Bearings are a part that you generally don’t give too much thought to as you don’t see them and you kind of forget that they’re there as they go about silently doing their job. They are a crucial, often overlooked component however as they are needed to help you move.
Wheel bearings in particular are generally not considered when you’re buying those shiny, slick, aero carbon wheels but in fact, the bearings are one of the most crucial elements of your wheel and here at Scribe, we have put a lot of thought into them.
- Cup and cone: which use loose balls between a cup and a cone which create the race, and there are cartridge (or sealed) bearings which is what we’ll discuss.
- Cartridge bearings: self-contained units that are easy to source, use, and replace. They are used in the overwhelming majority of hubs used today, and in almost all of the hubs we build (Shimano being the exception). Angular contact bearings are a subset of cartridge bearings, which are made to work in situations with lateral as well as radial loading.
What do the numbers mean...
There are three measurements that you need to know for any bearing: (i) Bore (or inside diameter), (ii) Outer diameter, and (iii) Width.
These are straightforward, and they then relate to the size name. For example, 6801 bearings have a 12mm bore, a 24mm outer diameter, and are 6mm wide. Any bearing with those measurements is a 6901 bearing and vice versa.
Lets use a 6802 as an example...
(6)802 - This first number relates to the bearing type, typically most bicycle bearings will be a “6” which is a “Deep Groove”. Occasionally you will find a “7” bearing which is a “Single Row Angular Contact”
6(8)02 - This second number relates the bearing series, which reflects the robustness of the bearing. As you go up the scale below from 9 to 4 the inner and outer race thickness will usually increase along with the ball size, this will be to help cope with extra load.
9 - Very thin section
0 - Extra light
1 - Extra light thrust
2 - Light
3 - Medium
4 - Heavy
68(02) - The 3rd and 4th digits of the bearing number relate to the bore size of the bearing, numbers 00 to 03 have a designated bore size depending on the number.
00 - 10mm
01 - 12mm
02 - 15mm
03 - 17mm
What do the letters mean… (these relate to the bearing seals)
There are several types of seals, which primarily go into two categories: contact seals, and non-contact seals. Contact seals have a positive connection to the inner and outer races, where non-contact seals have a positive connection at one race and sort of “float” against the other. Contact seals have better weather resistance, while non-contact seals have lower friction, and thus lower resistance to the elements.
*Bearing brands have different names for the same ‘type’ of seal and this is explained in the table below:
|SealType||Z||Z||Z||Z||1 Side Steel Seal, 1 Side Non-Seal|
|ZZ||ZZ||ZZ||ZZ||2 Side Steel Seal|
|V||LB||RU||NK||1 Side Rubber Seal (Non-Contact), 1 Side Non-Seal|
|VV||LLB||2RU||2NKE||2 Side Rubber Seal (Non-Contact)|
|DU||LU||RS||NS||1 Side Rubber Seal (Contact), 1 Side Non-Seal|
|DDU||LLU||2RS||2NSE||2 Side Rubber Seal (Contact)|
What bearings do I need for my Scribe wheels?
As riders ourselves, we know it's the small things that make the difference; especially when it comes to bearings
As many of us like to ride our bikes everywhere, regardless of the weather, we give you the option to run a Race Bearing, or this Endurance bearing. These bearings are designed to stand the test of time so you can ride as much as you want, with confidence your bearings will keep spinning smoothly - oh, and they are still fast!
|Front Hub||Rear Hub||Freehub|
|Carbon Rim Brake||6802||6802||6802|
|Carbon Disc Brake||6802||6902||6802|
|Pace, Race, Duty||6802||6802||6802|
*Please note: Race bearings are FAST, but they have non-contact seals which are less resistant to water.
You can see the difference between the seals below... (Left-contact seal Right-Non contact)