Olympic Steeltreks

[dreamin']

I have just picked up a set of Olympic Steeltreks for my Dormobile. They look good and ride A LOT better than the recap crossplies they replaced.

Can anyone tell me what tyre pressures are best for these - sidewall says test inflate 85 psi but assume this is not normal running pressure?

Roger

[Lotz-A-Landies]

Roger

The pressure label on the sidewall is the maximum tyre pressure.

The OEM owners manual for the 109 SIIa lists 25PSI for loads under 250Kg and 36PSI for loads over 250Kg

In the 88" its 25 and 30PSI respectively but that is on 6.00 16 tyres.

Diana

[rick130]

A radial needs vastly different tyre pressures to a bias/cross ply tyre as the case construction is so different.

WAG suggests starting at 40-45psi for a 7:50/16, then adjust from there, according to sidewall bag and contact patch.
ie. what's best depends on the vehicle and it's weight and what it's being used for, eg.highway pressures are a lot higher than what you'd use for predominantly dirt/gravel roads.

[Blknight.aus]

when I had them I used to run 30 all round in a LWB.

[rick130]

when I had them I used to run 30 all round in a LWB.

Strewth, what are they ? a sixteen ply ?

7:50/16's seem to need a lot more air in a 110/130

[Blknight.aus]

not surprising, your carrying nearly a ton more weight than a stripped down series.

Cant find my copy of the EMEI that details the inflation pressures for you.

[JDNSW]

A radial needs vastly different tyre pressures to a bias/cross ply tyre as the case construction is so different.

WAG suggests starting at 40-45psi for a 7:50/16, then adjust from there, according to sidewall bag and contact patch.
ie. what's best depends on the vehicle and it's weight and what it's being used for, eg.highway pressures are a lot higher than what you'd use for predominantly dirt/gravel roads.

The Series 2a owners handbook gives 25/25 (36) (loaded for a 109) on crossplies, and 20/20(35) for for radials. Yes, radials need different pressures.

The Steeltreks are very solidly built, and use of these low pressures on road will result in damage. I find that for on road, 35/35(45) and 25/25(35) round the property works well with them.

John

[Lotz-A-Landies]

The tyres are not branded for ply rating, but they react and have load ratings similar to 12 ply and remember the Army who were the largest customer for these particular tyres are not into using low ply rating tyres.

[goanna_shire]

Just a word of warning. They like to fall/fly to pieces at about half worn out. I have had 3 out of 5 do it on my perentie at 42 psi in the middle of nowhere.

Just my 2 cents I

[Lotz-A-Landies]

This is why the Army replacs the tyres bases upon a timeframe rather than a wear basis.

The reason is that rubber is porous and when vehicles stand in a single place for long periods, particularly on unpaved surfaces like Army pool vehicles do, the moisture can get into the tyre and rust the steel belt. This will cause delamination, hot spots and tread failure, as depicted in goanna_shire's post.

The rules are: When purchasing second hand Army tyres, have a very close inspection feeling the inside and outside of the casing for lumps and bumps. If present, don't buy them.
Try to avoid parking your part time drive vehicle on dirt surfaces.
Do inspect the tyres carefully prior to each use after a period parked up and also at the first rest stop on the next journey.Bias ply (cross-ply) tyres usually don't have a steel belt and don't suffer the rust problems. This is one reason for using conventional bias ply tyres for our historic vehicles.

[incisor]

i have had two blow at less than 20000klm and they were less than 12 months old.

it has been my experience that on a coil sprung vehicle they need to be pumped up around 50psi or they let go prematurely or scallop badly at best.

different story on leaf sprung

no doubt people will beg to differ.

[Blknight.aus]

they also blow more often when you dont use tubes in them, they are NOT a tubeless rated tyre.

[incisor]

they also blow more often when you dont use tubes in them, they are NOT a tubeless rated tyre.

didn't help mine.. and i had the good quality tube in them to boot...

[dreamin']

Thankyou all for your replies and advice

These ones are used but appear in very good condition.

I have them at 40 psi and will see how the go.

They are on 1 ton rims which are 6.5 inch wide - not sure if/how this may affect wear, but turning circle seems much tighter and I really love look of them - tyres sit out almost flush with bodywork.

Will take and post some pics on the weekend.

