replace all 4 tires when 2 go flat? '89 cherokee
 

hey guys-so my cousin runs over a wheel/tire that some jackass drops on the
freeway. going about 80 mph, he hits it and flattens both left side tires.
got towed to Pep boys (closest place) and gets told he need to change all 4
tires because he has a 4wd car and only changing 2 could damage his
drivetrain. what do u think about this?

i say BS. shouldn't the differentials handle the slightly different tire
sizes ok (new vs old) and in the snow, the tire slipping on the snow would
take care of that too right? he's in colorado (boulder) so snow is a
concern.

they are trying to sell him a pep boy-brand tire or something else that
costs a whole lot more ($95 pepboy tire vs $150 other brand (can't remember
which). no, they don't carry bfg's

thanks!

As long as they are approximately the same size (i.e have the same numbers
on the side) and he doesn't engage 4x4 on a hard surface, I can't see there
being a problem.

Dave Milne, Scotland
'91 Grand Wagoneer, '99 TJ

"Serg" > wrote in message
...
> hey guys-so my cousin runs over a wheel/tire that some jackass drops on
the
> freeway. going about 80 mph, he hits it and flattens both left side
tires.
> got towed to Pep boys (closest place) and gets told he need to change all
4
> tires because he has a 4wd car and only changing 2 could damage his
> drivetrain. what do u think about this?
>
> i say BS. shouldn't the differentials handle the slightly different tire
> sizes ok (new vs old) and in the snow, the tire slipping on the snow would
> take care of that too right? he's in colorado (boulder) so snow is a
> concern.
>
> they are trying to sell him a pep boy-brand tire or something else that
> costs a whole lot more ($95 pepboy tire vs $150 other brand (can't
remember
> which). no, they don't carry bfg's
>
> thanks!
>
>

Serg did pass the time by typing:
> hey guys-so my cousin runs over a wheel/tire that some jackass drops on the
> freeway. going about 80 mph, he hits it and flattens both left side tires.
> got towed to Pep boys (closest place) and gets told he need to change all 4
> tires because he has a 4wd car and only changing 2 could damage his
> drivetrain. what do u think about this?
>
> i say BS. shouldn't the differentials handle the slightly different tire
> sizes ok (new vs old) and in the snow, the tire slipping on the snow would
> take care of that too right? he's in colorado (boulder) so snow is a
> concern.
>
> they are trying to sell him a pep boy-brand tire or something else that
> costs a whole lot more ($95 pepboy tire vs $150 other brand (can't remember
> which). no, they don't carry bfg's

All four tires need to be close or bad things can happen. It is more
critical on axles that have limited slip and on the front axle because
having two different sized wheels contributes to deathwobble.

Generally it's not a good idea to run different size tires on a 4wd vehicle.

Having the same size front to back is only important if you have
4wd (ft or pt) and can't run 2w.

SchlepBoys can install other vendors tires.

--
DougW

Buy four tires, or a pair of used ones to get to shop of your
preference. You'll see the difference in the way the tire supports the
car at the same air pressures and size, due to their own radial design.
I once tried to get away with putting a used tire on the other side, but
I didn't get a thousand miles before the tread separated and blew out.
God Bless America, ßill O|||||||O
http://www.billhughes.com/

Serg wrote:
>
> hey guys-so my cousin runs over a wheel/tire that some jackass drops on the
> freeway. going about 80 mph, he hits it and flattens both left side tires.
> got towed to Pep boys (closest place) and gets told he need to change all 4
> tires because he has a 4wd car and only changing 2 could damage his
> drivetrain. what do u think about this?
>
> i say BS. shouldn't the differentials handle the slightly different tire
> sizes ok (new vs old) and in the snow, the tire slipping on the snow would
> take care of that too right? he's in colorado (boulder) so snow is a
> concern.
>
> they are trying to sell him a pep boy-brand tire or something else that
> costs a whole lot more ($95 pepboy tire vs $150 other brand (can't remember
> which). no, they don't carry bfg's
>
> thanks!

