Assessing Wheel Build Quality and Rebuild Options

[J. Matt]

I've just purchased a set of new machine-built mountain bike wheels with the intention of rebuilding
them before use. The spoke tension on the front wheel seems very low, while the tension on the rear
wheel seems somewhat high. I'm assessing the tensions by comparing the tone of the spokes when
plucked to a well-built wheel. The well-built wheel sounds a B2 on an electronic guitar tuner.

During a brief stint working in a bike shop several years ago, the mechanics when unboxing a new
bike would brace the wheel against their thighs and in a controlled fashion do a manuever using
their hands and forearms that would seem like they were trying to taco the wheel. During this
manuever, the wheel would often ping or creak. This, according to the mechanics, was a sign of a
cheaply built wheel that needed attention. When I did this manuever to the wheelset I've just
purchased, there was a good deal of creaking and pinging.

My plan is to detension the spokes to the point where the threads just show, and then to loosely
follow Sheldon Brown's instructions on his site from "Initial Tensioning" forward. The spokes seem
to be flush against the hub right after the bend but I can't imagine anyone has gone by hand and
bent them.

I'm concerned about several things. First, if the spokes threads have been properly lubed. How can I
tell, and if I use a very thin lube like ProLink, will it penetrate the threads without me having to
totally undo the spoke?

Also, since the tension seems high on the rear wheel, is there a chance the rim will be warped?
Would I be better off riding the set until problems arise or is preventitive building preferable?

Anything else I should be aware of? This will be my sixth build and while my wheels are never
perfectly true, they have been incredibly durable.

Thanks in advance

John Matthew

 

[Jobst Brandt]

John Matthew writes:

> I've just purchased a set of new machine-built mountain bike wheels with the intention of
> rebuilding them before use. The spoke tension on the front wheel seems very low, while the tension
> on the rear wheel seems somewhat high. I'm assessing the tensions by comparing the tone of the
> spokes when plucked to a well-built wheel. The well-built wheel sounds a B2 on an electronic
> guitar tuner.

> During a brief stint working in a bike shop several years ago, the mechanics when unboxing a new
> bike would brace the wheel against their thighs and in a controlled fashion do a maneuver using
> their hands and forearms that would seem like they were trying to taco the wheel. During this
> maneuver, the wheel would often ping or creak. This, according to the mechanics, was a sign of a
> cheaply built wheel that needed attention. When I did this maneuver to the wheelset I've just
> purchased, there was a good deal of creaking and pinging.

You should probably build your own wheels or at least know what and why wheels respond to such
treatments as they do. Your bicycle shop may have that book on their book shelf. The pinging is
residual twist in spokes left by the last adjustment. Spokes are long torsion springs that wind up
when the spoke nipple is turned. After final adjustments the spoke nipple should always be backed
off to the no twist position, something that is easy to feel with practice.

> My plan is to de-tension the spokes to the point where the threads just show, and then to loosely
> follow Sheldon Brown's instructions on his site from "Initial Tensioning" forward. The spokes seem
> to be flush against the hub right after the bend but I can't imagine anyone has gone by hand and
> bent them.

Don't do that. It has no benefit. On the other hand, just tightening each spoke about 1/2 turn while
backing off about 1/8 turn after tightening would be a good approach. I say that because most wheels
are not tight enough anyway. The backing off will get rid of the pings and then you need to stress
relieve all the spokes. DON"T start over!

> I'm concerned about several things. First, if the spokes threads have been properly lubed. How can
> I tell, and if I use a very thin lube like ProLink, will it penetrate the threads without me
> having to totally undo the spoke?

The worst lubrication problem is usually that between nipple and rim joint. Oiling that friction
is to allow the spoke nipples to rotate when tightening spokes. Try that primarily and use 30W
motor oil.

> Also, since the tension seems high on the rear wheel, is there a chance the rim will be warped?
> Would I be better off riding the set until problems arise or is preventive building preferable?

