Wheel truing with dial indicators

[Robin Hubert]

"Matt O'Toole" <[email protected]> wrote in message
news:[email protected]...
>
> "stu" <[email protected]> wrote in message news:[email protected]...
>
> > >Does anyone know why bikes are made with the right hand
> brake
> > >controlling the rear wheel? Most of us are right handed
> and would
> > >have better control if the right hand lever operated the
> front brake,
> > >in my opinion. But I digress.
>
> > move to Australia, we use right hand front brake. as to
> the reason l have
> > heard it has something to do with what side of the road
> you ride on, but as
> > far as l know no one has figured out for sure why some
> drive on the right
> > and some on the left so fell free to come up with your owe
> theory
>
> This horse has been beaten to a pulp here. I beleive it's in the FAQ too. Please try a Google
> search rather than start up another discussion about it! Please, oh please!
>

The truth is, just about every topic known to man regarding bicycling has been beaten to death here.
If old saws weren't re-sharpened, this newsgroup would be dead.

Robin Hubert

 

[Steven L. Sheff]

in article [email protected], [email protected] at
[email protected] wrote on
02/17/2003 12:18 AM:

> Shane Stanley writes:
>
>>> Depending on what sort of brakes and pad clearance you use, lateral alignment between +-0.005
>>> is fine.
>
>> What units are you using there?
>
> Oh how clever. What else? Did you perhaps think millimeters, nanometers, or Angstroms. This
> reminds me of Snap-on Tools changing their metric wrench markings to, for instance, to 10MM
> instead of 10, so the American will know it's not a 10inch end wrench, much less a 30inch on a
> large one. Lower case m's were not good enough either, while English sizes were not changed to
> show that they are in inches. I guess for some folks a 25x error is easy to make when measuring or
> selecting tools.

Listen, ****wad --

+-0.005 inches would be considered by most to be extremely accurate. +-0.005 mm is even
more accurate.

Can you visually tell the difference between 0.005 inches and 0.0001968 inches?

No? Neither can I.

That's why people use precision measuring tools, dipshit. As an engineer, you should know this and
know how important it is to specify units in measurements.

After all, some NASA engineer made a mistake converting units a couple years back which caused a
launched satellite to get mispositioned ... it became a multi-billion dollar pile of space-junk
simply because somebody didn't double-check the units of measurement.

Brown & Sharpe makes dial indicators accurate to 0.00005" ... that's
03/100,000 inches or 0.00127 mm, which is far more accurate than the +-0.005 "units" you suggest,
but refuse to elaborate on.

In case you have trouble figuring it out, the dial indicator I'm referring to is 100 times more
accurate than 0.005", and 3.9370078 times more accurate than 0.005 mm.

So which is it, Jobst?

Inches or millimetres?

--

Steven L. Sheffield stevens at veloworks dot com veloworks at worldnet dot ay tea tee dot net bellum
pax est libertas servitus est ignoratio vis est ess ay ell tea ell ay kay ee sea aye tee why you ti
ay aitch aitch tee tea pea colon [for word] slash [four ward] slash double-you double-yew double-ewe
dot veloworks dot com [four word] slash

 

[Jt]

"Steve Shapiro" <[email protected]> wrote in message
news:[email protected]...

>
> Does anyone know why bikes are made with the right hand brake controlling the rear wheel? Most of
> us are right handed and would have better control if the right hand lever operated the front
> brake, in my opinion. But I digress.
>

The right gear lever controls (usually) the rear mechanism. When stopping, one finds it more
convenient to shift down with the right and brake with the left, as there is (again, usually) a
greater gear variation possible with the rear mech.

But there are, as Churchill said, all kinds <of right/left brake
arrangements>.

 

[John Albergo]

Saltytri wrote:

>I just put together a truing stand with dial indicators for radial and lateral truing. Also, a dish
>tool with a dial indicator. (No flames on this, please - I know that some will say that this level
>of precision is overkill but I like making things.) While Jobst's fine book suggests that dial
>indicators have some value, I haven't found any reference that tells me what level of truing and
>dish accuracy is considered acceptable.
>
Probably because it's a matter of personal preference. One could say as long as you can spin the
wheel without the brakes rubbing, that's close enough. Hell, even a little brake rub isn't the end
of the world. So, to quote from Cool Hand Luke, "It's all up to You".

