‘They’ say that bolts on bearing holders (‘C-cups’) should only be tightened so much, so as to have the bearings not bind. I have found that binding is a gradual process in the sense that even a quite loose tightening slows down the wheel a little bit.
When I mounted the wheelset in my spanking new KH24 last week I thought I hit a good compromise. Yet the bolts on both sides came loose during the maiden trip. I could feel sloppiness in the wheel. Now I’ve tightened them a little more, not caring of even checking about them being more binding.
My question: what is wise?
a. Tightening them so much that they will stay in ‘for sure’?
b. Tightening them just so much that they probably stay put, and carry an Allen wrench on rides?
c. Tighten them only loosely and use loctite?
If a, the bearings will be binding. Probably not so much that it hinders riding, but it will provoke more wear.
If b, it seems like a design fault. I think it should not be NECESSARY to carry tools.
If c, again it seems like a design fault. There must be a way with a counter nut to tighten a bolt lightly, yet have it not work its way out. Oh, and also, if c, I should have to go out and buy the stuff, I’ve never used it I think.
I have found a solution. Use pinch nuts (you’ll have to upgrade your bolts too). They can be tightened to where they are just right and they won’t come loose. They are much better than Nyloc nuts too. You may have to hunt around for a supplier. I get mine from Wicks Aircraft (wicksaircraft.com), but that’s in the States.
Even the aerospace industrial equipment I work on can’t be made so that the bearings can be easily changed without having some kind of spacers in the mount. We’re talking ten thousandths of an inch here (micro meters) and the bearings can easily be deformed that much. You’re options for proper installation are:
>Have bearing holders made that completely encircle the bearing, to extremely fine tolerances. VERY expensive.
>Have bearing holders made to lesser tolerances, probably with shims. More expensive than you’d want on a unicycle.
>Add a spacer with shims and tighten so that the bolts don’t come loose. Loctite is still a good option here.
>Use a jam nut (usually thinner than a normal nut - used to lock the nuts together), but this will require a lot of fiddling to get the compression just right - as you tight the jam nut the main nut will move. This works ok - on something that doesn’t get beat on as our unicycles do.
>Loctite or similar anti-vibration treatment.
Obviously, Loctite is the easiest, least expensive option, a lot of our bolts (at work) get either lubricated (with anti-lock) or Loctited.
For the GB4 and Hunter frames, which have a very nice completely-encircling bearing holder, I tighten the bolts to 40 inch-pounds and use blue loctite on the threads. Works well but you still have to be aware of your uni’s feel to detect those little clunks and bumps, as well as frequent visual and tactile inspection.
The bearing holder bolts often come loose during the first couple of rides on a unicycle with machined bearing holders (KH, GB4, DM Vortex, Hunter, others). It happens to me too. My fix is to use Loctite threadlocker on the bolts. Medium strength Loctite is plenty strong enough, but you can also use the high strength stuff if that is all that you have on hand.
The Loctite will keep the bolt from vibrating and working itself loose. The Loctite is not strong enough to make it difficult to remove the bolts later.
When you later remove the bolts or have to readjust the bolts you’ll break the Loctite bond. But I’ve found that it is not necessary to immediately reapply the Loctite. The old dry Loctite in the thread grooves will continue to keep the bolt from vibrating even though it is no longer bonded in place.
I go for finger tight. I don’t have a torque wrench that can measure those small torques, so I can’t give you a torque measurement for what I use. My rule of thumb is that if I make a fist around the allen key I’m going to get it too tight. I just hold the allen key by my finger tips and get the bolts tight enough just to be snug. That seems to work for me.
I always carry an allen key that fits the bearing holder bolts. If something comes loose on my during a ride it will most likely be the bearing holder bolts. It is not wise to go on a muni ride without carrying at least a few tools. Muni has a way of making things vibrate loose. At a minimum you should carry allen keys to fit the bearing holder bolts, seatpost clamp, and crank bolts. I carry my little collection of allen keys and other small tools in an Altoids mint tin. It’s small. I just throw it in a pocket in my hydration pack.
I don’t have any Loctite at all. Am I strange or what? But, I will buy some. Would it be called Loctite over here?
How you describe finger tight, it already binds my bearings to a small degree, in that the wheel will not come to rest with the heaviest point at the bottom. Not a problem with riding at all, probably also not wear-wise.
That was how car drivers had to go out 50 years ago. Not anymore so. MUnicycles apparently live on an earlier stage of the evolutionary ladder.
> Thank you Mr. Loctite.
> john_childs wrote:
> > …you can also use the high strength stuff if that is all that you
> > have on hand.
> I don’t have any Loctite at all. Am I strange or what? But, I will buy
> some. Would it be called Loctite over here?
Loctite is a brand name, so you might find it where you live. I use a
different brand (whose name escapes me at the moment), but the product
is generically called “thread lock” or something simiar. Any hardware
or automotive store should be able to help you find the stuff.
The generic term is threadlocker. Loctite and Permatex are two common brands over here in the US. You should be able to get it at stores that sell automotive parts.
It’s just tight enough to be snug. The Gazz, or any large heavy tire, is too heavy to allow the wheel to settle the same way it does with a lighter street tire. The weight of the stem is insignificant compared to the massive weight of the tire. So you can’t rely on the spinning the wheel and watching the way that the wheel comes to rest. With lighter wheels the wheel will come to a jerky stop if the bearings are too tight or the valve stem will come to rest at the bottom. Not so with a big heavy Gazz. You have to go by general feel.
Unicycles and bikes are mechanical and they get some rough treatment. Things break or come loose during rides. It’s hard to avoid that. Putting threadlocker on the bolts that can vibrate loose will help minimize the chance of something coming loose during a ride, but it can’t eliminate it. I bring more tools when I ride my bike than when I ride my muni. Many more things to possibly need to fix on a bike. On my bike I’ll bring a chain tool, extra master link for the chain, a multi-tool, a few zip ties, spare tube, patch kit, tire levers, and pump. On my muni I’ll usually only bring a selection of allen keys. I don’t really worry about flats on the muni for most rides. Only on long epic rides do I bother to bring tire tools and a few extra tools.
One of the major reasons you don’t need to carry tools in your car is that the automotive manufacturers now use threadlockers. It’s actually designed in.