It may be high on the right side but the left will be low in comparison. Stress relieving will
reveal whether tension is too high.

> Anything else I should be aware of? This will be my sixth build and while my wheels are never
> perfectly true, they have been incredibly durable.

http://draco.acs.uci.edu/rbfaq/FAQ/8c.1.html

Jobst Brandt [email protected] Palo Alto CA

 

[David Kunz]

J. Matt wrote:
> I've just purchased a set of new machine-built mountain bike wheels with the intention of
> rebuilding them before use. The spoke tension on the front wheel seems very low, while the tension
> on the rear wheel seems somewhat high. I'm assessing the tensions by comparing the tone of the
> spokes when plucked to a well-built wheel. The well-built wheel sounds a B2 on an electronic
> guitar tuner.
>
> During a brief stint working in a bike shop several years ago, the mechanics when unboxing a new
> bike would brace the wheel against their thighs and in a controlled fashion do a manuever using
> their hands and forearms that would seem like they were trying to taco the wheel. During this
> manuever, the wheel would often ping or creak. This, according to the mechanics, was a sign of a
> cheaply built wheel that needed attention. When I did this manuever to the wheelset I've just
> purchased, there was a good deal of creaking and pinging.
>
> My plan is to detension the spokes to the point where the threads just show, and then to loosely
> follow Sheldon Brown's instructions on his site from "Initial Tensioning" forward. The spokes seem
> to be flush against the hub right after the bend but I can't imagine anyone has gone by hand and
> bent them.
>
> I'm concerned about several things. First, if the spokes threads have been properly lubed. How can
> I tell, and if I use a very thin lube like ProLink, will it penetrate the threads without me
> having to totally undo the spoke?
>
> Also, since the tension seems high on the rear wheel, is there a chance the rim will be warped?
> Would I be better off riding the set until problems arise or is preventitive building preferable?
>
> Anything else I should be aware of? This will be my sixth build and while my wheels are never
> perfectly true, they have been incredibly durable.
>
> Thanks in advance
>
> John Matthew

The pinging is the spokes unwinding -- when you tighten the nipple, sometimes, the spoke itself also
turns. This pinging is the spokes going back to neutral.

I wouldn't undo the rims. I'd do 2 things.

- Stress relieve. Take a screw driver and holding the business end in your hand, put the handle
between spoke pairs and twist. This seats the spokes better and bends them at the elbows to lie
better. They'll be less likely to break over time.

- Balance the tension and possibly bring the tension up. Read Sheldon's site and the site on
guessing spoke tension by pitch (I seem to remember a link on Sheldon't page). Find the tight
spokes -- look for a nearby looser spoke or a balancing tight spoke on the other side. Loosen the
tight spoke 1/4 turn and tighten the loose spoke 1/4 turn. Check true and adjust if you've shifted
things out -- looking for tight and loose spokes near the out of true point to adjust. Sometimes,
a spoke that is tighter or looser than it's neighbors and 3 or 4 away from the out of true spot
can be adjusted to bring it in!

Remember that the disc side in the front and the hub side in the rear will be tighter than the other
side. Set the tension on that side and let dish set the tension on the other side (dish is side-side
position -- between the brake pads if you have V brakes).

I'm lazy and don't worry too much about spoke wrap. I usually do the taco thing every so often
instead (unless I see or feel the winding/ unwinding of a stubborn spoke, then I work like the books
say ). But I also use brass nipples which are less prone to it than alloy nipples. If you're
worried about spoke wrap, try wrapping a small piece of tape like a flag around the stubborn spokes
-- then you put your turn in and then back-off to bring the flag back to it's neutral position.

And, get yourself a decent spoke wrench. The ones for doing spot trail fix-ups are pitiful and will
probably strip some of the nipples as you come up to full tension.

David

 

[Qui Si Parla Ca]

steel-<< I've just purchased a set of new machine-built mountain bike wheels with the intention of
rebuilding them before use.

