I just noticed today that my wheel does not sit straight in the drop-outs. This is a mountain bike term so let me explain in case one-wheelers don’t use that terminology.
My wheel at the top sits closer to the left frame arm than it does the right. I am wondering if I am looking at a manufacturing defect or if there is a way to adjust this. I am surprised I never noticed it earlier. I noticed it because I installed my brake after bleeding it and the left pad sits MUCH closer to the frame than the right pad. So upon closer inspection, the wheel has twice as much space for clearance on the right side.
Is there an adjustment I can make??? Or do I need to turn this in as a warrenty issue??
There have been posts on thios problem (with other makes of uni) before, and a search of the forum might help.
First, is the wheel in properly? Are the bearings sitting snugly in the holders?
Next, try taking the wheel out and putting it in the other way round. Now, is the problem on the SAME side (in which case it’s a frame problem) or the OTHER side (in which case it’s a wheel problem).
If it’s a frame problem, the frame could be slightly out of line. Take careful measuremeants of the length of each fork leg. Also try measuring diagonally from the bottom of the fork leg to the inside corner of the top of the other leg. Anything obvious jump out at you?
I don’t know specifically about the KH frame, but unicycle frames are pretty simple bits of kit, and I guess that they are pretty much thrown together by Taiwanes factory workers whose heart isn’t really in the job because they’re sitting there thinking, “These bikes will all be sent back - they don’t have enough wheels, even i can see that!” So, don’t expect precision engineering.
Remember that if you are noticing a difference of (say) 1/4 inch at the tyre, that’s 12 inches (approx) from the centre of the hub. At the hub, the ‘error’ might only be a tiny fraction of that. (It’s all to do with cosines an’ stuff.) So, putting a thin piece of metal in the bearing holder will make a big difference. This is called a ‘shim’. Cut with tough scissors from a soft drink can. Put it in the ‘drop out’ of the fork leg which seems too short. Experiment.
Or, if the frame appears slightly twisted, you could apply brute force and ignorance.
If your cranks are not really tight on the hub the bearings can get sloppy and rock back and forth on the axle. This bearing movement can cause the wheel to get off-center in the frame.
The splined hubs (like the KH and Profile) are designed to squeeze everything together to keep the cranks and bearings tight. The hub has spacers on each side of the bearings to position the bearings at the right place. When the cranks are tightened up they squeeze the spacers and make the bearings snug so the bearings don’t move.
The cranks need to be on very tight or else the hub and bearings will be loose.
The KH has two bolts on each crank. There is a pinch bolt and a larger retaining bolt at the end of the hub. Both bolts need to be tight.
First loosen up and remove the pinch bolt. Put some anti-seize on the pinch bolt threads. Now remove the retaining bolt. Put some anti-seize on the retaining bolt threads. Now remove the crank. Put some anti-seize on the splines on the hub and inside the crank. Put the crank back on the hub. Put the retaining bolt back on. Tighten up the retaining bolt. Make it really tight. Put the pinch bolt back in the crank and tighten it up.
The retaining bolts need to be really tight. I check the retaining bolts on my Profile cranks every couple of rides. If my cranks are just a little bit loose I can see noticeable movement of the wheel inside the frame.
A couple of notes:
You can get anti-seize at most auto supply stores (like NAPA). Ask for coper based anti-seize. You only need a few onces at most. Get the smallest size that you can. Even just 4 oz. jar will be a lifetime supply for a home user.
Tighten the retaining bolts equally. Don’t tighten one side up really really tight while the other side is loose. The axle is just press fit in the hub body and tightening up the retaining bolt on one side of the hub while the other side is loose can actually cause the axle to be moved off-center inside the hub. Tighten up the right side 1/2 a turn, then tighten the left side 1/2 a turn, then tighten the right side 1/2 a turn, etc.
> I just noticed today that my wheel does not sit straight in the
> drop-outs. This is a mountain bike term so let me explain in case
> one-wheelers don’t use that terminology.
