mixing radial and bias tires

I had to replace an old radial tire on my Dodge Ram 2500 on the right rear,
so I was without a spare for a bit. I decided to carry an old bias ply tire
I had around figuring that it was preferable to no spare in a pinch. Just
what does happen when you mix a bias and radial tire on the same axle? Is
the steering funny? Can you go slow on the shoulder of the road until you
get to a tire shop if need be? I presume that different effects would occur
if you put the mismatched pair on the front axle Vs the rear axle. I know
the rolling resistance of the radial is lower than bias so maybe on the rear
axle it works the differential spider gears a lot maybe. I have always heard
you cant/shouldn't mix the two, but never heard the reason why.

--
don paolino

On Sat, 11 Jun 2005, desperado wrote:

> I had to replace an old radial tire on my Dodge Ram 2500 on the right rear,
> so I was without a spare for a bit. I decided to carry an old bias ply tire
> I had around figuring that it was preferable to no spare in a pinch. Just
> what does happen when you mix a bias and radial tire on the same axle?

Dangerously unpredictable handling. Don't!

"desperado" > wrote in message
...
> I had to replace an old radial tire on my Dodge Ram 2500 on the right
rear,
> so I was without a spare for a bit. I decided to carry an old bias ply
tire
> I had around figuring that it was preferable to no spare in a pinch. Just
> what does happen when you mix a bias and radial tire on the same axle? Is
> the steering funny? Can you go slow on the shoulder of the road until you
> get to a tire shop if need be? I presume that different effects would
occur
> if you put the mismatched pair on the front axle Vs the rear axle. I know
> the rolling resistance of the radial is lower than bias so maybe on the
rear
> axle it works the differential spider gears a lot maybe. I have always
heard
> you cant/shouldn't mix the two, but never heard the reason why.
>

Imagine driving down the road with the car lurching back and forth.

Ted

> I had to replace an old radial tire on my Dodge Ram 2500 on the right
>rear,
> so I was without a spare for a bit. I decided to carry an old bias ply


It would work fine as a low speed spare. The different handling
characteristics between the two would make it unsafe for normal
driving though.

I would be worried about an old bias ply holding up for when put on
the truck though. That tire is probably 20 or more years old and
likely to disintegrate within a few miles.

Steve B.

Echo the thought on how old this bias ply tire must be, they went out of
common use in the 1970's. Bias ply and radial tires handle differently at
the limit of traction - under hard braking or cornering. Driving normally,
you would be hard pressed to tell the difference. But you can never predict
when you will go from normal driving to emergency driving, and mixing the
two types of tires will certainly be less predictable under emergency
conditions. I would say that mixing the two types will almost certainly be
no worse than the effect of driving on a donut spare.

Egads - "lurching back and forth" - let's not exaggerate totally out of
proportion to make a point. Yes, it's unsafe to mix on a normal basis.
It's probably a lot safer to put on this tire and get off the freeway to a
tire shop than it would be to wait on a shoulder for three hours for a
truck...

The real answer is drop into Price C;ub or wherever and pick up a tire for
50 bucks.

Brian


"Steve B." > wrote in message
...
>> I had to replace an old radial tire on my Dodge Ram 2500 on the right
>>rear,
>> so I was without a spare for a bit. I decided to carry an old bias ply
>
>
> It would work fine as a low speed spare. The different handling
> characteristics between the two would make it unsafe for normal
> driving though.
>
> I would be worried about an old bias ply holding up for when put on
> the truck though. That tire is probably 20 or more years old and
> likely to disintegrate within a few miles.
>
> Steve B.

desperado wrote:
> I had to replace an old radial tire on my Dodge Ram 2500 on the right rear,
> so I was without a spare for a bit. I decided to carry an old bias ply tire
> I had around figuring that it was preferable to no spare in a pinch. Just
> what does happen when you mix a bias and radial tire on the same axle? Is
> the steering funny? Can you go slow on the shoulder of the road until you
> get to a tire shop if need be? I presume that different effects would occur
> if you put the mismatched pair on the front axle Vs the rear axle. I know
> the rolling resistance of the radial is lower than bias so maybe on the rear
> axle it works the differential spider gears a lot maybe. I have always heard
> you cant/shouldn't mix the two, but never heard the reason why.
>

radials and bias ply tires are built differently.
(the cords run differently... look it up on google.)

As a result, they grip differently in response to steering input -
imagine an offroad tire on one side and a racing slick on the other side.

You can drive on it, but I'd recommend going to a junkyard and getting a
used radial tire for 10 bucks that looks in decent shape instead of
trusting a 20 year old mismatched tire that'll probably have gone flat
when you need it.

Ray

In article >, ray wrote:
>desperado wrote:
>> I had to replace an old radial tire on my Dodge Ram 2500 on the right rear,
>> so I was without a spare for a bit. I decided to carry an old bias ply tire
>> I had around figuring that it was preferable to no spare in a pinch. Just
>> what does happen when you mix a bias and radial tire on the same axle? Is
>> the steering funny? Can you go slow on the shoulder of the road until you
>> get to a tire shop if need be? I presume that different effects would occur
>> if you put the mismatched pair on the front axle Vs the rear axle. I know
>> the rolling resistance of the radial is lower than bias so maybe on the rear
>> axle it works the differential spider gears a lot maybe. I have always heard
>> you cant/shouldn't mix the two, but never heard the reason why.
>>
>
>radials and bias ply tires are built differently.
>(the cords run differently... look it up on google.)
>
>As a result, they grip differently in response to steering input -
>imagine an offroad tire on one side and a racing slick on the other side.
>
>You can drive on it, but I'd recommend going to a junkyard and getting a
>used radial tire for 10 bucks that looks in decent shape instead of
>trusting a 20 year old mismatched tire that'll probably have gone flat
>when you need it.

