Bearings - sizes and uses

Wheels of Happiness

Mechanics and friends cant and will not tell you bearing sizes.  Unless you disassemble the part and look the number on the seals.   I have experienced this many times.   Some bike shops will even tell you that the hub bearings cant be serviced so that they can sell you their WS>

If you view some yt you can learn how to replace your bearings.  You can order through Shopee and/or lazada.   You can order the more expensive ones (the ceramic bearings if your budget permits and if it is your preference:

Bottom bracket           Number                  THK           ID                   OD     (In mm)

           BB 30 PF30      6806                        6                  30                   42

           BB 386

           Campy             6805                         7                 25                    37

          Shimano

           

Hub bearings

                                    6000                       8                  10                      26

                                    6001                       8                  15                       28

                                   60100                      8                   10                      26

                                    6802                       5                   15                      24

                                    6902                       7                   15                      28

Headset                      Number             Depth      OD                ID                     Chamfer

Sample sizes only

                                    K936H35          6.5             38                27,14                    36  deg

                                    K345H6.5         6.5             41                30.5                      45

                                    K347H7            7.0             47                 35                        36

                                    K4051H7          7.0             52                 47                        45       

                                    

Headset guidehttps://www.bike-components.de/blog/en/guides/how-to-find-the-right-headset-for-your-bike-with-shis/

Component seller especially for headset will try to sell you the whole set.  But you can find the right bearing sizes and save plenty.  You pay only for the bearings (this is the only one that wears out

                                    

                 

Which cranks set is right for right 2x, 3x, compact, midcompact, what BB is compatible?

Wheels of Happiness

Rizal Philippines
March 4, 2018

It turns out  that for crankset alone, a lot has to be learned. There are various questions that raised:

1. What is meaning of compact, midcompact, and regular crank?

2. What is a triplet?

3. Which of number 1 fits me?

4. What about BB?

5. Can I use MTB cranks for RB or vice versa?

6. How about chaning the blades (the chains of the  chainsets)?

Crankset buying guide






Cheat Sheet for BCD (Bolt Circle Diameter) -Common Diameter of All Bolts in a Crank/chainset

Cheat Sheet For Finding Bolt Circle Diameter (BCD)

[table color=”grey” ]

# Bolts in Circle	Measurement Between Adjacent Holes		Bolt Circle Diameter ( BCD )
	Metric (Millimeter)	English (Inches)
4	45.3 mm	1.78 inch	64 mm
4	56.6 mm	2.23 inch	80 mm
4	73.5 mm	2.90 inch	104 mm
4	84.9 mm	3.34 inch	120 mm
5	43.5 mm	1.71 inch	74 mm
5	64.7 mm	2.55 inch	110 mm
5	76.4 mm	3.01 inch	130 mm
5	79.4 mm	3.12 inch	135 mm

[/table]

Look at the photos and compare to your crank or chainrings.  Find the number of bolts in the circle (Left Column) and the approximate measurement (metric or English) between adjacent holes.  Find those numbers in the table, then in the Right Column you’ll see the Bolt Circle Diameter (BCD).  Use this information to buy the correct chainrings for your bike.
__________

Again, Please NOTE:  This applies ONLY when the bolt holes are evenly spaced.  It will not apply, for example, to the newer 4-bolt road cranks from Shimano and Campy because the holes are not spaced evenly.

These newer cranks also have a bolt circle diameter, but you’ll need to measure directly across opposite holes to get it — not, as shown in the cheat sheet, center-to-center on adjacent holes.