WheelSmith Tensionometer: How to interpolate?

Pete Cresswell said:

Doesn't seem real intuitive.

Quoted message said:

Even 10's, no problem: If the two lines line up, that's it.

Quoted message said:

Also, what constitutes a lineup of the upper/lower lines? Exact alignment? Any part of one line
overlapping any part of the other line?

I think this should help:

saburchill.com0095.htmlOpen ↗

Quoted message said:

Is this what they call a "vernier" gauge? Seems like Park's readout is a lot easier to deal with -
but is Park's added precision just an illusion?

Their instrument uses too large a test load and is impeded by excess friction. By the way, it's a
"tensiometer".

Jobst Brandt [email hidden]

RE/

Quoted message said:

I think this should help:

saburchill.com0095.htmlOpen ↗

Quoted message said:

Is this what they call a "vernier" gauge? Seems like Park's readout is a lot easier to deal with
- but is Park's added precision just an illusion?

Their instrument uses too large a test load and is impeded by excess friction. By the way, it's a
"tensiometer".

From that, I conclude:

1) I just [censored] away a hundred bucks..

2) It's not a verier gauge.

tensiometer tensiometer tensiometer tensiometer tensiometer.... I think I've got it now....-)

At the beggining of all this, my instinct was to just take my wheels to somebody who does this for a
living - on the assumption that they can do it cheaper and better than I can.

But now my rear wheel's been in this guy's shop for going on three weeks... "The new rim hasn't
arrived yet....".... Oh well.... Thank goodness I have a spare....

So I figured I might as well bite the bullet and learn something - as well as avoid exposing myself
to similar situations in the future...

Recommendation(s)?
-----------------------
PeteCresswell

RE/

Quoted message said:

Sounds like the nature of the readout is that the maximum accuracy is 5.

I think I'm getting somewhere here. Seems like a single rotation of the nipple takes me from, say,
40 on the tensionometer to 50.... about 20 kg diff on 1.8mm spokes.

But I'm starting to realize how complicated and interdependent the tensions are. You tighten one,
and the tension changes on others. Ouch.

I was doing pretty well true/hop-wise just putting the wheel in a stand, making little marks at
various nipples and doing a quarter turn here, an eighth of a turn there....

Now I'm trying to get all spokes at the same tension and the thing wobbles like there's no
tomorrow...

But, of course, when I go back and measure the other side of the wheel after making all the spokes
on one side the same tension, the tensions on the other side are all over the place.

Questions for somebody who knows:

1) What's the proper technique for getting consistant readings? I find that if I rotate the
instrument back and forth a few times the reading changes and settles down after 2-3 movements.
Before using it, I give it a half-dozen squeezes and sometimes different squeezes produce
different "zero" readings - and I have to fiddle with the spring until I get exact zero - after
which I'm careful not to touch the spring during use.

2) I'm getting the feeling that tension is best played with with the wheel laying horizontal across
my knees instead of in the truing jig. True?

3) Is there a strategy for evening out the tensions? e.g. Working on opposite spokes same side?
Spokes from different sides?

4) For a front disc wheel, should the tension on each side be the same?

5) Rear disc wheel? (Rohloff hub - no dish)

6) If, by some miracle of obsessive-compulsive iteration, I manage to get identical tension readings
from all spokes - should a non-dished wheel then be true and free of hop?
-----------------------
PeteCresswell

RE/

Quoted message said:

impeded by excess friction.

I guess that's where the wiggling before reading comes in...
-----------------------
PeteCresswell

Pete Cresswell said:

I think I'm getting somewhere here. Seems like a single rotation of the nipple takes me from, say,
40 on the tensionometer to
50.... about 20 kg diff on 1.8mm spokes.

Quoted message said:

But I'm starting to realize how complicated and interdependent the tensions are. You tighten one,
and the tension changes on others. Ouch.

Don't use a tensiometer to tighten spokes, one by one, to the desired tension. Tighten the spokes
and true the wheel. Then measure how tight the wheel is by sampling a few spokes. Tension ought
to be fairly uniform before you make measurements if you have checked the tome of spokes around
the wheel.

Quoted message said:

I was doing pretty well true/hop-wise just putting the wheel in a stand, making little marks at
various nipples and doing a quarter turn here, an eighth of a turn there....

Quoted message said:

Now I'm trying to get all spokes at the same tension and the thing wobbles like there's no
tomorrow...

You are probably changing too much at once. Once you have some tension, even up the spokes before
adding more tension.

