I am a new unicyclist and I recently moved on to a 36inch uni. And the biggest challenge is the mechanical trouble I have been facing.
Long story short, one of my spoke snapped on the hub side, and the tire is touching the frame. Took it to my incompetent LBS to fix, and they made my wheel way too soft and one spoke broke when I applied heavy load on one of the pedals.
When I was trying to fix it myself, I noticed the wheel is off set to one side. At first I though this is completely normal as my uni has a disk brake installed inside of the frame. But as I research further, I learnt about asymmetrical wheel built for inner disk brake.
The question is, should I apply more spoke tension on the disk side of the wheel to make it more centered?
Welcome to the forum
To make an asymmetrical wheel (any unicycle with an disc inside the frame) centered in the frame the spoke tension will have to be different from the disc-side to the non disc-side. And yes the tension has to be higher on the disc-side than the non disc-side.
Thanks for replying. My spoke is 13g, do you know how much tension should I apply on both side of the rim?
No sorry (but it’s probably not that important…)
I have spoke tension meter but I don’t use it to get exact kgf numbers - which is probably also not realistic to do as spokes are different (read e.g. Spoke tension - the definitive guide to spoke tensioning). But it’s a nice tool for having spokes evenly tightened and that is probably more important than the exact spoke tension. But you can also build fine wheels by feel / sound of the spokes if you don’t own a tension meter.
Do stock unicycles made by nimbus and Q-Ax with inside disc brakes come with asymmetrical wheels? I added a Disc Brake to my Nimbus 26er muni with a D Brake adapter and My nimbus 29 road that had a factory brake mount many years ago without rebuilding my wheel.
I believe so. Else they would need to have a (large) offset rim to make the spoke angles equal. I recently build a 29" wheel with a 4.5mm offset rim and it’s still slightly asymmetrical.
You can get WTB HTZ i40 rims with 7mm offset which is the largest rim offset I know off. They might make it possible to build an inner disc wheel with equal spoke angles (I did not try to calculate it).
This is my 29er, I’m assuming it is a symmetrical build as this did not come with a disc brake installed from the factory With the dic brake installed naturally there is a difference in offset on either side of the hub. As my picture shows my wheel placement is dead center at the crown of my fork.
My lack of knowledge on this topic leads me to question the need to build a wheel asymmetrically. I feel a stock unicycle without a factory disc installed would come with a symmetrical wheel. My 26er with a 3 inch tire has no clearance issues either. I will look at how it tracks in the fork when I get to work as that is where it is, I don’t recall having any clearance issues there either.
Symmetrical vs asymmetrical is not about the tire/rim being centered in the fork. It’s about the hub. If the hub flanges does not have same distance to the fork legs the angles (and lenght) of the spokes will need to be different to have the tire/rim centered (unless you have a rim with a very large offset). Standard rims for unicycles are not offset rims so they have the spoke holes in the center of the rim.
And by having a disc in one side inside the fork legs the distance from the hub flange in the disc side will be larger than the non disc side. Alternatively you can think of this as it’s about the distance from the hub flanges to the center of the fork (the spoke holes in the rim is centered in a non offset rim). And this distance is shorter in the disc side than the non disc side.
To anyone with a 36inch nimbus with inner disk brake (or anything similar), can you tell us if they came with asymmetrical wheels? What are your spoke tension?
The absolute tension is difficult to specify in general and you would also need a tensiometer to measure it.
However the actual value is not all that important, what is important is that the rim should be centred on the hub and that all the spokes on each side should have about the same tension as all the other spokes on that side. Pick each one and listen to the sound, all the spokes on a particular side should be about the same frequency.
There are good wheel building videos on YouTube, I have always found the ones by Ali Clarkson useful.
I’ve got one and as I managed to make my rim somewhat centered and true, some of the spokes’ tension on the disk side is 135kgf while some on the other side is only like 50ish. That makes me feel really uncomfortable and I don’t want spokes snapping again when I pedal hard.
Okay – so you need to find out what the maximum tension the rim manufacturer specifies for the rim and make sure it is under that on the tight side, I don’t think the spoke gauge is actually important. Also the tensions don’t all need to be exactly the same, but near enough. You basically then just have to make the other ‘slacker’ side is what it needs to make the rim centred, you don’t really have much control over the value.
I seem to remember watching this particular Park Tool video in the past, which may be useful, but have not had time to check fully if it is the one I am thinking of. I seem to remember something about a website where you can log all your spoke tensions to record wheel builds.