tow bar spacers

[karl2]

can anyone please advise on the laws if any reagarding the use tow bar spacers i drive a 2001 nissan terrano and have a 2006 sprite major 5 with a alko hitch beacause of the spare wheel it is very difficult to hitch & unhitch the unit

 

[WatsonJohnG]

This is what Witter say (25mm)

http://www.witter-towbars.co.uk/towbars/vehicle_technical_details.aspx?VehicleTowbarID=719

 

[Lutz]

Note that this only applies to the Witter towbar for the Terrano. If you have another make, you MUST get approval from the respective towbar manufacturer. He is responsible for testing the towbar with or without predefined spacers and this is a requirement for legally required type approval.

 

[Steve L]

I think you will find that 25mm is the maximum spacer thickness defined across the board of all tow bars designed for bolt on tow balls. This is because the securing bolts come under more torsional strain from the extended distance from the tow ball to the tow ball mounting plate on the tow bar.

You could gain a bit more length (20mm) by using a 3500Kg rated ball and drop pin tow hitch. These are available form towsure. They are commonly used in the agricultural and construction industries and don't look out of place on a 4x4.

If you are going to use these parts, I would also go to your local engineer's merchants and buy two M20 x 120mm hex zinc plated bolts grade 12.9 which is commonly called super high tesile, and four nuts and four washers to suit. By doubling up on the nuts you will have increased the resistance to stripping the threads and the super high tensile bolts exceed the strength spec required.

Just one minor technicallity to bear in mind though is, to ensure that your insurance company approves the tow bar set up. Get this in writing as well as this avoids contraversy should you be involved in an accident. The spec of the above fittings do exceed the standard spec by a long way and is undoubtedly safer, but some eagle eyed insurance assessor might try to guide the insurance company down the get out of jail card route.

It's the same old story, if it aint on paper it aint been said!!

Steve L.

 

[WatsonJohnG]

I think you will find that 25mm is the maximum spacer thickness defined across the board of all tow bars designed for bolt on tow balls. This is because the securing bolts come under more torsional strain from the extended distance from the tow ball to the tow ball mounting plate on the tow bar.

You could gain a bit more length (20mm) by using a 3500Kg rated ball and drop pin tow hitch. These are available form towsure. They are commonly used in the agricultural and construction industries and don't look out of place on a 4x4.

If you are going to use these parts, I would also go to your local engineer's merchants and buy two M20 x 120mm hex zinc plated bolts grade 12.9 which is commonly called super high tesile, and four nuts and four washers to suit. By doubling up on the nuts you will have increased the resistance to stripping the threads and the super high tensile bolts exceed the strength spec required.

Just one minor technicallity to bear in mind though is, to ensure that your insurance company approves the tow bar set up. Get this in writing as well as this avoids contraversy should you be involved in an accident. The spec of the above fittings do exceed the standard spec by a long way and is undoubtedly safer, but some eagle eyed insurance assessor might try to guide the insurance company down the get out of jail card route.

It's the same old story, if it aint on paper it aint been said!!

Steve L.

They would need to be type approved

 

[Maginnis]

Apologies if you have already considered it, or know but discounted for some reason, but you can buy a 4X4 removable handle for the Alko. We have a similar problem with our Freelander and still have to remove the removable handle to hitch up initially, and reattach it when it comes to pushing it down to secure it.

They're available for about

 

[KnL]

We had the same problem with our last Terrano, even with a spacer fitted.

Whenever possible, keep the car at a slight angle to the van and with the wheel carrier being off centre, you'll find it increases the distance between the Alko handle and the wheel, allowing the handle to lift fully.

We toyed with the removable handle that Tina mentioned but once we discovered this tip we never had another problem.

 

[Steve L]

Just a quick rely to John G's question about type approval of the bolts I suggested are used to fix the tow ball and spacer onto the tow bar.

Standard tow bar bolts are 8.8 grade which is standard high tensile spec. 12.9 grade is a higher spec than 8.8 and as such will maintain the tortional, shear and tensile strengths required to avoid failure of the tow bar assembly.

As the bolts are CE marked and manufactured to ISO standards theyare already type approoved and have already have certification of conformity to way beyond the forces exerted on them by towing even upto 3500Kgs of trailer weight. I don't know of a road legal caravan with a 50mm ball coupling and over run brakes, that comes close to that weight.

Steve L.