Tyre tip for those who lower pressures

Submitted: Wednesday, Oct 05, 2005 at 08:07
ThreadID: 27001 Views:3513 Replies:4 FollowUps:5
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A very recent tyre thread jolted my memory about a tyre I had let go while away, and the consequent talk to Wally, the tyre repair bloke in Tibooburra.

While picking his brain about what tyres he repairs most often he told me he does a lot of repairs to people who let their pressures down, and don't put the caps back on, then they fill them again, the dirt in the valve is blown into the tyre and eventualy wears a hole in the tube. I thought it was a fairly obvious thing, but he gets enough repairs in to mention it, so I thought I'd pass it on here.

As for what tyres are better he said "there is a pile out the back you couldn't fly a plane over, anyone can have a search thru and see what tyre isn't there, then buy that sort"

Glenn
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Reply By: banjodog - Wednesday, Oct 05, 2005 at 09:17

Wednesday, Oct 05, 2005 at 09:17
Actually the valve cap is the “primary” seal for the valve stem not the valve. The valve is only there to stop the air coming out until you screw the cap back on – there is a rubber washer in the cap that seals against the top threaded area of the valve stem.

Whenever possible only use the metal valve caps as they seal better, are stronger and more robust than the plastic caps - and because the metal caps look good too they do get souvenired - I've had 3 sets taken over the years.

However, there are some good, strong plastic valve caps available too and are cheaper to buy.

AnswerID: 133109

Follow Up By: Patrol2 - Wednesday, Oct 05, 2005 at 10:52

Wednesday, Oct 05, 2005 at 10:52
The tyre cap is the 'secondary' seal for the tyre. The valve is the 'primary' seal. DO NOT rely on the valve cap to keep air in the tyre. It will help keep dirt out of the valve mechanism and will help keep air in in the case of a leaking valve, but not very well.

If no valve cap has been in place, flush the dirt out before forcing air into the tyre by quickly depressing and releasing the valve core, then find a replacement cap ASAP, preferrably metal.

Mike
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FollowupID: 387335

Follow Up By: Member - Oskar (Bris) - Wednesday, Oct 05, 2005 at 11:56

Wednesday, Oct 05, 2005 at 11:56
Mike
In a technical journal I read several years ago (Dunlop or Schrader or someone like that, they stated that the cap was the primary seal not the valve.
That point stuck in my mind, at that time, and I have only used metal valve caps since. (And screwed them down properly)
Unless there is new, updated info of course.

Just a hint for those who don't already know .....never put the valve cap in your mouth while inflating/deflating your tyres.
The reason ??
We all know what dogs do around cars!
Oskar
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FollowupID: 387342

Follow Up By: banjodog - Wednesday, Oct 05, 2005 at 12:31

Wednesday, Oct 05, 2005 at 12:31
My initial comments were what I remembered as an apprentice and stuck in my mind. There is also this article in PDF format - valve caps
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FollowupID: 387343

Follow Up By: Member - Davoe (Widgiemooltha) - Wednesday, Oct 05, 2005 at 20:15

Wednesday, Oct 05, 2005 at 20:15
I was forever losing caps off of the tyres of my camper and often it had none - didnt really seem to make much difference to anything
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FollowupID: 387388

Reply By: Member - RockyOne - Wednesday, Oct 05, 2005 at 09:28

Wednesday, Oct 05, 2005 at 09:28
I am a fusspot about always putting caps back on and never use those black plastic ones,Only steel ones with a proper seal rubber..Always keep at least two of my tyres with the valve caps that have the core remover slot on top..Good tip there about debri in tubes though..On trips up through the Gulf of Carpenteria,where,because of corrugations,all those in the know,had aired down to save the dashboard from falling in your lap,we noticed that every single punture we saw was through the sidewall..It gets worse..All were on the rear tyres..Lesson to be learned from that,as our tour leader indicated."Drive for your rear tyres,not the front" We came across a wagon of four folk,three tyres were staked through sidewall,all on the rear at the time..We lent them them a spare to get into Roper Bar,N.T..Oh yeah! .At servos,when airing up tyres,as soon as air chuck is removed,a little spit (what's a flash word for that? Expectoration? ;-) should be applied to valve opening to watch for bubbles which indicate leakage (soapy water if you just happen to have some in your kit)..Leaks a bit,press pin with little stick (who has matches these days and Bic™ liters won't fit) and let it slide off side to quickly release center valve pin..Mostly stops leak..Otherwise,replace..Yeah! I know..You old hands know all this,but we all had to start somewhere,way back in the burn on patches days..st.st.st!!MPG:7!
AnswerID: 133111

Follow Up By: Member - Davoe (Widgiemooltha) - Wednesday, Oct 05, 2005 at 20:18

Wednesday, Oct 05, 2005 at 20:18
flats on the rear are by far and away the most common because your front tyres flick up the previosly flat lying rock/stick and your back tyrespick them up
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FollowupID: 387389

Reply By: spondo - Wednesday, Oct 05, 2005 at 16:11

Wednesday, Oct 05, 2005 at 16:11
hey hey g'day

"Actually the valve cap is the “primary” seal for the valve stem not the valve."

this forum just keeps getting better and better.... lol

oh dear god give me strength
regards robs
AnswerID: 133140

Reply By: Member - RockyOne - Thursday, Oct 06, 2005 at 08:01

Thursday, Oct 06, 2005 at 08:01
"Front tyres flick up stones/nails etc" Yep! I found that out (different thread to the sidewall puntures/spikes tho) as I used to run a tandem trailer to the dump weekly wit 4 bald tyres..Never ever had a flat..Law tightened up after four years or so,then I but some "treaded" tyres on..You've guessed it..Had several puntures then,usually the rear...(did'nt need the tread for braking as the elect brakes had died years before)..(Not to be taken as evedence against me,as I speak with a forked tongue)
AnswerID: 133234

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