Tires on trailer not square -- causing wear?

"Mike Kruger" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Is it a problem if trailer wheels are not evenly spaced?

I purchased a used two-wheel two-child trailer at a garage sale a few
months ago. It's a Winchester brand. My children are older; I just use it
for errands.

The tires (20 inch / 406, taking 50 psi) are badly worn -- down to the
cord. This seems surprising for a trailer. The wheels are not "square"
in two ways:

1. The wheels are farther apart at the ground than they are at the top of
the wheel. I suppose this was to provide stability. As a result, though,
the tires wear on one edge. This part I understand. (In fact, not having
any 406 tires handy on a Sunday night, I just reversed the tire as a
short-term fix.

2. The wheels are farther apart at the front of the trailer than at the
rear. It's hard to measure with the trailer frame in the way, but this
seems to be maybe 3/8" on each side for a total of about 3/4". I'm
thinking that this means the contact point of the tires must move a bit
closer together as the trailer moves forward, and this would result in
rapid tire wear (and slow down a trailer that's no speed demon already).

I do know that if you have a metal generator wheel on a tire generator and
don't get the generator aligned directly on a radius, it moves a bit
during the contact time and this can result in substantial sidewall wear.
I'm thinking that the trailer would work similarly.

There's no evidence this was the result of accident, since the distance is
symmetric on both sides of the trailer. I think it was designed this way,
and before I consider trying to "fix" it I'm wondering if this is a common
thing in trailers -- and, if so, why.

Mike Kruger

Well my first thought is that trailers typically have some little bit of toe
in and toe out on the wheels like you describe to help stabilize them as you
pull them down the road.
It would be needed if you are going downhill at 30mph too. Otherwise the
trailer would track poorly and be all over the place pulling you along with
it.
The inward tilt seems normal for turning stability, but it could also have
been a overload condition that bent the axle or frame a little too. Sort of
like the kids got too big for the trailer or something. So I am inclined to
beleive the inward tilt is normal.

Mike Kruger said:

Is it a problem if trailer wheels are not evenly spaced?

I purchased a used two-wheel two-child trailer at a garage sale a few months
ago. It's a Winchester brand. My children are older; I just use it for
errands.

The tires (20 inch / 406, taking 50 psi) are badly worn -- down to the cord.
This seems surprising for a trailer. The wheels are not "square" in two
ways:

1. The wheels are farther apart at the ground than they are at the top of
the wheel. I suppose this was to provide stability. As a result, though, the
tires wear on one edge. This part I understand. (In fact, not having any 406
tires handy on a Sunday night, I just reversed the tire as a short-term fix.

2. The wheels are farther apart at the front of the trailer than at the
rear. It's hard to measure with the trailer frame in the way, but this seems
to be maybe 3/8" on each side for a total of about 3/4". I'm thinking that
this means the contact point of the tires must move a bit closer together as
the trailer moves forward, and this would result in rapid tire wear (and
slow down a trailer that's no speed demon already).

I do know that if you have a metal generator wheel on a tire generator and
don't get the generator aligned directly on a radius, it moves a bit during
the contact time and this can result in substantial sidewall wear. I'm
thinking that the trailer would work similarly.

There's no evidence this was the result of accident, since the distance is
symmetric on both sides of the trailer. I think it was designed this way,
and before I consider trying to "fix" it I'm wondering if this is a common
thing in trailers -- and, if so, why.

I don't know enough about the things to say anything definitive, but I'll agree
the toe-out doesn't seem to make sense. Certainly not that much toe. It doesn't
make sense for stability or anything else I can think of. The camber could well
be sensible.

Ron

Mike Kruger said:

1. The wheels are farther apart at the ground than they are at the top of
the wheel. I suppose this was to provide stability. As a result, though, the
tires wear on one edge. This part I understand. (In fact, not having any 406
tires handy on a Sunday night, I just reversed the tire as a short-term fix.

2. The wheels are farther apart at the front of the trailer than at the
rear. It's hard to measure with the trailer frame in the way, but this seems
to be maybe 3/8" on each side for a total of about 3/4". I'm thinking that
this means the contact point of the tires must move a bit closer together as
the trailer moves forward, and this would result in rapid tire wear (and
slow down a trailer that's no speed demon already).

