Tandem Roller Assembly, 3/8

There is groove that is .7" wide and about .2" deep this sits in. The window tilts/rocks to the side when you attempt to slide it open. I'm not sure if it needs larger wheels or some type of spacer on top. Currently it only has these wheels on the bottom and nothing on top.

This roller assembly is off a Reynolds slider window installed in 1980. Series 410 Any help would be great. Thanks

my sliding windows are really hard to open. I have cleaned everything out but may just need new wheels. The ones in place currently are identical to your 87-208nd. Right now there are only 2 per window, is it ok to install 4 per window? More wheels = easier to move the window? What are your thoughts ... (cont.)

Hi, I'm looking for a vinyl sliding window roller to match or improve on the Reynolds (52-724 I think). Original unit slides and snaps into bottom channel of window. A replacement with a tougher roller is also welcome, since the originals have a separate axle and roller that quickly become wear and ... (cont.)