Can you put boots in the tumble dryer?

No. Not leather boots, not insulated boots, and not waterproof-membrane boots. Canvas sneakers survive it; boots do not, and there are three separate failure modes rather than one.

What goes wrong, in order of how permanent it is

1. The leather shrinks and hardens - permanent

This is the one you cannot undo. Atsko’s care guidance: “Force drying - especially with heat - will cause leather to harden and shrink. In a few cycles, the boots are trashed.” Blundstone say never to dry boots by an artificial heat source because it makes the leather harden, shrink and crack. A tumble dryer is the most concentrated version of both: heat, applied to every surface at once, for a full cycle.

Once leather has shrunk, no conditioner returns it to its original dimensions. The fit changes and the flex point cracks on the next few wears.

2. The sole adhesive softens - usually permanent

Most modern boots are cemented rather than stitched, or stitched with a cemented midsole. Those adhesives are chosen to survive a hot day inside a car, not a heated tumbling cycle. The failure is rarely dramatic; it shows up weeks later as the toe of the outsole lifting away, at which point the repair costs more than the boots did.

3. Impact damage - to the boots and the machine

A wet work boot is a heavy, hard object rotating inside a thin metal drum. It dents the drum, it can crack the door glass, and the heel counter and toe cap take repeated hits. This is also the reason the noise is so alarming: you are listening to a genuinely destructive process.

What to do instead, when you actually need them by morning

1. Insoles and laces out. Non-negotiable, and it is most of the time saving.
2. One hour of newspaper, then throw it away rather than leaving it in.
3. Airflow, not heat. A box fan pointed into the open throats does most of what a boot dryer does.
4. A forced-air boot dryer on no-heat if you own one - published dry times are 1 to 2 hours, and the temperature is capped at 105 °F on the DryGuy range rather than the 130-150 °F a tumble dryer reaches.

The full overnight procedure is here, and the no-equipment version is here.

If you have already done it

Do not panic and do not oil them immediately - hot leather absorbs unevenly. Let the boots come back to room temperature over several hours, then condition them thoroughly and repeat in a week. Conditioning will not un-shrink leather, but it will restore some flexibility and reduce the chance of the flex point cracking on the next wear. The conditioning procedure.