I'm no physics professor but the measurements you are making are the
same as the measurements used to align a car's front end and I do know
a bit about that. Your measurement number 1 is camber while number 2 is
toe out. If you'd also measured from front to back you'd have been
checking for caster.
The camber you see is almost certainly part of the intended design for
the stability you mention but the toe out is just plain wrong. As you
move forward the wheels won't toe *in* but toe *out* even more. The
result will be that your tires won't be rolling as much as dragging
along the pavement. Factor in the (apparently) extreme camber and you
have a real tire grinder. I think I'd be looking at that trailer to
figure out a way to adjust the angles.

Regards,
Bob Hunt

"Bob" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Mike Kruger said:

2. The wheels are farther apart at the front of the trailer than at the
rear. It's hard to measure with the trailer frame in the way, but this
seems
to be maybe 3/8" on each side for a total of about 3/4". I'm thinking
that
this means the contact point of the tires must move a bit closer together
as
the trailer moves forward, and this would result in rapid tire wear (and
slow down a trailer that's no speed demon already).

I'm no physics professor but the measurements you are making are the
same as the measurements used to align a car's front end and I do know
a bit about that. Your measurement number ...2 is
toe out. If you'd also measured from front to back you'd have been
checking for caster.
... the toe out is just plain wrong. As you
move forward the wheels won't toe *in* but toe *out* even more. The
result will be that your tires won't be rolling as much as dragging
along the pavement. Factor in the (apparently) extreme camber and you
have a real tire grinder. I think I'd be looking at that trailer to
figure out a way to adjust the angles.

From just the first 3 replies, I have a theory. This trailer looks like it
was designed to be shipped disassembled, which would mean it was either put
together in a shop or by the purchaser. If they installed the axles "upside
down" or reversed left and right, then the intended "toe-in", which seems to
be a good thing, would become the "toe-out" I have, which seems to be a bad
thing. It looks like I could fix this in less than an hour of disassembly /
reassembly.

Mike Kruger said:

"Bob" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Mike Kruger said:

2. The wheels are farther apart at the front of the trailer than at the
rear. It's hard to measure with the trailer frame in the way, but this
seems
to be maybe 3/8" on each side for a total of about 3/4". I'm thinking
that
this means the contact point of the tires must move a bit closer together
as
the trailer moves forward, and this would result in rapid tire wear (and
slow down a trailer that's no speed demon already).

I'm no physics professor but the measurements you are making are the
same as the measurements used to align a car's front end and I do know
a bit about that. Your measurement number ...2 is
toe out. If you'd also measured from front to back you'd have been
checking for caster.
... the toe out is just plain wrong. As you
move forward the wheels won't toe *in* but toe *out* even more. The
result will be that your tires won't be rolling as much as dragging
along the pavement. Factor in the (apparently) extreme camber and you
have a real tire grinder. I think I'd be looking at that trailer to
figure out a way to adjust the angles.

From just the first 3 replies, I have a theory. This trailer looks like it
was designed to be shipped disassembled, which would mean it was either put
together in a shop or by the purchaser. If they installed the axles "upside
down" or reversed left and right, then the intended "toe-in", which seems to
be a good thing, would become the "toe-out" I have, which seems to be a bad
thing. It looks like I could fix this in less than an hour of disassembly /
reassembly.

That makes one heck of a lot of sense.

Ron

Bob said:

Mike Kruger said:

1. The wheels are farther apart at the ground than they are at the top of
the wheel. I suppose this was to provide stability. As a result, though, the
tires wear on one edge. This part I understand. (In fact, not having any 406
tires handy on a Sunday night, I just reversed the tire as a short-term fix.

2. The wheels are farther apart at the front of the trailer than at the
rear. It's hard to measure with the trailer frame in the way, but this seems
to be maybe 3/8" on each side for a total of about 3/4". I'm thinking that
this means the contact point of the tires must move a bit closer together as
the trailer moves forward, and this would result in rapid tire wear (and
slow down a trailer that's no speed demon already).

I'm no physics professor but the measurements you are making are the
same as the measurements used to align a car's front end and I do know
a bit about that. Your measurement number 1 is camber while number 2 is
toe out. If you'd also measured from front to back you'd have been
checking for caster.