Assume you mean retensioning, truing, rounding, dishing, stress relieving, not rebuilding...

<< I'm assessing the tensions by comparing the tone of the spokes when plucked to a
well-built wheel.

Same gauge??If not, this means nada...

<< This, according to the mechanics, was a sign of a cheaply built wheel that needed attention.
When I did this manuever to the wheelset I've just purchased, there was a good deal of creaking
and pinging.

Lots of residual spoke windup-

<< Would I be better off riding the set until problems arise or is preventitive building preferable?

No-if you ride it, you will bend the rim on a poorly built wheel, deforming it and then the tesnion
will not be even...do what you are planning to do-before you ride them..

Lube the nipps into the rim and the threads...

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"

 

[J. Matt]

Based on your thoughtful responses, I have more questions.

First, I'm assuming the technique the poster wrote of involving a screwdriver is similiar to that
posted on Sheldon Brown's site using a crank arm. I'm unclear on where exactly the object is
inserted, and what it accomplishes.

Second, after relieving the residual spoke windup, the tension (as gauged by tone) is very
uneven yet the wheel is still true. Two respondents recommended not detensioning the wheel first
but it seems to me it would be easier to start from a consistent baseline with each spoke right
at where the threads show rather than attempting to true an already true wheel with uneven and
low spoke tension.

On a side note, is there any reason to give new hubs (XT) new grease or is the quality and quantity
generally adequete? The hubs run a little rough, but I'm proficient in cone adjustment.

Thanks

John Matthew

 

[Qui Si Parla Ca]

steel-<< On a side note, is there any reason to give new hubs (XT) new grease or is the quality and
quantity generally adequete? The hubs run a little rough, but I'm proficient in cone adjustment.

I add grease to all new hubs and adjust after the build...

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"

 

[J. Matt]

[email protected] (J. Matt) wrote in message
news:<[email protected]>...
> Based on your thoughtful responses, I have more questions.
>
> First, I'm assuming the technique the poster wrote of involving a screwdriver is similiar to that
> posted on Sheldon Brown's site using a crank arm. I'm unclear on where exactly the object is
> inserted, and what it accomplishes.
>
> Second, after relieving the residual spoke windup, the tension (as gauged by tone) is very uneven
> yet the wheel is still true. Two respondents recommended not detensioning the wheel first but it
> seems to me it would be easier to start from a consistent baseline with each spoke right at where
> the threads show rather than attempting to true an already true wheel with uneven and low spoke
> tension.
>
> On a side note, is there any reason to give new hubs (XT) new grease or is the quality and
> quantity generally adequete? The hubs run a little rough, but I'm proficient in cone adjustment.
>
> Thanks
>
> John Matthew

Anyone?

 

[David Kunz]

J. Matt wrote:
> Based on your thoughtful responses, I have more questions.
>
> First, I'm assuming the technique the poster wrote of involving a screwdriver is similiar to that
> posted on Sheldon Brown's site using a crank arm. I'm unclear on where exactly the object is
> inserted, and what it accomplishes.

My understanding (if I'm wrong, I'll get corrected ). It bends the spokes to lie better at the hub
and seats them better. You put it in between the spokes where they cross closest to the center of
the wheel on the side closest to the rim. You twist the spokes apart.

> Second, after relieving the residual spoke windup, the tension (as gauged by tone) is very uneven
> yet the wheel is still true. Two respondents recommended not detensioning the wheel first but it
> seems to me it would be easier to start from a consistent baseline with each spoke right at where
> the threads show rather than attempting to true an already true wheel with uneven and low spoke
> tension.

When you build a wheel, you do the tension balancing step as you bring it up to full tension. You
don't just go around the rim adding (say)
1/2 turn to all spokes (unless you're balanced and almost at tension). If you detension back to
threads flush, you'll end doing a lot more work. One easy reason to understand is that not all of
the spokes have exactly the same amount of threads or is precisely the same length -- so you're
not any better off. And, even if they were, they'd have to be precisely the same diameter over
their length also .

