what is "ply"?
 

Doing tire research, I looked back through the google archives. There
is a lot of talk about Thornbirds being 2-ply, some tires being
bias-ply, others being other kinds of "ply." I am not familiar with
this term... could someone tell me briefly what it means?

Re: what is "ply"?
 

layer of material

Re: what is "ply"?
 

layer of material

Re: what is "ply"?
 

layer of material

Re: what is "ply"?
 

The 'plies' are the layers or belts that are inside the tires.

A heavy duty truck tire can be 8 'ply' which means there are 8 different
layers of belts in the sidewalls.

A Thornbird you say only has 2 plies.

The cheap BFG second line of mud tires, the Mud King's, only have 2
sidewall plies, real BFG muds have 3 sidewall plies.

This makes the sidewall much stronger and much more resistant to pinches
or perforations. It also makes it less flexible under full air
pressure.

So a 2 ply tire will lean into turns and dive the front end down way
more than a 3 ply sidewall or 8 ply one will do on the street.

Some tires will also list X number of plies for the tread and X # of
plies for the sidewall.

Bias ply means the belts go sideways at something like 20-45 deg across
the tire alternating zig zag front to back where radial plies go
straight across in a 90 deg to the rim or in line with the tire
'radius'.

Radial tires flex way more and couldn't work until technology improved
back in the 70's I think it was.

That is why bias ply tires should be rotated in a cross pattern, because
the belts go both ways, so the best wear is had my making them turn the
opposite way by flipping them side to side.

A steel belted radial will 'break in' the belts in the rotation they
were installed in and can and 'will' blow a belt if crossed in a
rotation so they spin the opposite direction.

'Modern' radials are 'supposed' to be able to be cross rotated according
to the tire makers, the same folks that want to sell you new ones
remember, eh....

Meanwhile, 'both' of my original Jeep owners manuals state point blank
to only rotate the tires front to back with radials, if you want to
rotate the spare in, it goes on the right rear, because the right rear
is the highest wear tire. It is the default power wheel for a stock
open diff. Dump the clutch and the right rear is always the one to
spin. The right front goes to the spare, then back to the right rear on
the next rotation. The left side only ever rotates front to back.

That is the main reason I only have a used BFG AT as a spare for my BFG
mud tires. As a spare, I am only going to use it to get to a place to
fix my 'expensive' tire so I don't give a ---- what side it has to go on
if I get a flat and it blows a belt as a spare. I can get another for
the cost of mounting it.

I just tossed 10 tires out of my garage, all with good tread and belts
that had let go. I bought the tires used from the scrap yard cheap with
the 50/50 factor if I could guess which way they were previously
installed.

I bought my Cherokee in 99 with 'modern' radial tires on it that were
cross rotated, and one blew a belt out. They were Hercules 'Terra Trac'
tires.

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

Joshua Nelson wrote:
>
> Doing tire research, I looked back through the google archives. There
> is a lot of talk about Thornbirds being 2-ply, some tires being
> bias-ply, others being other kinds of "ply." I am not familiar with
> this term... could someone tell me briefly what it means?

Re: what is "ply"?
 

The 'plies' are the layers or belts that are inside the tires.

A heavy duty truck tire can be 8 'ply' which means there are 8 different
layers of belts in the sidewalls.

A Thornbird you say only has 2 plies.

The cheap BFG second line of mud tires, the Mud King's, only have 2
sidewall plies, real BFG muds have 3 sidewall plies.

This makes the sidewall much stronger and much more resistant to pinches
or perforations. It also makes it less flexible under full air
pressure.

So a 2 ply tire will lean into turns and dive the front end down way
more than a 3 ply sidewall or 8 ply one will do on the street.

Some tires will also list X number of plies for the tread and X # of
plies for the sidewall.

Bias ply means the belts go sideways at something like 20-45 deg across
the tire alternating zig zag front to back where radial plies go
straight across in a 90 deg to the rim or in line with the tire
'radius'.

Radial tires flex way more and couldn't work until technology improved
back in the 70's I think it was.

That is why bias ply tires should be rotated in a cross pattern, because
the belts go both ways, so the best wear is had my making them turn the
opposite way by flipping them side to side.

A steel belted radial will 'break in' the belts in the rotation they
were installed in and can and 'will' blow a belt if crossed in a
rotation so they spin the opposite direction.

'Modern' radials are 'supposed' to be able to be cross rotated according
to the tire makers, the same folks that want to sell you new ones
remember, eh....

Meanwhile, 'both' of my original Jeep owners manuals state point blank
to only rotate the tires front to back with radials, if you want to
rotate the spare in, it goes on the right rear, because the right rear
is the highest wear tire. It is the default power wheel for a stock
open diff. Dump the clutch and the right rear is always the one to
spin. The right front goes to the spare, then back to the right rear on
the next rotation. The left side only ever rotates front to back.

That is the main reason I only have a used BFG AT as a spare for my BFG
mud tires. As a spare, I am only going to use it to get to a place to
fix my 'expensive' tire so I don't give a ---- what side it has to go on
if I get a flat and it blows a belt as a spare. I can get another for
the cost of mounting it.

I just tossed 10 tires out of my garage, all with good tread and belts
that had let go. I bought the tires used from the scrap yard cheap with
the 50/50 factor if I could guess which way they were previously
installed.