Quoted message said:

But, of course, when I go back and measure the other side of the wheel after making all the spokes
on one side the same tension, the tensions on the other side are all over the place.

I doubt that your rim is that out of whack. Whose instructions are you following?

Quoted message said:

Questions for somebody who knows:

Quoted message said:

1) What's the proper technique for getting consistent readings? I find that if I rotate the
instrument back and forth a few times the reading changes and settles down after 2-3 movements.
Before using it, I give it a half-dozen squeezes and sometimes different squeezes produce
different "zero" readings - and I have to fiddle with the spring until I get exact zero - after
which I'm careful not to touch the spring during use.

The change in reading when you wiggle the gauge back and forth is because you are relaxing friction
between and supports and anvil. The unit pictured in "the Bicycle Wheel" uses ball bearings as end
supports to avoid this. It also measures from the support side so the wire thickness does not enter
into the measurement.

Quoted message said:

2) I'm getting the feeling that tension is best played with with the wheel laying horizontal
across my knees instead of in the truing jig. True?

The wheel can be lying horizontal but that doesn't change the readings if you use the instrument
correctly. What does your lap do?

Quoted message said:

3) Is there a strategy for evening out the tensions? e.g. Working on opposite spokes same side?
Spokes from different sides?

Make the wheel true first, then check for tensions above and below average and balance them out
while checking trueness. This is where radial trueness should be as close as possible to true.

Quoted message said:

4) For a front disc wheel, should the tension on each side be the same?

That depends on the "dish". Is the rim off of the hub center?

Quoted message said:

5) Rear disc wheel? (Rohloff hub - no dish)

How can they have different tensions if the rim is centered?

Quoted message said:

6) If, by some miracle of obsessive-compulsive iteration, I manage to get identical tension
readings from all spokes - should a non-dished wheel then be true and free of hop?

Well it won't be dished if all spokes are the same tension.

Jobst Brandt [email hidden]

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

Quoted message said:

Pete Cresswell writes: I doubt that your rim is that out of whack. Whose instructions are you
following?

Instructions? You mean there are instructions? ....-) It's starting to dawn on me that maybe I ought
to break down and buy this guy Brandt's book.... got any in stock? (email is my first name at the
"FatBelly" commercial domain

Quoted message said:

The change in reading when you wiggle the gauge back and forth is because you are relaxing
friction between and supports and anvil. The unit pictured in "the Bicycle Wheel" uses ball
bearings as end supports to avoid this. It also measures from the support side so the wire
thickness does not enter into the measurement.

- So, does that mean that I should wiggle it? I think so....
- Is the "Bicycle Wheel" instrument the one called "DT"?

Quoted message said:

What does your lap do?

Ideosyncratic comfort issue. Easier to repeatedly apply the instrument and read it...

Quoted message said:

Make the wheel true first, then check for tensions above and below average and balance them out
while checking trueness. This is where radial trueness should be as close as possible to true.

Bottom line to me: the instrument is to make sure I don't exceed the mfr's specs on individual
spokes. Everything else is "just get it true..."

Quoted message said:

Quoted message said:

4) For a front disc wheel, should the tension on each side be the same?

Well it won't be dished if all spokes are the same tension.

Sounds like relative tension between the two sides is a product of dish.

In article <[email hidden]>, [email hidden] says...

Quoted message said:

1) What's the proper technique for getting consistant readings? I find that

if

Quoted message said:

I rotate the instrument back and forth a few times the reading changes and settles down after 2-3
movements. Before using it, I give it a half-dozen squeezes and sometimes different squeezes
produce different "zero" readings - and I have to fiddle with the spring until I get exact zero -
after which I'm careful not to touch the spring during use.

Make sure your spokes are clean. I've had my WS tensiometer for 10 years or so and it gives me the
same repeatable reading without having to play with it.

Quoted message said:

2) I'm getting the feeling that tension is best played with with the wheel laying horizontal across
my knees instead of in the truing jig. True?

No on the truing stand should work fine. Having to pull the wheel to check tension will add a lot of
time to your wheel building.

Quoted message said:

3) Is there a strategy for evening out the tensions? e.g. Working on opposite spokes same side?
Spokes from different sides?

If I need to move the rim to one side and the closet spoke is already at my target tension I check
the first spokes to the left and right of the high spot to see if they have room for an adjustment
and still stay in the range I need. That almost always works.

Quoted message said:

4) For a front disc wheel, should the tension on each side be the same?

