Because of AWD, I figured when one of the tires (front left) was damaged
beyond repair that I would have to replace both. That is, due to
difference in diameter for an old and new tire, I would have to replace
both tires on each end of the axle. That was also the recommendation
from my favorite car shop and I thought that is what the Subaru dealer
said.

Just got an oil change and that car shop said that I also need to
replace the rear tires. They are older and more worn but far from
needing replacement due to tread wear (probably more than half life left
on them). Like the idea that both tires on the same axle need to be the
same diameter, the guy at this shop says that I also should have new
tires put on the back. He sells tires but not the brand on the front so
he knows he wouldn't get my business to put them on the back, and even
mentioned that. So it wasn't like he was trying to drum up a sale and
he said the fronts are brand new and there would be no reason to replace
them to get a full set of 4 and instead go back to where I got the
fronts and get the same for the rears. He claims the tranmission would
blow due to the rears spinning faster than the front because of their
reduced diameter from being much more worn, and that the tranny would
see that as slippage on the rear.

So, is it true that if you lose one tire that you end up having to buy a
whole new set of 4 tires so they all are the same starting diameter?

Vanguard wrote:

> Because of AWD, I figured when one of the tires (front left) was damaged
> beyond repair that I would have to replace both. That is, due to
> difference in diameter for an old and new tire, I would have to replace
> both tires on each end of the axle. That was also the recommendation
> from my favorite car shop and I thought that is what the Subaru dealer
> said.
>
> Just got an oil change and that car shop said that I also need to
> replace the rear tires. They are older and more worn but far from
> needing replacement due to tread wear (probably more than half life left
> on them). Like the idea that both tires on the same axle need to be the
> same diameter, the guy at this shop says that I also should have new
> tires put on the back. He sells tires but not the brand on the front so
> he knows he wouldn't get my business to put them on the back, and even
> mentioned that. So it wasn't like he was trying to drum up a sale and
> he said the fronts are brand new and there would be no reason to replace
> them to get a full set of 4 and instead go back to where I got the
> fronts and get the same for the rears. He claims the tranmission would
> blow due to the rears spinning faster than the front because of their
> reduced diameter from being much more worn, and that the tranny would
> see that as slippage on the rear.
>
> So, is it true that if you lose one tire that you end up having to buy a
> whole new set of 4 tires so they all are the same starting diameter?

Technically that is true. There are some folks who have found shops to
shave one replacement tire down to match - shaving 2 is probably a false
economy since you're wasting exactly what you paid for! new tread. Some
folks say they just run newer tires a little lower in pressure. Possibly
a dangerous idea.
According to Subaru - the tires need to be within 1/4" in circumference.
Many folks say they have gotten away with varying from that number. How
much is OK and under what conditions? who knows? The risk is damage to
the center differential which detects any difference in front/rear axle
rotation as slippage and tries to engage on dry ,straight pavement
leading to 'torque bind' and possibly subsequent damage. If you have an
automatic transmission, placing the spare fuse in the FWD postion in the
fuse box under the hood SHOULD prevent damage to the center diff.

Carl


--
to reply, change ( .not) to ( .net)

