# Bullet proof tires!
**URL:** https://boards.straightdope.com/t/bullet-proof-tires/307854
**Category:** Factual Questions
**Created:** [June 11, 2005, 1:34pm UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854 "2005-06-11T13:34:57Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@Fargesto](https://boards.straightdope.com/u/Fargesto)
#### Post date: [June 11, 2005, 1:34pm UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/1 "2005-06-11T13:34:57Z")
Hi
I heard/saw/read somewhere that Kevlar was invented initially to be used in manufacture of tires.
Program on TV the other day where chase police shot out the tires of suspect vehicle to make him stop.
So why are tires not bullet proof?
If tires are not bullet proof how do military vehicles with those big all terrain tires not get stopped and disable by a single strategic shot???
š
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### Author:  [@Chefguy](https://boards.straightdope.com/u/Chefguy)
#### Post date: [June 11, 2005, 1:38pm UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/2 "2005-06-11T13:38:43Z")
[Run-flat tires.](http://www.roadandtravel.com/womensworkshop/runflattires.htm)
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### Author:  [@sewalk](https://boards.straightdope.com/u/sewalk)
#### Post date: [June 11, 2005, 3:27pm UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/3 "2005-06-11T15:27:56Z")
Kevlar has many more uses than in bullet-_resistant_ vests, more properly called body armor.
It is a synthetic fiber with a very high breaking strength. In tires, it would replace the steel and polyester belts that hold the carcass of a tire together (a tire is not just a hunk of rubber shaped like a donut).
Wheeled military vehicles often use a magnesium or hard rubber insert that keeps the rim from hitting the ground when the tire collapses. Ride quality sucks but the vehicle can keep rolling without losing the tire. Commercial runflat tires use either an insert or a bead lock that keeps the tire from coming off the rim.
Nothing mobile is bullet-_proof_. Bullet-resistant, maybe, but not bullet-proof. Even 1/4 inch steel plate used in executive limos is no proof against the good old Browning .50 round.
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### Author:  [@sewalk](https://boards.straightdope.com/u/sewalk)
#### Post date: [June 11, 2005, 3:36pm UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/4 "2005-06-11T15:36:58Z")
To continue the armor resistance thing, the US Armyās M2/M3 Bradley Fighting Vehiclesā sides are not completely resistant to even 7.62mm machine guns at close range.
If you step up to the M1 tank, it is essentially impervious to all small arms fire but itās Armor-Piercing, Fin-Stabilized, Discarding Sabot round is really just a big, fast-moving bullet and capable of defeating any armored vehicle in the world.
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### Author:  [@matt](https://boards.straightdope.com/u/matt)
#### Post date: [June 11, 2005, 6:07pm UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/5 "2005-06-11T18:07:21Z")
> [@sewalk](#):
>
> Kevlar has many more uses than in bullet-_resistant_ vests, more properly called body armor.
> It is a synthetic fiber with a very high breaking strength. In tires, it would replace the steel and polyester belts that hold the carcass of a tire together (a tire is not just a hunk of rubber shaped like a donut).
Good post!
Re the OP - kevlar is not automatically ābullet proofā or even bullet resistant. It needs to be woven and layered appropriately to capture a bullet and absorb its energy. Lesser fibres such as drawn nylon and silk can be woven into good soft armour as well. Carbon fibre is stronger than kevlar, but doesnāt have as good energy-absorbing properties (elasticity) and so hasnāt been used for this application as far as I know. Spider silk is very promising, but you canāt _get_ enough of it from spiders. Genetic modification of other organisms may create a source of spider silk. And it may find other uses unrelated to armour.
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### Author:  [@sewalk](https://boards.straightdope.com/u/sewalk)
#### Post date: [June 11, 2005, 9:06pm UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/6 "2005-06-11T21:06:44Z")
When I was wearing the stuff to work, it made good sense to learn how it worked. š
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### Author:  [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)
#### Post date: [June 11, 2005, 9:22pm UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/7 "2005-06-11T21:22:38Z")
Sort of along the same lines, a tire company back in the 80s or so, advertised a tire which basically had a sandwich design with a layer of Fix-A-Flat type goop inbetween that was supposed to seal any punctures in the tire. No idea of how well they would have worked. Iāve often wondered why someone hasnāt come up with a decent foam filled tire, so weād _never_ have to worry about checking the air in our tires again.