If he can get the 'exact' brand and size he already has and if he has
open diffs and part time 4x4 he can get away with it.

He has to put the two new ones on the same axle if he has a limited
slip. But that brings up reversing the spin on one of the whole tires
which can cause them to explode from belt separation. (ya ya I know
'they' say new tires aren't 'supposed' to explode like that anymore, but
once bitten a dozen or more times with used tires, I just don't believe
whoever 'they' are, plus both of my Jeep owners manuals say not to cross
rotate.)

The size difference from front to rear can mean he will have 'fun'
trying to get out of 4x4 on occasion, the t-case will wind up so goosing
it in reverse might be needed to make the shifter move. If there is too
much difference in wear, then even 4 high would be useless because you
can't shift out of 4x4 on the fly if it winds up.

Putting a different brand of tire on is 'not' a good idea. Brands flex
totally different so the vehicle could either dive into a turn or skew
the arse end so it swings out unexpectedly on a turn.

My $0.02,

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Serg wrote:
>
> hey guys-so my cousin runs over a wheel/tire that some jackass drops on the
> freeway. going about 80 mph, he hits it and flattens both left side tires.
> got towed to Pep boys (closest place) and gets told he need to change all 4
> tires because he has a 4wd car and only changing 2 could damage his
> drivetrain. what do u think about this?
>
> i say BS. shouldn't the differentials handle the slightly different tire
> sizes ok (new vs old) and in the snow, the tire slipping on the snow would
> take care of that too right? he's in colorado (boulder) so snow is a
> concern.
>
> they are trying to sell him a pep boy-brand tire or something else that
> costs a whole lot more ($95 pepboy tire vs $150 other brand (can't remember
> which). no, they don't carry bfg's
>
> thanks!

thanks for the replies guys. i've copy and pasted them to an email i sent
him. he has open diffs and part time 4wd. he decided to buy 2 tires, and
put them on the same axle. he just wants to get it driving so that he can
take it to a real shop.

"Mike Romain" > wrote in message
...
> If he can get the 'exact' brand and size he already has and if he has
> open diffs and part time 4x4 he can get away with it.
>
> He has to put the two new ones on the same axle if he has a limited
> slip. But that brings up reversing the spin on one of the whole tires
> which can cause them to explode from belt separation. (ya ya I know
> 'they' say new tires aren't 'supposed' to explode like that anymore, but
> once bitten a dozen or more times with used tires, I just don't believe
> whoever 'they' are, plus both of my Jeep owners manuals say not to cross
> rotate.)
>
> The size difference from front to rear can mean he will have 'fun'
> trying to get out of 4x4 on occasion, the t-case will wind up so goosing
> it in reverse might be needed to make the shifter move. If there is too
> much difference in wear, then even 4 high would be useless because you
> can't shift out of 4x4 on the fly if it winds up.
>
> Putting a different brand of tire on is 'not' a good idea. Brands flex
> totally different so the vehicle could either dive into a turn or skew
> the arse end so it swings out unexpectedly on a turn.
>
> My $0.02,
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> Serg wrote:
> >
> > hey guys-so my cousin runs over a wheel/tire that some jackass drops on
the
> > freeway. going about 80 mph, he hits it and flattens both left side
tires.
> > got towed to Pep boys (closest place) and gets told he need to change
all 4
> > tires because he has a 4wd car and only changing 2 could damage his
> > drivetrain. what do u think about this?
> >
> > i say BS. shouldn't the differentials handle the slightly different
tire
> > sizes ok (new vs old) and in the snow, the tire slipping on the snow
would
> > take care of that too right? he's in colorado (boulder) so snow is a
> > concern.
> >
> > they are trying to sell him a pep boy-brand tire or something else that
> > costs a whole lot more ($95 pepboy tire vs $150 other brand (can't
remember
> > which). no, they don't carry bfg's
> >
> > thanks!