Suggested Tyre Pressures for a Coaster Bus.

Baldbug · Veteran Member

Suggested Tyre Pressures for a Coaster Bus.

Peter_n_Margaret · Guru

You need to know the weight on each axle and the tyre specifications.
Without that information, you can only guess.

Cheers,
Peter

Aus-Kiwi · Guru

I thought 60 would be low ? A lot depends on the speed your doing also . On my 7 ton 19.5 inch 225 . The recommended on duel wheels is 90lb . At 80 to 90 kph we did fine with 60lb in them . Stopping every now and then to check tyres heat . Was warm to touch ., so assumed all as well . The lower pressure did help with undulations in sealed roads ! Too it easy on corners . The front being single . Run them at 75 lb .

Jaahn · Guru

Baldbug wrote:
The Coaster we have has been converted to a Motorhome 15 years ago.
The tyre pressures are around 50 - 60 psi.
What does everyone use for a Coaster with only 2 people and Motorhome conversion?

Hi Baldbug smile

One size does not fit every tire !! I agree with Peter.

Firstly what tires do you have on your bus. Size and ply rating. That certainly sets the maximum and probably less than one suggestion. Put it over a weigh bridge and see what the weight is on each axle, then calculate as necessary. hmm

Jaahn

-- Edited by Jaahn on Sunday 18th of March 2018 09:04:34 AM

Baldbug · Veteran Member

Our Coaster has six of these on it. I haven't checked the spare for brand but can see it has a full tread unused. Tyre has 73psi near the rim.

Peter_n_Margaret · Guru

We need the full information from the tyres. Check each and every one.
It will say max load single 1000kg at ....???... psi
Max load dual ..... at .... psi.
Then we need the actual load on the front axle and the actual load on the rear axle measured on a weigh bridge.

I would also advise that you check the age of the tyres - every single one....
You will find a 4 digit number on each - something like 2806, which would mean the tyre was manufactured in the 28th week of 2006.

Cheers,
Peter

-- Edited by Peter_n_Margaret on Sunday 18th of March 2018 05:40:49 PM

Ge · Senior Member

Why don't you call in into a truck tire fitting shop and ask, so much easier.

-- Edited by Ge on Sunday 18th of March 2018 08:04:56 PM

Peter_n_Margaret · Guru

Ge wrote:
Why don't you call in into a truck tire fitting shop and ask, so much easier.

They can't do it without the same information, but they probably won't care if they get it right or wrong either.

Cheers,

Peter

Ge · Senior Member

Peter_n_Margaret wrote:
Ge wrote:
Why don't you call in into a truck tire fitting shop and ask, so much easier.
They can't do it without the same information, but they probably won't care if they get it right or wrong either.

Cheers,
Peter

What are you saying if rocks in, in his bus and shows them asks them, they can't give him accurate information.

Get away.

Aus-Kiwi · Guru

Sheesh . The tyres fitted have a pressure and load rating . Just the tyre alone is enough ? If the correct tyre is fitted ??

Ge · Senior Member

Thank AK, my point exactly, some on here just make simple things so hard. smile

Aus-Kiwi · Guru

^^ the trouble googling for answers ^^

Peter_n_Margaret · Guru

Aus-Kiwi wrote:
Sheesh . The tyres fitted have a pressure and load rating . Just the tyre alone is enough ? If the correct tyre is fitted ??

Correct, but we don't know the answer to either of those questions yet and when we have them, we still won't be able to establish the optimal pressure for the tyre until we know the load it is carrying. In the case of the Canter, the rear tyres may well be carrying half the load each of the fronts. That does make a huge difference

That is the case for every car and truck tyre made.

Take a guess if you like, but the answer will only be as good as your guess.

It is not difficult information to establish. I don't understand the reluctance by some to get it right.

Cheers,

Peter

Terryt · Veteran Member

I am in the process of trying to work out the same thing. I have the info re the tires. ie max load is x psi. Once I get the fully loaded coaster weighed assuming it is less than the max weight what is the formula used to work out the appropriate pressures. And aus kiwi what is shown on the tire is the pressure needed at the max weight on the tire.

Baldbug · Veteran Member

The tyres have been on the Coaster for 15 years already we think. The Coaster had done 41,000 kms in the last 15 years as a Motor Home, and 130,000 previous as a bus. Major Service being on the Coaster today to tell me what condition it is in mechanically.

rockylizard · Guru

Gday...