I think not because the hub flanges are not symetrical. Just like on a rear wheel.

Quoted message said:

5) Rear disc wheel? (Rohloff hub - no dish)

NO idea.

Quoted message said:

6) If, by some miracle of obsessive-compulsive iteration, I manage to get identical tension
readings from all spokes - should a non-dished wheel then be true and free of hop?

Not always.
-----------------
Alex __O _-\<,_ (_)/ (_)

(Pete Cresswell) said:

RE/

Quoted message said:

Sounds like the nature of the readout is that the maximum accuracy is 5.

I think I'm getting somewhere here. Seems like a single rotation of the nipple takes me from, say,
40 on the tensionometer to 50.... about 20 kg diff on 1.8mm spokes.

But I'm starting to realize how complicated and interdependent the tensions are. You tighten one,
and the tension changes on others. Ouch.

I was doing pretty well true/hop-wise just putting the wheel in a stand, making little marks at
various nipples and doing a quarter turn here, an eighth of a turn there....

Now I'm trying to get all spokes at the same tension and the thing wobbles like there's no
tomorrow...

But, of course, when I go back and measure the other side of the wheel after making all the spokes
on one side the same tension, the tensions on the other side are all over the place.

Questions for somebody who knows:

1) What's the proper technique for getting consistant readings? I find that if I rotate the
instrument back and forth a few times the reading changes and settles down after 2-3 movements.
Before using it, I give it a half-dozen squeezes and sometimes different squeezes produce
different "zero" readings - and I have to fiddle with the spring until I get exact zero - after
which I'm careful not to touch the spring during use.

Mine gives that same reading unless I put it too close to the rim. It's very repeatable.

Quoted message said:

2) I'm getting the feeling that tension is best played with with the wheel laying horizontal
across my knees instead of in the truing jig. True?

Why? You check tension evenness by plucking the spokes and listening to the tone.

Quoted message said:

3) Is there a strategy for evening out the tensions? e.g. Working on opposite spokes same side?
Spokes from different sides?

There's an art to it. To start, you have to realize that a spoke as many as 3 or 4 away can impact
the truness of a position on the wheel. So, you pluck both sides of the wheel for several spokes on
each side of the out of true spot and listen to the sound on each side. Find the spoke that's the
most out of balance with the rest (different pitch when plucked) and add or remove 1/4-1/2 turn from
that spoke (depending on which way you want to move the out of true place and how different the
pitch is) and move on (or 1/4-1/2 turn on both sides to bring-in a high spot). Note that the drive
and non-drive sides will have different "pitches" because you want more tension on the drive side to
get the dish right (centering of the rim). When you have the wheel true and all of the spokes pluck
about the same on each side, then you check torque on a couple and see where you are (always low --
the question is how much). If it's truly balanced at that point, you can add 1/4-1/2 turns all of
the way around to bring the wheel up to full tension (note that a
1/4 turn on the drive side will pull more than a 1/4 turn on the non-drive side, so watch dish).

Quoted message said:

4) For a front disc wheel, should the tension on each side be the same?

No, the disc side will be tighter because it is inset.

Quoted message said:

5) Rear disc wheel? (Rohloff hub - no dish)

Mine is still not the same (Chris King Iso Disc).

Don't worry about matching the tension on both sides. Get the drive side tension right and when the
dish is right, the non-drive side tension will be also 🙂. Just make sure it's at least 60-70 kg.

Quoted message said:

6) If, by some miracle of obsessive-compulsive iteration, I manage to get identical tension
readings from all spokes - should a non-dished wheel then be true and free of hop?

No. You may have the same tension, but if you haven't balanced the adding of tension across multiple
spokes, the wheel won't be true (the spoke lengths will be wrong).

David

RE/

Quoted message said:

Make sure your spokes are clean. I've had my WS tensiometer for 10 years or so and it gives me the
same repeatable reading without having to play with it.

This isn't a wiseguy question, but how do you know
-----------------------
PeteCresswell

RE/

Quoted message said:

This isn't a wiseguy question, but how do you know

Oops, that one slipped out before it was done.

...how do you know the reading is the same without wiggling the device every so often to see if
it changes?
-----------------------
PeteCresswell

"(Pete Cresswell)" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

Oops, that one slipped out before it was done.

...how do you know the reading is the same without wiggling the device

every so

Quoted message said:

often to see if it changes?

Hey! This is a family newsgroup...

Bill "slow evening" S.