TULZ - Part Nine
Veeduber
Keeping Your Balance & Going Straight
When you buy new tires you always get them balanced, right? Sure you
do. Everybody does.
And you have them rebalanced as the tread wears off, right? Of course
you don't. Nobody does… except folks who like a good ride and
thousands of 'free' miles from their tires.
Here's a harder one: Did you balance your brake drums? Howzabout
your rotors? I mean, you balanced your tires, right? So when you install
a new brake drum you take it down and have it balanced, right? Okay,
so you don't balance your drums. But let me tell you why you should.
Your brake drums are castings. If the core that makes the hole for the
axle gets misaligned during the casting process the casting comes out
heavier on one side than the other. You never saw this sort of thing with
German parts but today, with most of your parts coming from Mexico and
Brazil where piece-rate labor is still common, it's a fairly frequent
occurrence. Why? When folks are paid piece-rates, quality goes out
the window. You see miscast cylinders, where the fins don't line up, and
miscast wheel cylinders and lots of miscast brake drums. Even miscast
cylinder heads. Hell of a problem.
Back in the Good Old Days, whenever that was, no auto-parts dealer
would carry such junk because no mechanic in his right mind would buy
it. But nowadays the typical buyer is a kid who shops only by price; he
doesn't know enough to tell a good part from a bad one. And the dealer
is there to fill the demand, right? Wanna guess what happens when
folks start paying good money for bad parts? GOOD PARTS vanish
from the marketplace. A basic rule of economics is that shoddy goods
will drive quality goods out of the market, a fact pointed out by Adam
Smith more than two hundred years ago.
The point of all this is that you could be driving around with wildly
imbalanced brake drums, hammering out your bearings and pounding
out your tie rods. But that's not the best part of this joke.
The punch line comes when you try to find good parts. You take your
calipers and mikes to the dealer and, if they'll allow it, you check their
stock of drums or cylinders or whatever and buy the best they have,
which are still pretty bad. THEN you gotta pay to have them balanced
and machined. By the time you get done your inexpensive parts end up
costing far more than the quality parts they've driven out of the
marketplace. Really kewl, eh? Saving all that money :-)
A nice example of this is seen in the stock muffler. Available from
Mexico, it costs about $25 while the ones made in Germany cost about
$45. Big savings, eh? Except the ones from Mexico often don't fit (!)
Mexican mufflers are famous for the misalignment of the carb heater
pipe, with buggered threads or even undrilled flanges. To make it fit
properly you have to do a bit of heating and bending and drilling and
tapping some threads. By the time that inexpensive, money-saving
muffler is installed, the bill is more than if you'd opted for the German-
made muffler. Welcome to reality :-)
But at least your wheels are straight, aren't they? Never over-torqued?
Spin in a perfect circle without the least sign of wobble? Ummm.. well…
okay. It's your ride.
STRAIGHT WHEELS
First thing you do is take off one of your front wheels, tighten up the
bearings and check to make sure the drum is true. To do that, you rig
yourself some sort of a fixture – a tool box will do – to hold a gauge, such
as that sooper-sophisticated machinist's instrument the #2 Yaller Pencil
(which is a Yellow Pencil for most folks, except it's not. Yellow. It's only
painted yellow. But there it is.)
You slowly rotate the brake drum, searching for the high spot. When you
find it, you extend the pencil to touch the drum at that point then fix the
pencil in position and rotate the drum again, this time looking for the low
spot. Ideally, you won't find one; high will be equal to low; the drum is
true. But if you DO find a low spot, and if it is more than a few
thousandths of an inch (use feeler gauges to measure the gap between
the pencil point and the brake drum), you need to take the drum to a
competent automotive machinist, explain the problem and have the
mounting surface of the drum turned perpendicular to the bore.
