Wheel Building: Truing A Bike Wheel
This article was originally posted by headstrong356 on the Bike198.com forums.
On your bike there are several key components that really make your bike perform on the trail. Wheels are one of these components. Wheels are amazingly strong for the few spokes keeping it together, but not indestructible. All wheels concentrate on taking vertical loads from things like jumps and bumps but are vulnerable to side loads which in turn knock it out of true. Sometimes it can be disastrous with the wheel looking like a taco shell, but other times really minor and have a wobble from side to side noticeable when viewed from above the wheel.
You can save your wheels as long as it has no more than an inch (2cm) of movement to each side. If there is more you are more than likely going to have to build the hub up to a new rim or buy a new wheel all together. Assuming you’re on the trail, regardless if the wheel is beyond the point of return, try to make it as true as possible and capable of returning back to your house or trail head. If your riding rim brakes make sure it can go between the brake blocks. As undoing the brakes to allow the wheel to spin again is not a good idea. Chances are after 10 minutes of careful riding you’ll be wiped-out remembering you undid the brakes a while back. If you have disc brakes you have it easy, just make sure it can pass within the space allowed by the fork or frame.
How To True A Bike Wheel
Now to get down to business, how do you true the wheel? It is simply a matter of balancing the force of the spoke pull on the left side to that of the ride side, causing the rim to make a true circle. By tightening a spoke the rim is pull toward that spoke and moved away by loosening. The spokes are tightened by turning the nipples counterclockwise and loosening by turning clockwise. The nipples are the little bits with flat faces that connects the spokes to the rim. They adjust the length of the spoke by spinning them and in turn the force each spoke applies on the rim. The spoke wrench grasps the faces of the nipple to turn it, like any wrench and bolt. It may take some time to remember this and can make for worsened wheels if you forget. It may help to write it down to and put it in your workshop or whatever you carry on the trail. I even knew a guy who engraved tighten on the place where force is applied when tightening on the spoke wrench he used. Which reminds me, to do this task the right way get a spoke wrench or multi-tool with the right size of spoke head as there are various sizes.
Step one: If you don’t have rim brakes you’ll have to find another way to map out the center point where the rim should be. You could use a wheel jig if you have one at home. If you don’t have rim brakes or don’t have a jig use the following placed on each side of the rim on the frame or fork: post-it-note, zip tie, pipe cleaner (kid craft type) or tape something up like cards. Use them as your reference point to notice the wobble and were the center should be (ideally the rim should be in the center).
Step two: Spin the wheel and stop it at the biggest bulge of movement. Find the spoke at the center of the bulge.
Step three: If the spoke leads to the side of the hub opposite to the bulge tighten the spoke and loosen the two on each side. If the spoke leads to the same side as the bulge loosen that spoke and tighten the ones beside it. Proceed with small quarter or half turns and take notice of the movement caused. When the bulge section is in the right place according to the reference point or centered, return to step two. If all the noticeable bulges are gone but you would really like to fine tune move the reference points in. If you are using a jig you can simply twist a knob located around the reference walls to move them in. If you’re using brake blocks tighten the cable of the system. If using something I suggested above, move it manually.
And there you have it a basic, but very important skill in the world of mountain biking and biking in general.
Notes: If you’re on the trail and have broken a spoke, use the spokes around the broken one to compensate until you can get a new one. After truing the wheel it is a good idea to flex the spokes to relieve some tension as the spokes may become twisted. This should result in a ping like noise. After flexing both side repeat step two.
Hope this helps… if notice any things I could add or change let me know (both spelling and wording). After all the easier it is to follow the better. I’ll be posting up more tutorials if time allows, suggestions are open.
Some Additional Wheel Truing Tips from fipogg
Few useful info I have found while learning theory over the internet and by personal experience while trueing my first wheels:
- Apply some light oil to the nipples before you begin to tighten the spokes.
- Ask your preferred bike shop for the correct spoke and nipple size in case you need to replace a broken one or you would like to build a whole new wheel on your own (Like me). Have your rim brand and model, the hub brand and model and the number of spokes. This is required information.
- On your rear wheel, the spokes on the freewheel side are tighter than those on the non freewheel side.
- If you are going serious about truing your own wheels at home, get a truing stand, a good spoke wrench and a spoke tension meter. The latter has helped me a lot build long lasting wheels.
Last but not least, have patience. Truing is a real trial and error time consuming task.
Image by alex_ferguson