Oil seal kit compatibility - MOTO and MTB

The original Marzocchi bicycle suspension products have been out of production for some time now. Aftermarket seals can be hit and miss, although there are some decent seals out there others can be poor. An alternative way of ensuring quality and correct fitment when choosing a replacement oil seal is to look at Marzocchi's moto fork line. Marzocchi produced both motorcycle and bicycle suspension in their factory in Bologna and many suspension models of the time used exactly the same oil seal, here are some tips to help you locate the correct seal.

Seal sizes are measured by inside diameter (ID) x outside diameter (OD) x height. The height may refer to two dimensions, example 6.5/9.5mm, this refers to outside edge and inside edge of the top part of the seal which is very important. The outside edge of 6.5mm is critical as there will be a retaining c-clip that installs at this height, an incorrect seal height may result in not being able to install the c-clip. The inside edge can be higher as the seal may have a raised lip (with spring, like a dust seal) that seals on the stanchion. 

Genuine Marzocchi oil seals were produced by NOK to Marzocchi's specification, these were black and later a reddish brown with a low friction material. Marzocchi also used the low friction blue seal made by SKF.

SKF seals are easily available

30mm
Original part number 528172NOK>B
Size ID x OD x height: 30 x 40 x 8/9mm 

Also used on Aprilia RS50/ Extrema 1993-98, Piaggio scooters etc

Aprilia RS50 1993-98, 30mm Marzocchi

32mm
Original part number 528230>A 
Size ID x OD x height: 32 x 42 x 6.5/9.5mm 

Also used on school boy or child's motocross bikes from Husqvarna, KTM and Pit Bikes etc

Husky Jr with Marzocchi 32mm fork

35mm

Original part number 528034/B 
Size ID x OD x height 35 x 47 x 10/10.5mm

Also used on school boy or child's motocross bikes on a SHIVER 35 from Husqvarna, KTM SX65 and Pit Bikes etc

KTM SX65 with Shiver 35 USD fork

40mm
Original part number 528053>A 
Size ID x OD x height 40 x 52 x 10/10.5mm

Also used on models such as Aprilia RS250, Cagiva Mito, Ducati SS600 etc

RS250 MK1 with Marzocchi 40mm USD fork