Mine too. I don’t trust machine built wheels, so I was planning to
true the wheel anyway. Moving it 1/4" laterally was no problem - I
just used the frame for reference and assumed the wheel was round to
start with. While I was at it, I upped the spoke tension and
“tension-relieved” the spokes just to be sure. I also noticed that
the spoke nipples are alloy (not brass as per Unicycle.com’s
description) and I couldn’t find a spoke wrench that fit them well.
To be honest, I didn’t consider that the beasings might need to be
shimmed to get the wheel to sit straight. So I just took a
straightedge and eyeballed the alignment of the wheel (holding the
straitedge against the tire at two points, and parallel to the frame).
It looks like the frame is out of alignment by maybe 1/16" (2mm),
which seems entirely acceptable when using a 3" tire.
> Is there an adjustment I can make??? Or do I need to turn this in as a
> warrenty issue??
Let us know when you find out.
Now I have a question: After 11 (not very intense) days with my KH24,
the bearing holder bolts came loose. How tight should these be
tensioned, and should I use locktite?
(remove lower case letters from domain)
P.S. sorry if the Reply-To: and From: fields are bogus. I’ll get
around to fixing them soon.
Zod, don’t come crawling to me, asking for help NOW!!! If you will remember, when you originally got your KH24, I willingly offered to do a full inspection and multiple test rides for you. BUT NO, you could only accuse me of trying to steal your new uni. I guess now you are regretting that decision!
One day you will say your sorry, and from that day forward, hopefully you might recognize a kind and caring fellow uni rider, willing to offer you his inspection and test riding skills.
From across the mountains, I still remain,
Inspection King… --chirokid--
The bearing holder bolts need to be tight enough so that they don’t come loose but not so tight that they bind the bearings. It is very easy to get the bearing holder bolts too tight, so tight that the bearing cannot spin freely.
My rule of thumb for tightening bearing cap bolts is to use only finger pressure. I hold the allen key with my finger tips. If you make a fist around the allen key you are going to get the bolt too tight.
You need to appreciate how much leverage a threaded bolt (or screw) can generate with just a 1/4 turn or less. It only takes 1/4 turn to go from just right to way too tight.
Hold the unicycle upside down. Loosen the bearing cap bolts. Now spin the wheel. Notice how freely it spins. Watch how the wheel comes to a stop very gradually and very smoothly.
Now tighten up the bearing cap bolts. Hold the allen key with your finger tips and use finger pressure only. Spin the wheel again. Does it still spin as freely as it did when the bearing cap bolts were completely loose? If the bearing cap bolts are way too tight the wheel will be jerky as it comes to a stop. The jerkiness is due to the bearing binding (the ball bearings cannot spin smoothly). If the bearing cap bolts are only slightly too tight the wheel will spin less freely and will come to a stop sooner.
Many many unicycles with the split bearing caps have the bearing cap bolts too tight. Surprisingly, unicycles at bike shops often have the bearing caps too tight too. Bicycle mechanics should know better than to over-tighten those bolts, but sadly some of them just don’t get it.
Loctite is helpful to keep the bearing cap bolts from getting loose. Blue (medium strength) Loctite is plenty strong enough. Loctite is a good thing ™. If you don’t use Loctite just check the bearing cap bolts after every couple of rides to make sure they’re not loose.
Well I can’t really use the brake because the wheel sits too far to one side… It works a little bit but not as well as I need it to in steep sections of trail. I would say you will most definitly want a brake. It is a powerful addition to the mUni arsenal!
I still haven’t had time to look at fixing my alignment problem…maybe tonight though
The KH20 and KH24 hub/cranks have spacers inside the bearings, and one spacer on each side outside the bearings. The spacer outside the bearings is large and tapered on one side.
