Difference Between Bearings 61809 and 6809

I have a shaft running in a tubular housing supported by 3 bearings, the two outboard bearings are 6809 LU by NTN and the center bearing is a 61809 RS with no manufacturer noted. These are all58mm OD,45mm ID and 7mm wide bearings. When pricing them, there is a big difference in the cost, and I was wondering if there really is a difference?


I was surprised how difficult it was to find those bearings.

Looks like the 61809 may be a “large” ball series, with attending greater radial capacity and lower limiting speed.

3 bearings on one shaft is fraught with perils, mostly manufacturing.
A hollow shaft can make bearing fits trickier.
A hollow shaft can bring on HUGE unbalance issues.

Above is a snippet.