bearing help please

I loved this Thread!

I wanted to say that I enjoyed reading this thread! It was one of th emore informative thereads with a bit of soapiness to it!

I have always loved Feel the Light’s posts. Very informative and he usually always has a very level headed common sense opionion on most debates. Sometimes he does rub people wrong but that is an ok price to pay for the information that he dispences. I also think that people are way to sensitive in our politically correct world today!

I have just purchased a spare pair of bearings for my KHX 2007s. When I was in reserves last month I rode a lot in the desert I started hearing some squeaking coming from one of my bearings. I took the bearing caps off and cleaned the outside of the bearings and the insides of caps with a toothbrush. They were full of sand. I did not remove the bearings from the ISIS hub and then I put the caps back on snuggly but not tight with some locktight. I have not had a problem since and the spare bearings are just sitting on a shelf unused! Besides this one incident I have never had a problem with bearings. Much more common is bolts comming loose. I also believe that bearings don’t need maintenance and once they go bad they should just be replaced. The thing is I never had a pair of bearings go bad on me!

Keep up the good posts FTL!

Keep up the Great Utube posts Terry!


Another aspect…

Hello people,

I agree it’s not a good idea to mess with sealed bearings but it happens that they get dirty and gritty inside when you ride the unicycle on long trails with mud / dust / wet dirt…Just hold the wheel closer to your ears and give it a spin (watch out for the pedals…). If you hear that scratchy sound coming from the bearings then you might have this problem (let’s not talk here about too-tight bearing caps…) What to do now?

hmmm. if you just ignore this, with time the annoying sound will eventually disappear but talking with it days from the bearings life!

So, you still might want to service it in this sad scenario. If you do the cleaning/re-greasing job properly you may get away somehow better…

see this:

if you get the bearings out of the axle many times (in some cases just one time means many!) it may slip next time you put it on - so the need for some Loctite adhesive (609?) or spacers may emerge…

Finally, I would also like to know other opinions from the experienced ones in this matter - I just don’t like when the bearings get “clogged”…and they do :frowning:


UAC- isn’t this a bit of apples to oranges ?

Skate bearings come packed with air and lightly oiled. Their “seal” is a metal plate retained with a circlip. It is designed to be removed and oiled periodically with the oil they provide.

Uni bearings come packed with waterproof grease. They are fit with a precision seal that will be damaged it you pry it off, crating a gap for water and dirt to enter. The manufacturer does not intend for the seal to ever be removed, it has no circlip.

Read this info page from SKF, maker of many uni bearings. Pay special attention to this quote from the second paragraph.

“The bearings with shields or seals on both sides are lubricated for life and are maintenance-free.”- SFK

Also, the way to test a bearing is not to spin the wheel and listen, as noise may have multi origins. Remove the wheel and rotate the outer shell of the bearing with your finger. If it turns smoothly without sticking in spots, it’s ok.

I suspect that if you find your bearings go bad after a short dip in the mud, you may have washed the waterproof grease from around the bearing seal. Or did you spray them with wd40 ? Note how in the above short article, they warn not to wash the bearing. A light spray with a hose should be fine I think, but blasts of soapy water may ruin the waterproof seal by dissolving the grease around the lip.

Some more info

The type of bearings we use are called “sealed bearings with contact seals”

Click on the above link, and note that bearings from 25 to 52 mm come with type RSH seals. (third paragraph) We use 42 mm.

Then go to the bottom and read the last paragraph

“Details regarding the suitability of RSH and RS1 seals for various operating conditions will be found in table 1.”

So click on table one.

Note that type RSH seal are rated excellent for water and dust exclusion, and grease retention.

But only if you don’t bugger them up !:slight_smile:

After my first muddy muni even, my bearings got grit in them, and I hadn’t touched them. It wasn’t that it fell into the lake. Replacing them was definitely the fix.

Another time and unicycle, found some really poor bearing on a new unicycle, not the most inexpensive model. Was missing the lip that holds the seal, didn’t even have a cover on it. Unicycles are made with rejected bearings, so you can’t count on that excellent quality.

One more thing, Unicycle frames, anything better than entree level should be made to hold the bearings without crushing them, like the great KH frames.

Bearing Questions

Feel the Light - Those are awesome data pages by SKF. Thanks for posting them.

