Camper + increased tyre pressure + corrugated roads = sore back

[Xfigio]

Hooking the goldstream wing up, I always increase tyre pressure to get the rear tires back to a normal profile / footprint.  For the first time this year, I've gotten a sore back after about 300km or corrugated dirt roads. 

Some specifics...
Camper is well loaded balance wise, very little additional weight in front of axle, so would be very close to the factory ball weight of the goldstream.

Tires are BFG ATs on the Prado, running about 48 psi cold.

I don't see how to alleviate this.  Upgrading the suspension/air bags etc won't change the required pressure in the tyres by my logic.

What do others do in this scenario?

[oldmate]

Drop your tyre pressure.  I've never run 48psi on our car, even on bitumin. 

[V8CRSA]

48 psi is way too much on the black top, and you need to half that for corrugated dirt roads.......

Matt

[Xfigio]

Drop your tyre pressure.  I've never run 48psi on our car, even on bitumin. 

if I run my regular pressure of 42, the rear tyres get pretty warm with the camper hooked up.  Do others just not bother about the heat?

[Xfigio]

Ok, looks like the consensus is to run lower pressures, and let the tyres "bell" a little more.  Though this does make me nervous on dirt with sharp rocks, as I've slashed a few sidewalks over the years, admittedly they were regular car tyres.

[oldmate]

if I run my regular pressure of 42, the rear tyres get pretty warm with the camper hooked up.  Do others just not bother about the heat?

Honestly, I've never stopped to check. On blacktop, I normally run around 38ish in the rear, maybe 40, and on dirt rds easy to drop below 30. Depending on load. But that's me and my car and tyre set up.  How are your tyres wearing with 48psi in them?

[Bad Scott]

The heat only increases about 4-5 psi. We run generally between 25-35 psi. Will lower pressures if conditions require it. Never had a flat on BFG muddies.
Sent from .................

[Xfigio]

Thanks for the responses guys.  The heat bothered me more in terms of being a symptom of the additional flexing of the sidewalks, potentially reducing tyre life.

I only generally run the higher pressure when towing, so am unable to tell the difference it makes to overall tyre wear.  Normal pressure is 42, and wear is good.

[MrCruza]

I run pressures similar to yours on the blacktop but drop them down to about 28-30 on dirt. Ride is MUCH better and as I'm travelling at a lower speed on dirt the temperature is not such an issue. Pump them back up when back on the blacktop. 

[BTMNDR]

I have a 200 Series with Cooper A/T3s, and regularly tow a 2.2 tonne camper.

Around town I run 35psi. On the highway 38 psi front, 40 rear, and 33 in the camper.  On corrugated roads, I've run as low as 20 psi, and driving to the conditions, never staked a tyre, or over heated one.


Edit: Dunno how corrugated got changed to cumulate?   

[Black Diamond]

Ok, looks like the consensus is to run lower pressures, and let the tyres "bell" a little more.  Though this does make me nervous on dirt with sharp rocks, as I've slashed a few sidewalks over the years, admittedly they were regular car tyres.

It shouldnt be making you nervous because you have less of a chance of a sharp rock going through a tyre carcass when the pressure is down allowing the Tyre to roll over the sharp rock not impact it harder when the tyre is not as submissive

[Pog]

Tires are BFG ATs on the Prado, running about 48 psi cold.
For the first time this year, I've gotten a sore back after about 300km or corrugated dirt roads.

I am not surprised... 48 PSI (cold) is very high. When hot, they surely must be increasing well above 50 PSI.

Drop them to 32 - 34 PSI (cold) and take some pressure readings after a drive (hot). You will see an increase in pressure, but notice a much better ride.

On rough roads, many people drop pressures to 28 PSI and slow down a bit. The ride is significantly better.

On the highway and around town, I run 38 PSI (cold) on our Prado. If going off road, depending on the surface and the type of driving, I will lower them down to what ever I need to to ensure enough traction and a smooth ride.

[KingBilly]

Try the old 4 psi rule.  Inflate all tyres to your normal pressures using your own guage.  Then go for a drive, about 30 plus minutes, to get them hot and check pressures again.  If the difference between cold and hot is more than 4 psi, your starting pressure is too low.  If less than 4 psi, it is too high.  Adjust your cold pressures accordingly.

