If I want to order bearings from a jobber instead of say All Balls is it just a matter of presenting them with ID, OD, Thickness and whether or not it needs to be sealed on one side or both?
Bearing nomenclature
- Thread starter timtune
- Start date
TK4
Well-known member
Depending on the bearing, there should be a number stamped right on it (6304,etc.) You can specify shielded one side, both sides, loose fit (C2 or C3). If it's a tapered bearing (steering head, wheel bearing) it's best to give them dimensions. You can also look on the genuine replacement parts list, sometimes that will tell you what bearing is used.
guzzirider
Well-known member
Beware of cheap bearings! Stick with USA, Japanese or German manufactures. Wheel bearings are usually a standard metric size and are the same as used in electric motors. The same bearings where used on 2 stroke crankshafts that ran for 20+ years. Buy from a bearing supply house not PAuto or CA Tire. If you take the bearing to them they will measure it for size if you can not read the numbers.
You will often find bearings with seals or shields on both sides are cheaper and easier to find than sealed/shielded on one side.
Just remove the seal/shield on one side. I just use sealed bearings because they are designed to run for years continuously at a wide range of temperature. The seals add minimal amounts of drag that you will never notice. They will also add greater moisture protection. When installing only put force on the outer race. As a caveat I will mention if you intend to travel at extreme speeds sealed bearings may cause some skidding of the bearing on the axle. Most hubs are designed in such a matter that when the axle nut is tightened the bearing inner races are locked to the axle. Make sure the spacer between the inner races is not worn.
Machinist/Millwright for 50 years with experience of 1000's of bearings ranging from 3/8 to 36 inches.
You will often find bearings with seals or shields on both sides are cheaper and easier to find than sealed/shielded on one side.
Just remove the seal/shield on one side. I just use sealed bearings because they are designed to run for years continuously at a wide range of temperature. The seals add minimal amounts of drag that you will never notice. They will also add greater moisture protection. When installing only put force on the outer race. As a caveat I will mention if you intend to travel at extreme speeds sealed bearings may cause some skidding of the bearing on the axle. Most hubs are designed in such a matter that when the axle nut is tightened the bearing inner races are locked to the axle. Make sure the spacer between the inner races is not worn.
Machinist/Millwright for 50 years with experience of 1000's of bearings ranging from 3/8 to 36 inches.
Mad Mike
Well-known member
Most bearings used in motorcycles are precision ground bearings, they will have a number engraved into the seal or bearing. Some have prefixes and suffixes - you need those as they describe variants that are really important.
Tapered bearings are 2 parts, cup and cone, they are rarely used in motorcycles - mostly in aftermarket steering head bearings. The cone has the needle rollers and a race, the cup has no moving parts, it’s just a race.
Mad Mike
Well-known member
When axle nuts are tightened, the bearing’s inner race is locked to the fork and hub (or spanner bushing) not the axle.
TK4
Well-known member
And why its important to grease the axle sticks.
Mad Mike
Well-known member
I don’t think this happens in a precision wheel bearing that is in spec. You would need that bearing to exceed 50,000rpm, that would be around 3,000 mph on a motorcycle.
According to this you want 2x 6302 for the front and 2x 6304 and a 6305 for the rear... ya gotta love Honda's part numbers, the bearing number is part of the part number. With Yamaha and Suzuki they give you the size.
Anyways those are standard bearings and are available at any bearing house, and if you followed the links I posted earlier and read up on bearing nomenclature, you're gonna know that if you want ONE rubber seal you want 6302R (which no one will have, take the 6302-2R and remove one seal... or do what I do; 6302 Z, one metal seal, then toss the OEM rubber dust seal that goes over the bearing, #18 on the front)
Motorcycle wheel bearings aren't very taxing, not a lot of load, not a lot of RPM, they're easy to get to, you DON'T need to spend a lot of time and money on 'em. ANY bearing that fits is good.
Mad Mike
Well-known member
I don’t think you need to worry about seals at all, just leave them — there’s no other lube going in — that’s the only reason for removing a seal.
Pretty sure the AllBalls kits don’t bother pulling seals.
I'm just here learning about bearings: why do we want to get rid of one of the seals? Less drag? It doesn't serve any purpose at all in this application?
Theoretically, the seal only needs to be present between the inside of the assembly and the outside world. A bearing on each side of a wheel probably (depends on the design of the wheel) is only exposed to the outside world on the outside sides of each bearing. Removing the unnecessary seal removes a microscopic amount of friction. In this application, I don't bother removing it.
Mad Mike
Well-known member
Seals prevent outside world stuff from entry, but sometimes seals also prevent lubrication. If a standard 6203 is used inside an engine, it asks for oil lube on the inside, so removing the seal on one side is essential.
I was rebuilding an alternator and tried getting a replacement from a bearing supply house. They took one look at it and said it was automotive and they wouldn't have it.
Other considerations are bearing loads, longitudinal and radial. RPM etc.
If you can get a replacement at a bearing supply it will be a fraction of the price at a dealer.
Other considerations are bearing loads, longitudinal and radial. RPM etc.
If you can get a replacement at a bearing supply it will be a fraction of the price at a dealer.
I use quite a few 6305Ns. Crank bearings for almost all '60-80s Yamaha twins, transmission output shafts for Triumphs, it's a popular bearing.
The Yamaha OEM bearing is a NSK, about $65
I use a Koyo, that has a 20% higher maximum RPM, 15% more axial load, 20% higher static and dynamic load, a better bearing: $9.60 (wholesale price, about $13 retail)... when there is stock. When I find them I buy a box of 10.
The SKF/NTN/Timken 6305 equivalent is $25-35.
The Yamaha OEM bearing is a NSK, about $65
I use a Koyo, that has a 20% higher maximum RPM, 15% more axial load, 20% higher static and dynamic load, a better bearing: $9.60 (wholesale price, about $13 retail)... when there is stock. When I find them I buy a box of 10.
The SKF/NTN/Timken 6305 equivalent is $25-35.
Mad Mike
Well-known member
The seals should be left in place if the bearing is not lubricated by oil or periodic packing. The seal keeps grime out, and the permanent grease in.