Isn't caster the forwards/backwards offset from the projection of the
steering pivot onto the ground to the contact point of the wheel?
Therefore I think it only applies to wheels that steer.

"Mike Kruger" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

"Bob" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Mike Kruger said:

2. The wheels are farther apart at the front of the trailer than at the
rear. It's hard to measure with the trailer frame in the way, but this
seems
to be maybe 3/8" on each side for a total of about 3/4". I'm thinking
that
this means the contact point of the tires must move a bit closer
together as
the trailer moves forward, and this would result in rapid tire wear (and
slow down a trailer that's no speed demon already).

I'm no physics professor but the measurements you are making are the
same as the measurements used to align a car's front end and I do know
a bit about that. Your measurement number ...2 is
toe out. If you'd also measured from front to back you'd have been
checking for caster.
... the toe out is just plain wrong. As you
move forward the wheels won't toe *in* but toe *out* even more. The
result will be that your tires won't be rolling as much as dragging
along the pavement. Factor in the (apparently) extreme camber and you
have a real tire grinder. I think I'd be looking at that trailer to
figure out a way to adjust the angles.

From just the first 3 replies, I have a theory. This trailer looks like it
was designed to be shipped disassembled, which would mean it was either
put together in a shop or by the purchaser. If they installed the axles
"upside down" or reversed left and right, then the intended "toe-in",
which seems to be a good thing, would become the "toe-out" I have, which
seems to be a bad thing. It looks like I could fix this in less than an
hour of disassembly / reassembly.

I agree, I didn't see that part about the toe in and out being reversed.
it sure does sound like the axles are on backwards.

On Mon, 25 Sep 2006 01:02:27 GMT, "Mike Kruger"
<[email hidden]> wrote [much snipped]:

Quoted message said:

Is it a problem if trailer wheels are not evenly spaced?

1. The wheels are farther apart at the ground than they are at the top of
the wheel. I suppose this was to provide stability. As a result, though, the
tires wear on one edge. This part I understand.

2. The wheels are farther apart at the front of the trailer than at the
rear. It's hard to measure with the trailer frame in the way, but this seems
to be maybe 3/8" on each side for a total of about 3/4". I'm thinking that
this means the contact point of the tires must move a bit closer together as
the trailer moves forward, and this would result in rapid tire wear (and
slow down a trailer that's no speed demon already).

There's no evidence this was the result of accident, since the distance is
symmetric on both sides of the trailer. I think it was designed this way,
and before I consider trying to "fix" it I'm wondering if this is a common
thing in trailers -- and, if so, why.

Consider how you turn at speed on a bike. You lean, and once in the
curve, your wheels are nearly straight with respect to each other. A
wheel that's leaning to one side tends to roll in a curve.

A trailer with both wheels vertical is not as stable as one with the
wheels leaning slightly inward...but when the wheels are tilted
(cambered) inwards at the top, they each will have a natural roll
tendency toward the center of the trailer. To counteract this, when a
trailer is built with cambered wheels, they are often toed out
slightly as well. Whether the toe-out is in the correct amount is
another issue.

I'd say that you probably just bought a trailer with a lot of miles on
it.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Mike Kruger wrote:

<snip>

Quoted message said:

1. The wheels are farther apart at the ground than they are at the top of
the wheel. I suppose this was to provide stability.

No, this was done because it's cheaper to build a trailer without
support for both sides of the wheel. If you look at the better trailers
such as the Burly d'lite, the Trek Doodlebug line, or the Schwinn Mark
III, you'll see that they don't have the problem you describe, because
they support the wheels properly.

SMS said:

Mike Kruger wrote:

<snip>

Quoted message said:

1. The wheels are farther apart at the ground than they are at the top of
the wheel. I suppose this was to provide stability.

No, this was done because it's cheaper to build a trailer without
support for both sides of the wheel. If you look at the better trailers
such as the Burly d'lite, the Trek Doodlebug line, or the Schwinn Mark
III, you'll see that they don't have the problem you describe, because
they support the wheels properly.

What is wrong with single-sided hubs? Most commercial trikes and some
bicycles (e.g. Cannondale Lefty) used single-sided hubs.

--
Tom Sherman - Here, not there.

