ktm868 it looks like you will have to pull your bearings and seals and record the numbers and then you could post em up i have a 03 125 sx and i,m cheap i always go to the bearing store but not for this bike yet, if anyone has the numbers please post em up
wheel bearings
Started by ktm868, Feb 09 2012 06:05 PM
26 replies to this topic
Posted 20 February 2012 - 07:35 AM
"Industrial bearings" aren't any better quality, they just have different materials (ceramic bearings, phenolic cages, etc) or closer tolerances that can still wear out just as quickly under adverse conditions. I've never heard of a roller bearing burning up from being packed with grease unless its the wrong type of grease. If a tapered bearing burns up, its due to being adjusted incorrectly.
Moose Racing repackages All Balls bearing kits (says so right on the Moose label). Are the bearings loose in the hub possibly? I've seen a number of KTM wheels get loose around the outer race of the bearings. If you're going through bearings that fast, I'd be repacking bearings as a preventive as part of normal maintenance.
Moose Racing repackages All Balls bearing kits (says so right on the Moose label). Are the bearings loose in the hub possibly? I've seen a number of KTM wheels get loose around the outer race of the bearings. If you're going through bearings that fast, I'd be repacking bearings as a preventive as part of normal maintenance.
Posted 20 February 2012 - 09:40 AM
The "wheel" bearings specified for our bikes are indeed "industrial" bearings. Probably the most common application of these bearings is in electric motors, which operate at much higher speeds than we see on our wheels. Many common electric motors run at 3600 rpm.
The factory/manufacturer will grease the bearings for this high speed use. To us it looks like not nearly enough, but take a wheel bearing, pack it fully with grease then spin it up to 3600 RPM and see what happens to all that "extra" grease.
To see 3600 RPM on a bike wheel (in round numbers):
Front tire circumference = 87" x 3600 = 313,200 inches per minute
313,200 / 12 = 26,100 feet per minute
26,100 / 5280 = 4.94 miles per minute
4.94 x 60 = 296.4 miles per hour
Think about the heat and pressure at almost 300mph. In a "fully packed" bearing the grease is going to expand, try to push past the seal and may eventually push the seal itself out.
The tiny amount of grease installed from the factory is adequate lubrication on our wheel bearings but leaves plenty of room for dirt/water intrusion. Pack your bearings "full" if you want, but don't think your are doing it for more lubrication, do it to to take up the extra space in an attempt to keep water intrusion to a minimum.
Personally, I've gone back and forth on adding grease. We don't see much water in winter desert riding but most every summer ride entails deep creek crossings. Long term, I have not seen much, if any, difference in bearing life one way or the other. YMMV
The factory/manufacturer will grease the bearings for this high speed use. To us it looks like not nearly enough, but take a wheel bearing, pack it fully with grease then spin it up to 3600 RPM and see what happens to all that "extra" grease.
To see 3600 RPM on a bike wheel (in round numbers):
Front tire circumference = 87" x 3600 = 313,200 inches per minute
313,200 / 12 = 26,100 feet per minute
26,100 / 5280 = 4.94 miles per minute
4.94 x 60 = 296.4 miles per hour
Think about the heat and pressure at almost 300mph. In a "fully packed" bearing the grease is going to expand, try to push past the seal and may eventually push the seal itself out.
The tiny amount of grease installed from the factory is adequate lubrication on our wheel bearings but leaves plenty of room for dirt/water intrusion. Pack your bearings "full" if you want, but don't think your are doing it for more lubrication, do it to to take up the extra space in an attempt to keep water intrusion to a minimum.
Personally, I've gone back and forth on adding grease. We don't see much water in winter desert riding but most every summer ride entails deep creek crossings. Long term, I have not seen much, if any, difference in bearing life one way or the other. YMMV
Posted 25 February 2012 - 10:47 PM
lol come on all you rocket scientists what size are 03 sx125 bearings and seals?
Posted 26 February 2012 - 11:53 PM
crf-500, on 25 February 2012 - 10:47 PM, said:
lol come on all you rocket scientists what size are 03 sx125 bearings and seals?
You too can be a rocket scientist!
Go here, find your bike, find the bearing/seal, the universal number or dimensions will be there:
http://cyclehuttktm....icheFinder.aspx
Posted 27 February 2012 - 08:04 AM
Why don't you just take your bearings and seals out and find the numbers yourself. Or if the numbers don't work for you then take a caliper and measure the ID the OD and width. Then go to any bearing manufacturer catalog and find the bearing there. Or you could give a company like motion industries a call and tell them the sizes you got and tell them that you want the bearings to be factory sealed and that they are ball bearings. Thats what I would do. Or just but some all balls or pivot works bearing kits specifically for your bike, if you don't want oem.