A few quick questions:
How do you know that we have RSH bearings? I mean the KH bearings on my unicycles say Qu-Ax 224212-RS. What does the RS and or RSH stand for?

Also can we close the Kris Holm frames all the way until the bearing cap touches the frame or should we leave a slight little space?

Right now there is about a quarter to half mm crack between my bearing caps and frame on both my KH unicycles. All three of them seem doing be doing fine.


My KH 29 frame has the caps touching the frame, the are bolts tight, there is no drag on the bearings.

-RS means “Rubber Sheild”, technically the bearing should have -2RS on it as this means that it has rubber sheilds on both sides.

as for tightness of the bearings…
Please, please, please read the instructions that come with the unicycle!

If the bearings housings are touching then they are way way too tight and you will probably have distroyed your bearings. Certainly your wheel will not be turning smoothly. There should be a gap. The bolts should be only a little bit above hand tight as the outer bearing casing are delecate.


Thanks Roger and more info

Hi Roger,

I always post informative leters for the public to read and not as Private Messages. Thanks for the post.

First of all I got the bearing that I ordered form you very fast. Less than 5 days after ordering they arrived! That has got to be a record for both the Israeli and British mail systems! I do not actually need them right now but I figure that it is good to have a spare set.

I closed my KH bearing caps on all 3 KH models that I have just a tad bid more than was required so that the wheel did not rattle in the frame. This left about a half mm space between the flat parts of the bearing caps and frame. Another quarter to half turn of the bolt would have brought the bearing caps and the frame in contact. Would this be to tight? I don’t know. It seems like many riders are riding this way with no bad effect on the bearings. It seems like KH would have designed his bearing caps and frames to fit snugly against each other. I figure that I will feel it if the bearings get loose in the holders and I always have the basic tools to do a quick 20 second tightening. Therfore I leave the little space. I have written to Kris about posting the maintenance instructions and technical information on his site. I got the instructions in German only from MDC.
On my Onza there is a good centimeter space between caps and frame. this is understandable because they are pressed from CroMoly and are not forged or CNCed solid aluminum. I think that most people have to be careful with the CroMoly frames. The KH Aluminum frames at least seem to be desinged to fit togethr perfectly therefore giving an idiot proof safeguard against over tightening.

All the Best!


Wow! My KH bearings were to tight !

When I wrote that you must be careful not to tighten the caps down on MOST unicycles, it was because I, like the rest of us (except Roger), thought that KH was an exception, and that KH caps could be put on all the way, with no gap.

So after reading Roger’s comments, I flipped over my '07 KH 20 and gave the wheel a spin. It spun around smoothly, for 4 revs. Seemed ok to me.

But when I loosened the cap bolts a half turn each and gave the wheel the same shove, it spun around for 12 revs!

As usual, Roger is right. :sunglasses: I also had to loosen the caps a bit on my 05 KH 24. Oh well, live and learn. I hope they aren’t damaged. I’m real fussy about my motorcycle wheels, and will replace a bearing for the slightest sticky spot. The uni’s don’t worry me much. It’s not going to be driven 100 mph ! So I’ll just wait until tire change to check them.

Some of us may be using SFK bearings (UDC sells them). There are many brands, and they are all pretty similar IMHO. Perhaps, like anything else, it is possible to find some junk from China or something. If you can find some in your size, the ones with teflon shields may be better, but that is just a guess. They seem to cost slightly more.

RS1 means one rubber seal. This is used on motorcycles, where the unsealed side faces inward to the hub.

RS2 means two rubber seals. I guess SFK’s RSH means the same as RS2.

Z means one metal shield and ZZ means 2. I would avoid these, they are less water resistant then rubber, and cost the same.

OMG, Even after reading Roger’s post I thought KH was and exception to ‘carefully snug’ tightening the cap bolts. But, with the last post from ‘feel the light’ I had to check my KH. The wheel does roll better with the cap bolts loosened.

I hadn’t notice the difference when I put the wheel on the frame. With the bolts tight it rolled well, but loosen a bit and it coast twice as far.

Thank you ‘Roger’ and ‘feel the light’ for explaining this.

I remember Roger telling us this handy bit of information during a maintenance class at BUC and thinking “That’s a really good piece of advice. I should post that on the forum next chance I get.”

And promptly forgot about it.

What if my wheel won’t spin anymore…Something tells me that they NEED mantinence…