MTB Bearing Kit BSA

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  • 68 mm / 73 mm / 73 mm E-Type
85,00 €
inkl. 19% Mwst.
71,43 € Netto
Art-Nr. :
“MTB Bearing Kit BSA”

For B.O.R MTB cranks and Tune MTB cranks with “Smart Spindle System” which need to be mounted into a BSA MTB bottom bracket with 68 mm width, 73 mm width and 73 mm width + eType.

For MTB cranks of other manufacturers who provide a 30 mm spindle and a K-Factor of minimum 88,5 / 93,5 / 98,0 mm which need to be mounted into a BSA MTB bottom bracket with 68 mm width, 73 mm width and 73 mm width + eType (see “K-Factor / Competitor Cranks”)

The bearing kits of the “Smart Spindle System” are used eqally by B.O.R and Tune and are identical! See Tune - Smart Foot Cranks.



BOR Germany do NOT know which of the more than 25 existing bottom bracket variants is in YOUR frame. This information can only be obtained from the manufacturer of your frame, i.e. from his dealers! If you already know for sure what bottom bracket is in your frame, you / your dealer will find the relevant product info in the section Bottom Brackets “Smart Spindle System”.

Cross Country
NOT for Downhill / Enduro
Fully CNC machined (Light Alloy 7075)
Anodizing (Coloring, Coating, Hardening)
Laser Edging
Tool for BSA + ITA bearing cups
BB30/BB905 30x42x7
Enduro-Bearing 30x42x1,5 (contact lip seal)
30 mm aluminum spindle cranks ONLY
What is the K-factor?

The K-factor of a crank is the clear width on the spindle (“space” on the shaft) when both arms are mounted! (See chart).

B.O.R MTB cranks: They have a K-factor of 96 mm. This “width” is optimized on just fitting into the widest available MTB bottom bracket on the market. For shorter bottom brackets the resulting gap is filled using spacers or additionally shortened by positioning the bearings further outboard.

Competitor Cranks:

Of course, B.O.R do not know the technical specifications of cranks that are produced by other manufacturers. YOUR K-Factor, i.e the clear width on your spindle, can either be measured by yourself or will be given to you by the respective crank manufacturer or one of its dealers.

In order to use this “MTB BSA bearing kit” your crank MUST have a 30 mm spindle! You can either measure this yourself, or obtain this inform you manuals, from the respective manufacturer or one of its dealers.

In a bottom bracket “MTB BSA” with 68 mm width, your crank requires a minimum K-factor of 88.5 mm.

In a bottom bracket “MTB BSA” with 73 mm width, your crank requires a minimum K-factor of 93.5 mm.

In a bottom bracket housing “MTB BSA” with 73 mm width + eType recording, your crank requires a minimum K-factor of 98 mm.

Was ist ein “K-Faktor” , “U-Faktor , “Q-Faktor” ?



Developed in 2010 in cooperation with Tune, the “Smart Spindle System” was designed for cranks with 30 mm spindle and secures the installation of our crank platform in virtually any bottom bracket shell (except Trek BB90). It is the first fully compatible bottom bracket and crank concept, which aims at being compatible for a maximum number of bottom bracket environments. (An equally innovative solution came in 2011 from Corratec with “UBBS” as a frame-based approach. Rotor moved in 2013 with his “UBB” a while later.)

The “Smart Spindle System” is based on a K-factor of 96 mm for MTB cranks, on a K-factor of 91 mm for Road cranks. The K-factor is the spindle/shaft clearance with arms fully assembled (see chart)! All MTB and road bike bearing kit of the “Smart Spindle System” adjust / are shimmed to the respective K-factor. The bearing kits sets of B.O.R and Tune are therefore identical!

There are 4 different bearing cups, 3 different spacer rings and two bearings existing. These few parts allow for composing 7 “MTB Bearing kits” to fit into 11 different MTB bottom bracket housinBB environments. 8 “Road Bearing Kits” are needed for 9 different BB environments. And, well, it is also enough for the 5 bottom brackets, already existing for Fatbikes.

All of these minimum 25 bb variants are clearly specified (see graphics in “Bearing Kits Smart Spindle System”), manufacturers such as BSA, SRAM, Shimano, Cervelo, Open, Specialized, FSA, etc. The individual frame manufacturers decide on what bb they integrate into each of their frame models! So, if you want to know what bb is in YOUR frame, contact the dealer of your frame manufacturer!

Thus, the “Smart Spindle System” tries to clean up the mess, “created” by too many “creatives”! And it gives at least some guidance to public consumers, dealers and even to journals, who seek orientation themselves. (And the byproduct is a very smart crank system!)



Type Weight Price
MTB BSA68 +98g 85,- Euro
MTB BSA73 +94g 85,- Euro
MTB BSA73 eType +92g 85,- Euro
MTB ITA70 +94g 85,- Euro
MTB BB30/73 Cannondale +62g 59,- Euro
MTB BB85/84,5 Specialized +59g 59,- Euro
MTB PF30/73 +72g 85,- Euro
MTB BB386EVO/91,5 PRESSFIT +72g 85,- Euro
MTB BB Right/84 PRESSFIT +70g 85,- Euro
MTB BB92/89,5 sym. PRESSFIT +74g 124,- Euro
MTB BB92/92 asym. PRESSFIT +72g 124,- Euro



Type Weight Price
FATBIKE BSA100 for 170/177 RDS +98g 85,- Euro
FATBIKE PF30.100 for 170/177 RDS +72g 85,- Euro
FATBIKE BB121 for 170/177 RDS +72g 85,- Euro
FATBIKE BSA100 for 190/197 RDS +98g 89,- Euro
FATBIKE BSA120 for 190/197 RDS +98g 85,- Euro
FATBIKE PF30.100 for 190/197 RDS +72g 89,- Euro
FATBIKE PF30.132 for 190/197 RDS +72g 85,- Euro



Type Weight Price
Road BSA68 +98g 85,- Euro
Road ITA70 +94g 85,- Euro
Road BB30 +62g 59,- Euro
Road BB Right Standard +58g 59,- Euro
Road PF30 +72g 85,- Euro
Road BB30 OS Specialized +75g 85,- Euro
Road BB386EVO PRESSFIT +70g 85,- Euro
Road BB Right PRESSFIT +70g 85,- Euro
Road BB86 Pressfit +70g 124,- Euro