How does the spare tire hoist work?

I know this is a dumb question, but...

Today I installed a lock kit on my new 2014 Tacoma. The kind of kit that uses a special shaped adapter to fit the mechanism. Like a lug nut lock.

I lowered the tire. Installed the adapter. Raised the tire. Finished.

But then I got to wondering... There is no locking mechanism on the chain hoist. No ratchet. Nothing. What keeps the weight of the tire and the force of bumps and potholes from just unwinding the chain and lowering the tire?

I would hate to have it fall while I was going down the road.

I have been driving pickups for 20 years, but never paid that much attention.

Ron

 

Just the crank tension usually. My Chevy has a lock that secures the tire in place.. so it can't be lowered.

 

The compound curve/pitch angle of the gears is the gravity defying magic.

 

Don't know for sure, never been inside the spare winch but a worm and worm gear will only allow the driven worm gear to move when the worm drives it and not the reverse. This arrangement would also take care of the need for a 90 degree angle between the input shaft and the spool for the lift cable. So you turn the worm with the crank, the worm gear rotates winding up or unwinding the lift cable. Stop turning the crank and the worm gear cannot drive the worm to rotate so the system remains stationary.

 

Are you asking how to lower the spare? If so... If you have it, there is a long thin bar, Usually behind the rear seats. The long bar slides into the opening above the rear License Plate and then you turn to lower the crank. Its kinda like lowering/ Raising a bottle jack.

 

No, he is asking how does the tire stay up and not come back down by itself. Seeing how there is nothing you do to lock the tire in place

 

It is operated by pfm (pure fing magic )

 

Worm gears don't creep.

 

BAM

 

Don't ever lose that key. The used 2001 tacoma I bought from a dealership didn't have the key for that tire winch. Never new until 4 years later when my son had a flat off at school. Swore to me it wouldn't work, well he was right. I pried and pried until the frustration set in and I just cut the dang cable. From there, I bought a used one on Ebay for 80 bucks, had to remove the bed to get to the winch bolts. A whole Saturday spent bonding with my son. I never under stood why GM made the spare tire so hard to remove from the cable. Toyota has gotten this setup right.

 

Here is the answer you seek: Eccentric Shafts and gears. It has nothing to do with any type of worm gear.

http://patents.com/us-4059197.html
[SIZE=+1]
US Patent # 4,059,197, Spare tire carrier
[/SIZE]
A spare tire carrier utilizing an eccentric gear mechanism for hoisting a spare tire, in which said mechanism comprises means for restricting the movement of the external gear such that the internal gear driven by the external gear makes the pilgrim-step motion, whereby the mechanism may be positively prevented from the accidental reversal movement so as to prevent the drop of the spare tire.

http://patentimages.storage.googleapis.com/pages/US4059197-1.png
http://patentimages.storage.googleapis.com/pages/US4059197-2.png
http://patentimages.storage.googleapis.com/pages/US4059197-3.png
http://patentimages.storage.googleapis.com/pages/US4059197-4.png
http://patentimages.storage.googleapis.com/pages/US4059197-5.png
http://patentimages.storage.googleapis.com/pages/US4059197-6.png
http://patentimages.storage.googleapis.com/pages/US4059197-7.png
http://patentimages.storage.googleapis.com/pages/US4059197-8.png
http://patentimages.storage.googleapis.com/pages/US4059197-9.png
http://patentimages.storage.googleapis.com/pages/US4059197-10.png
http://patentimages.storage.googleapis.com/pages/US4059197-11.png
http://patentimages.storage.googleapis.com/pages/US4059197-12.png
http://patentimages.storage.googleapis.com/pages/US4059197-13.png

 

There isn't a lot of information on these devices. They work really well, I was so glad to see when they went back to these chain hoists over the cable hoist that they used for a while. The cable hoists tend to corrode and come apart at the crimp or just bind up tight.

I don't even want to discuss that piece of Shit Chevy uses on their trucks! Look it up for a good read.

 

Thanks for all the replies! I can rest easy now!

 

I cranked mine down today just to look over the spare and check the air pressure.
It's very easy, just insert that hook in the hole just above the read bumper and crank down.
I took the spare all the way out, wanted to also check everything above it.

 

Had a flat this morning. When I tried the lower the spare it was froze up solid. I aired up the flat a drove over to Les's got the flat fixed for free. I asked about the hoist and they said they are made of plastic and if cranked to tight will break. Is that possible?

 

The Tacoma tire hoists are metal on the ouside and I'll bet the gears and bearings are too. The 'freezing' problem is rust and it seems to happen to all under-bed mounted spares. Typically the mechanizm freezes first, so you can't get the tire off the truck. If you don't catch the rust at this point, the next issue is the entire mecanism rusts free of its mounts and the spare falls off on the truck.

Funny, unless it happens to you --- first you can't get the spare off, then you can't keep it on!

Yearly under-spray and a full down-up cycling helps a lot.

 

I agree. The spare tire is the forgotten child until you need it. I drop mine every few months, WD40 the moving parts, air it up and wind it back up. The spring load keeps it in place. It should be checked routinely if you live in a salted road state.

 

Just needed my spare tire down on my '10 Tacoma. Thought I'd break the mickey mouse jack handle crank getting the cable hoist to work, but it finally came loose. I have heard some about the chain hoist on later model Tacoma's, and am wondering if the chain hoist will bolt up clean in place of the stock cable hoist.