Most people's sense of "quality" is going to lead to better trueness than the above anyway. Given
that, you should probably focus more on stress relief, even tension and good spoke line. A wheel
with 1mm deviation but otherwise sound will stay that way for a long time. A wheel can be built to
near perfect trueness but ignoring the other factors can self-destruct on the first ride.

This is why a dial indicator is not of much use, in my opinion. We're not machining a bearing
surface -- again, we're only trying to "fit" inside the brake shoes, and maybe a bit better than
that, to have smooth braking. Radially, we want to prevent any feeling of "hop" and the same level
of accuracy works there too. A visual (and auditory) observation with a fixed reference tells you as
much as you need to know to get the wheel WAY more than true enough. All else is vanity.

> I don't have enough experience to know by look/feel/calipers when a wheel is considered good
> enough so I can't translate build quality by those more subjective standards into objective
> measurement criteria. What are reasonable targets in thousanths?
>
.001M

 

[E & V Willson]

I have trued wheels to +-0.004" (0.1 mm) in both hop and wobble (radial and lateral) using magnetic
bases to hold dial indicators on the chain stays. Then I bought a truing stand. The stand
instructions suggest that all that is necessary is +- 1/2 mm (0.020") for both hop and wobble. Since
getting the stand the +- 1/2 mm has been my standard, with no noticabable difference in performance
from the earlier 0.004". HTH

Ernie

Saltytri wrote:

> I just put together a truing stand with dial indicators for radial and lateral truing. Also, a
> dish tool with a dial indicator. (No flames on this, please - I know that some will say that this
> level of precision is overkill but I like making things.) While Jobst's fine book suggests that
> dial indicators have some value, I haven't found any reference that tells me what level of truing
> and dish accuracy is considered acceptable. I don't have enough experience to know by
> look/feel/calipers when a wheel is considered good enough so I can't translate build quality by
> those more subjective standards into objective measurement criteria. What are reasonable targets
> in thousanths?

 

[Cbike]

I've been using a dial indicator for wheel truing for the past year and wouldn't go back. Once on to
a technique I find it speeds the time considerably in truing. I shoot for 0.010" which is relatively
quick to get to.

Charlie

 

[Benjamin Weiner]

Frank Krygowski <[email protected]> wrote:
> Jon Isaacs wrote:

>> Ten years ago I had a "mechanical engineering" student working in my (Materials Science) Lab
>> as a helper. One day I sent him out to change the spark plugs in the old beater van and gave
>> him the plugs and wrenches. He came back about an hour later and hadn't been able to find the
>> spark plugs.

> ... He said "What is it??" "It's your ignition lead." "What do I do with it?" "You put it between
> your coil and your distributor." "What's a coil? What's a distributor?" Some engineers are much
> better at partial differential equations than they are at elementary common knowledge.

Hey you hosers,

This is a BICYCLE newsgroup. Cars are not necessarily elementary common knowledge. There is a
tradition of young people (often men) learning by dinking around with cars in their adolescence, but
not everybody does that.

I am mechanically inclined, but I grew up in a city and didn't learn to drive until the age of 21.
(We had a car, I just didn't need to drive it for the independence.) I taught myself to fix a broken
bicycle axle before I learned to change a spark plug. Cars are also big, expensive and intimidating,
and many people simply do not want to mess around under the hood.

Modern cars are also less amenable to shade-tree repair (and more reliable so you don't need to
bother). My current car doesn't even have a distributor. Geez-, uh, veteran engineers might want to
keep this in mind next time they are inclined to lament the mechanical inability of the younger
generation.

Despite occasional noises about the passing of the Good Old Days, bicycles have not evolved nearly
as far as cars in the direction of home inserviceability; most repairs can still be effected with
simple hand tools. (I guess cartridge BBs, STI levers, and some boutique wheels to be the
exceptions.)

 

[Jobst Brandt]

Benjamin Weiner writes:

> This is a BICYCLE newsgroup. Cars are not necessarily elementary common knowledge. There is a
> tradition of young people (often men) learning by dinking around with cars in their adolescence,
> but not everybody does that.

It's not cars but machines that interest mechanically attuned people. Some people do not recognize
that we are surrounded by machines and tools, be they child's toys or kitchen mixers. They all
deserve scrutiny by the future engineer or household mechanic.

> I am mechanically inclined, but I grew up in a city and didn't learn to drive until the age of 21.
> (We had a car, I just didn't need to drive it for the independence.) I taught myself to fix a
> broken bicycle axle before I learned to change a spark plug. Cars are also big, expensive and
> intimidating, and many people simply do not want to mess around under the hood.