On Mar 29, 8:15 pm, Carl 1 Lucky Texan <alcky...@swbell.not> wrote:
> Vanguard wrote:
> > Because of AWD, I figured when one of the tires (front left) was damaged
> > beyond repair that I would have to replace both. That is, due to
> > difference in diameter for an old and new tire, I would have to replace
> > both tires on each end of the axle. That was also the recommendation
> > from my favorite car shop and I thought that is what the Subaru dealer
> > said.
>
> > Just got an oil change and that car shop said that I also need to
> > replace the rear tires. They are older and more worn but far from
> > needing replacement due to tread wear (probably more than half life left
> > on them). Like the idea that both tires on the same axle need to be the
> > same diameter, the guy at this shop says that I also should have new
> > tires put on the back. He sells tires but not the brand on the front so
> > he knows he wouldn't get my business to put them on the back, and even
> > mentioned that. So it wasn't like he was trying to drum up a sale and
> > he said the fronts are brand new and there would be no reason to replace
> > them to get a full set of 4 and instead go back to where I got the
> > fronts and get the same for the rears. He claims the tranmission would
> > blow due to the rears spinning faster than the front because of their
> > reduced diameter from being much more worn, and that the tranny would
> > see that as slippage on the rear.
>
> > So, is it true that if you lose one tire that you end up having to buy a
> > whole new set of 4 tires so they all are the same starting diameter?
>
> Technically that is true. There are some folks who have found shops to
> shave one replacement tire down to match - shaving 2 is probably a false
> economy since you're wasting exactly what you paid for! new tread. Some
> folks say they just run newer tires a little lower in pressure. Possibly
> a dangerous idea.
> According to Subaru - the tires need to be within 1/4" in circumference.
> Many folks say they have gotten away with varying from that number. How
> much is OK and under what conditions? who knows? The risk is damage to
> the center differential which detects any difference in front/rear axle
> rotation as slippage and tries to engage on dry ,straight pavement
> leading to 'torque bind' and possibly subsequent damage. If you have an
> automatic transmission, placing the spare fuse in the FWD postion in the
> fuse box under the hood SHOULD prevent damage to the center diff.
>
> Carl
>
> --
> to reply, change ( .not) to ( .net)- Hide quoted text -
>
> - Show quoted text -

Thanks for the reminder about the FWD fuse. I think that converts to
just FWD drive, right? I'll call the shop where we got the new front
tires to ask if they would measure the diameter of the fronts versus
rears to see if the rears are within 1/4" of the fronts. Thanks again.

On Mar 29, 11:15 pm, Carl 1 Lucky Texan <alcky...@swbell.not> wrote:
> Vanguard wrote:
> > Because of AWD, I figured when one of the tires (front left) was damaged
> > beyond repair that I would have to replace both. That is, due to
> > difference in diameter for an old and new tire, I would have to replace
> > both tires on each end of the axle. That was also the recommendation
> > from my favorite car shop and I thought that is what the Subaru dealer
> > said.
>
> > Just got an oil change and that car shop said that I also need to
> > replace the rear tires. They are older and more worn but far from
> > needing replacement due to tread wear (probably more than half life left
> > on them). Like the idea that both tires on the same axle need to be the
> > same diameter, the guy at this shop says that I also should have new
> > tires put on the back. He sells tires but not the brand on the front so
> > he knows he wouldn't get my business to put them on the back, and even
> > mentioned that. So it wasn't like he was trying to drum up a sale and
> > he said the fronts are brand new and there would be no reason to replace
> > them to get a full set of 4 and instead go back to where I got the
> > fronts and get the same for the rears. He claims the tranmission would
> > blow due to the rears spinning faster than the front because of their
> > reduced diameter from being much more worn, and that the tranny would
> > see that as slippage on the rear.
>
> > So, is it true that if you lose one tire that you end up having to buy a
> > whole new set of 4 tires so they all are the same starting diameter?
>
> Technically that is true. There are some folks who have found shops to
> shave one replacement tire down to match - shaving 2 is probably a false
> economy since you're wasting exactly what you paid for! new tread. Some
> folks say they just run newer tires a little lower in pressure. Possibly
> a dangerous idea.
> According to Subaru - the tires need to be within 1/4" in circumference.
> Many folks say they have gotten away with varying from that number. How
> much is OK and under what conditions? who knows? The risk is damage to
> the center differential which detects any difference in front/rear axle
> rotation as slippage and tries to engage on dry ,straight pavement
> leading to 'torque bind' and possibly subsequent damage. If you have an
> automatic transmission, placing the spare fuse in the FWD postion in the
> fuse box under the hood SHOULD prevent damage to the center diff.
>
> Carl
>
> --
> to reply, change ( .not) to ( .net)- Hide quoted text -
>
> - Show quoted text -

I heard the center diff. could be damaged if there were different
sized tires on fr and rr. Heard a guy went through 3 before they
figuired it out. Maybe it was long ago, or no one knew.

