Power Kite Forum - Is this why our bearings wear out?

Is this why our bearings wear out?

rtz - 25-4-2014 at 08:26 PM

The grease(oil?) gets hot and thins out and "centrifugal force" causes it to migrate outwards and the weight of itself causes it to get forced out of the edges of the "dust shields". This is where all the bearing grease goes and how eventually the bearings run dry.

I read somewhere that too much grease in the event of a repack will cause the bearings to be slow due to having to churn their way through all that grease.

Besides there being different types of grease; the issue of not mixing certain types.

Some interesting reading on grease:

https://www.etrailer.com/faq-grease.aspx

----

Something I find amusing: You know how with new bearings they won't freewheel? I know someone and he has some very well worn bearings and they will "spin" for a very long time. I can hear them; but they seem to work just fine. I went through 2 sets of China bearings and they wore and got notchy due to water getting in them. The notchy bearings also roared when I'd ride on them. I haven't got these bearings wet yet..

RedSky - 25-4-2014 at 09:37 PM

I bought a set of new bearings and packed them with white marine grease. I was bored after the first two with six more to do but months later and seven beach sessions in they're still running completely silent which is not normal.

When I opened up the new bearings I was shocked to see only a thin film of clear grease. No wonder they never lasted.

Oh the novelty of silent running bearings, its lovely. Placing music over ones buggy videos to hide the shame of squeaky bearings. Now I can hold my head up high as I pass on by. :D

bigkid - 25-4-2014 at 10:13 PM

you dont pack new bearings.
you tighten the axle until the wheel starts to slow down as you spin it, then back it off a hair, done.
not sure why people repack bearings, i have never repacked any of my bugs. I have on;y replace 2 bearings in all the wheels I have rode on. I abuse the bearings by going everywere and never cleaning them. I do wash off the crap from from the bug from time to time but the bearings are not worth the effort or time to mess with, in my opinion.

USA_Eli_A - 26-4-2014 at 09:58 PM

yikes, be careful if you repack your bearings.

Only pack them just under half way, or they might leak.

Silent bearings are great, leaky not so great.

I've seen bearing as little as $30 for 10 count!

Chrisz - 27-4-2014 at 05:54 AM

There is a difference in made in China bearings and made in USA bearings. I use to go through a lot of bearings on my idler wheels on my snowmobile I quit buying the $10.00 bearings and went back to the OEM Ski doo berings, problem fixed.

I would get 4,0000 miles out of the expensive bearings and only about 1,500 miles out of the cheep bearings. Bearings on a snowmobile take a beating, water, ice snow and -30 below temperatures most likely running over 200 mph when I am snowmobiling at 50 mph.

Buy good bearings!

BeamerBob - 27-4-2014 at 08:41 AM

A year ago, I bought 30 bearings for $50. I've been running them on 2 of my Landsegler wheels since then and they are silent and spin freely. No way would I take the time to clean and repack bearings for this application. I also can't justify spending any more money on supposedly better bearings while getting such good service from such inexpensive bearings.

Oh, bearings that spin freely in your hand don't have any grease in them.

AudereEng - 27-4-2014 at 11:48 AM

I have purchased these ebay bearings with good results which fit plastic wheels with a 20mm axil.
http://www.ebay.com/itm/6204-2RS-PremiumSealed-Bearing-20-x-...
I received KML part number 6204-2rdqe6

They are cheap (made in China) bearings but the dual seals seem to help for my local conditions.

On the beach we get a lot of blowing sea mist from the ocean even if you avoid the standing water runs.
It often looks like an engineering salt air test here... for example, disk brakes can get covered with rust while you buggy.
I have found washing down the buggy with a water spray hose around the bearings is a bad idea and just leads to faster failure...
Silicon oil spray does not help...
But with the dual seals I get 50+ sessions from a set of bearings. YMMV..

bigkid - I am confused - I assumed the internal wheel spacer (aka a bearing spacer) takes up all the axil load?

John Holgate - 27-4-2014 at 03:51 PM

Quote:

I assumed the internal wheel spacer (aka a bearing spacer) takes up all the axil load?

I think in theory it is suppose to. However, I find the same as Jeff - if I overtighten the axle nut, the bearings get too much friction and the wheel slows down - so I end up doing exactly what Jeff said. This with both plastic and sysmic wheels that do have the spacer in between.

