Recently one of our active mountain biking customers contacted us with some frustration. See below this case study and how we were able to help.

As an avid mountain biker outside of Bend, Oregon, he frequently encounters water throughout his rides.

He was consistently having issues with his bike feeling “slow” or as if he was “riding through sand” and has already replaced bearings a few times hoping to fix the issue.

Once we consulted with him, we uncovered that when he replaced the bearings, he wasn’t taking the seal into consideration.

This is a common occurrence and most avid cyclists don’t realize that the seal is just as important as the bearing when it comes to replacement.

]In this article, we will break down the common types of bearing seals and the differences of each.

Types of Seals

The most common types of seals that you run into in the bike industry are:

  • RS Seals
  • RH Seals
  • RZ Seals
  • Z Shields

The RS Seal

The RS is a rubber seal that has a light contact between the seal and the bearing inner ring during rotation. This type of seal is the most popular and offers great protection against contamination. The light contact between the seal and the bearing will create minimal “drag” during rotation (minimal rolling resistance).

The RH Seal

The RH seal has about three to five times more contact on the bearing than the RS seal. The benefit of this heavier seal is that it is better at keeping out smaller contaminant particles and liquids.  The slight downside of this seal is that the rolling resistance requires slightly more effort. Just in the beginning until you “break” in your new bearing & seal.

The RZ Seal

The RZ seal is a rubber seal that has no contact on the bearing.  This type of seal is best for higher RPM situations because there is nothing creating resistance when the bearing is in rotation. The protection you receive from contaminants is less than the other two options, RS and RH, but still a good choice when looking for the least amount of drag. You can interchange a shield with an RZ seal, if needed.

The Z Shield

A Z stands for a metallic shield and is different than seals in the fact that they they 1) are made of metal, not rubber and 2) typically are non-removable after installation. Depending on what type of contaminate you run into, metal shields may provide you with the type of protection you need. These metal shields aren’t recommended if you are going through water, opt instead for a rubber seal.

The Mountain Biker Seal

Back to our mountain biker in Bend, Oregon, we switched him to RH seals and he hasn’t had an issue since.

As always keep the questions coming by emailing us at


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