Johnny Sunset aka Tom Sherman said:

What is wrong with single-sided hubs?

The original poster posted what's wrong with the single-sided hubs, the
wheels splay out at an angle, and the tires don't wear properly because
they are not contacting the pavement properly when the trailer is
loaded. I guess it's not a terribly big deal, 20" tires aren't that
expensive. Still, a Burley d'lite is very stable and doesn't have the
problem of the Winchester.

On a commercial tricycle, I think that the axle goes all the way across
through both wheels, and doesn't bend much.

On Tue, 26 Sep 2006 17:42:24 -0700, SMS <[email hidden]>

Quoted message said:

Johnny Sunset aka Tom Sherman said:

What is wrong with single-sided hubs?

The original poster posted what's wrong with the single-sided hubs, the
wheels splay out at an angle, and the tires don't wear properly because
they are not contacting the pavement properly when the trailer is
loaded. I guess it's not a terribly big deal, 20" tires aren't that
expensive. Still, a Burley d'lite is very stable and doesn't have the
problem of the Winchester.

On a commercial tricycle, I think that the axle goes all the way across
through both wheels, and doesn't bend much.

Cambered wheels make a more stable trailer, which is why I'm sure that
the OP's unit was built that way on purpose. The same tech is used on
racing wheelchairs. Although the cambered and splayed wheels do have
a higher tire wear rate than a straight and parallel setup would
provide, the wear rate is low enough (and the tires are cheap enough)
that the wear is probably viewed as an acceptable price for the
performance gain.

Whether the toe-out is correct as built is another matter, as I
originally noted.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

"SMS" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Johnny Sunset aka Tom Sherman said:

What is wrong with single-sided hubs?

The original poster posted what's wrong with the single-sided hubs, the
wheels splay out at an angle, and the tires don't wear properly because
they are not contacting the pavement properly when the trailer is loaded.
I guess it's not a terribly big deal, 20" tires aren't that expensive.
Still, a Burley d'lite is very stable and doesn't have the problem of the
Winchester.

Funny you should mention that.

I got the Winchester for practically nothing because they had bought a new
Burley to carry their two kids in. For me, it was a cheap trailer to carry
some groceries (etc.) in occasionally when I have too much for panniers. I
can fit a whole grocery cart full of stuff in there.

SMS said:

Johnny Sunset aka Tom Sherman said:

What is wrong with single-sided hubs?

The original poster posted what's wrong with the single-sided hubs, the
wheels splay out at an angle, and the tires don't wear properly because
they are not contacting the pavement properly when the trailer is
loaded. I guess it's not a terribly big deal, 20" tires aren't that
expensive. Still, a Burley d'lite is very stable and doesn't have the
problem of the Winchester.

On a commercial tricycle, I think that the axle goes all the way across
through both wheels, and doesn't bend much.

Most (non-cargo) trikes have single-sided hubs like this:

<http://www.ihpva.org/incoming/2002/Dragonflyer/df11.jpg>,
<http://www.ihpva.org/incoming/2002/Dragonflyer/df12.jpg>,
<http://www.ihpva.org/incoming/2002/Dragonflyer/df13.jpg>.

--
Tom Sherman - Here, not there.

Johnny Sunset aka Tom Sherman said:

SMS said:

On a commercial tricycle, I think that the axle goes all the way across
through both wheels, and doesn't bend much.

Most (non-cargo) trikes have single-sided hubs like this:

<http://www.ihpva.org/incoming/2002/Dragonflyer/df11.jpg>,
<http://www.ihpva.org/incoming/2002/Dragonflyer/df12.jpg>,
<http://www.ihpva.org/incoming/2002/Dragonflyer/df13.jpg>.

That's a tadpole. Most of the common upright conventional trikes use
a rear axle with only one driven wheel; design executions vary, but
"the axle goes all the way across and doesn't bend much" isn't
accurate. While the axle *assembly* goes all the way across, the hubs
are almost always supported from one side only (except on some
heavy-duty cargo trikes I've seen), and the non-drive side can be on
the end of what amounts to a stub of a front axle. The one I had back
in the late '60s (seldom used; I still don't know why it was bought)
was like that, and the ones I've seen lately don't appear to have
changed all that much.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Werehatrack said:

That's a tadpole. Most of the common upright conventional trikes use
a rear axle with only one driven wheel; design executions vary, but
"the axle goes all the way across and doesn't bend much" isn't
accurate. While the axle *assembly* goes all the way across, the hubs
are almost always supported from one side only (except on some
heavy-duty cargo trikes I've seen), and the non-drive side can be on
the end of what amounts to a stub of a front axle.

