 fronts. I couldn't find four tires
> of either size in town. Yes they are awsome.
> And yes I do drive them hard. I live four
> miles up a twisty (slightly bumpy) canyon
> road and that pretty much says it all.

> I might get 6,000 miles on them before they
> are bald. So if that's normal, so be it.

> As for casper's question about negative
> camber and ride height:

> I think if anything it appears to be
> positive camber. That would be looking at it
> from the rear , the wheels are angled as
> they would if you jacked the car up, just
> not nearly as much.

> About the toe in. I guess I could put a tape
> measure between the two wheels and see if
> there is a difference between front of tire
> and rear of tire.

> I'll let you know.

> Thanks

> Matt

I think 3000 sounds a little too fast myself. Have you considered taking it to a good alignment shop (as in not midas or another bend you over and try to take advantage of you chain shop) You could have worn bushings or a bent lower control arm. But as stated above it could be the springs causing the wrong camber. Another bad possibility is that your car was wrecked previously and it wasn't properly straigtened. I know my first Z liked to eat tires in the back though I wrote the whole car off before I ever figured out the problem.(yes I know I should hang my head in shame, but it was a rust bucket) I recall you saying you live in SLC, so Maybe try Wayne's tires wholesale on 39th south and state street The owner is an old friend of the family, and if I refer you I don't think he'd try to hose you over. (I doubt he would anyways, but email me if you want some contact info.) Also if they have a bad reputation or anything I apologize, I haven't lived in Salt Lake for 10 years so I don't really keep up on things like that.
 

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Re: Other possibilities

> I think 3000 sounds a little too fast
> myself. Have you considered taking it to a
> good alignment shop (as in not midas or
> another bend you over and try to take
> advantage of you chain shop) You could have
> worn bushings or a bent lower control arm.
> But as stated above it could be the springs
> causing the wrong camber. Another bad
> possibility is that your car was wrecked
> previously and it wasn't properly
> straigtened. I know my first Z liked to eat
> tires in the back though I wrote the whole
> car off before I ever figured out the
> problem.(yes I know I should hang my head in
> shame, but it was a rust bucket) I recall
> you saying you live in SLC, so Maybe try
> Wayne's tires wholesale on 39th south and
> state street The owner is an old friend of
> the family, and if I refer you I don't think
> he'd try to hose you over. (I doubt he would
> anyways, but email me if you want some
> contact info.) Also if they have a bad
> reputation or anything I apologize, I
> haven't lived in Salt Lake for 10 years so I
> don't really keep up on things like that.

I have the same problem when looking at the car closely the rear wheel had a lot of toe in. I upgraded to urethane bushing to strainen in up a bit. Seems to have worked well. I just need to test out a new set of tires. Hope this helps.

Sam 75 280z
 

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Discussion Starter · #8 ·
Re: TOE IN PROBLEM!!!

> I have the same problem when looking at the
> car closely the rear wheel had a lot of toe
> in. I upgraded to urethane bushing to
> strainen in up a bit. Seems to have worked
> well. I just need to test out a new set of
> tires. Hope this helps.

> Sam 75 280z

I did a crude measurement with my tape measure and yes it appears to be toeing in about a half an inch, maybe more because I'm estimating with a little bend around the exhaust pipe to pull the tape straight on the front side of the tires. I know nothing about alignments, but that seems like it would chew up tires pretty good.

There isn't an alignment adjustment for the rear, Right?

You mentioned replacing the bushings.
So if the new bushings don't do it, what's next. I don't think it was wrecked-- no signs of that, and the control arms don't look bent, either.

Any other input as to toe in????

Thanks,

Matt
 

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Re: TOE IN PROBLEM!!!

Motorsports and Victoria British sells rear camber adjustment kits I would imagine if you adjusted it a certain way it would affect the toe in. I would call motorsports and find out. I'm fixing to take mine and get an alignment done I'll get back to you on the rear toe in results of the bushings.

Sam 75 280z
 
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