I bought my Cherokee in 99 with 'modern' radial tires on it that were
cross rotated, and one blew a belt out. They were Hercules 'Terra Trac'
tires.

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

Joshua Nelson wrote:
>
> Doing tire research, I looked back through the google archives. There
> is a lot of talk about Thornbirds being 2-ply, some tires being
> bias-ply, others being other kinds of "ply." I am not familiar with
> this term... could someone tell me briefly what it means?

Re: what is "ply"?
 

The 'plies' are the layers or belts that are inside the tires.

A heavy duty truck tire can be 8 'ply' which means there are 8 different
layers of belts in the sidewalls.

A Thornbird you say only has 2 plies.

The cheap BFG second line of mud tires, the Mud King's, only have 2
sidewall plies, real BFG muds have 3 sidewall plies.

This makes the sidewall much stronger and much more resistant to pinches
or perforations. It also makes it less flexible under full air
pressure.

So a 2 ply tire will lean into turns and dive the front end down way
more than a 3 ply sidewall or 8 ply one will do on the street.

Some tires will also list X number of plies for the tread and X # of
plies for the sidewall.

Bias ply means the belts go sideways at something like 20-45 deg across
the tire alternating zig zag front to back where radial plies go
straight across in a 90 deg to the rim or in line with the tire
'radius'.

Radial tires flex way more and couldn't work until technology improved
back in the 70's I think it was.

That is why bias ply tires should be rotated in a cross pattern, because
the belts go both ways, so the best wear is had my making them turn the
opposite way by flipping them side to side.

A steel belted radial will 'break in' the belts in the rotation they
were installed in and can and 'will' blow a belt if crossed in a
rotation so they spin the opposite direction.

'Modern' radials are 'supposed' to be able to be cross rotated according
to the tire makers, the same folks that want to sell you new ones
remember, eh....

Meanwhile, 'both' of my original Jeep owners manuals state point blank
to only rotate the tires front to back with radials, if you want to
rotate the spare in, it goes on the right rear, because the right rear
is the highest wear tire. It is the default power wheel for a stock
open diff. Dump the clutch and the right rear is always the one to
spin. The right front goes to the spare, then back to the right rear on
the next rotation. The left side only ever rotates front to back.

That is the main reason I only have a used BFG AT as a spare for my BFG
mud tires. As a spare, I am only going to use it to get to a place to
fix my 'expensive' tire so I don't give a ---- what side it has to go on
if I get a flat and it blows a belt as a spare. I can get another for
the cost of mounting it.

I just tossed 10 tires out of my garage, all with good tread and belts
that had let go. I bought the tires used from the scrap yard cheap with
the 50/50 factor if I could guess which way they were previously
installed.

I bought my Cherokee in 99 with 'modern' radial tires on it that were
cross rotated, and one blew a belt out. They were Hercules 'Terra Trac'
tires.

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

Joshua Nelson wrote:
>
> Doing tire research, I looked back through the google archives. There
> is a lot of talk about Thornbirds being 2-ply, some tires being
> bias-ply, others being other kinds of "ply." I am not familiar with
> this term... could someone tell me briefly what it means?

Re: what is "ply"?
 

Ply means layers.

Plywood is wood that is layered. Plys on tires are similar. The plies can
run around the circumference tire, and they are called bias plys when they
do this. Radial plies run across the tire.

2 ply tires have 2 plies, 3 ply tires have three plies. The higher number of
plies is presumably stronger, or stiffer, but if the plies are thinner, they
might not be stronger.



"Joshua Nelson" <spam_box@ev1.net> wrote in message
news:b102b6e4.0310071232.35d89abc@posting.google.c om...
> Doing tire research, I looked back through the google archives. There
> is a lot of talk about Thornbirds being 2-ply, some tires being
> bias-ply, others being other kinds of "ply." I am not familiar with
> this term... could someone tell me briefly what it means?

Re: what is "ply"?
 

Ply means layers.

Plywood is wood that is layered. Plys on tires are similar. The plies can
run around the circumference tire, and they are called bias plys when they
do this. Radial plies run across the tire.

2 ply tires have 2 plies, 3 ply tires have three plies. The higher number of
plies is presumably stronger, or stiffer, but if the plies are thinner, they
might not be stronger.



"Joshua Nelson" <spam_box@ev1.net> wrote in message
news:b102b6e4.0310071232.35d89abc@posting.google.c om...
> Doing tire research, I looked back through the google archives. There
> is a lot of talk about Thornbirds being 2-ply, some tires being
> bias-ply, others being other kinds of "ply." I am not familiar with
> this term... could someone tell me briefly what it means?

Re: what is "ply"?
 

Ply means layers.

Plywood is wood that is layered. Plys on tires are similar. The plies can
run around the circumference tire, and they are called bias plys when they
do this. Radial plies run across the tire.

2 ply tires have 2 plies, 3 ply tires have three plies. The higher number of
plies is presumably stronger, or stiffer, but if the plies are thinner, they
might not be stronger.



"Joshua Nelson" <spam_box@ev1.net> wrote in message
news:b102b6e4.0310071232.35d89abc@posting.google.c om...
> Doing tire research, I looked back through the google archives. There
> is a lot of talk about Thornbirds being 2-ply, some tires being
> bias-ply, others being other kinds of "ply." I am not familiar with
> this term... could someone tell me briefly what it means?