Check to make sure that this large spacer isn’t rubbing slightly on the bearing housings. The tolerance is very close. If it is, then it is simple to fix- just flip the large spacer around by 180 degrees. This moves it slightly outwards due to the taper on one side of the spacer, and solves the problem.
When I got my KH24 this spring I had the same problem. The wheel was
so far out of alignment that it made it awkward to ride and one sided.
The wheel builder at my local mountain bike store had to rebuild the
wheel. It was very poorly built, some of the spokes were so tight they
had trouble releasing the tension, others were loose. The rim was off
to one side 3/8".
I sent an email complaint to Unicycle.com but got no response. You
would think they would at least offer to pick up the cost of the
rebuild, althought I would have been more interested in an apology. If
they want to ship product like this they should at least specify the
wheel should be tuned before use.
I thought I might have trouble with the spokes in the future but so
far all is ok.
I can afford the cost, but I’m sure a lot of riders have to save like
hell to buy a Uni like this.
> When I got my KH24 this spring I had the same problem. The wheel was
> so far out of alignment that it made it awkward to ride and one sided.
> The wheel builder at my local mountain bike store had to rebuild the
> wheel. It was very poorly built, some of the spokes were so tight they
> had trouble releasing the tension, others were loose. The rim was off
> to one side 3/8".
> I sent an email complaint to Unicycle.com but got no response. You
> would think they would at least offer to pick up the cost of the
> rebuild, althought I would have been more interested in an apology. If
> they want to ship product like this they should at least specify the
> wheel should be tuned before use.
If it makes you feel any better, Unicycle.com Help Desk apologized to
me for my poorly dished wheel when I emailed them last month. It cost
me a new spoke wrench (which still didn’t fit the nipples very well)
since I trued it myself. Also, they told me they hadn’t heard this
I have been riding my mountain bike exclusively the last few months so I had not looked at my KH24 issues. I am going for some mUni today however so last night I stripped it all down and looked for the problem.
This time it didn’t take me long to find it. With everything off the frame I eyeballed the frame and it’s clearly visible to the naked eye that one fork is signifcantly shorter than the other. I even had my wife look at it to make sure I wasn’t making it up. I was not super concerned since people say making a shim can solve this issue. So I could ride today I tried the soda can shim method. I used 4 aluminum shims and it still didn’t get the wheel anywhere near sitting centered in the drop-outs. I couldn’t use anymore than 4 shims because it would have made the bearings sit higher than the groove on the frame. I would guess it would take about 8 shims to center the wheel.
I am not a picky person but this to be is an unnacceptable amount of frame defect and really should not have gotten past QA inspections. I am going to contact uni.com today about getting a replacement frame. I certainly hope they are understanding but I always have faith in Christian based businesses.
This IS a new problem you are describing. All the frames that we have checked and those we have had reported back to us have not had one leg longer than the other, but have had a problem with the frame being out of square. This is due to the frame design and the large about of welding that is required during construction, it basically pulls during manufacture.
If you could check using the instructions on the web page on how to bend the frame. It will confirm that it is definatley a new problem.
Thanks Roger for the quick response. I know it’s not the wheel…the first thing I checked back in November was truness and dishing. The wheel is perfect.
I really don’t think the frame is tweaked, upon close inspection it looks fine, except for one leg being way too short. I still need to measure the legs though and if they are the same then I will try the bending technique BUT only after I talk to uni.com in the USA and make sure they are OK with me doing so. I don’t want to void any chance of me getting this frame replaced…that’s a lot of money
Well I measured the legs tonight and it turns out the legs ARE the same length…so I guess the frame needs to be straightened.
I tried to do so as you instructed Roger but this is damn near impossible with the KH-24. I can’t get the thing to budge at all it’s just too burely. The hardest part is step #7. The KH-24 is just too strong to bend the leg by pulling upward. All you end up doing is pulling your foot off the ground where you are “gently” trying to push down on the seat post.
This might work OK with cheap unicycles but it doesn’t appear to work at all with the KH???