I reckon ya jest provided the solution.

I reckon pump the existing tyres up to probably 50PSI and then drive it to the nearest tyre-fitter and have a new set fitted.

It seems the existing tyres are a bit like most of us on this forum ... a fair way past it.

They will set the pressures of the new tyres at the right pressures and ya can then head off happy and safe.

Cheers - John

Peter_n_Margaret · Guru

Terryt wrote:
I am in the process of trying to work out the same thing. I have the info re the tires. ie max load is x psi. Once I get the fully loaded coaster weighed assuming it is less than the max weight what is the formula used to work out the appropriate pressures. And aus kiwi what is shown on the tire is the pressure needed at the max weight on the tire.

Proportion the maximum pressure as a % of the actual weight compared with the maximum weight marked on the tyre. plus about 5psi for single wheels.

For the dual wheels, the load ratings are lower, but still shown on the tyre.

The 6.50R16c tyres on the OPs Canter are a smaller section and lower load rating than most I have seen on Canters which are typically 7.00R16 or 7.50R16, so I suggest he also needs to check that the correct size is fitted too. The vehicle will have a tyre placard.

But I agree that if they are 15 years old (or more, they could easily have been several years old when fitted), they should be replaced immediately. Check the manufacturing dates on the tyres to confirm that.

And PLEASE get it weighed first, one axle at a time while fully loaded.

I find the trust put in the local tyre fitter to get these things right quite misplaced.

Cheers,

Peter

-- Edited by Peter_n_Margaret on Monday 19th of March 2018 10:41:10 AM

Terryt · Veteran Member

Thanks Peter.

Baldbug · Veteran Member

I took the Coaster in for a Service on Last Monday and picked it up this morning:)

As well as the Vehicle Service the mechanic who we get our other 3 vehicles done with suggested a few upgrades and general maintenance to the vehicle as it had not had much done for a long time.

So I now have new rear shockers and bushes, new glow plugs, new fuel relay, new clutch slave cylinder cylinder because of small leak, repaired radiator which had 2 small pressure leaks and all over check of rest of vehicle, grease and motor service and steam clean. Front brakes are good, rear brakes will have to be checked by truck mechanical because my mechanic doesn't have the gear to check them but there is nothing to indicate that there is anything wrong. Next service the front Shockers and bushes etc will be added to service.

Tyres are nearly all good with one inside tyre nearly needing replacement soon and they not 15 years old. Mechanic put 64 psi in all tyres.

The mechanic said the overall condition of the Coaster is in excellent condition with no rust anywhere and everything working as it should be.

The gas systems have been checked and approved, the 12 volt system checked along with 240 volt system, and the 2 freshwater tanks and grey water tank checked, the Thetford toilet system is as new and everything inside the Coaster is as new but 15 years old with little use.

I will get the vehicle weighed when I can. I will supply some pics when we take it out at Easter for a couple of nights.

Thanks to everyone above for their comments and after seeing another post about vehicle weight that is the next thing to get done.

wendyv · Guru

You still need to know the age of your tyres. 5-7 years seems to be age suggested for replacement, irrespective of tread left.

A tyre service company that put a new tyre on our LWB '94 Coaster said to run front at 75psi and backs at 65psi.

Tony Bev · Guru

Hello Baldbug

I point out that people were not trying to be unhelpful, when they were asking for the exact tyes you had, and the weight of your vehicle

For example your vehicle, a Coaster, now has 64 PSI in each tyre, as that is what your mechanic has decided is correct

While wendyv (above) who also has a Coaster, has 75 PSI on the front axel, and 65 PSI on the back axel

The tyre pressure for both vehicles are probably correct
The difference will be the size/manufacturer of tyre, and weight of vehicle, which are three varibles which dictate the pressure required

Baldbug · Veteran Member

Sorry I have been away for a few days. Which is un normal for us. We've been giving some friends a 5 day Guided Tour of Tassie and are just back in front of the Macbookpro. I'll take all the help I can get as the Coaster is 29 years old. The invoice arrived today for the initial service and parts replacement and is $1600.00 with a recommendation to change the Front Shocks, and Front control arm inner bushes next service and one tyre to monitor. We'll load the coaster up and take it out on Saturday for a couple of nights at a powered site and check everything out.