As I now look more closely at cars, I'm progressing with the tow bar + trailer side of things. The intention is to have a detachable tow bar
fitted and buy a suitable trailer, and I had a few questions that I hoped for some input on please;
- the tow bar is to be fitted on to a new model 320D Touring; I've had 3 quotes so far (all fitted); £487 inc mobile fitting, £650 and £712
(both at their premises which will cause some logistic challenges). I don't know the details of the first two tow bars but the most expensive
one came with a full quote for a Witter tow bar which Witter themselves sell + fit for c. £590 (does this mean they are just taking the p*ss then).
Are there any questions I should be asking of the first place (BMW software issues / electrics)? Does this sound 'too cheap'?
- I'm looking for a trailer for a car that will likely weight <500kg; single axle / double axle needed? Any benefits to the latter?
- on that note, anyone have anything suitable for sale / aware of any particularly good trailers on ebay etc?
- will I be able to reverse a trailer up a reasonable incline on my driveway?
I'm ok with the weight / MAM side of things thankfully.
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Building: Sold turboblade, back to tin tops
posted on 6/2/15 at 02:33 PM
Taking the pee, i would look on eBay for a second hand bar myself.
Single axle, easy to push about and nice to tow and for 500kg it'd fine.
Twin axle, if loaded wants to go in a straight line and hard to shuffle about, tends to chatter on the hook more as the hitch height may not match the
hook height, less critical on where you place the weight.
Have had both, prefer single axle myself, in all cases look for a decent drawbar, longer the better as it will sway less and use a chain to locate my
little car.
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Building: Hatred of Loughborough's Speed Humps
posted on 6/2/15 at 02:54 PM
I'm assuming that the car is after 1998, in which case anything you buy/fit will have the appropriate certification. I can't see why the
price would vary too much for the bar, fitting it, yes.
My advice would be twin axle. Single axles are very easy to push around, turn, are much lighter and cheaper too. Most caravans are single axle, works
for those lovely things and they have the aerodynamics of a Seven. However, if you have any problems, tyres, wheel bearings, bicycles falling off the
car in front, or have to brake suddenly you'd wish you had a twin axle. Twin axles are heavier, larger, a real pig to turn around in tight
spaces and more expensive. Twin axles are very stable under tow, singles less so.
I tow the competition car around the country, pretty much all summer, so my needs are probably different to yours. Buy accordingly. I see single axle
caravans in ditches all over the country (most memorably there was a stretch of the A30 - Sourton Cross, massive tailback I was stuck in one summer, 4
caravans on their sides, stuff scattered all over the place, mayhem). .
Sounds like you have to compromise on axles/weight/whatever so pick a solution for that compromise.
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Building: Sold turboblade, back to tin tops
posted on 6/2/15 at 03:14 PM
Single trailer, load it right, weight low down get the optimum balance, I find heavy in the hitch better, engine forward of the axle and I can tow at
any speed.... But get the balance wrong and you will have issues.
A poorly loaded caravan is doomed, people put things in the overhead lockers, have limited experience and purchase sway bars to try and correct bad
practice. Loaded correctly and you do not need a sway bar.
For example my wet wheels & tyres bolt under the bed, not on a high up frame, it all helps.
I have a a BMW E91 which I use for towing. I bought a witter detachable tow bar and bypass relay off ebay and fitted it myself, think it set me back
£220. There is a towbar fitter half a mile from my house and they wanted around £450 to supply and fit exactly what I bought myself. If your handy
enough with basic hand tools no reason you cant fit it yourself. I watched a couple of videos online on how to remove the rear bumper, the rest is
easy.
As for a trailer, I have a twin axle but cant really comment on a comparison with a single axle as I have never had one. I do however like the fact
that it is very stable when towing.
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Building: My car is history now, burnt out,
posted on 6/2/15 at 03:52 PM
I have bought three towbars and electrics off ebay, all around £150-£180 and everything is in the kit to complete a full installation
As for the towing/reversing, the longer the trailer is the easier it is to reverse, our current caravan is 7 metres long single axle and is a breeze
to tow, and reversing is a doddle, our old vans were 4m and 5m long and were not so easy to reverse
Ive never towed a twin axle trailer/caravan, so cant comment on there suitability
steve
Thats was probably spelt wrong, or had some grammer, that the "grammer police have to have a moan at
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Building: Toyota 4AGE powered Locost/restored 1958 Frogeye
posted on 6/2/15 at 04:08 PM
I have 4 trailers all single axle, going from gross vehicle weight of 1300 lb (caravan) to 4000 lb gvw (car trailer) and two boat trailers 1600 gvw
and 3500 gvw.
Things are much different on this side of the pond as brakes are only require on trailers with a gvw of over 3000 lb, mostly because the laws have not
caught up to the fact that the old family cars weighed 4000 lbs and had large lazy v8s.
All of these trailers for the past 17 years have been towed with 4wd Jeep Cherokees the current one is a 2008 Liberty (Cherokee).