Once you know the run-out of your drum, mark it clearly on the drum with
chalk. Imagine the brake drum is the face of a clock. A five-hour face for
old drums or a four-hour face for newer models. Use whatever notation
you want so long as the data is clear. I show the run-out by each lug in
thousandths of an inch with a plus or minus sign. Counting around from
'noon' it might look like this: +2, +1, 0, -1, +1.5. That tells me I've got
three thou of run-out. (That is, the total magnitude of +2 plus –1.)
Anything under .005, I can live with.
Once you know the run-out of the drum you install the wheel you're going
to check, torquing it to spec in the proper criss-cross pattern. Move your
gauge to pick off the run-out from the rim of the wheel and do the above
test again, this time making notes of the run-out or if you're a slob like
me, writing on the tire with chalk. Don't be surprised if you see a LOT of
run-out. But whatever you see, you adjust the reading by the data you
recorded for the drum, adding the negative values and subtracting the
positives.
Did that come across? Let's say you gauged the wheel and recorded
two thou of run-out at the same relative location you recorded three thou
of run-out on the DRUM. Whatever your figure, part of it is the DRUM,
not the WHEEL. So you need to cancel-out the drum's run-out from the
wheel's run-out.
(What we're doing here is 'blueprinting' our rims. Since most of you
don't have massive surface plates, spin fixtures or precision instruments,
I've described a method of using a wheel as your spin fixture.)
So what can you get away with? See your manual for the exact spec but
if it's more than a sixteenth of an inch, about 1.5mm (ie, about sixty-
thou), it's too much.
What's the fix? There is none. You have to scrap the rim. Which is why
Ford and Renault and Saab and lotsa other car makers stopped using
this type of wheel. They are easily sprung and once bent, you can't
straighten them, you just keep chasing the bend around the wheel.
What causes them to become sprung? If you mean what kind of
DRIVING will spring a wide-five, cobblestones will do it. Or hitting a
good chuckhole. But you don't even have to leave your driveway to
damage your wheels. Over-torquing the lug bolts is enough to trash a
wide-five rim. Good tire shops understand this and are careful to tighten
Volkswagen wheels to the proper spec & sequence. Bad shops like to
see how fast they can destroy your rims, using pneumatic tools set for
200 ft/lbs :-) If you'll examine the wheel you'll see that each lug bolt hole
has a tapered rim. Over torquing flattens that rim and distorts the wheel.
Why is this important? Because the amount of run-out is how far the tire
travels SIDEWAYS for every revolution. (Yeah, I know. That answer
isn't scientifically correct. But it is FUNCTIONALLY ACCURATE.) So
junk the bent rims. They're causing your tires to wear out a hell of a lot
faster than they should but the real horror story is what those bent rims
are doing to your suspension and steering.
About half the VW wheels you run into are bent out of spec, thanks to
being over-torqued by idiots with pneumatic tools. To make things even
crazier, a lot of after-market rims are out of spec even when brand new!
A lot of kiddies get all bent outta shape when you tell them their wheels
are. "Oh yeah? Well, if it's such a big deal how come I never see
nothing about it in the magazines."
Good question.
The problem with 'wide-five' rims (wide six on some makes) has been
recognized since about 1937 when Ford stopped using them. Yet you
still hear a lot of instant experts telling the kiddies a bent wheel is no big
deal. Read the manual. Decide for yourself. Keep in mind that the
greater the amount of asymmetry, the greater the amount of tire wear.
You can get sixty thousand miles and more from a set of tires on a
Volkswagen with straight rims & drums. Or less than twenty thousand if
you've got a serious wobble. (And don't even THINK of pushing that
thing over 40mph or thereabouts.)
Unfortunately, with bent rims accelerated tire wear is only the tip of the
iceberg. The real problem is what happens to the rest of that sideways
energy generated by a bent rim. It is being dumped into your steering
and suspension system, literally hammering them to death. I know a kid
who was looking at his THIRD set of ball joints in six months when he
sold his bug to the next sucker in line, disgusted with 'That piece of shit.'
Alas, the only fecal matter in view was those lovingly polished chrome
rims… that wobbled so badly you could see it even from the side.