> On a side note, is there any reason to give new hubs (XT) new grease or is the quality and
> quantity generally adequete? The hubs run a little rough, but I'm proficient in cone adjustment.

Always.

David

 

[David Kunz]

David Kunz wrote:
> J. Matt wrote:
>
>> Based on your thoughtful responses, I have more questions. First, I'm assuming the technique the
>> poster wrote of involving a screwdriver is similiar to that posted on Sheldon Brown's site using
>> a crank arm. I'm unclear on where exactly the object is inserted, and what it accomplishes.
>
>
> My understanding (if I'm wrong, I'll get corrected ). It bends the spokes to lie better at the
> hub and seats them better. You put it in between the spokes where they cross closest to the center
> of the wheel on the side closest to the rim. You twist the spokes apart.

I hate to correct my own posts -- what I meant was to put it just past the spoke crossing that's
midway between the hub and the rim and twist them apart -- not gently.
>
>> Second, after relieving the residual spoke windup, the tension (as gauged by tone) is very uneven
>> yet the wheel is still true. Two respondents recommended not detensioning the wheel first but it
>> seems to me it would be easier to start from a consistent baseline with each spoke right at where
>> the threads show rather than attempting to true an already true wheel with uneven and low spoke
>> tension.
>
>
> When you build a wheel, you do the tension balancing step as you bring it up to full tension. You
> don't just go around the rim adding (say)
> 1/2 turn to all spokes (unless you're balanced and almost at tension). If you detension back to
> threads flush, you'll end doing a lot more work. One easy reason to understand is that not all
> of the spokes have exactly the same amount of threads or is precisely the same length -- so
> you're not any better off. And, even if they were, they'd have to be precisely the same diameter
> over their length also .
>
>> On a side note, is there any reason to give new hubs (XT) new grease or is the quality and
>> quantity generally adequete? The hubs run a little rough, but I'm proficient in cone adjustment.
>
>
> Always.
>
> David

 

[Sheldon Brown]

J. Matt wrote:
>>
>>> Based on your thoughtful responses, I have more questions. First, I'm assuming the technique the
>>> poster wrote of involving a screwdriver is similiar to that posted on Sheldon Brown's site using
>>> a crank arm. I'm unclear on where exactly the object is inserted, and what it accomplishes.

David Kunz wrote:

>> My understanding (if I'm wrong, I'll get corrected ). It bends the spokes to lie better at the
>> hub and seats them better. You put it in between the spokes where they cross closest to the
>> center of the wheel on the side closest to the rim. You twist the spokes apart.
>
> I hate to correct my own posts -- what I meant was to put it just past the spoke crossing that's
> midway between the hub and the rim and twist them apart -- not gently.

The screwdriver technique resembles the old-crank technique, but they're actually rather different.

The screwdriver is inserted between the innermost crossing and the hub flange, and is used primarily
as a way to improve the "spoke line" so that the spokes, especially the heads-in ones, will lie
close against the hub flange.

I don't generally do this while building a wheel, but sometimes do when repairing a wheel that
somebody else built. When I build a wheel myself, I do the spoke lining by hand. This is easy to do
if you do it right after lacing the wheel, before applying any tension to the spokes.

The thing I do with the old crank is primarily to stress relieve the spokes, as described by Jobst
Brandt. I use this variant technique because I have thin-skinned, delicate hands, and using the
specific technique he recommends hurts, if enough pressure is applied.

I put the crank in outward from the outermost (laced) crossing, and I twist the spokes _together_
not apart. A side effect of this is that the spokes acquire a slight bend where they lace past one
another at the outermost cross, rather than the broad curve they start with.

See: http://sheldonbrown.com/wheelbuild.html#seating

Sheldon "Stress Relief" Brown +---------------------------------------------+
| I have suffered from being misunderstood | but I would have suffered a hell of a lot | more if I
| had been understood. | --Clarence Darrow |
+---------------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone
617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com