I tend to get two seasons out of the cheap Chinese bearings but do much better out of brand name precision bearings....but then they cost more too. I've cleaned out and repacked a seized bearing - it worked and I had the spare time and inclination to do it rather than chuck a new one in. I can't stand noisy bearings or rusty ones either but I guess it's different strokes......

BeamerBob - 27-4-2014 at 06:20 PM

I tighten my bearings the same way. Bind it up and then back up an eighth of a turn.

rtz - 27-4-2014 at 08:35 PM

How does the axle bolt stay tight after it has been loosened up?

soliver - 27-4-2014 at 09:27 PM

I have never re packed bearings, but I did find a great product called Invisilube. It's an aerosol grease that sprays out as an aerosol liquid then coagulates into a standard grease. I work in facilities maintenance where we have access to a boatload of different types of lubricants for HVAC equipment, and I found this one to be great.

I had all 6 of my bearings out when I was reworking my buggy about 4-5 months back and basically hosed down my bearings with the stuff... Sprayed it in and all over and around them til I felt they were penetrated well enough, let them sit overnight and they haven't run better since they were new.

John Holgate - 27-4-2014 at 10:33 PM

Quote:

How does the axle bolt stay tight after it has been loosened up?

In my case, all my axles are gal or stainless threaded rod with nylocks on the end - I think I got that idea from Beamer Bob.

Before that, backing off just a smidge still had the bolt under plenty of tension.

BeamerBob - 28-4-2014 at 06:47 AM

John I got the idea from Popeye the Welder. Soliver, there is a range of when the axle nut is "tight". Too tight makes the wheel turn slower, but backed off just a bit to free up the bearing is still "tight" enough to not loosen.

soliver - 28-4-2014 at 09:15 AM

Thanks for the info Bobby, but I think someone else was asking that question :smilegrin:

I do the same thing with my axle bolts... Tighten it up until it binds a little then back off a tidge. It's also a little different with my VTT bug where the axle bolt goes through a 1/2" plate (welded to either side of the main axle piece) and receives a lock-nut on the other side unlike most bugs where the bolt screws right into the axle. I can tighten the nut up til the wheel binds and back off a little and never worry about it coming loose since it's a nylock style lock nut.

BeamerBob - 28-4-2014 at 10:20 AM

Quote: Originally posted by soliver

Thanks for the info Bobby, but I think someone else was asking that question :smilegrin:

Hah! Busted!

awindofchange - 28-4-2014 at 05:50 PM

You can also get a jam nut on the inside of your axle bolt, that way you can properly tension the bolt against the bearings, then crank on the jam nut against the axle to make sure your bolt is tight and won't come out. If you want to add jam nuts onto your PL or other buggy, you may need to check the threads left on the bolt before the bolt is inserted to make sure the bolt has enough threads inside the axle after the jam nut is installed.

food for thought....

USA_Eli_A - 28-4-2014 at 09:44 PM

:thumbup:

RedSky - 29-4-2014 at 05:23 AM

So I'm the only one who packs new bearings? Yes Red, it would seem so.

AudereEng - 30-4-2014 at 10:21 AM

I pulled the seals off the last set of bearings I replaced.
This bearing had just started to tick - not yet to the whine stage.

I see enough grease in the bearing but the seal failed (probably due to sand abrasion) from the riders side of the wheel.
The outside bearing was good on both sides.

The good side, The bad side + closeup

USA_Eli_A - 1-5-2014 at 09:00 AM

Quote: Originally posted by RedSky

So I'm the only one who packs new bearings? Yes Red, it would seem so.

It's a great idea to repack them if you live on the beach. Bison, and Jellis know not to repack them with too much grease!

If the seals leak you get that stuff everywhere....

It isn't fun, but I saves throwing them in the scrap metal pile!

RonH - 1-5-2014 at 06:00 PM

If the the space in the center of the rim and the spacer match within about 0.0005" then you can tighten all you want and there won't be any noise or slow down... Most of the spacers are junk. That is why you have to back the nut/bolt off a bit...

awindofchange - 1-5-2014 at 06:04 PM

Totally agree with RonH. If the spacer is the correct size, you can crank the bolt down tight without having any drag on the wheel. If the spacer is not correct, if you tighten it down it will cause drag on the wheel. If you need to back the bolt off, your spacer is not correct.

