Not happy with nitrogen inflated tyres.
Submitted: Tuesday, Apr 24, 2012 at 08:12
ThreadID:
95104
Views:
6707
Replies:
11
FollowUps:
5
This Thread has been Archived
Member - Richard H - West NSW
Picked up a new Jayco van from
Mildura, and noticed the green valve caps.
I was told that Jayco now inflate the tyres on their new vans with nitrogen.
The van was towed
home empty, and sat in the driveway for a couple of weeks whilst I set it up for a quick trial run. As I was departing
home my neighbour came over, and looking at the tyres said that they appeared to be down. The van had the usual collection of unnecessary junk installed, full water tanks & 2 x 9 kg gas bottles, and a bit of tucker and some clobber.
O.K. I had a look and did a quick pressure
check, both tyres around 35 PSI, so I cleared out. I got down the road into S.A. and stopped at a
rest area to give the dogs a run and on checking the van I saw that the nearside tyre looked like it was going down. So, after a lot of sweating, bashing at flies and knocking skin off my knuckles, I got the spare off, and changed the tyre. When I eased the jack off it too looked deflated. A
check reveal a similar reading to that seen previously.
So I got my 12v air pump out and pumped it up to 45 PSI, and did the same with the offside tyre. Since then no problems.
What's the setup with nitrogen inflated tyres. When they get hot, which they did on that day as it was a shocker, does the gas contract or go through some alteration? I don't know as it's a long time since I did science at school.
Anyway, in future I'm going to use the time tested method of keeping the tyres on my vehicles inflated, with air.
And...gees I hate people who feel it obligatory to tighten wheel nuts up to the point that they are almost impossible to ease off. If that person had appeared at the scene I would have strangled him/her.
Reply By: Ron N - Tuesday, Apr 24, 2012 at 10:02
Tuesday, Apr 24, 2012 at 10:02
Had a good chuckle at some of the Caravanners
Forum comments in the link put up by Rod.
Karl on that
forum has nailed it exactly. With racing, and with aviation, using pure nitrogen in tyres has measureable, and often important benefits. Removing an oxygen supply assists with a reduction in fire potential.
For caravans, using nitrogen in tyres is unnecessary and merely sales hype. As Karl says, air is nearly 80% nitrogen anyway, so, a 20% increase in the niitrogen level, for caravan use, has barely-measureable benefit.
I suspect perhaps the tyres the caravan manufacturers are using, may be borderline in load capacity (a common problem) - and by using nitrogen, they're hoping that their marginal tyres will last, until the warranty runs out.
Richard - The alternative to excessively tight nuts is loose ones, and that can be a nasty experience. Been in a car where a wheel fell off because someone never tightened the nuts.
The problem with excessively tight nuts, though, is the potential for wheel stud fracture.
Wheel studs are high tensile, and high tensile fasteners are heat treated and rely on a set amount of stretch created by correct torque application (or "elastic deformation" as the engineers call it), to keep a certain amount of pressure on the item to be retained in position.
Once a high tensile stud is stretched beyond its elastic deformation limits, the stud will fracture. That fracture may not be readily visible, but a fractured wheel stud will break without warning when a load peak is applied, in circumstances such as cornering.
Thus, it's fairly critical to ensure that correct torque is applied to wheel nuts.
I shudder when I see people using rattle guns on wheel nuts, with no final hand torque
check - and I always re-
check wheel nuts after a tyre
shop has done them.
A rattle gun isn't a device that can supply a set torque range, the torque output varies according to rattle gun lube, air pressure to the gun, and the torque setting adjustment screw. They're handy tools, but you never rely on them to set final torques.
Cheers - Ron.
AnswerID:
483994
Follow Up By: Echucan Bob - Friday, Apr 27, 2012 at 14:38
Friday, Apr 27, 2012 at 14:38
Someone with a bit of what was known in the Navy as CDF.
Well said Ron.
FollowupID:
759638