I don't share your perception of a mechanically inclined person. I for one, with friends, repaired
cars long before I was old enough for a learner's license. It was fixing household equipment and
vehicles that I got my engineering education that was formalized later with the underlying science
in school.

> Modern cars are also less amenable to shade-tree repair (and more reliable so you don't need to
> bother). My current car doesn't even have a distributor. Geez-, uh, veteran engineers might want
> to keep this in mind next time they are inclined to lament the mechanical inability of the younger
> generation.

That is true, but for that there are many more machines that can be fixed and they need not be cars.
However, a former service manager at a major auto mechanic shop told me recently that when his car
stops, all he can do is call the towing service, trivial parts no longer failing in new cars. That
doesn't mean that we don't know how the car works. I have never worked on a diesel engine,
caterpillar or railroad, but don't find their workings foreign. The same goes for steam engines.

> Despite occasional noises about the passing of the Good Old Days, bicycles have not evolved nearly
> as far as cars in the direction of home inserviceability; most repairs can still be effected with
> simple hand tools. (I guess cartridge BBs, STI levers, and some boutique wheels to be the
> exceptions.)

That is primarily the case because the motor, the human being on the bicycle is the main failure
component. I hope not to see more electronic or more complex hardware on bicycles because they don't
improve the bicycle. The shape of ball bearings and parts are not going to change visibly,
regardless of how hard manufacturers try to make them more "space aged".

Jobst Brandt [email protected] Palo Alto CA

 

[Kraig Willett]

"Lindsay Rowlands" <[email protected]> wrote in message
news:[email protected]...
> I don't buy Jobst's version of brake pads rubbing on rims. Curiously, my single pivoted bike
> climbs just as easily as my dual pivoted one. Sounds like bicycle folklore.

What don't you buy, that rims rub brakes, or, that racers open up their rear brakes?

I can definitively comment on the rub issue, since I made the physical measurements with a dial
indicator while riding.

It depends on the wheel, of course, but many of today's low spoke/lightweight wheels rub pads.

The measurements I made were published in this online magazine article:

http://tinyurl.com/6424

--
==================
Kraig Willett www.biketechreview.com
==================

 

[Kraig Willett]

Back when I used to work in the wheel industry (3 years ago now - whew, how time flies!), the spec
we enforced was in the 0.012" TIR range.

--
==================
Kraig Willett www.biketechreview.com
==================

 

[David Damerell]

Benjamin Weiner <[email protected]> wrote:
>Frank Krygowski <[email protected]> wrote:
>>... He said "What is it??" "It's your ignition lead." "What do I do with it?" "You put it between
>>your coil and your distributor." "What's a coil? What's a distributor?" Some engineers are much
>>better at partial differential equations than they are at elementary common knowledge.
>This is a BICYCLE newsgroup. Cars are not necessarily elementary common knowledge.

Are they to me? No; I don't drive and I don't generally live with motorists.

[That said, even I know what the parts in Frank Krygowski's anecdote are, although I couldn't
recognise them.]

But the anecdote is not about any average person; it's about an engineer who owned a motor car.
--
David Damerell <[email protected]> flcl?

 

[Steve Shapiro]

"jt" <[email protected]> wrote in message
news:<[email protected]>...
> "Steve Shapiro" <[email protected]> wrote in message
> news:[email protected]...
>
> >
> > Does anyone know why bikes are made with the right hand brake controlling the rear wheel? Most
> > of us are right handed and would have better control if the right hand lever operated the front
> > brake, in my opinion. But I digress.
> >
>
> The right gear lever controls (usually) the rear mechanism. When stopping, one finds it more
> convenient to shift down with the right and brake with the left, as there is (again, usually) a
> greater gear variation possible with the rear mech.
>
> But there are, as Churchill said, all kinds <of right/left brake
> arrangements>.

Thank you, I hadn't thought of the shifting while braking issue. I'd guess this could be important
to racers or anyone seeking speed. My road bike has down tube shifters, and you are correct, the
only way to shift and brake simultaneously is to use two hands. I'm not real good at it. But my
hybrid has rapid-fire shifters and ATB brake levers. It's no problem for me to brake and shift with
one hand as long as braking is light to moderate. My personal preference remains to use the front
caliper, right hand combination and downshift before or after deceleration.

