Towing Instability with 2017 Jaguar XF Sportbrake.

Geoff

I have a Sprite Major 4SB that I previously towed with a 2012 Jaguar XF 3LD. The 2012 XF was a rock solid tow car that maintained control even under very trying conditions.

I currently have a 2017 Jaguar XF Sportbrake 3LD towing the same Major 4SB with same loading set-up except with the higher nose weight specified for the Sportbrake. The Sportbrake is a nightmare to tow with. It is dangerously unstable even under fairly mild adverse conditions (e.g. cross winds, passing HGVs).

The 2017 Jaguar XF is a very different car to the older 2012 XF, it’s lighter with an aluminium chassis and body panels. Despite this it is often claimed to be a good tow car in the motoring and caravan press.

I have ensured loading of the caravan, tyre pressures etc. are correct. My caravan service engineer confirms that the caravan has no undercarriage faults and the hitch stabiliser is in good condition.

When a caravan is attached, the Air Suspension of the Sportbrake restores the rear end to the same height as when solo. This means that I cannot achieve a slightly nose down posture that I would prefer and this is the only reason that I can think is causing the severe instability.

I have also noticed that when parked alongside a friend with the same Major 4SB, towing with a BMW X3, his tow bar sits significantly lower than mine although without excessive drop in the rear suspension.

Jaguar will not engage with me in respect to the TT after-market tow bar but they have stated that, even with a genuine Jaguar tow bar, the towing software doesn’t alter the behaviour of the air suspension and it will always return to the solo ride height.

I have a Tow Trust (TT) tow bar fitted (same make as fitted to my previous Jaguar XF).

TT and my local tow bar specialist have confirmed that the car has the correct tow bar, electrics and swan neck. TT will not provide an alternative, shorter, swan neck so that I can get the hitch to sit lower. I guess they are constrained by the ‘type approval’ rules.

So, I am stuck and looking for ideas that I might try before being forced to sell the Sportbrake and take the significant hit on exchange value!

Does anyone have any ideas on what I might try? Has anyone had similar problems with towing with a Jaguar Sportbrake of the same vintage, did you find a solution?

Many thanks for any suggestions.

Mick2

What does the towcar / caravan match return if you input your specific car and caravan? You state that the new car is somewhat lighter - is it possible that it's not heavy enough for the caravan?

https://www.caravanclub.co.uk/CaravanClubApps/Applications/omd/select.aspx

Geoff

Many thanks for this suggestion. In fact the Club's matching service doesn't offer the 2017 Sportbrake as a selectable option for some unknown reason, just a bug I think. However, I've checked with other providers including C&CC and my Sportbrake is a GOOD match.

Mick2

Trailer load distribution maybe? I had that problem with one change of vehicle - although the nose weight was ok, some heavier items had "migrated" (aka by my mistake) to behind the axle, resulting in an unpleasant ride with the slightly lighter towcar.

Geoff

Hi Mick, yes I think that could help. We did move some weight forward but I think we will have to be more radical and empty the space under the bed completely to see if that fixes it.

eribaMotters

Geoff, you may not have to move as much as you think.. 5kg moved from the back of the van to the front has a far bigger effect than you think. 5kg x 2m behind the axle = 10kg. If this is then moved 2m forwards of the axle the total difference at the hitch could be 20kg. That is enough to have a noticeable "feel" on the car/caravan combo stability.

You mention in your original post that you prefer a slightly nose down set-up of the van. I shared your thoughts on this until I realised this is not really critical and more visual. The important thing is the nose weight produced by correct loading of the van.

In my initial days of towing I was totally oblivious to the nose weight issues and have towed happily with what was 25kg on the hitch of a 1000kg van. Having said that, the only time I have ever experienced stability issues was due to under inflated caravan tyres when Hymer/Eriba had issued incorrect data.

If I can correct, your Sprite Major 4SB has a MTPLM of 1476kg. I'm guessing you are running 185 or 195 R14C with a load index of 102/104, possibly 106. These have a recommended axle load of about 1500kg and a max permissible of 1700/1800. They should be inflated to 4.5 bar or 65psi.

I carry a print off of the attached which you may find of use.

TyreSafe Caravan tyres leaflet - 2021.pdf

Colin

Geoff

many thanks Colin. I will print the document and study it.

Freddy55

Hiya. I just lifted this from a webpage, which may or may not be of assistance…

“Therefore, you should work based on it being between five and seven per cent of the caravan's MTPLM (Maximum Technically Permissible Laden Mass). For example a caravan MTPLM of 1400kg, the nose weight would be 70kg at 5 per cent or 98kg at 7 per cent.”

Wildwood

The club do recommend a slight nose down setting although a level one should not be a problem. As you say the car is generally regarded as a good tow car and the outfit should work in theory. I suspect a little playing with the loading is needed.

Lutz

https://clubtogether.caravanclub.co.uk/discussion/comment/871311#Comment_871311

I fail to understand the logical reasoning behind a nose down setting. So long as the noseweight is adequate under actual conditions, whatever the stance, whether up, down or level, it shouldn’t make any difference to stability. Why should it? One can perhaps say that a nose up stance “looks wrong” and it does reduce the ground clearance at the back of the caravan, but that’s about it.