Towbar hitch

[UKenGB]

Can I weld a towball hitch?

I have a swan neck tow ball for a BMW, made by Westfalia. It looks forged to me. Would it be possible to weld onto this? I want to convert it to the US style square receiver tube. I have a spare swan neck and also the receiver tubing, but can I weld the 2 together?

I contacted Westfalia to ask for more details on the materials and manufacturing process used, but they were unwilling to discuss it at all. Their position was simply it must not be modified. I guess they're just worried about liability and no amount of pleading would get them to divulge any information.

Is it possible to TIG weld onto this? Anyone done it? Anyone got any idea at all? Any advice would be much appreciated.

 

[zzr1200]

I guess they're just worried about liability and no amount of pleading would get them to divulge any information.

You already have the answer supplied by the most qualified people to answer it...


The simple answer is no...

 

[KemppiFrog]

Westfalia's lack of info is based on law. All cars built after a certain date (93?) must have an approved towbar. Your welding two bits together would make it unaproved and potentially invalidate your insurance.
KF

 

[madkayaker]

1998 the rules changed for cars. I would imagine it would weld but vosa, police and your insurance company would all want stern words with you if it raised its head.

 

[UKenGB]

Can I just clarify at this point that I'm not interested in the legal position. I seriously doubt it has any bearing in the UK, but in any case that's not what I'm asking.

Westfalia's refusal is of course NOTHING to do with the technology involved and since I never got to speak to an engineer, they were most certainly NOT qualified to pass judgement about the technical feasibility of what I was proposing.

Welding bits of metal together is of course possible since the entire car and much of a tow bar's support structure is exactly that, so please, no-one try to tell me how bad an idea it is.

I am however, not an experienced welder and am looking for advice on how to weld DOM tubing to a probably forged steel component. It may well not be a good idea due to the materials involved and I accept that (hence my alternative plan for a bolt on adapter), but it occurred to me it may be an easy task with the right rods and technique. Indeed someone here may well have done it themselves. What are the technical possibilities of this. Is it CRUCIAL to know exactly of what the swan neck is made?

The aim, BTW, is to allow me to attach a motorcycle rack to the rear of the car. For obvious reasons, I wouldn't want it to break apart while in use.

 

[armalites]

As already said with many things in life that aren't a problem until something goes wrong.

If you were to lose a trailer,caravan or motorcycle off the back then I don't think you would be getting any support from anywhere.

I've never understood why the receiver hitch system hasn't caught on here as it seems a really versatile setup.

If you are converting to that system is not just as cheap to buy the correct tow hitch to fit the receiver?

 

[sm-]

. What are the technical possibilities of this. Is it CRUCIAL to know exactly of what the swan neck is made?.

Short answer YES

 

[madkayaker]

I've never understood why the receiver hitch system hasn't caught on here as it seems a really versatile setup.

Big difference is in eu things are much more standard with 50mm ball. In us I believe there is a whole raft of different size balls which more or less match vehicle size with trailer size.

There are systems for commercial vehicles Landrover etc that can tow different type of trailers

 

[armalites]

I appreciate that but there are loads of other stuff that can be used on the receiver system,

Winches,seats,steps,luggage carriers,bike carriers recovery points,brake lights etc

It also means the hitch is easily removed.

Admittedly many of these benefits wouldn't apply to a normal car but more suited to a truck or 4x4

 

[hotrodder]

1.Forging 'adds strength' due to the grain structure imparted. Welding is, in effect, casting and will locally destroy the grain structure i.e. a perfect weld (no such thing) will still leave it weaker
2. Google 'tow ball hitch manganese steel'. I promise you they ain't simple basic mild steel, that'd wear too quickly
3. Don't weld it if it's gonna be used on the road!

 

[UKenGB]

1.Forging 'adds strength' due to the grain structure imparted. Welding is, in effect, casting and will locally destroy the grain structure i.e. a perfect weld (no such thing) will still leave it weaker
2. Google 'tow ball hitch manganese steel'. I promise you they ain't simple basic mild steel, that'd wear too quickly
3. Don't weld it if it's gonna be used on the road!

That was my first thought, then it seemed sensible to ask you experts first. Thanks for the advice.

I have a plan to make a bolt up adapter that will clamp to the ball/swan neck and require no modification to the forging. I will persevere with that.

I cannot mod the rack to fit a UK ball by virtue of it being a rack that needs to NOT swivel on a ball. I could mod it to clamp onto the ball directly instead of via the receiver and an adapter, but weight then becomes an issue when trying to locate the entire assembly into the car. With the adapter I just insert the adapter and swan neck assembly into the car. Then the much heavier rack is just slid into the receiver as originally designed.

I also cannot understand why the US square receiver is not used over here. Seems to me it could be easily incorporated into most cars and then there's a standard to which ALL other fittings can be made. Slide in a ball ended adapter if you need to tow a trailer, or insert a bike rack, or winch or countless other devices. The only problem is manufacturers like BMW wouldn't be able to then charge almost £1000 for a tow hitch that is specific for just the one car and you'd need to buy all over again when you change cars.

