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Car tyres don't have inner tubes, do they.

mrs quoad

Well-Known Member
So they're kept inflated just by pushing the rubber bit against the metal bit?

How does that work, then?

And no, I don't do cars, before anyone asks :D

And I had tried googling 'how do car tyres work,' but the first two hits are uninformative and then I got bored :(

e2a: also, to make myself look knowledgeable, I ended the thread title with a '.' instead of a '?'.
 

Pingu

Credo
So they're kept inflated just by pushing the rubber bit against the metal bit?

How does that work, then?

And no, I don't do cars, before anyone asks :D

And I had tried googling 'how do car tyres work,' but the first two hits are uninformative and then I got bored :(

by pushing the rubber up against the metal bit.


motorcycle tyres on the other hand have to have little leprechauns inside them to stop them falling off the rim
 

100% masahiko

i is a professor and is magical like totoro


Most decent cars have flat runs now (super dooper reinforced rubber that keeps it's shape even after a puncture. Can run even on 0 pressure). I love them but so expensive to replace.
 

weltweit

Well-Known Member
Yes, they don't have innertubes (not any more but they used to years ago)

The air pressure keeps the beading on the side of the tyre pushed up tight against the edge of the wheel rim and creates an airtight seal. The wheel itself is solid so also airtight and the only hole in the wheel is where the valve is inserted.

Motorbike tyres on spokeless wheels are also tubeless and work in a similar way to car tyres. Older motorcycles and / or that have spoked wheels have tubes and spoke protectors etc ..

BMW innovated recently with spoked wheels that take tubeless tyres, quite clever, the spokes go from the hub to the edge of the aluminium rim, because the spokes are at the edge of the rim, the rest of the rim where the tyre sits can be solid and thus accepts a tubeless tyre.
 

Pingu

Credo
there is a beading strip that helps a lot. and the shape of the rim etc all help to make a near airtight seal
 

pogofish

Testicle Hairstyle
Car tyres don't have inner tubes, do they
Depends on the car and the tyre TBH.

Inner tubes are still pretty common on older vehicles and far from rare on small commercials etc as they can use much cheaper tyres/tyre sizes.

Similarly offroad vehicles still regularly use tubes so tyres can be run at lower pressure for soft ground without the risk of blowing the air out the side of the tyre or losing seal because of grit getting between tyre and wheel rim.

Tubes are more likely to be needed on pressed steel wheels, with alloys being nearly all tubeless. You can use either on some alloys but I understand this is much less common now. This was useful on my old Saab as I simply started using tubes when the alloy rims would no longer hold a reliable seal.

They work by having a very tight-fitting and strong seal (usually reinforced by steel cable) between the tyrewall and the wheelrim, hence the special machines/very long levers that fitters need to put them on with.
 

bi0boy

Power User
Most decent cars have flat runs now (super dooper reinforced rubber that keeps it's shape even after a puncture. Can run even on 0 pressure). I love them but so expensive to replace.

Runflats are shit because:

1. The tyre wall is stiffer resulting in poorer handling on corners.
2. You can only run 50 miles at 50mph before you need to change them anyway, but likely won't have spare :facepalm::facepalm:
3. They need a tyre pressure monitoring system otherwise you won't know they're punctured, and they're expensive and hard to fit.

Most decent cars don't have them, but BMWs generally do.
 
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