Instead of chains or changing out tires, how about changing the tire's pressure, and then spikes appear or are engaged.

1) Increase pressure, spikes come out

In this version, normal inflation doesn't reveal tire spikes. "Over-inflating" tires causes spikes to pop out because of increased tire pressure. Only downside is that usually under-inflated tires have better natural traction and reduce chance of tires digging into snow due to increased surface of tire patch.

2) Decrease pressure, spikes engage

This seems a hard technology to implement, but normal inflation doesn't engage tire spikes, but when the tire is under-inflated, spikes emerge or engage. I think the only way to do this would be to have the spikes on the sidewalls, then when under inflated, the sidewalls are now in contact with the road surface, and the spikes now make contact.
-- simpleknight, Oct 21 2018

Automatic studs https://jalopnik.co...now-real-1524486488
Studs without spikes [whatrock, Oct 21 2018]

Snow tire with retractable studs https://patents.goo...atent/US3672421A/en
Patented [Klaatu, Oct 21 2018]

I like the pressure increase idea better, perhaps the spikes residing within the tread have their own controllable air supply, an increase of which forces the spikes out.
-- whatrock, Oct 21 2018


// I think the only way to do this would be to have the spikes on the sidewalls, then when under inflated, the sidewalls are now in contact with the road surface, and the spikes now make contact. //

My bike winter tires (Schwalbe Snow Stud) are like that, so I'll say that version (which is the better of your two) is baked.

However, another way to do it would be to put the studs on hoops, with rubber blocks between them that are sprung by the rubber to retract, but get pushed outward by the air pressure. Then, with low pressure, the blocks would move radially inward, reducing their radius to less than that of the studs; with high pressure, they'd move outward, increasing their radius to greater than that of the studs.

[+] anyway.

Anybody have an idea how those Nokian retractable studs work? Their own website doesn't say, just that they exist.
-- notexactly, Nov 07 2018



random, halfbakery