Coatings for Steels and Titanium.

A long Time ago Ohlins started to coat the Fork-Legs with a TIN Coating, to reduce Friction for more Sensitivity and to improve the durability.
Meanwhile this TIN ( Titanium-Nitride ) coating is very common for Motorcycle Forks, not for all, but lot's of Manufacturers meanwhile are coating their Forks with TIN too.

The TIN- Coating Specs

• Vickers-Hardness : 1800-2000 Hv
• Friction Factor : 0.04
• Thickness : ~ 0.002 mm
• Colour : Gold
• Applicable to : Steel and Titanium

The TIN- Coating Applications:
Moreless all those Parts where the shiny gold Color is more important than the technical Aspect, because the coatings mentioned below are far superior.

But as Development in Coatings does not rust, there are meanwhile a couple of other different coatings possible, and most worth to mention here - for Motorcycle Applications- is the WCC ( Wolfram-Carbide) Coating, which is superior to TIN

The WCC- Coating Specs

• Vickers-Hardness : 1500 Hv
• Friction Factor : 0.01
• Thickness : ~ 0.002 mm
• Colour : Black/Grey
• Applicable to : Steel and Titanium

The HV Value is lower, but due to a 400% better Friction Value the WCC coating last much longer than TIN, at even higher Sensitivity !
Tests on a BMW (Fork was coated with WCC), used on road (30.000 miles a year on road Summer to Winter), showed a noticeable wear after 150.000 miles !!
Even the Life-Expectation of Sealings ( Fork/Brake... etc. ) is 300% higher.

The WCC- Coating Applications:
Front Fork
Shock-rod
Transmission Axles
Transmission Gears
Primary- and Clutchgear
Bearings
Brake-Pistons
Valves
Rockers

Also worth to mention for special applications - the DLC ( Diamond Like Carbon ) Coating:

The DLC- Coating Specs

• Vickers-Hardness : 3000 Hv
• Friction Factor : 0.01
• Thickness : ~ 0.002 mm
• Colour : Black/Grey
• Applicable to : Steel and Titanium

The DLC Coating Applications :
Piston-Bolts
Buckets
Camshafts

A Comparison, I.E.: Hardchrome coating

• Vickers-Hardness : 500-700 Hv
• Friction Factor : 0.08
• Thickness : 0.002 mm
• Colour : Silver
• Applicable to : Steel