Didn't know there was a fuse to change the drive axles. Is that with
an Auto, or all of them?

VF

Okay, I've been through 3 different Subie owner manuals (for 1992, 2002,
and 2003) and even a Chilton repair book. I've found mention of the FWD
fuse (which was not by direct mention in the owner manuals but instead
regarding a dash light). I have yet to find out what SIZE fuse goes
into the FWD slot.

houndman@phonom.net wrote:
> On Mar 29, 11:15 pm, Carl 1 Lucky Texan <alcky...@swbell.not> wrote:
>
>>Vanguard wrote:
>>
>>>Because of AWD, I figured when one of the tires (front left) was damaged
>>>beyond repair that I would have to replace both. That is, due to
>>>difference in diameter for an old and new tire, I would have to replace
>>>both tires on each end of the axle. That was also the recommendation
>>>from my favorite car shop and I thought that is what the Subaru dealer
>>>said.
>>
>>>Just got an oil change and that car shop said that I also need to
>>>replace the rear tires. They are older and more worn but far from
>>>needing replacement due to tread wear (probably more than half life left
>>>on them). Like the idea that both tires on the same axle need to be the
>>>same diameter, the guy at this shop says that I also should have new
>>>tires put on the back. He sells tires but not the brand on the front so
>>>he knows he wouldn't get my business to put them on the back, and even
>>>mentioned that. So it wasn't like he was trying to drum up a sale and
>>>he said the fronts are brand new and there would be no reason to replace
>>>them to get a full set of 4 and instead go back to where I got the
>>>fronts and get the same for the rears. He claims the tranmission would
>>>blow due to the rears spinning faster than the front because of their
>>>reduced diameter from being much more worn, and that the tranny would
>>>see that as slippage on the rear.
>>
>>>So, is it true that if you lose one tire that you end up having to buy a
>>>whole new set of 4 tires so they all are the same starting diameter?
>>
>>Technically that is true. There are some folks who have found shops to
>>shave one replacement tire down to match - shaving 2 is probably a false
>>economy since you're wasting exactly what you paid for! new tread. Some
>>folks say they just run newer tires a little lower in pressure. Possibly
>>a dangerous idea.
>>According to Subaru - the tires need to be within 1/4" in circumference.
>>Many folks say they have gotten away with varying from that number. How
>>much is OK and under what conditions? who knows? The risk is damage to
>>the center differential which detects any difference in front/rear axle
>>rotation as slippage and tries to engage on dry ,straight pavement
>>leading to 'torque bind' and possibly subsequent damage. If you have an
>>automatic transmission, placing the spare fuse in the FWD postion in the
>>fuse box under the hood SHOULD prevent damage to the center diff.
>>
>>Carl
>>
>>--
>>to reply, change ( .not) to ( .net)- Hide quoted text -
>>
>>- Show quoted text -
>
>
> I heard the center diff. could be damaged if there were different
> sized tires on fr and rr. Heard a guy went through 3 before they
> figuired it out. Maybe it was long ago, or no one knew.
>
> Didn't know there was a fuse to change the drive axles. Is that with
> an Auto, or all of them?
>
> VF
>


Auto tranny, - it tells the ECU (or TCU?) to engage the duty solenoid C
constantly which places the center diff in FWD max bias.


if I recall correctly.

Some folks have rewired their cars to a toggle switch to 'force' FWD,
4WD or AWD at their discretion.


Carl

to reply, change ( .not) to ( .net)

Vanguard wrote:

> Okay, I've been through 3 different Subie owner manuals (for 1992, 2002,
> and 2003) and even a Chilton repair book. I've found mention of the FWD
> fuse (which was not by direct mention in the owner manuals but instead
> regarding a dash light). I have yet to find out what SIZE fuse goes
> into the FWD slot.
Pretty sure its 15A - the spare (or larger of the spares.)