Cheers

R

[C00P]

I've got a set of these on my machine and I suspect they are the originals- dated from 1976.
There is a little superficial crazing around the sidewalls which had me a bit concerned, but have run them at low pressures (15-20psi) in sand and not seen any progression of the crazing. I use the recommended pressures (ie 25 front and rear if lightly loaded, 25 front 36 rear if heavy). Have done 25,000 on them myself so far (50,000 in total) with no problems. The spare is like new- never been used.
My understanding is that they are a 10 ply rating light truck tyre. Moulded on the sidewall is "10 PR".

Coop

[Blknight.aus]

didn't help mine.. and i had the good quality tube in them to boot...

probably in protest at the rapid speed changes effected by inadequately adjusted and setup brakes.

[incisor]

probably in protest at the rapid speed changes effected by inadequately adjusted and setup brakes.

Brakes were fine

One blew on a dry day on the last downhill run into cooma and the other let go in the wet hrading uphill at 90kph

No warning with either and no scalloping or other evidence of missuse

[Blknight.aus]

feel your pain, I've had to abandon a trailer to keep a perentie mobile on an exercise for the same reason (on more than one occasion)

[Lotz-A-Landies]

<snip>
They are on 1 ton rims which are 6.5 inch wide - <snip>
Cheers
RMost of the Perenties are 6" rims.

If you don't mind me asking, what part number are the "I ton rims"?

The only reason is that genuine 569204 1 ton rims are very rare here in Oz, mostly they are 569203 SIIb rims or 583384 SIIa FC/early SIIb rims Or even early 130 rims.

[Hall]

I had a set of these tyres on my old truck. Because they had aged the rubber had hardened up they did not like wet tar roads at all. In fact all you had to do was pass a picture of a wet road past them and they would lose grip :angel: So after a couple of adventures on wet roads I let some one else discover the absolute joy of these tyres in the wet.
Cheers Hall

[dreamin']

[QUOTE=Lotz-A-Landies;

If you don't mind me asking, what part number are the "I ton rims"?


Hi Diana - all I know is what the previous owner told me.

Each rim has four separate stampings on the flats between the stud holes

One is dimensions '6 1/2 L x 16 x 20.6'

One says 'ANR 1534'

One has an arrow symbol (like an old Dunlop symbol?) and the number 1372

The other is a number that seems to be different on different wheels, and not clear to read (at night, in the rain). One of them looks like 94283. Others may begin with a letter.

Please let me know if this is enough to identify them, or what else to look for.

I only have four, and would be keen to pick up anoth for my spare.

Roger

[rick130]

Sound like early 127/130 rims.
The centres will be riveted rather than welded as the late 130 rims are.

[dreamin']

Sound like early 127/130 rims.
The centres will be riveted rather than welded as the late 130 rims are.

Thanks rick130

Will look for the rivets next time I have one off

R

[goanna_shire]

Just thought I'd add there was no evidence of rust on the chords when either delaminated. I do agree rubber is porus but not sure this was the cause here;).

[JDNSW]

These are vey thick walled tyres - so operating at low pressure will cause rapid overheating when driven at high speed, and a resultant blowout. I would suspect a slow puncture was the cause of most blowouts and other failures experienced rather than delamination.

The big advantage of these tyres is their resistance to damage because of the heavy construction.

John

[goanna_shire]

What pressure would be recommended for the 750 16 steeltrek for highway use? I noticed the bulging of the sidewalls as if they weren't very happy tyres. Maybe I was running too low a pressure. It was 38 psi for highway. Too low?

Cheers
Brian

[Mick_Marsh]

The Army run them at 250kPa

[schuy1]

At the earth moving place I worked at once they used SteelTreks on all their work 'cruisers. I cannot ever recall a failure of the wall or tread. And they used to get a work out! If it could fit on the tray we carted it :D and towed it, from ingersol compressor trailers to a tri axle flat top with D6 stickrakes and pull chains. Now that was scary!:o Hydraulic overide brakes on 1 set of wheels! Cant recall inflation but probly until the sidewall stood up!.

Cheers Scott

[123rover50]

Never again no more:(

[Mick_Marsh]

Never again no more:(
As nasty as that is, I've seen that happen on other types or tyres.
Why should steeltreks be immune?

[Cobber]

I've got them for my 109 2a, and never had a problem what so ever. :cool:

On the road I run them at about 40psi all around, on dirt 30psi all around. You could probably go lower again off road, but this works for me :)

[Mick_Marsh]

I've got some bar treads that have delaminated an a Desert Dueller that blew a side wall on the freeway.