What has been said about proper weight balance when loading is very important on single axle trailers, one bad trip with a too short trailer almost
cost me my 125e race Anglia when the weight was too far to the rear and at 90 mph it began to fishtail using 2 lanes of the highway before I got it
under control.
Check tires and suspension as well as the hitch, special attention to the lights before every trip.
Lack of maintenance is one of the major reasons for trailer problems.
I have done some strange things in 50 years of towing, the ones that don't look like they will work usually don't , like towing a MK 2
Sprite race car with a modified Cooper S, first turn the trailer pushed the mini sideways down the road.
quote:
TextI have done some strange things in 50 years of towing, the ones that don't look like they will work usually don't , like towing a MK 2
Sprite race car with a modified Cooper S, first turn the trailer pushed the mini sideways down the road.
You will find the witter full kit has a proper can bus control unit that has the same functionality as the genuine kit, cheapy towbars like anker or
towtrust do not, and will often fob you off with a bypass relay that is not up to the job anyway.
A can bus wiring kit will change the stability control settings when you hook up the trailer electrics, which will stop the asr/dsc trying to correct
the trailer movement unnecessarily.
It will also cancel the rear fog on the car when hooked up to stop dazzle off the trailer, warn you of bulb failure in the same way as on the vehicle
& turn off your rear parking sensors so you can reverse without continual bleeping.
These functions are not done by a normal bypass relay, and led rear lamps on some bmws do not play ball with bypass relays well anyway.
Any can bus unit may require additional coding of the abs/asr/dsc system to match, i'm not too sure with bmw's, but definately with vag
group cars, the instructions with the kit should show this.
You should be roughly 120-160 for the towbar depending on brand/quality, about 90-130 for a can bus control unit & wiring kit, and a couple of
hours to fit the bar and electrics.
Ebay does seem to be cheaper than any of our trade suppliers at work, some of the retail prices they give are ridiculous anyway.
With regards to trailers, a twin axle is nice and stable on the road, but tight maneuvering is hard on the trailer & will scrub the tyres and
strain the axles/wheel bearings, so needs more maintainance than a single axle.
Moving by hand is awkward, but a cheat is to wind up the jockey wheel to make the front axle clear the ground, making it easier to spin around.
The auto reverse mechanism brakes can strain the clutch when reversing up a hill (the combination of the weight and the force required to disengage
the brake on all 4 wheels), an automatic is better suited to maneuvering about.
I've only ever moved cars on twin axle trailers, don't think I'd fancy a single axle trailer with a car on it.
Reversing up hill is only a problem if anything grounds out, especially the bag of the trailer.
Reversing uphill can be a problem if you have a more modern type of brake actuating hitch.
Under normal forward motion if the tow car brakes then the hitch mech compresses and the trailer brakes come on,
either by mechanical rods or cables or hydraulics.
Older hitches had a lever or plate that you could flip over to prevent the mech compressing so that it could be used
if you wanted to reverse uphill. The powers that decide how we should live our lives didn't like these as it was possible
to drive off without flipping the lever back so they were outlawed.
My Alko hitch is the improved ( yeah, right ) modern design so has no override, and is OK for reversing on the flat,
even with a tonne on board, but try reversing up even a moderate slope and I am pushing 4 locked wheels.
I've made what I call a "bodge rod" that overcomes this and so converts the hitch back to a manual type.
Seems a better idea than changing a burnt out clutch, and cheaper too. Just need to remember to remove it afterwards.
The more recent (I. E. Since the 90s) hitches are really supposed to be used with auto reversing hubs where the brake assembly will rotate slightly
and cam inward as you reverse so they shouldn't affect your ability to reverse as long as they are set up right.
after a few times not being able to reverse uphill i had a look inside the drums, most of the brake linings fell out when the drums where removed.
new brake shoes and it reversed uphill no problem.
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Building: Toyota 4AGE powered Locost/restored 1958 Frogeye
posted on 7/2/15 at 06:26 PM
I assume the brake mechanisms being used are what we call surge brakes, brake master cylinder mounted on hitch, vehicle weight applies the brakes when
tow vehicle slows. The newest versions of these have a servo which stops the brakes from being applied for reversing, the servo is connected to the
reversing light circuit.
A lot of the trailers in North America feature electric brakes that use a motion sensor mounted in the tow vehicle to apply the brakes, which also has
a manual over ride system which can apply the trailer brakes while the tow vehicle is not slowing (to stop a swaying trail). These have no problem
reversing up a hill as the sensor is not activated at such a slow speed.
In the seventies my parents' caravan had a simple spring and damper that compressed on overrun and applied the brakes using rods. There was a
flip over collar to prevent the compression for reversing - it usually popped out of place half way through the manoeuvre though, so I sat on the gas
bottles, holding it down during any reversing. There was an option of fitting a solenoid operated collar.
Their next caravan (1976 model) was similar, but had no collar. Instead, when reversing the brakes were applied, but the reverse rotation of the
wheels twisted the backplates round and released them. Similar systems exist on trailers now, but often use Bowden cables rather than brake rods.
I'm sure there are probably systems using hydraulics instead of rods or cables these days, but I've never seen one.