Carl


--
to reply, change ( .not) to ( .net)

On Apr 3, 1:11 am, Carl 1 Lucky Texan <alcky...@swbell.not> wrote:
> hound...@phonom.net wrote:
> > On Mar 29, 11:15 pm, Carl 1 Lucky Texan <alcky...@swbell.not> wrote:
>
> >>Vanguard wrote:
>
> >>>Because of AWD, I figured when one of the tires (front left) was damaged
> >>>beyond repair that I would have to replace both. That is, due to
> >>>difference in diameter for an old and new tire, I would have to replace
> >>>both tires on each end of the axle. That was also the recommendation
> >>>from my favorite car shop and I thought that is what the Subaru dealer
> >>>said.
>
> >>>Just got an oil change and that car shop said that I also need to
> >>>replace the rear tires. They are older and more worn but far from
> >>>needing replacement due to tread wear (probably more than half life left
> >>>on them). Like the idea that both tires on the same axle need to be the
> >>>same diameter, the guy at this shop says that I also should have new
> >>>tires put on the back. He sells tires but not the brand on the front so
> >>>he knows he wouldn't get my business to put them on the back, and even
> >>>mentioned that. So it wasn't like he was trying to drum up a sale and
> >>>he said the fronts are brand new and there would be no reason to replace
> >>>them to get a full set of 4 and instead go back to where I got the
> >>>fronts and get the same for the rears. He claims the tranmission would
> >>>blow due to the rears spinning faster than the front because of their
> >>>reduced diameter from being much more worn, and that the tranny would
> >>>see that as slippage on the rear.
>
> >>>So, is it true that if you lose one tire that you end up having to buy a
> >>>whole new set of 4 tires so they all are the same starting diameter?
>
> >>Technically that is true. There are some folks who have found shops to
> >>shave one replacement tire down to match - shaving 2 is probably a false
> >>economy since you're wasting exactly what you paid for! new tread. Some
> >>folks say they just run newer tires a little lower in pressure. Possibly
> >>a dangerous idea.
> >>According to Subaru - the tires need to be within 1/4" in circumference.
> >>Many folks say they have gotten away with varying from that number. How
> >>much is OK and under what conditions? who knows? The risk is damage to
> >>the center differential which detects any difference in front/rear axle
> >>rotation as slippage and tries to engage on dry ,straight pavement
> >>leading to 'torque bind' and possibly subsequent damage. If you have an
> >>automatic transmission, placing the spare fuse in the FWD postion in the
> >>fuse box under the hood SHOULD prevent damage to the center diff.
>
> >>Carl
>
> >>--
> >>to reply, change ( .not) to ( .net)- Hide quoted text -
>
> >>- Show quoted text -
>
> > I heard the center diff. could be damaged if there were different
> > sized tires on fr and rr. Heard a guy went through 3 before they
> > figuired it out. Maybe it was long ago, or no one knew.
>
> > Didn't know there was a fuse to change the drive axles. Is that with
> > an Auto, or all of them?
>
> > VF
>
> Auto tranny, - it tells the ECU (or TCU?) to engage the duty solenoid C
> constantly which places the center diff in FWD max bias.
>
> if I recall correctly.
>
> Some folks have rewired their cars to a toggle switch to 'force' FWD,
> 4WD or AWD at their discretion.
>
> Carl
>
> to reply, change ( .not) to ( .net)- Hide quoted text -
>
> - Show quoted text -

I take it that 4WD has the same power going to all the wheels all the
time.

I have thought it would be interesting to have a car that started out
in RWD, maybe switch to 4WD, and then cruise in FWD, and then switch
to AWD when needed.

VF

"Carl 1 Lucky Texan" <alckytxn@swbell.not> wrote in message
news:lCjQh.4564$YL5.4046@newssvr29.news.prodigy.ne t...
> Vanguard wrote:
>
>> Okay, I've been through 3 different Subie owner manuals (for 1992,
>> 2002, and 2003) and even a Chilton repair book. I've found mention
>> of the FWD fuse (which was not by direct mention in the owner manuals
>> but instead regarding a dash light). I have yet to find out what
>> SIZE fuse goes into the FWD slot.
> Pretty sure its 15A - the spare (or larger of the spares.)

