Reasons why you should not put a tube in a tubeless tire:
* The tire may not seal properly. The bead of the tire may not seal properly against the rim of the wheel, which can cause the tire to leak air and lose pressure. This can be dangerous, especially if you are operating the lawn mower on a slope or uneven terrain.
* The tube may overheat. The tube can overheat and burst due to the increased friction between the tube and the tire. This can cause the tire to blow out and could cause serious injury to the operator or bystanders.
* The tube may damage the tire and wheel. The tube can rub against the inside of the tire and cause damage to the tire's inner liner. It can also damage the wheel by causing rust or corrosion.
If you have a leak in the side of your riding lawn mower tubeless tire, you should take it to a qualified tire shop to have it repaired professionally. The tire shop will be able to properly seal the leak and ensure that the tire is safe to use.