BeamerBob - 1-5-2014 at 07:08 PM

Many machine shops can't hit .0005, or if they can they will charge highly for it since they will have several that are culls before they get one right. Machinists say that as "half a thousandth". My calipers only measure that high precision and it's hard to even measure consistently and repeat a measurement to that precision.

RonH - 1-5-2014 at 08:17 PM

Quote: Originally posted by BeamerBob

Many machine shops can't hit .0005, or if they can they will charge highly for it since they will have several that are culls before they get one right. Machinists say that as "half a thousandth". My calipers only measure that high precision and it's hard to even measure consistently and repeat a measurement to that precision.

And that's why we have problems...

The other problem is Aluminum is the wrong material for a spacer. All my original spacers were aluminum. They would have been better if they were made instead of just cutting and pipe that was close in diameter but not close enough. It also deforms easily.

Plated steel is hard to control too. How thick is the plating???

Are we going to pay for SS spacers? No...

Cheap $2 bearings work just fine here... A full set is less than 1 skf bearing!

AudereEng - 1-5-2014 at 09:56 PM

I think 0.0005" is the wrong way to look at the problem - the length could be within +/- 0.01" with no issues.
The parts only need the ends to be roughly perpendicular to the tube.
What matters is the ends are parallel.

It is easy to make these parts on a CNC lathe and not hard on a manual lathe.
Angus sent me some very nice spaces with my last wheel set...

Many parts are instead a crude chop saw job.

LOL - lapping could easily get these parts very perpendicular, flat and parallel. 10 millionths - fairly easy...

rtz - 1-5-2014 at 11:51 PM

With the bolt backed off; I think it allows the inner race to spin on the bolt.

RedSky - 2-5-2014 at 06:07 AM

Quote: Originally posted by AudereEng

I think 0.0005" is the wrong way to look at the problem - the length could be within +/- 0.01" with no issues.
The parts only need the ends to be roughly perpendicular to the tube.
What matters is the ends are parallel.

It is easy to make these parts on a CNC lathe and not hard on a manual lathe.
Angus sent me some very nice spaces with my last wheel set...

Many parts are instead a crude chop saw job.

LOL - lapping could easily get these parts very perpendicular, flat and parallel. 10 millionths - fairly easy...

Yes I've seen this with buggies I've owned in the past.
With the wheel spacers held together end on end would show daylight through where they join.

This has the effect of ever so slightly pushing out the seal on the bearings very slightly on each revolution of the wheel. A cause perhaps of premature wear?

You can often see bearings do this when turned by hand if the spacers are not completely flat.

Demoknight - 2-5-2014 at 06:09 AM

Rtz wouldn't that mainly happen during a lateral load? If the inner race spins with the bearing during a hard side load, to me that could create tiny flat spots on the bearings that would cause them to wear faster over time. I prefer my bearings locked down tight, with spacers that fit. I have just a cheap peter Lynn comp xr+ and my bolts are all very tight, but spin freely.

ssayre - 2-5-2014 at 06:17 AM

I noticed when I first assembled my xr that on one side I could tighten it down and the wheel spun freely while the other side wouldn't.

RonH - 2-5-2014 at 07:23 PM

While I agree that the parts need to be perpendicular... Make 1 spacer the right size and the other .010" short. Can you guess which one fails first?

Quote: Originally posted by AudereEng

AudereEng - 3-5-2014 at 06:25 AM

I have yet to see a spacer which is the "right" size as I think you are defining it?
If right is the actual spacing from the inside wheel flange to flange then you would be correct.
The spacer would be effectively not be present at 0.01" short - the same thing happens at any minus measurement.

But every spacer I have seen is "extra" long and by more than 0.02" so +/- 0.01" would not change the situation other than the amount the bearings are sunk into the hubs.

RonH - 4-5-2014 at 09:32 AM

I stand by my 1st statement... Nobody would have to worry about backing off the bolt / nut to stop the wheel slowing down or making noise if the spacers were made correctly.

That's it.

Quote: Originally posted by AudereEng

I have yet to see a spacer which is the "right" size as I think you are defining it?
If right is the actual spacing from the inside wheel flange to flange then you would be correct.
The spacer would be effectively not be present at 0.01" short - the same thing happens at any minus measurement.

But every spacer I have seen is "extra" long and by more than 0.02" so +/- 0.01" would not change the situation other than the amount the bearings are sunk into the hubs.