If the rear wheel is clicking on your Oscar Mx, this can be resolved easily.
To isolate the issue, remove the wheel from the stroller, hold the wheel pin and spin the wheel in your hand.
When you do this, if you can still hearing the clicking in the wheel, there is a simple fix for this.
You'll need a Philips head screwdriver to fix it.
Please keep the wheel off and look at the inner side of the wheel where you'll see a circle of small holes. In two of the small holes, you'll see a screw - these two screws need to be removed and once removed, the hubcap will come off.
It is possible that there is a loose washer within the housing. If so, you can remove this and discard it, it is not necessary.
If you can't see anything loose, then the issue was just that the hubcaps had been screwed in a little too tight and were causing a part inside to push against the wheel as it turns, creating the noise you are hearing.
In either case, you can replace the hubcap and once you've done this, the issue should be resolved.
If the issue continues, please email us at firstname.lastname@example.org