Towing with an RRC (EAS) - not cool!

I did my first towing journey with the RR this weekend, and it wasn’t brilliant to be honest.

One problem was not really the cars fault, more the tyres I have put on it. The Insa Turbo Traction Tracks are much more aggressive than I expected, so make a lot of noise at motorway speeds.

However, there were other issues. Firstly, there seemed to be a severe lack of power – particularly running on LPG. I was expecting the Range Rover to barely notice the additional weight once it got going (3 motorbikes on a Brian James flat bed twin axle car trailer, total weight approx 1100-1200kg). However, it was the exact opposite – at slow speeds it was barely noticeable but at motorway speeds it really struggled – even the slightest incline saw speeds drop to 55mph and required a kick down a gear and holding it around 4,000 rpm to keep at that speed. Rubbish.

My friend has a Ford Focus and that towed the same trailer, albeit with just one bike, with ease. On a private test track it would tow at 100mph quite happily – I would expect the Range Rover to cope with such duties easier than an 8 year old diesel Focus, even taking into account the two extra bikes we had!

Secondly, there was a serious amount of weaving going on. I think this was partly due to too much weight over the front of the trailer (tongue weight) as my friend had positioned the mountings for two bikes at the front, one at the rear and we did not have time to amend this. Even so, because the RR has air suspension, the car remained level so it should not have taken too much weight off the front of the vehicle. What could cause this weaving and how can it be rectified? We will be repositioning the bike tie-down points, but can anything else be done to improve the situation?

On the plus side it was comfortable and used two tanks of gas to do a 400 mile round trip, cost around £120 – not totally horrendous given it was dragging the trailer, 3 motorbikes, 3 people and our luggage/leathers/toolkit up to Cadwell Park and back I guess.

Any suggestions in improving the performance and handling would be appreciated, as this was one of the three main duties I had planned for the car (being trackday transport, winter driving/recovery and expedition use).

Cheers!

the fact air has kept back level doesnt alter the weight transfrence that much .your towing point is behind rear axle hence the reason tractors used to have towing point attached in front of rear axle,ive allways found h/d coils felt better towing on classic , nose weight is very important as you know, 3.9 on gas is a litle disappointing depending on gas kit ,as i used to know with my caravan ,your shifting alot of air hence inadequate at higher speeds, if youd had coils id beefed up front back with gas shocks too, with air sprung discos with double axle trailers some have found these beneficialhttp://www.dixonbate.co.uk/images/buttons/gifs/buttons_shocklinkmkII_f2.gif what gas system have you got single point ?

Thanks James. That looks a good bit of kit, but very expensive. It will probably only tow this around 5 times a year, at a guess.

The LPG kit was installed several years ago, so my guess would be a single point injection system. It runs well on gas but is a bit down on power.

The rear has two new air springs plus uprated Monroe Adventure shocks.

I've attached an image of the setup - sits nice and level. Each bike weighs around 180kg, we put the two lightest at the front and the heaviest at the back, plus a 20L jerry can of fuel strapped down at the back of the trailer.

looks good ,i live down the road from cadwell only been once and that was to go round cutting grass with tractor and flail spent half the day driving round,not quite as exhilarating on tractor though,levelness isnt quite the same thing as weight transference, id set bikes with tow bar on scales get it as good as possible imo single point is disappointing towing fast

LPG is less energetic when it burns than petrol by 15-20% so expect a performance loss due to this. Also this will be exaggerated when towing hence the slowing down on hills.

Diesel Oil is actually fairly energetic when it burns which is why you get better MPG and Torque in a diesel as less fuel is needed to do the same amount of work.

This is why the Diesel Focus is 'seen' to tow your trailer with 'relative' ease.

Infact the Focus is doing more 'work' than the RRC in towing the trailer as the RRC will tow happily, just not at the speeds you are expecting.

BHP and Torque mean two different things but are related to a degree....

For example, consider someone banging a rod into the ground....

BHP is how many times in a minute the guy can hit the rod with a hammer.

Torque is how big the hammer actually is.

You can hit it really fast with a small hammer (the Focus) and do more work just looks like it is getting done quickly.

Or you can smack it with a sledge hammer (the RRC) slower but takes less work.

Don't dis the RRC, it is a very capable tow vehicle, just don't expect rocketship towing speeds.

Onthe subject of stability, the weaving sounds like to much weight on the tow hitch (tongue weight, nose weight, ball weight - however you wish to describe it)

The stability issue is more likely down to tyres and tyre pressure. The weight should not be a problem . Tongue weight can be measured with bathroom scales , weigh at towball height of range rover in travelling position . The gearing on range rover means you need to be travelling quite quickly for best engine performance .
LPG power drop off is not peculiar to range rover V8 as i had a Ford Falcon 4.1ltr efi six with gas and i used to switch to petrol when climbing hills towing . HTSH

Cadwell is a brilliant circuit, probably my favourite in the UK - shame it is 200 miles away!! Never been round in a car, but its great fun on a bike.

Back to the RR, why would the tyres make it unstable, the large treadblocks? Tyre pressures I was running 28 psi front, 34 psi rear - the maximum psi on the tyres was 36 psi and they got pretty warm on the run. Have since filled them with Nitrogen rather than air to try and regulate the heat build up a bit.

How much difference would the weight distribution on the trailer make to the swaying then - quite a bit?

With regards to power (or the lack thereof), can you update a single point system to multi-point injection? Failing that, I guess switching to petrol for uphill sections would be the answer - is it bad for the engine to flick between the two?