The FWD slot is inside the fusebox inside the engine compartment.
Inside the lid are 10, 15, and 20 amp fuses together and a 30 amp fuse
farther away. You'd think they could put the amperage fuse in the same
icon as "FWD" on the inside of the lid.

houndman@phonom.net wrote:
> On Apr 3, 1:11 am, Carl 1 Lucky Texan <alcky...@swbell.not> wrote:
>> hound...@phonom.net wrote:
>>> On Mar 29, 11:15 pm, Carl 1 Lucky Texan <alcky...@swbell.not> wrote:
>>>> Vanguard wrote:
>>>>> Because of AWD, I figured when one of the tires (front left) was damaged
>>>>> beyond repair that I would have to replace both. That is, due to
>>>>> difference in diameter for an old and new tire, I would have to replace
>>>>> both tires on each end of the axle. That was also the recommendation
>>>> >from my favorite car shop and I thought that is what the Subaru dealer
>>>>> said.
>>>>> Just got an oil change and that car shop said that I also need to
>>>>> replace the rear tires. They are older and more worn but far from
>>>>> needing replacement due to tread wear (probably more than half life left
>>>>> on them). Like the idea that both tires on the same axle need to be the
>>>>> same diameter, the guy at this shop says that I also should have new
>>>>> tires put on the back. He sells tires but not the brand on the front so
>>>>> he knows he wouldn't get my business to put them on the back, and even
>>>>> mentioned that. So it wasn't like he was trying to drum up a sale and
>>>>> he said the fronts are brand new and there would be no reason to replace
>>>>> them to get a full set of 4 and instead go back to where I got the
>>>>> fronts and get the same for the rears. He claims the tranmission would
>>>>> blow due to the rears spinning faster than the front because of their
>>>>> reduced diameter from being much more worn, and that the tranny would
>>>>> see that as slippage on the rear.
>>>>> So, is it true that if you lose one tire that you end up having to buy a
>>>>> whole new set of 4 tires so they all are the same starting diameter?
>>>> Technically that is true. There are some folks who have found shops to
>>>> shave one replacement tire down to match - shaving 2 is probably a false
>>>> economy since you're wasting exactly what you paid for! new tread. Some
>>>> folks say they just run newer tires a little lower in pressure. Possibly
>>>> a dangerous idea.
>>>> According to Subaru - the tires need to be within 1/4" in circumference.
>>>> Many folks say they have gotten away with varying from that number. How
>>>> much is OK and under what conditions? who knows? The risk is damage to
>>>> the center differential which detects any difference in front/rear axle
>>>> rotation as slippage and tries to engage on dry ,straight pavement
>>>> leading to 'torque bind' and possibly subsequent damage. If you have an
>>>> automatic transmission, placing the spare fuse in the FWD postion in the
>>>> fuse box under the hood SHOULD prevent damage to the center diff.
>>>> Carl
>>>> --
>>>> to reply, change ( .not) to ( .net)- Hide quoted text -
>>>> - Show quoted text -
>>> I heard the center diff. could be damaged if there were different
>>> sized tires on fr and rr. Heard a guy went through 3 before they
>>> figuired it out. Maybe it was long ago, or no one knew.
>>> Didn't know there was a fuse to change the drive axles. Is that with
>>> an Auto, or all of them?
>>> VF
>> Auto tranny, - it tells the ECU (or TCU?) to engage the duty solenoid C
>> constantly which places the center diff in FWD max bias.
>>
>> if I recall correctly.
>>
>> Some folks have rewired their cars to a toggle switch to 'force' FWD,
>> 4WD or AWD at their discretion.
>>
>> Carl
>>
>> to reply, change ( .not) to ( .net)- Hide quoted text -
>>
>> - Show quoted text -
>
> I take it that 4WD has the same power going to all the wheels all the
> time.
>
> I have thought it would be interesting to have a car that started out
> in RWD, maybe switch to 4WD, and then cruise in FWD, and then switch
> to AWD when needed.
>
> VF
>
Why ?