I run 38 psi cold and have regularly tested them at 41 to 42 hot.  But that is with my load, yours may be different.

On dirt roads, I drop to 28 cold, or 32 hot, and keep to around 80kph which suits me on the dirt.  Offroad or sand, I drop further.

My trailer pressures are 32 on bitumen and whatever I drop my vehicle to on dirt etc.

KB

[time]

Try the old 4 psi rule.  Inflate all tyres to your normal pressures using your own guage.  Then go for a drive, about 30 plus minutes, to get them hot and check pressures again.  If the difference between cold and hot is more than 4 psi, your starting pressure is too low.  If less than 4 psi, it is too high.  Adjust your cold pressures accordingly.

I run 38 psi cold and have regularly tested them at 41 to 42 hot.  But that is with my load, yours may be different.

On dirt roads, I drop to 28 cold, or 32 hot, and keep to around 80kph which suits me on the dirt.  Offroad or sand, I drop further.

My trailer pressures are 32 on bitumen and whatever I drop my vehicle to on dirt etc.

KB

X 2 on my GU IV Patrol pulling a KK.

This link may be of interest http://outbackjoe.com/macho-divertissement/macho-articles/tyre-pressure-guide/

[Bird]

Tires are BFG ATs on the Prado, running about 48 psi cold.

[WilSurf]

When we drove home after a week away, we ended up behind a caravan on corrugated road. He was almost crawling because of the bumps.
Before we came up to him, we were doing 60-70 and had no issues. When we were crawling as well it was horrible. We felt every bump.

Tyre pressure are never over 40 on mine, 38 on the road, 28 on tracks, 15 or lower on the beach.

[cloakle]

I run myn at 33

[theins]

Check the manufacturer specifications. 48 cold sounds way too high!

If the pressure is too high the Tyre will wear quicker and your suspension will have to work over time,  as usually the Tyre absorbs some of the bumps...

Cheers,

[jetcrew]

Hooking the goldstream wing up, I always increase tyre pressure to get the rear tires back to a normal profile / footprint.  For the first time this year, I've gotten a sore back after about 300km or corrugated dirt roads. 

Some specifics...
Camper is well loaded balance wise, very little additional weight in front of axle, so would be very close to the factory ball weight of the goldstream.

Tires are BFG ATs on the Prado, running about 48 psi cold.

I don't see how to alleviate this.  Upgrading the suspension/air bags etc won't change the required pressure in the tyres by my logic.

What do others do in this scenario?

wow mate, that will be flogging the crap out of everything including your back, but imagine how every part of the camper chassis and suspension feels

AS BD says the higher pressure will result in more tyre damage then a lower one on corro roads.

Increasing tyre PSI to account for load is a recipe for disaster IMHO.

Jet

[theins]

Just from memory - the manufacturer in my case states
- normal load 36 psi
- full load 38 psi

Cheers

[Mongoose]

I traded my Prado in after 3 years & 96,000 KMs. The BFG AT's that I put on it on day 1 still had 20,000KMs left. I ran them at 32-36 PSI on black top and 20-24 in the bush. Never had a puncture, and certainly never had a bad back.

[Xfigio]

Thanks for the responses all.  I have lowered the pressures as suggested here, and the ride is a whole lot more comfy.  I'll check against the 4psi rule as we go, and just trust the tyres to be ok with the extra "belling".

Thanks a lot for all your responses.

[duggie]

Now that you have lowered your tyre pressures , you will find that you can increase your speed on the dirt/corrugated roads, by this I mean find a speed that you are sitting on top of the corrugations ( somewhere between 90 to 100 kph ) this will give you, your car and trailer a smoother ride as the tyres and suspension are working at there best. 

cheers duggie

[fridayman]

On my Prado I start with 30psi in the rears if I'm towing the camper on corrugations.

Without exception, all the people that we've stopped to help with blowouts had not dropped their tyre pressures.

[Gunsrunner]

4psi  rule, regulate speed for safest, smoothest ride, keep weight to minimum.
I would measure your tow ball weight and GTM, don,t just guesstimate.
You do need to use the flex in the side wall over corrugations, but watch the side wall temperatures don't get to hot. Hence the 4psi rule.
I bought a Tire Pressure Monitor system for $150, made it a hell of a lot easier.