Rethread Tyres

[demuire]

My dad mentioned to me the other day (he flies ultralights and stuff) that most airplanes use rethreaded tyres, apparently there's some "property" about them that makes them favourable to use rather than brand new tyres... He didn't know why though. Is there any truth to this? If so, what is it about them that makes them a more preferred choice?

 

On a sidenote, have just gotten some Hankook Ventus HRII tyres on the Satria, I'm rather surprised - they're pretty good. As good as, if not better, than the original tyres that were on the car (Michelin MXF Sport)... And they don't squeel as much either. They're 205/45R16's.

[Redwarf]

Yep, most airliner tyres are retreads. Just about the only time you see new tyres on a plane is when the plane is new.

 

Aircraft tyres can be retreaded up to nine times. Each time they are retreaded, the carcass is x-rayed and ultrasound checked for condition. Other things can also put them out, particularly if you've U/Sed it for being staked, or if its partially thrown a tread. (If it's thrown a tread, it can be a warranty/ insurance issue because they can cause a fair bit of damage to flaps, gear doors, wiring, and believe it or not, tailplane.)

 

The date of the retread, plus the amount of times the trye has been retreaded are stamped into the side of the tyre. It appears like; R4 0904, Meaning fourth retread, done in September 04.

 

The main property that allows them to do this, is that basically they're built like a brick proverbial, with the sidewalls being about an inch thick. (No, I won't convert to metric, it's a Boeing, and therefore Imperial measurements! :P) The main tread area is thicker again.

 

Main wheels on a 737NG last between 2 and 4 weeks, and I used to change it once a good bit of canvas was showing, or it got down to the second layer of canvas. (Canvas you say? Well they're not driving to the next port, are they??) Lets face it, it would be too uneconomical to keep buying new tyres. Gee, and some of you guys thought YOU had tyre wear issues!

 

Before anyone asks, I never did find out what a new tyre for one of those things are worth.....

 

Cheers

 

R

[irokin]

EG

[irokin]

I found some really cool info recently. Theres these jacks for aircraft, that work off the pressure in the tyre. For example the nose wheel of a B737-700 is 208psi...!!! No wonder they cause so much damage when they blow...

[demuire]

Rob: So there isn't a certain "property" about rethreaded tyres that makes them better, apart from the fact that it is cheaper?

 

Thanks :P

[andrew]

i know that the car ones fly off under speed, i had retreads on a car i had once, and it flew of (the tread) and took out my mirror

[Redwarf]

Economic reasons are the main one, but they certainally take strength into account when they manufacture then.

 

Irokin,we used to run 200 psi in the noses, 180 psi mains on the 700's and the other way around on the 800's. You can use trye pressure to pump up the jack, but it's quicker if you pump it up by hand.

 

Usually they won't actually "blow" as such, merely throw the tread of it. I've seen nose wheels that have thrown the complete tread, but still held pressure.