A short course for mounting a new rim
The mounting of a new rim is not as hard as you think. Just a little patience, some accurate work and some guts.
From start to finish It takes about three hour for one wheel.
We only change the rim and use the same spokes and hub.
In this course we use a brand new Mavic
26-inch XC717 32-hole rim.
What U need
Spoke tensioner, screwdriver ,
First we remove the outer tire, innertire and rimtape.
Then we loosen the spokenipples, one by one, one whole turn. And this three time around the wheel, to loosen the spoke tention gradually.
Now we take the new rim and put it on the old rim . Tape the new rim to the old one on three places , taking care of the right hole position.
Now we change the spokes, one by one, from the old to the new rim,
By loosen the nipple with a right size screwdriver from the outside of the rim.
Unscrew the nipple,put a little vasaline on the thread of the spoke and put the spoke in the new rimhole.
Put a little vasaline on the nipples and screw on the spoke. .
Thighten the nipples with a screwdriver from the outside of the rim, just far enough so that the end of exterior screw thread of the spoke is just covered by the end of the nipple.
Still the spokes are very loose.
Remove the old rim by cutting the tape
Now the real part begins, tightening the spokes !
Put the wheel back in the frame and tighten the nipples roughly a whole turn, one by one, around the wheel . Do not let you distract you by anyone in the counting.
Mostly three or four turns is enough to get some tesnsion in the spokes again, this depends on the spoke-lenght. Now we have a spoked wheels with some medium tension in the spokes.
First we look at the hight discrepancy of the rim. Turning the wheel and see if there apairs to be any wobble in the hight. Mostly when using a new rim and you have tensioned the spokes equally no wobble accurs. If there should be an light wobble, you can correct this by changing some spoke-tension in the area of the wobble and 180 degrees opposite the wobble. Make shure you tighten the spokes on both sites, so left and right equally.
Second we look at the weight discrepancy of the rim. Turn the wheel and use a referency point. I mostly use the vbrake pads as a guide. Straighten the rim by changing the spoke tension. When the rim wobbles to the right , increase the spoke tension of the left spoke(s) just litlle by little in very small steps at a time.
Try to get the weight error witin a millimeter all along the rim, this can take a while, be accurate.
Now we gonna have to crack the wheel to get the tension out of the contactpoint of spoke, hub, nipples and rim. Take out the wheel and put it flat on the ground, balancing it on its skewer. Push short hard down on the rim with two hand 180 degrees apart. You hear a cracking sound, turn the wheel slightly and push again until you have come around the whole wheel. Then flip the wheel over on the other site and to the same pushes.
Tracking and Umbrella
After the first cracking put the wheel back in the frame. Now we gonna make sure the rim runs in the middle of the frame, so the tracking of front and rear wheel is inline. Because we work on a rear wheel we have to make the spoke tension on the right site is greater than on the left site, so called making an umbrella.
Check the tracking by using the v-brake as a referency and flip the wheel over in the frame a few times.
By tightening the nipples of the spokes on one side we are able to move the rim to the desired side.
Meanwhile crack the wheel now and then.
The last thing we have to do is setting the correct spoke tension for all the spokes. This a feelingly thing, Tighten the nipples just a eighth turn at a time. You can use the other wheel as reference. Notice that in practice more spokes brake as a lack of tension than too much tension.
After you set the right spoke tension and a final crack we do the last check of wobbels and tracking,
Now the wheel is ready for lots of new rough trails.
Tipp: The less you use your brakes , the longer the rim last.