If the inside diameter of the generic wheel fits snuggly on the axle then simply apply a small amount of grease with your finger and your good to go.

If you are attempting to install a wheel that does not fit correctly on the axle, meaning that its sloppy/loose, then I strongly suggest purchasing the correct wheel for your mower or finding a generic with the correct diameter hole with a brass insert bushing.

If the bushing on the wheel is slightly to small, you may be able to drill it out slightly while ensuring you have some of the bushing insert remaining. The plastic is not strong enough and will crack/wear very quickly so some of the insert must remain after drilling it out slightly larger.

Alternately, you can remove the height adjusting assembly from the deck housing and replace the "axle" bolt with one that fits correctly to the wheel(s) you are trying to install.

Kevin,
Kevins Small Engine service,
South Berwick ME. 03908

Outlaw; if that mower is a Honda, it's worth it to get the replacement wheels with bearings. It's a lot better than trying to make something work and ending up with a half -fast job. Other mowers with ball-bearing wheels are usually commercial-grade and parts for them are available too, generally.