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### Author:  [@Nanoda](https://boards.straightdope.com/u/Nanoda)
#### Post date: [June 11, 2005, 9:55pm UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/8 "2005-06-11T21:55:16Z")
> [@Tuckerfan](#):
>
> Iāve often wondered why someone hasnāt come up with a decent foam filled tire, so weād _never_ have to worry about checking the air in our tires again.
Behold, the [Tweel](http://www.gizmag.com/go/3603/).
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### Author:  [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)
#### Post date: [June 11, 2005, 9:58pm UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/9 "2005-06-11T21:58:58Z")
> [@Nanoda](#):
>
> Behold, the [Tweel](http://www.gizmag.com/go/3603/).
Yeah, Iāve seen those. Iām gonna wait until they show up on military vehicles and prove themselves in combat before I consider putting them on one of my cars. They just donāt look too sturdy to me.
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### Author:  [@Nanoda](https://boards.straightdope.com/u/Nanoda)
#### Post date: [June 11, 2005, 10:19pm UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/10 "2005-06-11T22:19:20Z")
I think thatās probably a likely proving ground for this technology (mentioned [here](http://www.fastcoolcars.com/airless-tires.htm), along with some interesting info)
[Michelinās site shows](http://www.michelinmedia.com/naias_2005/html/tech_tweel_gallery.htm) some prototypes working decently on some heavy machinery already.
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### Author:  [@Padeye](https://boards.straightdope.com/u/Padeye)
#### Post date: [June 11, 2005, 11:45pm UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/11 "2005-06-11T23:45:21Z")
> [@sewalk](#):
>
> Nothing mobile is bullet-_proof_. Bullet-resistant, maybe, but not bullet-proof. Even 1/4 inch steel plate used in executive limos is no proof against the good old Browning .50 round.
It doesnāt take nearly that much to puncture steel plate. Iāve made targets out of cold rolled 3/8" plate that were heavily cratered and quickly punctured by 5.56mm at short range. If I get a chance I may do some tests with half inch plate and a cache of .30 caliber AP I have. That ammunition is the only true armor piercing type that isnāt prohibited by federal law but should have about the same ballistics as 7.62mm NATO though probably a bit better performance due to a heavier bullet.
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### Author:  [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)
#### Post date: [June 12, 2005, 12:03am UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/12 "2005-06-12T00:03:54Z")
> [@Nanoda](#):
>
> I think thatās probably a likely proving ground for this technology (mentioned [here](http://www.fastcoolcars.com/airless-tires.htm), along with some interesting info)
>
> [Michelinās site shows](http://www.michelinmedia.com/naias_2005/html/tech_tweel_gallery.htm) some prototypes working decently on some heavy machinery already.
The thing that concerns me is they **donāt** show any shots of the wheels working in a muddy, watery (say slightly flooded roadbed) or snowy environment. All those open spaces are just prime targets for getting loaded down with gunk, and then when you hit pavement and begin driving at a fairly decent speed, that stuff is going to go _flying_.
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### Author:  [@sewalk](https://boards.straightdope.com/u/sewalk)
#### Post date: [June 12, 2005, 12:09am UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/13 "2005-06-12T00:09:30Z")
I know, **Padeye**. Iām whacking a fly with a sledgehammer for emphasis.
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### Author:  [@silenus](https://boards.straightdope.com/u/silenus)
#### Post date: [June 12, 2005, 12:23am UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/14 "2005-06-12T00:23:22Z")
> [@Padeye](#):
>
> If I get a chance I may do some tests with half inch plate and a cache of .30 caliber AP I have.
Iāve punched through half-inch plate with my Garand. The jacketing siezes in the hole but the lead goes on through. 3/8ths plate might as well not be there if it gets hit dead-on with a modern military round.
