Bearings: Shielded or Sealed?

[SKOGDOG]

I ordered a rear tire and set of 3 rear wheel bearings (Fafnir 205KDD2) for my 08 K9, and arranged for installation. The bearings didn’t arrive in time, so I stopped at NAPA and bought another set (NAPA 6205VSP25). After dropping off the tires and bearings for installation today, got home to find the Fafnir bearings in my mailbox (damn!). At least I’m set for next time, haha.
Upon inspection, I noticed the Fafnir bearings are shielded and the NAPA bearings are sealed. The shielded bearings have a metal cover on both sides and the sealed have a rubber seal on both sides.The rubber seal is tight and the metal shield is protective, but not sealed tight against all dust or moisture.
With every change of the front tire, I change all wheel bearings. Roughly every 18-20K miles. It’s possible that this frequent replacement means it doesn’t matter. I don’t know.
So here’s the Q: Which bearing type—the sealed or shielded—is the best to use for touring in differing weather conditions?

 

[pknowles]

I would think the sealed. The "25" at the end of the napa part number dieaent mean 25 mm does it,?

 

[kickstart]

I'm sticking with the sealed, keeps the dirt out and I bought several ten packs of each size.

 

[SKOGDOG]

Update: I contacted my bro-in-law, who is a Mechanical Engineer (Purdue Univ). He tanks the sealed bearings would be preferable but given the low probability of water contamination the shielded would work OK too. The shielded are better for high speed use (not really at issue for a BDM wheel).
Paul, here are the SKF (NAPA) specs:

 

[liferider]

When it comes to wheel bearing on my bike, my trailers I learned this trick along time ago. Pop off the seal bearing covers and pack the bearings with high temp wheel bearing grease and put the bearing covers back on.

 

[SKOGDOG]

A great tip, Jonathan. Thanks for that video.

 

[elsabeth]

Given your use case for touring and exposure to different weather conditions, sealed bearings are generally the better choice. Their rubber seals offer superior protection against moisture and dirt, which is crucial for the longevity and performance of wheel bearings in varying environmental conditions. Since you replace your bearings roughly every 18-20K miles, the difference in longevity between shielded and sealed bearings might not be as critical. However, using sealed bearings could potentially extend the intervals between replacements by providing better protection.

 

[elsabeth]

Given your use case for touring and exposure to different weather conditions, sealed bearings are generally the better choice. Their rubber seals offer superior protection against moisture and dirt, which is crucial for the longevity and performance of wheel bearings in varying environmental conditions. Since you replace your crossed roller bearings roughly every 18-20K miles, the difference in longevity between shielded and sealed bearings might not be as critical. However, using sealed bearings could potentially extend the intervals between replacements by providing better protection.

Given that you replace your bearings around every 18-20K miles, sealed bearings could help you go even longer between replacements by providing better protection. This could save you both time and effort in the long run, making your rides smoother and more reliable.

 

[HMAN]

Just my silly way of thinking....18k-20k is a lot of miles on cheap azz china bearings, or any other one for that matter. Im on 2 wheels with 5 bearings between me and the pavement. At 80mph a faliure would make a hellva mess outta my meatsack puny body. I'll change em out with the tires and ride on. They are one of the cheaper parts you can buy for a Dog anyway. Party on!