Difference between revisions of "Tow bar"
(Copied the entire text (with some adjustments) from the old "How to" BigJimny PDF guide at http://www.bigjimny.com/images/documents/jimny_towbar_install.pdf (and incorporated it into the "Wiring the tow bar electrics" chapter)) |
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The 12n socket on the tow bar should have a cable attached with the following wiring: | The 12n socket on the tow bar should have a cable attached with the following wiring: | ||
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− | + | Tow bar electrics wiring - figure 02 - Jimny without rear bumper and rear vertical lamp.jpg|Figure 02 - Jimny without rear bumper and rear vertical lamp | |
− | + | Tow bar electrics wiring - figure 03 - intercepted wiring for the rear vertical lamp.jpg|Figure 03 - intercepted wiring for the rear vertical lamp | |
− | + | Tow bar electrics wiring - figure 04 - scotch locks for tow bar plug installed on the wiring for the rear vertical lamp.jpg|Figure 04 - scotch locks for tow bar plug installed on the wiring for the rear vertical lamp | |
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[[Category:Modifications]] | [[Category:Modifications]] |
Revision as of 16:52, 18 December 2017
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Contents
Introduction
If your vehicle already has a tow bar, you are probably settled, but you might still find some interesting information in this article.
Having a tow bar installed provides several benefits, apart from the obvious role to tow a trailer.
Terminology
It appears that the terminology and meanings regarding the tow bar and its elements vary significantly from one region of the world to another. Another cause of confusion are so many types of connecting elements for the tow bar. There are balls, hitches, hooks, jacks, prongs, necks, swans, etc.
Therefore, this chapter is just meant to establish the nomenclature for this particular article. It's impossible to cover all combinations and terminologies.
- A tow bar is a transversely-mounted rail (typically hollow, but made of thick metal), which is mounted on vehicle's rear chassis rails (in factory-made mounting points on the chassis rails).
- A tow neck is a short pipe or plate which is welded or bolted on to the center of the tow bar, and protrudes orthogonally to the tow bar itself. Some tow bars don't have this, instead the tow ball or tow hitch connects directly to the tow bar.
- A tow ball is a non-hollow metal ball onto which you actually clamp the towed or carried object. Some tow balls are a single-piece with the tow neck and some bolt onto the tow neck. Some tow balls bolt on directly onto the tow bar.
- A tow hitch is a hook to which you attach another object.
Notes on terms
- Sometimes the term "tow bar" is applied to the entire assembly (tow bar + tow neck + tow ball / hitch), but sometimes it means strictly only the tow bar itself. It depends on the context.
- Tow neck can be die-cast as a single piece together with the tow ball, or be a separate piece.
- Some tow balls bolt on directly to the tow bar, without a tow neck.
- Tow ball dimensions are defined by international standards.
- Sometimes the term "tow ball" is applied to the entire "tow ball + tow neck" assembly (especially if they are die-cast as single piece).
- The term "tow hitch" is sometimes used to actually refer to the "tow ball".
- A single tow bar can usually have either a tow ball or a tow hitch attached at the same time, but not both. However, there are cases of combined "tow ball + tow hitch" elements.
This general Wikipedia article can explain all the complexity of the terms a bit better.
Types of tow bars
There are several different general designs of tow bars for Jimnys.
They depend both on the region of the world and on the era when they were made (remember, Jimnys have been in production since 1998).
The design differences concern primarily the design of the tow neck or tow ball section.
Some tow bars (primarily very old ones) use fixed tow necks/balls - they are welded to the tow bar.
Most newer tow bars use detachable tow necks (tow neck can be disconnected from the tow bar). The methods of (de)attaching the tow neck vary significantly (from having to use tools and spanners to having some various convenient "click-on" or "push-in" systems). This depends on the manufacturer.
The length of the tow neck varies significantly depending on the model of the tow bar, and this plays an important utility and safety role. Some tow necks are even significantly longer than the width of the spare tyre (they protrude under it). Read more about this below.
- This is a typical tow hitch sold in the UK.
- The tow ball should not be left in place in normal driving as it obscures the number plate.
Some pictures of Jimnys with very long tow balls (all from continental Europe):
Benefits, issues and risks
Benefits
- You can tow a trailer (obviously).
- You can carry a bicycle carrier.
- You can carry a cargo box - typical use is to transport hunting dog(s).
- Tow bar weights approx 15 - 20 kg, so it adds beneficial weight on Jimny's rear axle, slightly decreasing vehicle's tendency to slide in bends and to wheel slip in 2WD mode on wet tarmac.
- When off-roading, if you exceed vehicle's departure angle, the tow bar is most likely to impact the ground before the rear bumper or other vulnerable body parts. It is much better to hit the tow bar than anything else in the rear. Tow bars can take a beating.
- You can weld on a pair DIY "recovery" points between the tow bar and vehicle's rear left and right factory tow points. When combined, those should provide good anchorage. Then you can attach shackles on those points for recovering the stuck vehicle.
- Having a tow bar fitted makes your vehicle appear more serious (if that turns you on).
For additional details on above benefits, see wiki articles "Bicycle carriers", "Cargo space expansion and management" and "Recovery points".
There are no technical disadvantages of having a tow bar, except possibly a minuscule increase of fuel consumption because of added weight.
Legal issues
In some regions of the world, like some European Union countries, there could be various legal restrictions on using the tow bars.
- You might not be permitted to have a tow neck + tow ball attached to the tow bar when you are not towing a trailer or carrying a bicycle carrier (that is why detachable tow neck designs primarily exist).
- It might pose a legal issue if the tow neck + tow ball protrudes further than the spare tyre.