I understand what you are saying about the diesel Focus SaintV8, but a 185bhp V8 with 320Nm of torque should still tow it far easier than a 115bhp 1.8 diesel with 250 Nm. Even allowing for a 20% drop through the LPG it should still be around 150bhp and 260Nm...

not done in a tractor neither i bet ,getting the right weight is vital for high speed towing,multipoint can be fitted easy enough ,basic system uses manifold with 8 pipes to take gas to connector near each injector to fully sequential system have a google,switching between the two is no issue with efi as no carb bowls to empty i used to do it with mine ,off road tyres arent going to be as good as road

Re tyre pressures , tyre pressures on vehicles are set for normal air , and take into a/c ie rely on a pressure rise from heat build up . Ideal is a 4psi rise, if you are getting more than that then tyre pressure is too low for that load. If less than 4psi cold to running temp then pressure was too high for that load . If i am correct that insa are a remould then rubber compound will be softer than a new tyre . They are also a heavy tread tyre so heat build up will be more than for a lighter treaded tyre . Out of interest a heavy tread tyre on a airport RIV can actually start melting if used at speed on highway for extended run . If you are sure that all your bushes esp panhard rod are in good condition then it has to be tyres, and to be honest its usually a classic overloaded tyre symptom . Re gas wont hurt your engine at all going from one to another.
were you talking multipoint liquid gas injection , they are usually far more efficient. Do you have a ign retarding unit fitted thats activated by the switch between fuels , as this makes quite a difference to performance on gas.

The only prob I have had with heavy loads behind range rovers is they seem to get affected more than a 110 when braking at speed going downhill

tacr2man said:

The stability issue is more likely down to tyres and tyre pressure. The weight should not be a problem . Tongue weight can be measured with bathroom scales , weigh at towball height of range rover in travelling position . The gearing on range rover means you need to be travelling quite quickly for best engine performance .
LPG power drop off is not peculiar to range rover V8 as i had a Ford Falcon 4.1ltr efi six with gas and i used to switch to petrol when climbing hills towing . HTSH

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I was going to say that but thought better of it incase I got a verbal ****ing from the guru.

re lpg...

i find on mine i get more power on gas than pertrol..(prehaps a wee bit weak on petrol
)..but mine is sequential amnd running boost which lpg realy likes!and i have spent ages driving around mointoiring a/r ratios and with the laptop plugged in..your ign timing may well need altering too..

Ref BHP and Torque...

It is all about when and how each vehicle produces it....

The Focus will produce all its BHP way after the Torque Curve and the RRC will Prduce the Torque earlier in the BHP Curve....

This has the effect of the RRC being a better tower at lower speeds and be able to overcome the Moment of Inertia to get a weight moving, wereas the Focus will be slow to accelerate the mass but be able to run faster with it once it has got moving.

zen said:

re lpg...

i find on mine i get more power on gas than pertrol..(prehaps a wee bit weak on petrol
)..but mine is sequential amnd running boost which lpg realy likes!and i have spent ages driving around mointoiring a/r ratios and with the laptop plugged in..your ign timing may well need altering too..

Click to expand...

Running boost? Is your V8 turbo charged??

Heavist should have been in front of trailer axle. It's weight behind the axle that causes weaving. Most weight should be in front of trailer axle. Weaving is cause by too little nose weight.

wammers said:

Heavist should have been in front of trailer axle. It's weight behind the axle that causes weaving. Most weight should be in front of trailer axle. Weaving is cause by too little nose weight.

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Really?? Because there was definitely more weight over the nose than the tail. If two of us stood on the back of the trailer (total weight of us both approx 160kg) just about balanced it out. And it was weaving like crazy!!

Surely it can't all be down to the tyres?

Tyres can really affect a vehicle I had a 130 HCPU had michelin 750r16 OE tyres fitted , was changing them to 265/75r16 BFG MT. I had fitted two to rear and had to go to a breakdown with a trailer , the vehicle was just about undrivable without there even being anything on trailer . I had to go back and get 110 to tow with. By your desciption of two of you stood on back of trailer to balance sounds as if noseweight might have been a bit excessive, but you dont mention distance you were from axle (pivot point) . esp in relation to tow bar length from axle to towball. Your noseweight was ceratinly not negative so its unlikely trailer loading was a problem. Its got to be down to three possibles , tyres inc pressures, loose steering box or balljoints , or worn bushes (panhard or susp arms) .

I take it your tow ball height was not causing the trailer to travel with front higher than back?

I just reread your pic caption . re loading of bikes etc . wsa their more weight behind axle than in front ? if yes than that is the reason , thats why if you transport a VW you load it backwrds as its tail heavy , and other vehicles are loaded facing forward . The trailer needs to be loaded so that its level to nose down , with c.o.m. slightly in front of 1st axle (this is so if rear axle tyre blows the trailer com does not go behind cog causing it to start snake) The tow ball height affects the noseweight transfered to vehicle which in turn will unload front axle and increase noseweight.

i just work logically trailer has to be level with two axles, nose weight does need to be correct springs and shockers need to be capable tyres need to be write ,as well as bushes ball joints etc,its usually a collection of a few problems that need looking at

Well the tyres are new, all four air springs are new and the rear shocks are new and the local garage reckons all the bushes are OK, so I'm stuck! The EAS keeps the car level. There was more weight over the front of the trailer than the rear.

Maybe it is the tyres - but which element? Pressures were correct. Is it the size? Or type (chunky A/T's)? Or the fact they are Insa Turbo's (remoulds)??

i would high speed tow on remoulds,never discount parts cant be faulty cos there new nose weight does matter