Tyre Pressure

Silverfox · 07 January 2012, 07:43

Does anybody know what the correct tyre pressure should be on my twin axle SBS that is carrying an Osprey Viper Max? One tyre has a reading of 28psi, the other three vary in pressure but are less than that. Thanks.

Boats&Outboards · 07 January 2012, 07:59

I don't know but it will say on the tyre wall what it's rated to.

Peter ~ Boatsandoutboards4sale ~ askboatsandoutboards4sale@sky.com ~ 07930 421007

hadd · 07 January 2012, 08:00

Quote:

Originally Posted by Silverfox

Does anybody know what the correct tyre pressure should be on my twin axle SBS that is carrying an Osprey Viper Max? One tyre has a reading of 28psi, the other three vary in pressure but are less than that. Thanks.

Hi silverfox, It should say on the side of the tyre what pressure should go in there , my tyres take 60psi i always put 55psi in them

Silverfox · 07 January 2012, 08:13

The tyre wall on my car tyre is rated way above the 32psi that are in them, as 32 is what the manufacture recommends. Is it right therefore to go to nearly the max rated psi of the tyre? Won't the trailer be very bouncy when towed?

AMac · 07 January 2012, 09:07

the trailer manufacturer will be able to give you a pressure if you tell them the weight of the load being carried on the trailer

Boats&Outboards · 07 January 2012, 09:21

Trailer guy will give you definitive advice but generally when towing any distance (ie motorway) with tubeless tyres you want them to be inflated quite close to max rating. This helps preventing them from heating up which gives a greater risk to blowout, shredding etc. If they are under-inflated they become weaker on the tyre walls. Even some of the smaller 10 inch wheels are inflated past what a car needs.

Peter ~ Boatsandoutboards4sale ~ askboatsandoutboards4sale@sky.com ~ 07930 421007

willk · 07 January 2012, 09:56

My SBS 2000 came with crappy Comac tyres, I had a twin motored 6.5m on it and ran the tyres around the 40psi mark. I was never towing over 50mph for any time and I never found any warming (or bouncing). I'd agree with checking it with SBS....

Leapy · 07 January 2012, 10:14

Having weighed my RC5.3 and had a shock

the wheels and tyres were uprated with - for a trailer - some sexy looking low profile jobbies rated at 96psi which is what I was told to run them at.

I actually run them at 85psi and no problems though the 12v tyre pump has a tear in it's eye everytime it sees the trailer.

Silverfox · 07 January 2012, 11:16

Thanks everybody for you assistance. I think my 12v pump is going to also wince like Leapy's very soon!

Trailer Guy · 07 January 2012, 12:06

Hi Silverfox

As B&O suggested, you need to keep on top of your trailer tyres, especially if you're towing good distances. Obviously it'll affect the towing characterisctics, but under inflated tyres will also have a greatly detrimental effect on your fuel consumption

TBH, your tyre rating will all be down to your tyre type / size / rating. Here's a previos post on identifying the spec of your tyres: http://www.rib.net/forum/f49/trailer...cky-44849.html

As suggested, SBS should be able to guide you. However, they sometimes put the psi rating on the chassis plate too, so that may be worth a check. You should find it n/s front on the drawbar / a-frame. As others have said, the rating should also be on the tyre too. It'll say something like "60psi cold", or similar. Check there too.

If you don't get any joy let me know the tyre info and I'm sure I'll be able to assist.

Erin · 07 January 2012, 12:39

I've always wondered whether it makes any difference as to whether you set the pressure when the trailer is laden or unladen. Presumably with a loaded trailer there is more weight and compression on the tyre resulting in an increased air pressure within? Or is the difference so negligible that it makes no odds?

Trailer Guy · 07 January 2012, 12:41

Have now added some common tyre pressures to this page:

http://www.rib.net/forum/f49/trailer...tml#post437589

mick · 07 January 2012, 13:14

I am on 10 " 8 ply I haven't chequed them yet but reckon about 60 psi should do.

Trailer Guy · 07 January 2012, 13:16

5.00 x 10 8ply?

mick · 07 January 2012, 13:19

Quote:

Originally Posted by Trailer Guy

5.00 x 10 8ply?

Correct.

Trailer Guy · 07 January 2012, 13:24

If they've a load index of 84 then their max capacity (@ 100kph) is 900kg and their max psi is 65. Ergo, you were bang on with your 60psi average - though I'm sure you were never in doubt!

mick · 07 January 2012, 13:27

Quote:

Originally Posted by Trailer Guy

If they've a load index of 84 then their max capacity (@ 100kph) is 900kg and their max psi is 65. Ergo, you were bang on with your 60psi average - though I'm sure you were never in doubt!

Well i am a good guesser not sure if there cross plys as well

Trailer Guy · 07 January 2012, 13:31

Quote:

Originally Posted by Erin

I've always wondered whether it makes any difference as to whether you set the pressure when the trailer is laden or unladen. Presumably with a loaded trailer there is more weight and compression on the tyre resulting in an increased air pressure within? Or is the difference so negligible that it makes no odds?

I've often wondered myself Erin! I guess, theoretically, there could be a change in pressure, due to additional load, but it's likely compensated for by the deformation of the tire. Therefore the actual internal volume doesn't change (ergo pressure) as the tyre compensates for it.

Theoretically anyway! lol Doubtless there'll be someone along, far more astute than the pair of us, to correct us in a minute

Trailer Guy · 07 January 2012, 13:34

Quote:

Originally Posted by discomick

Well i am a good guesser not sure if there cross plys as well

Yes sir, the 5.00 x 10 denotes cross ply. If they said 145R10 then the 'R' would indicate radial.

CJL · 08 January 2012, 22:22

SBS Manual - http://www.sbstrailers.co.uk/pdf/Service_Manual.pdf

Tyre pressures on page 3.

Chris