Steve Shapiro

 

[Steve Shapiro]

"Kraig Willett" <[email protected]> wrote in message
news:<[email protected]>...
> Back when I used to work in the wheel industry (3 years ago now - whew, how time flies!), the spec
> we enforced was in the 0.012" TIR range.

I know what you mean about time. I did want to take the time to say thank you for the information.
This may sound stupid, but I assume you speak of hand built vs. machine built wheels. Right?

Steve Shapiro

 

[Steve Shapiro]

"Kraig Willett" <[email protected]> wrote in message
news:<[email protected]>...
> "Lindsay Rowlands" <[email protected]> wrote in message
> news:[email protected]...
> > I don't buy Jobst's version of brake pads rubbing on rims. Curiously, my single pivoted bike
> > climbs just as easily as my dual pivoted one. Sounds like bicycle folklore.
>
> What don't you buy, that rims rub brakes, or, that racers open up their rear brakes?
>
> I can definitively comment on the rub issue, since I made the physical measurements with a dial
> indicator while riding.
>
> It depends on the wheel, of course, but many of today's low spoke/lightweight wheels rub pads.
>
> The measurements I made were published in this online magazine article:
>
> http://tinyurl.com/6424

Thanks for pointing me to your article. I enjoyed it. Suspicions confirmed. One quick question: Did
you do any of the deflection tests with a 36 spoke, basic hub, basic rim wheel?

Steve Shapiro

 

[Steve Shapiro]

Frank Krygowski <[email protected]> wrote in message news:<[email protected]>...
> Steve Shapiro wrote:
> >
> > Lindsay Rowlands <[email protected]> wrote in message
> > news:<[email protected]>...
> > > I aim for less than 1mm - 0.039" - which is pretty easy to achieve. I doubt there is any real
> > > benefit in a lower figure other than some kind of perverse satisfaction....
> >
> > Regarding how true is true, I think it is a good question ‘cause I am interested to see the
> > opinion of others. It seems as if ±0.005" is a good objective. A total swing of 0.01" easy to
> > see without indicators, but the difference between 0.005 and 0.006" is impossible to know
> > without dial indicators. I think I'll try to find some old feeler gauges or get some shim stock
> > just to give me an idea how true my wheels are.
>
> I just put a dial indicator on the wheels of a new bike we bought (decent quality Terry bike,
> maybe 100 miles on it) and found 0.020" TIR. Looking at this visually, I'd probably be perfectly
> satisfied with this if I were building the wheel.
>
> I didn't put the dial indicator on the two bikes I ride the most, but it looks to me like they're
> at roughly 0.040" TIR. Like Lindsay, I'm satisfied with that. It would need to be much worse
> before I'd feel the need to straighten them. I should mention, though, that those bikes (my
> touring bike and my commuting bike) both have cantilever brakes, so dragging a super-sensitive
> double-pivot brake shoe isn't one of my concerns.
>
> Regarding Steve's statement: I'm not convinced "a total swing of 0.01"
> [is] easy to see without indicators." A machinist's six inch rule goes down to 0.01" resolution,
> and that's not real easy to read even with a workpiece that's sitting still. Maybe you can
> see 0.01" on a rotating wheel - but I bet you can't see it from five feet away!

You win the bet from five feet, but I maintain it is easy to see .010" when viewed from a
comfortable wheel truing distance (assume no tire, assume white background like on a Park stand. As
I write, my electronic caliper is set to 0.0100" and I'm looking at the gap between the jaws. It is
easy to see. On the other hand, I have no arguement with how important it is to build wheels to any
particular tolerance. Whatever serves and pleases you.

Steve Shapiro

 

[Kraig Willett]

"Steve Shapiro" <[email protected]> wrote in message
news:[email protected]...
> "Kraig Willett" <[email protected]> wrote in message
news:<[email protected]>...
> > "Lindsay Rowlands" <[email protected]> wrote in message
> > news:[email protected]...
> > > I don't buy Jobst's version of brake pads rubbing on rims. Curiously,
my
> > > single pivoted bike climbs just as easily as my dual pivoted one.
Sounds
> > > like bicycle folklore.
> >
> > What don't you buy, that rims rub brakes, or, that racers open up their
rear
> > brakes?
> >
> > I can definitively comment on the rub issue, since I made the physical measurements with a dial
> > indicator while riding.
> >
> > It depends on the wheel, of course, but many of today's low spoke/lightweight wheels rub pads.
> >
> > The measurements I made were published in this online magazine article:
> >
> > http://tinyurl.com/6424
>
> Thanks for pointing me to your article. I enjoyed it. Suspicions confirmed. One quick question:
> Did you do any of the deflection tests with a 36 spoke, basic hub, basic rim wheel?
>

I don't own any 36 hole rear wheels; however, I think I did measure some of my other wheels at the
time. Let me dig through the data and put something together.