Skimping on tires is one thing I'll never be able to understand.
Considering that the only thing holding your car on the road are four
patches each roughly the size of a postcard, I'd want those patches to be
as perfect as possible and that includes the structural support for them.
The mind boggles at why some people would want to save a few tens of bucks
on old questionable tires instead of new ones.

--
/"\ Jan Kalin (male, preferred languages: Slovene, English)
\ / http://charm.zag.si/eng/, email: "name dot surname AT zag dot si"
X ASCII ribbon campaign against HTML in mail and postings.
/ \ I'm a .signature virus. Copy me to help me spread.

In article >,
desperado > wrote:
>I had to replace an old radial tire on my Dodge Ram 2500 on the right rear,
>so I was without a spare for a bit. I decided to carry an old bias ply tire
>I had around figuring that it was preferable to no spare in a pinch. Just
>what does happen when you mix a bias and radial tire on the same axle? Is
>the steering funny? Can you go slow on the shoulder of the road until you
>get to a tire shop if need be? I presume that different effects would occur
>if you put the mismatched pair on the front axle Vs the rear axle. I know
>the rolling resistance of the radial is lower than bias so maybe on the rear
>axle it works the differential spider gears a lot maybe. I have always heard
>you cant/shouldn't mix the two, but never heard the reason why.

as one poster previously noted, the tread belts run differently....
typically a 45 degrees for bias ply, and radials close to or at 90
degrees.

This results in different "slip angles" (the angular difference in the
direction the rim is pointing and the direction the contact patch
is headed). This is something you don't want to mix and match on,
you can end up with horrendous "oversteer" and a car that will snap
spin on a dime if you are forced into even a medium speed maneuver.


Slow on the shoulder straight to a repair shop? Yeah, but the $10 used
radial others have suggested, as well as the fact that your bias
ply tire is probably a tad old, is a much better option.

Missized tires on the rear end *is* another story. Even w/all radials,
a missized (diameter) tire on the drive axles will put the differential
in to a "constant differential" situation...not really too bad for
an open diff but will wear out a limited slip diff pretty quickly.
If forced to, I would take the mismatched spare and swap it with
one of the non-driveline tires, and then use that to replace the flat,
driveline tire.move that one to the flat driveline tire.


--Ken
--
Ken R. Dye '67 Bonneville ragtop "Juan": suncar
Chicago, Illinois '01 Z28 ragtop "???": funcar
www.geocities.com/MotorCity/Track/8746 '82 Chevy Z28 "Jay": racecar
dye1146 at comcast dot net '78 454 ¾ ton Suburban "Brian": towtruck

Jan Kalin wrote:
> In article >, ray wrote:
>
>>desperado wrote:
>>
>>>I had to replace an old radial tire on my Dodge Ram 2500 on the right rear,
>>>so I was without a spare for a bit. I decided to carry an old bias ply tire
>>>I had around figuring that it was preferable to no spare in a pinch. Just
>>>what does happen when you mix a bias and radial tire on the same axle? Is
>>>the steering funny? Can you go slow on the shoulder of the road until you
>>>get to a tire shop if need be? I presume that different effects would occur
>>>if you put the mismatched pair on the front axle Vs the rear axle. I know
>>>the rolling resistance of the radial is lower than bias so maybe on the rear
>>>axle it works the differential spider gears a lot maybe. I have always heard
>>>you cant/shouldn't mix the two, but never heard the reason why.
>>>
>>
>>radials and bias ply tires are built differently.
>>(the cords run differently... look it up on google.)
>>
>>As a result, they grip differently in response to steering input -
>>imagine an offroad tire on one side and a racing slick on the other side.
>>
>>You can drive on it, but I'd recommend going to a junkyard and getting a
>>used radial tire for 10 bucks that looks in decent shape instead of
>>trusting a 20 year old mismatched tire that'll probably have gone flat
>>when you need it.
>
>
> Skimping on tires is one thing I'll never be able to understand.
> Considering that the only thing holding your car on the road are four
> patches each roughly the size of a postcard, I'd want those patches to be
> as perfect as possible and that includes the structural support for them.
> The mind boggles at why some people would want to save a few tens of bucks
> on old questionable tires instead of new ones.
>
I don't skimp on tires.
However, for a spare tire that'll probably spend it's entire lifespan in
the trunk, I see no need for a new tire.
Tires don't age well...
Although, rereading the OP's question with regards to the flat, I'd
probably use the opportunity to get two new tires and use the one
remaining good one as the spare if a used tire makes him nervous.

(I especially don't skimp on performance tires. BF Drag Radials can cut
2 tenths off your 60 foot times at the drag strip. However, for the
winter truck it's not the same concern...)

On Sun, 12 Jun 2005 14:44:38 GMT, Steve B. > wrote:

>> I had to replace an old radial tire on my Dodge Ram 2500 on the right
>>rear,
>> so I was without a spare for a bit. I decided to carry an old bias ply
>
>
>It would work fine as a low speed spare. The different handling
>characteristics between the two would make it unsafe for normal
>driving though.
>

It would be at least as safe as putting the little 60 psi space saver
spare on a car and probably would actually be safer.


>I would be worried about an old bias ply holding up for when put on
>the truck though. That tire is probably 20 or more years old and
>likely to disintegrate within a few miles.
>
> Steve B.