Tire Pressure

[Tomfoolery]

A lower pressure for a given load means a larger tire, or at least a larger contact patch on the ground, in a general sense. So either those tires are overloaded, or they're much larger than the ones normally used for the Macs. Probably should check the max load rating that corresponds with the max pressure rating.

[raycarlson]

at 32psi max those are definitely P tires, not ST or LT, check the load rating, it probably says max load 1700lbs at 32psi.

[Russ]

Automobile tires are not suitable for our boats. I've seen people put car tires on trailers. Not good.

--Russ

[mastreb]

My 32 PSI tires are the factory stock tires on my trailer, mounted on trailer hubs, and the spare is the same. So I'm certain other people are rolling these on their trailers.

They're both at 32PSI now, and appear to have proper wear and shape. I'll take a photo of the sidewall when I'm down there and post it.

Matt

[beene]

Had a flat the other day
Bringing the boat along a road at 40mph
Felt a shudder
Looked in side mirror and saw left trailer tire was running on the rim and tire was coming off the rim
Pulled over
First my truck jack would not come out as it was seized in there
Finally got it out after 2 hours of working at it
Then discovered it could not life the trailer
Not enough power
The thing worked like it was designed in China by a tonka toy company!
POS!!
I was screwed
Thankfully someone stopped to see if I needed help
He had a hydraulic
Got her up
Swapped on the spare
Brought home boat
Took tire into garage
They had it back up and ready to go in minutes
Said my tire was an expensive "Run Flat" tire
Very good quality for trailering they said
Got it home
Swapped it back on and put the spare away on front

Lesson learned
Now carry a hydraulic 4 tonne jack at all times while trailering

G

[Catigale]

Geoff - what max pressure does your sidewall state on those tires please?

[Russ]

Said my tire was an expensive "Run Flat" tire
Very good quality for trailering they said

I've never heard of a run flat rated for trailering. I had them on a car I owned. They are VERY expensive, however mine wore out in 10,000 miles. They have thick sidewalls.
I don't know much about trailer tires, but I wouldn't use anything on my trailer except tires rated for trailers and the load they are carrying.

[beene]

My trailer tires are stock

'06 built
'07 model 26m

65 psi rating on both

my spare is also stock

and it has a less load rating and 55 psi

G

[Boblee]

Said my tire was an expensive "Run Flat" tire
Very good quality for trailering they said

I've never heard of a run flat rated for trailering. I had them on a car I owned. They are VERY expensive, however mine wore out in 10,000 miles. They have thick sidewalls.
I don't know much about trailer tires, but I wouldn't use anything on my trailer except tires rated for trailers and the load they are carrying.

Had my first experience with run flat tyes at duck opening when one of the boys got a flat in his Audi AFAIK they are for emergencies only and are limited to 80kph speed just a waste of time but they store better.
As for the camber anyone with a single straight axle mac trailer is going to get this unless they bend the axle back AT the stubs as the axle bends under weight, when I bent the original axle back on one side I also fixed the camber, it's a job but can be done with jacks and a heavy weight to bend against but better done in a press if available, note ours was perfect after fixing and no more tyre wear.
Those axles are exceptionally hard and springy trust me but if installing another axle the same I would give serious consideration to putting lighter (and/or longer) springs under it as the originals are too stiff and short and also have poor bushing.
Photo's drilling a hole in an opal mine dugout wall to insert steel bar to jack axle against note axle in backgound (didn't work), ultimately used the axles on some of the heavy machinery in the background of the second picture to jack against, it was a long weekend and nothing was open so saw this bloke using a backhoe outside his opal shop in the main street of Coober Pedy and asked if we could use the hydraulics to bend the axle but he took us up to his workshop?
I did give him a bottle of whisky and bought him a good Barra on the way back as he wouldn't accept payment.




It should be noted here that if I had my new dual axle trailer on in that situation I would have remained stranded 200 + k's outside Adelaide but with the single axle just put old spares on and drove to Coober Pedy but would not have made Alice Springs which was the next service place.

[raycarlson]

why would you have been stranded with a dual axle, you can just remove the flat and continue on the way with one tire per side.

[Boblee]

Ray
If I had a tandem and bent the front axle I would not have been able to continue as the tyres would have been fighting against each other too much and unless both axles (tyres and springs) were each able to carry the whole weight I couldn't disable the bent one, even if it (the second axle) could carry the weight there would be a fair weight on the towball and A frame due to the second axle being further back.
We had this discussion at the time as the bloke travelling with me suggested thats why you need two axles, as it was the trailer towed perfectly well just 18" towards the edge of the road but after 400+ k's the spares which weren't real good anyway, weren't going to make another 500k's to where there would have been a press.
It would have been a case of leaving the trailer and getting to the nearest communication 1-200k's to organise a truck to load the trailer on or trying to get parts sent from a capital city which would be easier now as the trailer has all parts that are easily sourced in Aust but still a week at least.
It is pretty cold in that desert country and just out of Alice it was -5c in the boat and -3c in the fridge in the morning so didn't want to spend too much time there and there was no way I was going back to Port Augusta to wait at least three days on the chance I could get something.
Need to be able to fix things on the run here as help can be a long way off, hard to contact and really expensive especially inland.

[Sumner]

Ray
If I had a tandem and bent the front axle I would not have been able to continue as the tyres would have been fighting against each other too much ....

I would think that if you had a single axle and had bent it that bad you would also not of gone on very far. I guess we can find scenarios where any combination won't be good, but overall the one that has proven to be best most of the time is the one to go with. Remember when many people said they didn't want to wear seat belts as they didn't want to be trapped in a burning car? Kind of the same deal. I wouldn't want to go back to a single axle. Sure I could tow with one but the boat just pulls much better and safer in varying conditions with the two axles and the surge disc brakes,

Sum

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[raycarlson]

Have never heard a person who had towed their boat that had been converted to two axles say, " Man this is terrible, I'm going back to a single axle trailer" once you've had two axles you'll never go back.

[mastreb]

So I have these mounted: http://www.carlisletransportationproduc ... port-trail

In the 225/75D15 size. The site lists a minimum of 50 psi despite what the sidewall says:



They're wearing like they're under pressure, so I'll top them up. You guys were right.

Also, it's pretty clear I've got a negative camber. Not sure what can be done about that aside from adding an axle.

[seahouse]

Matt -

While I can't read the last sentence on the tire, it might be relevant to note the distinction between the maximum tire pressure, and the maximum tire pressure to seat the bead (used by the installer). They're two different numbers.

- Brian.