Thread: Low Height Motorcycle Trailer

Just a comment - the 9 leaf spring appears excessive, what’s their weight/load rating. Wouldn't a 4 to 6 leaf have sufficed?

Originally Posted by Wood66

This is how it looked when I thought I had it all together 'properly'. (I'm not sure if I've got the spacer and fishplate in the right spots). The clearance to ground is only about 90mm - So I've tried to configure the ubolts / spring fitting so other ways. Are these feasible

==== Found this in the VSB =====

21.5 Ground Clearance
The ground clearance of a trailer measured from the horizontal road surface of any point on the
underside of the trailer except the tyres, wheel and wheel hubs must, when unloaded, be not less
than:
 100 mm for any point in the width of the vehicle which is within one metre fore and aft of any
axle;

So is this correct - because the wheel will cause the axle to rise/fall the clearance doesn't need to meet the 100mm - and it is within the 1mtr distance

The very first pic is the way it's usually set up, and the ground clearance measurement is generally in reference to the bodywork rather than the axle itself, which is why the 1M fore & aft reference is there.

I'm with Rod, they must be pretty heavy bikes to warrant 9 leaf springs. Or you got false information by the company selling you the parts. Those springs would be around 1800Kg rated for the pair.

Originally Posted by Yonnee

I'm with Rod, they must be pretty heavy bikes to warrant 9 leaf springs. Or you got false information by the company selling you the parts. Those springs would be around 1800Kg rated for the pair.

...which could, potentially, tear your rails apart, I've seen that happen.

Good thinking guys. I was concentratine on the setup & didn't even notice the springs

Thanks guys for your replies,

So there's no problem with the axle height just the body - cool

I thought about the use of the trailer down the track, although initially it is going to only transport 2 bikes, I would like to convert to a box trailer later on, I asked the guys at SA Trailer to provide me with a meaty axle and spring for at least 1200kg, (I know I don't have brakes on this and I didin't plan well in this regard - but hope I can retrofit the backing plate for the brakes down the track.) So it is 9 spring and a 45mm Sq axle.

So I hope even with the heavier springs - that won't cause issues at the moment?

Originally Posted by wood_or_metal

The first setup looks to be the "usual" setup; you may want to double check with a pro about the (lack of) heightof the bolts, just to be safe.

I'm interested to see the progress of this project as to how you'll bring the draw bars back up to standard I'll keep watching...

There was someone else I saw, they doubled up the the draw bar height with a fair section of overlap on top just welded on,,,,, can't find it right now. One of the off road vans I think.

Initially I just though adding on a small box type section to the top put figure it wouldn't have much strength (weakest link)... so I'm still not decided.

The top of the trailer deck will be around 420mm the height to the tip of the tow bar is 400mm (not including the ball) but taking the 50mm drop from the frame to draw bar still needs to be factored in.

Originally Posted by Wood66

There was someone else I saw, they doubled up the the draw bar height with a fair section of overlap on top just welded on,,,,, can't find it right now. One of the off road vans I think.

The Off-Road van would have it welded underneath to drop the coupling down to offset the higher "off-road" setup.

Initially I just though adding on a small box type section to the top put figure it wouldn't have much strength (weakest link)... so I'm still not decided.

The top of the trailer deck will be around 420mm the height to the tip of the tow bar is 400mm (not including the ball) but taking the 50mm drop from the frame to draw bar still needs to be factored in.

This is common practice on low trailers, particularly with 4" drop axles. I've done it many times before using a piece of 50mm x 4mm SHS stitch welded on top of the main drawbar (usually 75 x 50 x 3mm RHS) overlapping by about 12-18" (300-450mm) and overhanging the front by the length of the coupling plate.

Okay gents, a little more advice needed.

I miss calculated the distance for the axle/spring placement and welded the hangers about 6"/90mm to far to the rear. ( The rule is 1/2" for every foot of length of frame - I wont forget now!)

1. Can I cut/grind the hangers from the frame and use them again?
2. Will I have to weld a support to the frame where I've cut these off?

I wasn't going to post photo's but will when I get the suckers off.

Originally Posted by Wood66

1. Can I cut/grind the hangers from the frame and use them again?
2. Will I have to weld a support to the frame where I've cut these off?

1. That depends on how well you welded them on
2. That depends on how well you cut them off.

I can only think of one reason why you can't reuse the hangers: as they're welded the hangers may have a tendency to spread, but if you tighten a nut & bolt through them first that shouldn't happen.

If you're reeeeally careful when cutting them off & cut more towards the hanger than the frame ( they have more meat on them & they'll be rewelded anyway) then the frame should be ok. If you use the 1mm cutting discs you won't be cutting too much away.


This is a good example of why tacking everything together first is a great idea

Hopefully, you've only welded along the chassis and not across it, you should be able to carefully run the cutting disc just through the weld, being particularly careful not to cut into the chassis rail. Once you cut through both sides, gently tapping fore and aft with a hammer should break the hanger free.
Once free, you can grind back the excess weld on both the hanger and the chassis rail, and then reposition the hanger, tack, check twice, measure again, then weld... but only along the chassis rail.

If you welded fully around the hanger (across the front and rear), I would just cut the ears of the hangers off, get new hangers, and start again. With alot of care and patience, you can remove the hangers completely, but you need to be extra careful not to cut into the chassis rail, and you end up sacrificing the hanger in doing so.

Thanks Gents, great info - I've got some thin cutting discs now, Will try and get into it this week - between the rain forecast.

I have only welded fore/aft so should not be a problem, see how I go with my steady hand and get them off without fracturing too many of these discs.

Here we go, I was sort of nervous at cutting this and getting it wrong or shattering a wheel and catching it with my forehead!!

Gentle pass, another gentle pass... gee this is like cutting butter, bash bash...

But after I got the first hanger off - I don't think it was a bad job.

Hopefully there is enough meat left to weld these back on - the photo showing the cut through the corner of the hanger hopefully shows this.

While I'm at it...

Extension to make up for the drop on the drawbar. Welds getting better.

Originally Posted by Wood66

Hopefully there is enough meat left to weld these back on.

The beautiful part is you can add more meat as you're welding it back on.

I may be wrong, I'm only going off what I can see in your photos but, I think you can use a bit more heat in those welds; they don't appear to have a lot of penetration.

Also, If you have any Vice Grips, locking pliers, call them what you want, or even G clamps, use them to clamp the hanger in place while you weld. What I can see from the photos is a lot of slag between the two surfaces: clamping will prevent this &, in the long term, create a stronger join because there won't be any movement.

As I suggested earlier, put a nut & bolt through the hanger with a bit of tension on it when you reweld it to prevent the ears from spreading ('coz the will )

Busy weekend, (Apart from laying turf in the front yard!)...

Got the drawbar on with gussets, hangers rewelded, axle in and set each side, wheels on, Coupling tacked on.

Height to top of chassis is 397mm, gap between chassis and tyre is 38mm, gap at fishplate to tyre is 15mm.

I should be able to fit a standard guard over these I think.