BALANCING YOUR WHEELS
A bubble balancer works fine… up to about 120 miles per hour. So why
does everyone use dynamic balancers? Two reasons: The first is cost.
It takes less time to balance a wheel with an automated dynamic
balancer. The second is also cost. You don't need any skill to run a
dynamic balancer, just watch the pretty lights and be able to count from
one to seven and know the inside of the rim from the outside. Ex-burger
flippers planning a career change are welcome at most tire shops. If
they're husky, that is :-)
Using a bubble balancer takes lots of patience and a fair degree of skill.
If you use a bubble balancer you'll need an adapter that supports a wide-
five rim. Some balancers come with such adapters (J. C. Whitney sells
one) or you can make your own using a wide-five adapter; any of them
that has a round hole in the middle. But before you start balancing
wheels you have to balance the adapter. Deburr the central hole then
take it down to the balance shop and have it balanced to a gnat's ass or
.1gm/cm, which ever is closer. Have it balanced without the hardware.
Then balance the hardware. You can do that yourself using a gram
scale. Just find the LIGHTEST of the lug bolts or nuts and file or grind
the heads of the other four to match within half a gram, plus or minus.
It's not nearly as hard as it sounds, the major problem being half of you
haven't any idea in the blue-eyed world what I'm talking about :-)
Once you have a balanced adapter you zero the balancer. To do that
you install it, permanently if possible, and true it up so the bubble is
perfectly centered or quartered or whatever indicates zero on your
particular balancer. Now you put the adapter onto the balancer and
hope the sonofabitch reads the same. It won't. But it will if you gently
raise the adapter, rotate it a few degrees and sit it back down. Keep
doing that until you find the 'sweet spot,' where the bubble is nicely
zeroed. When you do, mark that orientation on the cone & adapter and
thereafter ALWAYS place the tire in that orientation. If you NEVER find
the sweet spot, make one. Mark the orientation of the adapter to the
cone THEN zero the balancer.
When you think you've got the balancer & adapter all trued up, check.
Ask someone else to put the adapter on the cone and read the bubble.
Come to understand the significance of parallax. When you're sure the
thing is true, put a dab of fingernail polish on the adjuster screws.
To balance a wheel you bolt the adapter to the wheel, place it on the
balancer then start herding the bubble to zero by sitting balance weights
on the rim of the wheel. You'll quickly come to realize why everyone
uses those quick & easy dynamic balancing machines :-) But you should
also know that a bubble balancer can do a perfectly good job… if you do.
We're balancing our wheels because they are made out of balance. The
rim has a hole in it to accommodate the tire's valve and the tire itself is
never perfectly uniform in construction. Even at the slow speeds a tire
rotates, the moment-arm is enough so that minor imbalances can have a
major effect on how the vehicle steers and how quickly the steering
components, suspension and tires wear out.
So you make sure you have straight wheels then you balance them and
KEEP them balanced, checking them at least once a year in order to
accommodate tread wear. Get a flat? Plug the hole? Then you gotta
rebalance the wheel. No mysteries here, just simple old-fashioned Auto
Shop 101.
(John Muir's 'Idiot' book contains a nifty method of balancing your
wheels. Unfortunately, it doesn't work. But it does a nice job of
measuring the drag of your oil seal & bearings.)
TIRE TOOLS
If you do a lot of traveling in the boondocks you're probably running
tubes in your tires. Tubes are easy to patch and you don't need a Baja
Tire Pump to seat the tire back onto the rim. (Baja Tire Pump. Tubeless
tire has broken the bead. You can't pump it up. You're ninety miles from
Nowhere, the temperature is a hundred in the shade and there ain't no
shade. So you pour about two ounces of gasoline into the tire, slosh it
around, let it lay there and vaporize. Then, from a few feet upwind, you
toss the match. WHOOP! And the tire is tight to the rim. It doesn't do
the tire much good… but you can always buy another tire, assuming you
haven't died of thirst in the desert. PS – Don't set the tire on fire :-)
Patching a tubeless tire is pretty easy. You use a plug gun. J. C.
