Replacing the Wind Cups

If the wind cups get damaged in shipping, we will provide a free replacement. But even if you happen to break your wind cups, it is easy to replace them. The cups have a tiny magnet in the flange at the base, and a brass jewel bearing in the top.  The jewel has a tiny inverted V cut into the lower end, that spins on the pin on the end of the axle with virtually no friction.

For removing the wind cups, we do not recommend unscrewing the brass nose cone, which has adhesive so it won’t unscrew accidentally. Just loosen [1] the black dome nut and [2] the brass set screw in the side of the black axle tube.  Use a 2 mm (or 5/64") Allen key for the brass set screw. 

There are two different sizes of dome nuts:  use an 8 mm wrench to turn the aluminum one, or a 3/8" wrench if you have the newer nylon version.  Remember to turn counter-clock wise to loosen, to avoid stripping the threads on the nut.  The replacement is quick and simple, but if you do the repair yourself, SailTimer Inc. is not responsible for any damage that is caused.

Once the wind cups are off, it is a good idea to check that the axle is clean.  The 2017 axle under the wind cups has very precise machining and no lubrication should be used. 

For 2016 and earlier axles, lubricate the axle before putting on the new wind cups.  This is usually less of a priority if you have the fall 2016 AirGap™ axle, which requires less lubrication.  The procedure that we have found most effective is to use a very thin film of 3-In-One White Lithium Grease on the wide base of the axle.  Then on the inside of the tube in the wind cups, we also add a film of thinner WD40 Specialist High Performance White Lithium Grease, which is thinner and more liquid. That will make the cups spin perfectly, and the lubrication will be waterproof and long-lasting. 

You can use the same maintence procedure on the lower axle, although it is not as sensitive.  If you are in a remote location with no WD40 Water-Resistant Silicone Lubricant available, a very thin coating of machine oil or motor oil would be the second choice to lubricate both axles.  However we have noticed that when oil is used alone (without the WD40 Water-Resistant Silicone Lubricant above), water may get mixed with the oil film from the cup spinning, turning it a milky brown color.  The water may reduce the lubricant performance, eventually requiring maintenance.

You can adjust the jewel bearing in the top of the wind cup, if the flange at the bottom of the wind cups is rubbing. By using a jeweller's screwdriver to turn the jewel bearing, you can raise or lower the wind cups on their axle.  For up to the 4th-generation Wind Instrument (all cups shipped until the end of May 2017), then put UV-resistant adhesive on the jewel bearing so it won’t undo itself (e.g., a sealant such as Marine Goop).  Leave the jewel bearing in the threads, and put the adhesive on top and on the sides of the threads (to avoid getting adhesive onto the jewel).  No adhesive is needed if you have the 5th-generation Wind Instrument or replacement cups shipped in June 2017 and later. The threads are tighter on these newer cups, which means they are harder to turn but that no adhesive is required to ensure that they don't unscrew themselves.

When putting the new cups on the axle, make sure the cups spin free.  If not, check that the pin in the end of the axle is as straight as possible, so it is sitting in the V of the jewel.  Try not to pull the pin out if you need to straighten it;  just push the point sideways, so that the pin stays glued in place in the axle.

During reassembly, put some adhesive on the threads under the dome nut to make sure that nothing comes unscrewed.  With the metal dome nut, Loctite Removable Thread Locker works well (e.g. the red permanent version).  If you have the newer nylon nut, Gorilla Super Glue holds it well.  Marine Goop would also work on the metal or the nylon nuts because it is UV-resistant, although other kinds of outdoor caulking would be suitable too. 

Then tighten the brass set screw, and you're done.  It seats firmly without needing any adhesive. 

This will be clearer once you take it apart; don’t worry, it is pretty easy. You just remove the dome nut and loosen the set screw, then pull the tail back, to get the cups off.


| Photos | Technical | FAQ | Air Link - NMEA | Accessories | Order

Media | Optimal Tacks | The API | Apps | Warranty | Corporate | Newsletter | Contact | Home

Share on Facebook

Copyright 2005-2015 © SailTimer Inc.