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Why can’t 21” tire flaps for wood wheels be used in 21” Ford wire wheels
Posted: Sun Apr 13, 2025 3:17 pm
by JTT3
If the flaps/liners can be used in 21” split rims why can’t they be used for wire wheels too instead of the small rubber liner? Best John
Re: Why can’t 21” tire flaps for wood wheels be used in 21” Ford wire wheels
Posted: Sun Apr 13, 2025 3:37 pm
by Moxie26
Wire wheel rims are what are called drop rim wheels. ...... Drop rim configuration makes it easier for mounting and dismounting tires on that rim..... Solid rim and Demountables on wood wheels are not drop rim.. the thick tire flap will not conform to the drop rim.
Re: Why can’t 21” tire flaps for wood wheels be used in 21” Ford wire wheels
Posted: Sun Apr 13, 2025 3:45 pm
by speedytinc
JTT3 wrote: ↑Sun Apr 13, 2025 3:17 pm
If the flaps/liners can be used in 21” split rims why can’t they be used for wire wheels too instead of the small rubber liner? Best John
Who says they cant be used in a wire wheel??
Re: Why can’t 21” tire flaps for wood wheels be used in 21” Ford wire wheels
Posted: Sun Apr 13, 2025 3:46 pm
by JTT3
Robert I get that but what’s the science of why it wouldn’t work? The flaps are wide enough they would still wrap the sides of the tube inside the tire to a lesser degree but not so much that the edges stuck straight up on tube instead of following the curvature of the tube against the wall of the tire& inflated tube. Best John
Re: Why can’t 21” tire flaps for wood wheels be used in 21” Ford wire wheels
Posted: Sun Apr 13, 2025 3:48 pm
by JTT3
John I googled it first before I asked the forum and basically the answer was because you can’t ha. Best John
Re: Why can’t 21” tire flaps for wood wheels be used in 21” Ford wire wheels
Posted: Sun Apr 13, 2025 3:54 pm
by Steve Jelf
Did Ford include flaps on any kind of Model T wheel?
Re: Why can’t 21” tire flaps for wood wheels be used in 21” Ford wire wheels
Posted: Sun Apr 13, 2025 3:55 pm
by Moxie26
John, it ain't science... It's physical practicality. ...

Re: Why can’t 21” tire flaps for wood wheels be used in 21” Ford wire wheels
Posted: Sun Apr 13, 2025 4:04 pm
by Jerry VanOoteghem
I would guess because a 21" split rim has a flat bottom, the flap can seat against that while nested between the tire beads, while the 21" wire wheel, drop center rim, would cause the wide tire flap to be pushed into the deep "drop" and get too deformed by the excessive contour of the rim. In other words, I don't think the liner would fully conform and may therefore put odd pressure points upon the tube.
Re: Why can’t 21” tire flaps for wood wheels be used in 21” Ford wire wheels
Posted: Sun Apr 13, 2025 4:08 pm
by Moxie26
I agree. Jerry, plus it will create a definite imbalance in that wheel
Re: Why can’t 21” tire flaps for wood wheels be used in 21” Ford wire wheels
Posted: Sun Apr 13, 2025 4:26 pm
by speedytinc
Flaps will form down into the drop as do inflated tubes. They provide added protection to the tube from the edges of the tire.
Do I run flaps? No.
1)Using a quality heavy duty tube is good enough. 2)I do use rim strips to protect the tube from the little high spots from the welded spokes as I do with normal adjustable spoke wheels. 3) flaps are not easy to well center. Possible/probable negative gyroscoping imbalance. I dont recall a flapped tire disassemble that had the flap reasonably still in its correct position.
Re: Why can’t 21” tire flaps for wood wheels be used in 21” Ford wire wheels
Posted: Sun Apr 13, 2025 7:27 pm
by Jerry VanOoteghem
Jerry VanOoteghem wrote: ↑Sun Apr 13, 2025 4:04 pm
I would guess because a 21" split rim has a flat bottom, the flap can seat against that while nested between the tire beads, while the 21" wire wheel, drop center rim, would cause the wide tire flap to be pushed into the deep "drop" and get too deformed by the excessive contour of the rim. In other words, I don't think the liner would fully conform and may therefore put odd pressure points upon the tube.
... and furthermore, when a flap has been forced down into the drop, it will jam between the tire beads and not allow them to meet in the middle and fall into the drop center, which they need to do in order to remove the tire.
Re: Why can’t 21” tire flaps for wood wheels be used in 21” Ford wire wheels
Posted: Mon Apr 14, 2025 9:44 am
by 36mike
Mounting would be almost impossible on a drop center wheel.
When mounting a tire on a split/demountable rim, the tire/tube/flap assembly goes on together. The split rim is drawn together so that it will go inside. I was taught that the same is true on clincher rims. Assemble the tire/tube/flap and stretch both beads on at once.
Mike
Re: Why can’t 21” tire flaps for wood wheels be used in 21” Ford wire wheels
Posted: Mon Apr 14, 2025 10:11 am
by DanTreace
Re: Why can’t 21” tire flaps for wood wheels be used in 21” Ford wire wheels
Posted: Mon Apr 14, 2025 10:17 am
by DanTreace
Steve Jelf wrote: ↑Sun Apr 13, 2025 3:54 pm
Did Ford include flaps on any kind of Model T wheel?
Yes.....Ford put flaps as standard in the 21" Split Rims, as the split can rip or tear a tube as the jagged edges of the split can never be fully aligned..
Note the wire wheel comment, as flaps used in wood wheel split rims are not to be used in the wire wheels.

- No flaps in wire wheels.jpg (86.04 KiB) Viewed 2308 times
Re: Why can’t 21” tire flaps for wood wheels be used in 21” Ford wire wheels
Posted: Mon Apr 14, 2025 10:39 am
by JTT3
Dan & all thanks ever so much. Just bought new tires & flaps then decided to go with wire wheels though not correct for the model year. Looks like rim liners it is. Best John