Whitney sellzem. The trick is pumping it back up. Once it's seated on
the rim both types need air.
Most of those little 12v air compressors are junk but they'll work… once
or twice. If you're a serious traveler you probably carry a bottle of high-
pressure air with a regulator, hose & tire chuck. The handiest air
compressor is hard to find nowadays. It is a tiny one-cylinder
compressor that screws into a spark plug hole. Unlike what you
generally hear, they DON'T use the fuel-air mixture to pump up the tire;
they only use the pressure of the compression stroke to drive the little
piston, which pumps outside air into the tire. Displacement is typically
one cubic inch or about 2.5 cfm at an idle but the thing will pump up to
300 psi, meaning it will fill even a big tire in a hurry. For down & dirty
reliability, include an old-fashioned MANUAL tire pump in your kit if
you're using tubes or air mattresses or whatever.
Most of your tire tools should travel as on-board spares. You need a tire
pressure gauge, some spare valve cores and valve stem caps and the
little tool that lets you remove a valve core. But the most important part
of this particular kit is the box you carry it in. The valve cores are
relatively fragile. Their small size and fragile nature often causes them to
become lost in the depths of your tool kit to become damaged by the
time you discover them. So carry them, suitably padded, in a little metal
box. I use one that sez 'Altoids' on the lid. Some kinda breath mint, I
think. A strip of tape will keep it closed. (I usta use a Prince Albert can
but it got away from me and they let the Prince outta the can years ago.).
If you plan on patching tubes you'll need tire irons and a patch kit. If you
use cold patches, replace the kit fairly often even if you don't use it. The
cement tends to evaporate and the raw rubber tends to dry out. Read
the Muir book if you've never patched a tube. For patching tubeless
tires, the instructions come with the plug gun.
GOOD TIRES
For your bug or Ghia you can get by with passenger car tires but the
Transporter is in fact a light truck and needs LT's (ie, light truck tires).
Conventional Wisdom says the VW bus gets blown all over the road.
That's bullshit. It is a high-centered, high-profile vehicle but so is a
Greyhound or a semi. How such vehicles handle side gusts is a
reflection of their suspension, steering and tires.
Like any high-profile vehicle your VW Transporter needs tires with stiff
sidewalls. In plain language that means tires with actual ply counts of
four or six. This 'Four-Ply Rating' is more bullshit, a device to sell crappy
two-ply tires to the dweebs.
Fitted with proper tires, with the steering up to spec and the front end
properly aligned, a Volkswagen bus handles cross-winds BETTER than
a lot of modern high-profile vehicles. So why the bad rep? Because
with the proper tires and shocks and no play in the steering your
Transporter will drive & feel exactly like what it is, a small truck. Yuppies
got tender asses or something; they're always talking about the 'quality'
of the ride, in which softer is better, having mistaken road-handling for
toilet paper. Trucks are trucks. Try to make it ride like a car and you'll
end up getting blown all over the road.
The typical VW on the road today is wearing the wrong tires, mounted on
bent rims bolted to brake drums that are probably out of spec with regard
to balance and run-out. The steering is sloppy and the front end
probably hasn't been aligned since Jonah was a Seaman Deuce. The
truth is, the typical VW owner has no idea how well their vehicle CAN
drive. It was in bad condition when they got it and from that day to this
they've spent most of their time making it look pretty rather than making
it run good.
-Bob Hoover
-5 May 2K
Kyle
--
Kyle
57 single cab
59 single cab
61 Kombi
67 Westfailure
57 Oval
"Veeduber" <veed...@aol.com> wrote in message
news:20000506001122...@ng-df1.aol.com...
John Connolly
Thanks Bob!
--
John Connolly
Aircooled.Net Inc.
Veeduber <veed...@aol.com> wrote in message
news:20000506001122...@ng-df1.aol.com...