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### Author:  [@sewalk](https://boards.straightdope.com/u/sewalk)
#### Post date: [June 12, 2005, 12:40am UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/15 "2005-06-12T00:40:10Z")
At what ranges are you guys punching this stuff? Iām used to thinking of 100m as short range for this kind of data and 3/8" as being proof against 7.62x51mm FMJ at 300-500m or so. Are we just thinking in different orders of magnitude or what? I approach armor penetration thinking as a machine gunner or a scoped-rifle marksman (Iād never self-apply the term sniper - Iām not that disciplined).
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### Author:  [@silenus](https://boards.straightdope.com/u/silenus)
#### Post date: [June 12, 2005, 1:32am UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/16 "2005-06-12T01:32:23Z")
Short-range. Most of the stuff Iāve punched has been at 100m or so. Usually because I donāt feel like walking 500m to check my targets all that often! š
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### Author:  [@Metacom](https://boards.straightdope.com/u/Metacom)
#### Post date: [June 12, 2005, 1:53am UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/17 "2005-06-12T01:53:09Z")
> [@Tuckerfan](#):
>
> Iāve often wondered why someone hasnāt come up with a decent foam filled tire, so weād _never_ have to worry about checking the air in our tires again.
Itās not uncommon for off-highway equipment (tractors, skid-steers, etc.) to have foam-filled tires. They donāt use special tires for it, just fill regular pneumatic ones with foam (done at a tire shop that has the equipment). Itās pretty expensive though (around $90 per tire for the front tractor of a small utility tractorāabout the same size as a sedan tire).
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### Author:  [@Nanoda](https://boards.straightdope.com/u/Nanoda)
#### Post date: [June 12, 2005, 1:56am UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/18 "2005-06-12T01:56:13Z")
> [@Tuckerfan](#):
>
> The thing that concerns me is they **donāt** show any shots of the wheels working in a muddy, watery (say slightly flooded roadbed) or snowy environment. All those open spaces are just prime targets for getting loaded down with gunk, and then when you hit pavement and begin driving at a fairly decent speed, that stuff is going to go _flying_.
Good call - Ok, the final product would surely have the side blocked off (perhaps transparent for kewlness) because like you said, mud or (definately around here) ice and snow would make for _seriously_ unbalanced wheels.
Thinking about it more, I can also imagine some regions might have critters nesting in them, and if they donāt chew it up inside, the mess they make when you spin them around and around and around and around wouldnāt be pretty š
Oh! And if even if you sealed it up, a leak might let water _in_ which wouldnāt be goodā¦ ok, lots of things left to solve. š
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### Author:  [@Drum\_God](https://boards.straightdope.com/u/Drum_God)
#### Post date: [June 12, 2005, 4:12am UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/19 "2005-06-12T04:12:46Z")
Tangentially related to the OP, but Kevlar is used in marching band drumheads. While not bulletproof, or bullet resistant, they are virtually unbreakable in normal use. If the head breaks, itās because some component other than the Kevlar failed ā such as the crimping around the edge.
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### Author:  [@I\_can\_t\_believe\_that\_s\_butter](https://boards.straightdope.com/u/I_can_t_believe_that_s_butter)
#### Post date: [June 12, 2005, 5:13am UTC](https://boards.straightdope.com/t/bullet-proof-tires/307854/20 "2005-06-12T05:13:06Z")
> [@Drum God](#):
>
> Tangentially related to the OP, but Kevlar is used in marching band drumheads.
And, also by some kit drummers as wellāusually hard rock or metal-type drummers, though the odd popular-style drummer will use them. I donāt know if Ricky Lawson still uses a Kevlar head.
And, just a few years ago a company was marketing these for normal drumkit use, in various models. The company didnāt last, though; speculation suggests that the heads lasted too long to turn a profit for the company. š
They arenāt without certain disadvantages, though. For one, I absolutely dislike the ācrackā sound they make when tuned tightly in marching bands (which is the fashion these days; easier to play intricate figures, I guess). Secondly, they feel like hell when used on a snare drum and cranked for durabilityāthey feel exactly like a piece of wood. This non-giving nature can easily lead to tendonitis and CTS.
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