Right, but the cause of the wheels splaying on the trailer is because
each axle assembly isn't staying level. A solid axle, all the way
across, as used on industrial tricycles such as the Worksman, prevents
this from happening. If the Winchester had such an axle, the problem
that the original poster had wouldn't have happened. Of course on a
trailer, such an axle is impractical as the trailer needs to fold.

Here's what I wrote in 1994 about the Winchester:

"Two weeks ago a new freeway in California had a pre-opening
party. I've never seen so many bike trailers in one place at
a time--literally hundreds of cyclists were towing their kids
and/or dogs. It was a good chance to compare the different
types.

Most of the trailers were Burley's, but there were quite a few
Winchesters as well, one Price Club Motiv Jogger-cycle, and a
few un-named ones. I didn't see any Cannondales.

My conclusion from looking at the Winchesters is that they are
total garbage. The way the wheels are mounted, without support
on both sides of the axle for each wheel results in the wheels
splaying out at a ridiculous angle. No wonder the tires wear out
fast--only a tiny section of tread is in contact with the road."

"http://groups.google.com/group/rec.bicycles.marketplace/browse_thread/thread/3da3b3e2b619d7ee/c7a60ff424871cbd"

On Tue, 26 Sep 2006 21:19:46 -0700, SMS <[email hidden]>

Quoted message said:

Werehatrack said:

That's a tadpole. Most of the common upright conventional trikes use
a rear axle with only one driven wheel; design executions vary, but
"the axle goes all the way across and doesn't bend much" isn't
accurate. While the axle *assembly* goes all the way across, the hubs
are almost always supported from one side only (except on some
heavy-duty cargo trikes I've seen), and the non-drive side can be on
the end of what amounts to a stub of a front axle.

Right, but the cause of the wheels splaying on the trailer is because
each axle assembly isn't staying level.

The Winchester was designed with cambered wheels; it's explicitly
mentioned in their old literature. It was that way as delivered,
unloaded, new. The camber wasn't caused by loading, or lack of
support, it was caused by the intentional placement of the axles in
that orientation. Whether they got the camber and toe-out right is a
different matter.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Werehatrack said:

On Tue, 26 Sep 2006 21:19:46 -0700, SMS <[email hidden]>

Quoted message said:

Werehatrack said:

That's a tadpole. Most of the common upright conventional trikes use
a rear axle with only one driven wheel; design executions vary, but
"the axle goes all the way across and doesn't bend much" isn't
accurate. While the axle *assembly* goes all the way across, the hubs
are almost always supported from one side only (except on some
heavy-duty cargo trikes I've seen), and the non-drive side can be on
the end of what amounts to a stub of a front axle.

Right, but the cause of the wheels splaying on the trailer is because
each axle assembly isn't staying level.

The Winchester was designed with cambered wheels; it's explicitly
mentioned in their old literature. It was that way as delivered,
unloaded, new. The camber wasn't caused by loading, or lack of
support, it was caused by the intentional placement of the axles in
that orientation. Whether they got the camber and toe-out right is a
different matter.

I think that they stated that in the literature because they realized
that there was no way that they could keep the wheels straight under
load. So they cambered the wheels slightly, and when the loaded trailer
caused more camber, they could call it "normal."

"SMS" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

My conclusion from looking at the Winchesters is that they are
total garbage. The way the wheels are mounted, without support
on both sides of the axle for each wheel results in the wheels
splaying out at a ridiculous angle. No wonder the tires wear out
fast--only a tiny section of tread is in contact with the road."

"http://groups.google.com/group/rec.bicycles.marketplace/browse_thread/thread/3da3b3e2b619d7ee/c7a60ff424871cbd"

Later in that 1994 thread you wrote
"buy a Burley. I don't work for them, I just admire
an excellent product. It was worth having a baby just to be
able to buy one of their trailers."

That baby would now be a teenager. Still worth it? 😉