 

[geoffdown]

That was my first thought, then it seemed sensible to ask you experts first. Thanks for the advice.

I have a plan to make a bolt up adapter that will clamp to the ball/swan neck and require no modification to the forging. I will persevere with that.

I cannot mod the rack to fit a UK ball by virtue of it being a rack that needs to NOT swivel on a ball. I could mod it to clamp onto the ball directly instead of via the receiver and an adapter, but weight then becomes an issue when trying to locate the entire assembly into the car. With the adapter I just insert the adapter and swan neck assembly into the car. Then the much heavier rack is just slid into the receiver as originally designed.

I also cannot understand why the US square receiver is not used over here. Seems to me it could be easily incorporated into most cars and then there's a standard to which ALL other fittings can be made. Slide in a ball ended adapter if you need to tow a trailer, or insert a bike rack, or winch or countless other devices. The only problem is manufacturers like BMW wouldn't be able to then charge almost £1000 for a tow hitch that is specific for just the one car and you'd need to buy all over again when you change cars.

You say bike rack push or motorbike as with heavier motorbike then it can not by law with rack and bike be over a certain weight think bmw state 75kg

 

[DrNik]

you could make a flat topped tube with a slot in it that slides over the ball and all the way down over the swan-neck,that would stop it from leaning left and right, the slot would allow it to fall towards the car so a bracket back to the car would stop that from happening, or how about a slit tube with a way to clamp the tube so it gets smaller the more you do it up, as long as it sprung open when you want to remove it,100kg is the normal nose weight of a trailer, so as long as you dont go overboard with your construction you should be ok

 

[geoffdown]

you could make a flat topped tube with a slot in it that slides over the ball and all the way down over the swan-neck,that would stop it from leaning left and right, the slot would allow it to fall towards the car so a bracket back to the car would stop that from happening, or how about a slit tube with a way to clamp the tube so it gets smaller the more you do it up, as long as it sprung open when you want to remove it,100kg is the normal nose weight of a trailer, so as long as you dont go overboard with your construction you should be ok

on a car nose weight can be as low as 50kg or as high as 150kg(mainly 4x4) its not trailer nose weight u need to worry about but what the towbar can handle

 

[Shox Dr]

Ok my turn

Firstly *if*you need to ask such a question, then by default it is unlikely you have basic knowledge of welding. Thus it is also unlikey you would be able to perform such a weldment with satisfactory results.



As for a tilt ramp I built one for the back of a Navara, so firstly a commercial vehicle, so the same rules don't apply.

I built the lot, and load tested it to 1200kg using bags of cement (a known weight) borrowed from the local builders merchants used itfor carrying a yzf400 and yzf250

The important bit is to know the max weight at the known distance from the back axle.


Fantastic bits of kit

 

[UKenGB]

Ok my turn

Firstly *if*you need to ask such a question, then by default it is unlikely you have basic knowledge of welding. Thus it is also unlikey you would be able to perform such a weldment with satisfactory results.

Well, I know enough to ask the right questions and also to not attempt anything so crucial myself, until I have a lot more experience. I would have used someone else to do the actual welding, but that's irrelevant now.

One thing to remember is that when pulling a large trailer the forward and back forces on the towbar will probably be many times the nose weight. Imagine an emergency stop. However, a bike rack doesn't vary that much, so even though it may be more than the nose weight of a trailer, it will likely put less overall stress on the towbar.

Fact is, people have been carrying around dirtbikes on the back of their cars like this for years. I've been doing it on other cars, but only just getting around to setting this up on the X5 so I can go riding off road again without having to dig out the trailer. It's a great solution for carrying a single bike and no silly speed restrictions like for a trailer.

I thank you all for the advice about the welding.

 

[dan.taylor.1]

I wouldn't even attempt it, and tbh my Audi has a towbar which has the plate for a std ball welded to a neck which bolts in, so could be modded to fit a box type setup. Also the forces you talk about above under braking etc are on anything over a 750kg trailer taken up by the damper in the hitch on the trailer and the fact it should have brakes by law. also they are accounted for when the likes of westfalia make the towbar mountings, as they usually have a vertical plate in like with the axle so it takes forces, and the rest takes the side to side pull.

Seen as x5's are sold in the US why not look for a hitch thats made over there?

Dan

 

[Tino]

One thing to remember is that when pulling a large trailer the forward and back forces on the towbar will probably be many times the nose weight. Imagine an emergency stop. However, a bike rack doesn't vary that much, so even though it may be more than the nose weight of a trailer, it will likely put less overall stress on the towbar.

Smells like bull s**t to me. You are making guesses and assumptions about something which if it failed could kill some one.

 

[CompoSimmonite]

Receiver hitches for the BMW X5 are common US items so why not simply sell your Westfalia item and buy one of the type you require ?
Quick look on eBay shows brand new they are £123 -

http://www.ebay.co.uk/itm/Curt-1307...r_Truck_Parts_Accessories&hash=item231dfe09a7

Paul H

 

[simonallen]

can't you buy a bolt on ball and just make something to fit into the reciever with box section? ie exactly what you are proposing but with a plate welded to the end of the DOM instead of the ball.you can then bolt the ball onto it.