> TULZ - Part Nine
>
> Keeping Your Balance & Going Straight
>
>
> When you buy new tires you always get them balanced, right? Sure you
> do. Everybody does.
>
> And you have them rebalanced as the tread wears off, right? Of course
> you don't. Nobody does. except folks who like a good ride and
> Spin in a perfect circle without the least sign of wobble? Ummm.. well.
> okay. It's your ride.
>
> STRAIGHT WHEELS
>
> First thing you do is take off one of your front wheels, tighten up the
> bearings and check to make sure the drum is true. To do that, you rig
> yourself some sort of a fixture - a tool box will do - to hold a gauge,
such
> as that sooper-sophisticated machinist's instrument the #2 Yaller Pencil
> (which is a Yellow Pencil for most folks, except it's not. Yellow. It's
only
> painted yellow. But there it is.)
>
> You slowly rotate the brake drum, searching for the high spot. When you
> find it, you extend the pencil to touch the drum at that point then fix
the
> pencil in position and rotate the drum again, this time looking for the
low
> spot. Ideally, you won't find one; high will be equal to low; the drum is
> true. But if you DO find a low spot, and if it is more than a few
> thousandths of an inch (use feeler gauges to measure the gap between
> the pencil point and the brake drum), you need to take the drum to a
> competent automotive machinist, explain the problem and have the
> mounting surface of the drum turned perpendicular to the bore.
>
> Once you know the run-out of your drum, mark it clearly on the drum with
> chalk. Imagine the brake drum is the face of a clock. A five-hour face
for
> old drums or a four-hour face for newer models. Use whatever notation
> you want so long as the data is clear. I show the run-out by each lug in
> thousandths of an inch with a plus or minus sign. Counting around from
> 'noon' it might look like this: +2, +1, 0, -1, +1.5. That tells me I've
got
> three thou of run-out. (That is, the total magnitude of +2 plus -1.)
> rims. that wobbled so badly you could see it even from the side.
>
>
>
>
> BALANCING YOUR WHEELS
>
> A bubble balancer works fine. up to about 120 miles per hour. So why
> also know that a bubble balancer can do a perfectly good job. if you do.
>
> We're balancing our wheels because they are made out of balance. The
> rim has a hole in it to accommodate the tire's valve and the tire itself
is
> never perfectly uniform in construction. Even at the slow speeds a tire
> rotates, the moment-arm is enough so that minor imbalances can have a
> major effect on how the vehicle steers and how quickly the steering
> components, suspension and tires wear out.
>
> So you make sure you have straight wheels then you balance them and
> KEEP them balanced, checking them at least once a year in order to
> accommodate tread wear. Get a flat? Plug the hole? Then you gotta
> rebalance the wheel. No mysteries here, just simple old-fashioned Auto
> Shop 101.
>
> (John Muir's 'Idiot' book contains a nifty method of balancing your
> wheels. Unfortunately, it doesn't work. But it does a nice job of
> measuring the drag of your oil seal & bearings.)
>
> TIRE TOOLS
>
> If you do a lot of traveling in the boondocks you're probably running
> tubes in your tires. Tubes are easy to patch and you don't need a Baja
> Tire Pump to seat the tire back onto the rim. (Baja Tire Pump. Tubeless
> tire has broken the bead. You can't pump it up. You're ninety miles from
> Nowhere, the temperature is a hundred in the shade and there ain't no
> shade. So you pour about two ounces of gasoline into the tire, slosh it
> around, let it lay there and vaporize. Then, from a few feet upwind, you
> toss the match. WHOOP! And the tire is tight to the rim. It doesn't do
> the tire much good. but you can always buy another tire, assuming you
> haven't died of thirst in the desert. PS - Don't set the tire on fire :-)
>
> Patching a tubeless tire is pretty easy. You use a plug gun. J. C.
> Whitney sellzem. The trick is pumping it back up. Once it's seated on
> the rim both types need air.
>
> Most of those little 12v air compressors are junk but they'll work. once