--
==================
Kraig Willett www.biketechreview.com
==================

 

[Kraig Willett]

"Steve Shapiro" <[email protected]> wrote in message
news:[email protected]...
> "Kraig Willett" <[email protected]> wrote in message
news:<[email protected]>...
> > Back when I used to work in the wheel industry (3 years ago now - whew,
how
> > time flies!), the spec we enforced was in the 0.012" TIR range.
>
> I know what you mean about time. I did want to take the time to say thank you for the information.
> This may sound stupid, but I assume you speak of hand built vs. machine built wheels. Right?

All the experience I have is with hand built wheels.

--
==================
Kraig Willett www.biketechreview.com
==================

 

[Tom Nakashima]

I once had a Japanese engineer give me the measurement of .005 centimeters, in which I thought the
unit of measure was inches. In inches it was actually .00197", simple mistake, large error. -tom

<[email protected]> wrote in message news:[email protected]...
> Shane Stanley writes:
>
> >> Depending on what sort of brakes and pad clearance you use, lateral alignment between +-0.005
> >> is fine.
>
> > What units are you using there?
>
> Oh how clever. What else? Did you perhaps think millimeters, nanometers, or Angstroms. This
> reminds me of Snap-on Tools changing their metric wrench markings to, for instance, to 10MM
> instead of 10, so the American will know it's not a 10inch end wrench, much less a 30inch on a
> large one. Lower case m's were not good enough either, while English sizes were not changed to
> show that they are in inches. I guess for some folks a 25x error is easy to make when measuring or
> selecting tools.
>
> Jobst Brandt [email protected] Palo Alto CA

 

[Jobst Brandt]

Tom Nakashima writes:

> I once had a Japanese engineer give me the measurement of .005 centimeters, in which I thought the
> unit of measure was inches. In inches it was actually .00197", simple mistake, large error.

That sounds odd for an engineer, and one who uses the metric system. Engineering is done in
millimeters, be that a wristwatch or a railway locomotive. Centimeters are used in architecture and
are not used to
1/1000 resolution. I'm curious what the measurement was and how it came to be given in centimeters.

Jobst Brandt [email protected] Palo Alto CA

 

[Frank Krygowski]

Benjamin Weiner wrote:
>
> Frank Krygowski <[email protected]> wrote:
>
> > ... He said "What is it??" "It's your ignition lead." "What do I do with it?" "You put it
> > between your coil and your distributor." "What's a coil? What's a distributor?" Some engineers
> > are much better at partial differential equations than they are at elementary common knowledge.
>
> Hey you hosers,
>
> This is a BICYCLE newsgroup. Cars are not necessarily elementary common knowledge. There is a
> tradition of young people (often men) learning by dinking around with cars in their adolescence,
> but not everybody does that.
>
> ...Cars are also big, expensive and intimidating, and many people simply do not want to mess
> around under the hood.

FWIW, we were talking about engineering students. Personally, I feel that a person who's going to be
a mechanical engineer _should_ know what goes on inside that big, intimidating engine compartment. I
think that, in a prospective engineer, failure to learn that hints at a mistaken career choice.

Come to think of it, I guess I think _everyone_ should know at least a little about what goes on
inside their car. Hell, I know a woman who is a teacher and poet, and who has changed her own oil,
replaced her spark plugs, replaced her own pads and rotors, etc. The willingness to tackle jobs like
that speaks well of her, I'd say.

For poets, housewives, accountants etc. this knowledge at least allows one to take minimal care of
their vehicle, to avoid destroying it before its time. It also helps to avoid being ripped off by
unscrupulous repair shops.

But for anyone with minimal technical curiosity - how can you _not_ be curious about your car? You
probably rely on it very heavily in daily life. Do you really want to rely on some incomprehensible,
sealed black box? Do you somehow get all nervous and trembly when you lift the hood? How strange!

Go to the library. Get out a book on the workings of the car, something intended for novice
consumers. Read the book, look at the pictures, and find the parts they discuss inside your own
engine compartment. It can't do you any harm, and it might do you a lot of good.

--
Frank Krygowski [email protected]