I did just start looking at the caster wheels I got from Shirley, and am seeing a LOT of issues...
The wheel itself looks nice, gold cad? plate steel, but the bearings are mounted in the center hub with no spacer in the middle (bad for ball bearings like these that get side loads when turning...)
The bearings themselves are steel 6202Z - metal shielded rather than rubber, which isn't a big deal...
Another annoyance is that 3 out of the 4 bolts on the one caster I've taken apart so far were over-torqued to the point of thread damage, about 1/2 turn from being stripped.... As far as I'm concerned, that means needing to replace them...
I also notice that the bearings are not inserted to a uniform depth, or apparently against the ridge inside the hub... The first wheel showed depths from the edge of the hub to the bearing 0.084" / 2.15mm and 0.161" / 4.10mm. The second wheel had depths of 0.107" / 2.72mm and 0.168" / 4.27mm... I tried pressing the bearings in further with a bolt and some flat washers, got a good bit of movement - and now show 0.170" / 4.33mm on both sides....
Poor QA on assembly, but fixable...
However what is a significant issue, is that the hubs are longer than the forks are wide... My caliper says the hub is 3.060" / 77.68mm wide, while the fork is only about 2.965" / 75.33mm between the legs.... I also subtract points for not cleaning the welding splatter off the flange before plating it...
Unlike the rear wheels or the power supply, these seem like rather a poor quality item overall... I can make them work I'm sure (as BM says, it's just metal...) but it will take a good bit of work...
Shirley, I believe these were supposed to be the same wheels you used on your chair? If so, how did you adapt them?
Did they fit inside your forks without being cut down? Or did you cut them down or spread the forks? (they seem like a heavy casting that would be hard to spread...)
I also noticed the end of the valve stem sticks out past the rim - does it clear the fork?
Unless there are other suggestions - it looks like what I will need to do is:
1. Get a better set of measurements on how centered the hubs are in the wheel and take a total of about 3mm off the ends, keeping the wheel centered in the fork.
2. Make a center spacer - presumably around 0.75" / 19mm OD, with a 15mm step down on each end, and a 7/16" bore (the stock axle diameter) and put it in while replacing the bearings.
3. Make end spacers to fill the gap between the bearings and the outside of the forks - I'll probably try to make something that is a fairly close fit to the recess in the hub just to try and minimize the 'furball' buildup... So about 34mm OD, with a narrow 15mm step on the inside and a 7/16" bore...
Do you think aluminum would be OK, or would I need to try doing stainless?
Shirley, does the place you got the caster wheels from have any dimension drawings by any chance? I can do my own measurements (and probably will regardless) but having manufacturer specs would be good as a double check...
ex-Gooserider