Just picked up a Lexa 100 for really cheap. I was wondering if anyone has replaced the plastic bushing behind the spool tension knob with a bear? If so what size is it.

Just curious as to why you would want to replace this? I've had this reel since Christmas and I love it! Daiwa as a company has peaked my interest and now I own 3 Daiwa reels. I've been a life-long Abu and Shimano user.

I would get a set of calipers and measure the od of the bushing. thickness and od of the shaft and od of the shaft.
This will give you the specs to order a bearing.

Jody Im like you. I was a hardcore Lew's fan but now all but a few of my reels are Daiwa. They make good reels. As to the OP's question I believe you can get on Boca's website and they should have a printout of bearing size chart. The chart is actual size so you would just put the bushing on the printout and see which one it matches up to and then you will have your size.

And Jody putting a bearing there instead of a bushing should help with casting distance as a bearing will have less resistance than a bushing.

I was just curious if anyone had done the upgrade to see if it made a difference and also if they had the numbers by any chance before I took it out and measured it. I

A print out will not give you all the sizes.
Just get a ruler most bearings will have a od 12 mm x 4 mm id 3mm thick.
This will take a few minutes to do I don't have one or I would do it for you.