True Your Own Wheels

November 24, 2007 at 6:23 PM

Prelude

I went on a nice bike ride today to offset some of the gluttony brought on by Thanksgiving. Before I went, I did some basic maintenance: I trued the wheels, lubed the chain, and checked to see if the headset (which I installed myself, using nonstandard methods) is still intact.

Truing wheels is often viewed with trepidation; most people I know pay to have their wheels trued. Because of that, they also are more tolerant of slight wobbles than they need to be — who's going to pay to have a minor wobble adjusted? Most people will just live with it.

Using this tutorial, I learned how to true my wheels. That tutorial is very detailed, and I think that its level of detail can be more confusing than helpful during the initial stages of learning. Below are my supplemental instructions to the above tutorial. This information will be enough to help you true you wheels in under 15 minutes; the other tutorial is still very useful, especially for background information. Mine has pictures, though, which I believe are invaluable to learning any mechanical function.

Tools

There's really only one thing needed: a spoke wrench. I bought the one in the previous link because I didn't know which size I needed; it works great, and it's small enough to keep in a saddle bag.

Concepts

In order to be able to true a wheel, it really helps to have the following mental image in your mind:

Conceptual wheel, top view.

Ok, ok — my graphics skills are lacking. Here's the idea: if you stand over your wheel and look down, you'll see an image similar to this. Your tire creates the thick line, and alternating spokes stick out from it on either side.

Conceptually, each thin line in the picture is a spoke; they all exert force on the thick line (the rim). If I tighten spoke 3 too much, the rim gets pulled upwards in the picture, in the direction that spoke 3 is pulling.

Your objective in truing a tire is to make the forces on either side essentially equal; the odd numbered spokes must pull just as hard as the even numbered spokes for the line to remain straight.

But what should I do: loosen spoke 3, or tighten the other spokes? This question leads us to rule #1:

Rule 1: Always tighten spokes to fix a wobble.

"Why?", you may ask. Think about it for a minute: how will one of your spokes become too tight? Only if you tighten it too much. If you over correct a wobble, you'll know — just undo what you did and tighten a little less. Riding your bike alone cannot tighten your spokes, so all wobbles induced by riding are the result of spokes loosening due to vibration. Finding and tightening the loose spokes will result in a true wheel.

Rule 2: Righty-tighty, Lefty-loosey is WRONG! Do it backwards when truing wheels.

"What!", says you — I know, it's hard to believe. But look at the following picture and you'll understand why turning the spoke to the right loosens it instead of tightening it:

Spoke-screw diagram, from the side

Imagine that my crude graphic is a view from the side of your wheel, focusing on the place where one spoke attaches to the rim. The long and short of it is that the screw goes through the rim and into the top of the spoke. This screw is a normal screw, which is what makes things... er... screwy!

The issue arises because truing the wheel does not involve directly rotating the screw; rather, the spoke wrench grabs the black base into which the screw is mounted and turns the entire spoke! So, while turning the screw to the right would tighten the spoke, one must turn the spoke to the LEFT to achieve the same effect.

The Process

Now you have the conceptual understanding you need! The spokes pull the rim in one direction or the other; tightening the ones that are too loose will true the wheel. To tighten a spoke, turn to the left.

But how does one know which spokes are too loose? By the presence of a wobble, of course!

Step One: Find A Wobble

Don't bother buying a stand for your bike — just flip it upside down!

Finding a wobble is a relatively easy task. With your bike upside down, spin the wheel in question really fast. Slowly, very slowly, tighten the brake until you hear (or feel) the slightest brush of the rim against the brake pad.

The place on the rim that is rubbing against the brake pad is the largest wobble. If you think about the overhead view again, it's the part of the rim that sticks out the furthest from the center — naturally, it hits the brake first.

As the wheel decelerates, it will eventually stop with this largest wobble resting on the brake pad. Make note of which side the wobble rests on — that indicates which side of the spokes are winning the tug-of-war depicted above.

Step 2: Fix the Wobble

If the wheel stops while touching the brake pad on the even side, it means that the ODD spokes are too loose. So, follow Rule #1, and tighten some of the odd spokes! I tend to tighten the nearest two (or three, if the wobble is centered on a single spoke) spokes to the wobble. For really large wobbles, a few turns may be necessary. For smaller ones, half a turn can suffice.

Don't worry about fixing it all in one shot, though. This brings us to rule 3:

Rule 3: Make small changes, then test again.

After you make adjustments, spin the wheel and let it slow down just as before. Hopefully, the wobble has decreased; in an ideal situation, you may even be led to another wobble that was smaller than the first!

Step 3: Repeat!

Repeat this until all of the wobbles are gone. It's really that simple.

Review

The three rules you'll need to remember:

  1. Always tighten spokes to fix a wobble.
  2. Righty-tighty, Lefty-loosey is WRONG! Do it backwards when truing wheels.
  3. Make small changes, then test again.

Apply them like so:

  1. Find a wobble
  2. Fix the wobble
  3. Repeat