- Installing a tow bar on a vehicle "afterwards" (after the vehicle was sold as new from a saloon without the tow bar) might require some vehicle recertification in some countries, even if it is a OEM tow bar.
There are two reasons why a certain country might prohibit the presence of a tow ball / hitch on a tow bar while it is not used:
- It presents a hazard for the vehicles trailing you;
- If it obscures the number plate (this is the case with Jimnys with most tow ball designs);
In some countries neither reason is important, while in some both reasons are eliminatory.
For example, in United Kingdom, using standard tow bars (including those supplied by Suzuki!) with the tow ball attached without a trailer can be illegal, as the tow ball obscures the number plate. A lot of MOT inspectors let this go, but enforcement is getting more widespread now.
Risks
- If a vehicle rams you from behind while your tow neck is fitted, that vehicle might sustain nasty damage to its front end, especially if your tow neck is longer than the width of your spare tyre.
- If you reverse in a parking lot for example with the tow neck fitted, you need to be more careful not to hit another vehicle with it.
NEVER attach a rope or strap to a tow ball or tow neck when recovering a stuck vehicle or when someone is recovering your stuck vehicle !!!
Although it might seem like a logical attachment point when recovering, tow balls and tow necks are not designed to endure shock loads which can be enormous when recovering a stuck vehicle. If a tow ball or tow neck breaks off under load, it becomes a lethal flying missile.
Broken off tow balls have destroyed other vehicles and killed people in spectacular manners!
You certainly do not want to participate in such a spectacle!
Buying a tow bar
The best place to buy a tow bar would be from a dead Jimny in a vehicle junkyard.
You can of course buy a new OEM tow bar from Suzuki or from an aftermarket manufacturer, but expect a very high price.
There are many aftermarket manufacturers of tow bars, and some of them make the models for Jimny. An example is Westfalia.
Manufacturing a custom tow bar
In certain regions of the world, there are workshops which manufacture custom tow bars. It is usually some generic design adopted to a particular vehicle. They usually also supply some certificate along with the manufactured tow bar.
If you can not obtain a genuine or afermarket made tow bar which was specifically made for Jimny, taking your vehicle to such a workshop to have this "generic" tow bar customized for it might also be a practical solution.
Tow bar installation
- The procedure of installing a tow bar is a relatively simple bolt on job.
- No fabrication is required, just a socket and a spanner set.
- A genuine new Suzuki tow bar will even come with all the necessary nuts and bolts to secure it to the chassis.
- You will need to remove the rear (vertical) lights and then the rear bumper to fit the tow bar though.
- If you want to increase your chances of ever dismounting the tow bar in the future again, it might not be a bad idea to spray / coat the nuts and bolts with some anti seize chemical before mounting.
Using bicycle carriers or cargo boxes
Bicycle carriers
The wiki article Bicycle carriers contains everything about choosing and using bicycle carriers on a Jimny, including tow bar mounted ones.
Cargo boxes
The wiki article Cargo space expansion and management contains a dedicated chapter about tow bar mounted cargo boxes and dog boxes.
Common remarks
Beware that the load limit for most tow bars is in the range of 50 - 75 kg! (Nose weight - the vertical weight on the ball/hitch). You must count in the weight of a bicycle carrier or cargo box together with the bicycles or cargo when doing the weight calculation.
Note: Using tow bar mounted bicycle carriers or cargo boxes can have legal restrictions in some countries. Examples could be mandatory additional license plates and brake + turn lights on those objects, or issues of animal treatment if transporting hunting dogs, etc. These all are non-Jimny related generic issues which you need to explore on your own.
Wiring the tow bar electrics
If you do not intend to tow a trailer, or are not required to have additional brake+turn lights on the tow bar mounted cargo boxes or bicycle carriers, then you do not need to install wiring for the tow bar electrical socket.
If you have to install wiring for the tow bar, there are several solutions available.
Suzuki did not install wiring for the tow bar in Jimnys which did not have factory-fitted tow bars.
Solution 1
You can buy OEM tow bar wiring kit from Suzuki. The exact details on part numbers are not yet investigated, but the price is certainly high.
Solution 2
Introduction
Alternative is to install custom wiring, but this is best left to be done by professional vehicle electricians.
However, here is one possible solution if you are confident to do it yourself (or if you want to get yourself acquainted before visiting an electrician).
Some people consider this to be an "el-cheapo" solution which tends to produce electrical glitches in the long term, primarily because of the use of "scotch locks".
Therefore, consult with a good electrician beforehand! Write your experiences here for a common benefit.
Procedure
The 12n socket on the tow bar should have a cable attached with the following wiring:
Terminal number | Function | 7-core wire colour |
---|---|---|
1 | Indicator left | Yellow |
2 | Rear fog lamp | Blue |
3 | Earth | White |
4 | Indicator right | Green |
5 | Side lamp right (also marker lamps & number plate lamp) | Brown |
6 | Brake lamps | Red |
7 | Side lamp left (also marker lamps & number plate lamp) | Black |
The cable from the tow bar needs to be connected into the jimny wiring harness that feeds the rear lights. I located the wiring loom, found the necessary wires, then used scotch locks to tap into them.
This was done on a 2002 soft top Jimny.
Access procedure:
- Remove the rear passenger / nearside seat;
- Remove the plastic trim;
- This will reveal the wiring harness that goes to the rear lamps;
The Jimny wiring harness at the rear lamps is as follows:
Jimny wiring color |
Jimny function | Tow bar wiring color |
---|---|---|
red / green | indicator left | yellow |
yellow / green | indicator right | green |
green / white | brake lamp | red |
red | side lamps | brown / black |
Page last edited on 18/12/2017 by user Bosanek