Offroad Trailer custom Build

Hi Everyone,

I run a mountain bike company in Scotland and one of the products we offer is an uplift service using our 8 seater 110. This is for downhill mountain bikers who want a lift to the top of a hill so they can ride their big heavy bikes down the technical terrain. We had a trailer from Burtech and whilst the trailer is well made for roads etc, anything rougher than a smooth fireroad and it was being shaken to bits. Our route to the top is only on forest fireroads and at speeds of 10-15mph.

We have discovered that when not underload, the suspension design was not activated causing shaking and sheer fractures at welds and weak points. The wheel size also meant the trailer felt every bump and so we are looking at landy sized wheels, rather than standard trailer wheels.

We are looking at alternatives and are just waiting on a reply from Douglas Motors about their Merlin Trailer. We would need a custom job able to take 12 bikes, without any damage being done to them, (we can't just sling them in a cattle trailer without suitable protection for each bike).

My reason for posting is this: We have £2000-£3000 to spend on a trailer suitable for the job. If Merlin can't do it, is there either another company or one of you that is handy with a welder and some spare parts and would like to be commissioned to do the job? Specs are:

• 12-15 bikes each weighing up to 45-50lb. Wheelbase of bike approx 120cm. and tyre width up to 2.6 inches.
• Each bike needs to be individually attached using rachets, ties or bungees but must not touch any other bike or part of the trailer (except for the tyres obviously).
• Handbrake and rear lights required
• Suspension and wheels suitable for rough fireroads (sustained bumps and ruts of 1-3 inches)

Please let me know ASAP if you are interested or would like to know more!

Many thanks

Adam Flint

Sounds quite easy.

My opinion on this is something like a peugeot 405 torsion bar with dampers setup would be better. A matched spring and damper combination will stop bouncing greatly.

Be aware new trailers need type approval ministry check I believe

sible88 said:

Sounds quite easy.

Click to expand...

If you fancy the job please let me know! I am sure if you have the know-how and the tools (which sadly I do not), you could make some money from this project!

A better suspension system would be ideal, but we have two options. Either get a full refund on the trailer and have to start from scratch, or get the trailer back as standard and try to put on the more suitable bits, but we will have spent most of our money.

progressionbikes said:

If you fancy the job please let me know! I am sure if you have the know-how and the tools (which sadly I do not), you could make some money from this project!

A better suspension system would be ideal, but we have two options. Either get a full refund on the trailer and have to start from scratch, or get the trailer back as standard and try to put on the more suitable bits, but we will have spent most of our money.

Click to expand...

Is it a single or double axle trailer, weight on rating plate and is it normal trailer suspension units?

Reason being normal trailer suspension units are bouncy unless well laiden and generally no dampers fitted.

If you specified the use when buying-Satisfactory and Fit for purpose Sale Of Goods ACT

This is what we had below.

I do just want to point out that the guys at Burtech couldnt have been nicer with regards to the trailer. They did initial modifications to suit our needs and were always quick to reply and help out. This trailer would work fine for roads for activity centres etc. They did say that ones were used in other forests and in the Alps, but for us, on our uplift route, it didnt work out.

B20 Bike Trailer Braked


Code: BUR/TRBI20B

Price: £2,326.00



Length 5320mm x Width 1880mm x HT 1700mm(unladen)
HT 1900mm approx (loaded with bikes)
Unladen weight 275Kg (Less spare wheel @ 8.5kg) Gross weight 630kg

only touch the trailer with their tyres
are individually held and accessible
don't damage each other in transit
are secured by a single strap looped around the handlebar
rear wheel slot adjustable for different sized bikes
horn carrier for infants' bikes can be added on

spare wheel and jockey wheel
fully integrated and protected lights
lockable coupling
plug park
coiled electrical connection
securing straps
quick change number plate system
hot dip galvanised
available unbraked or with auto reverse brakes
rear wheel slot shortening pins
unique and compacy design
ease of use
extremely robust construction

My view on that is it could be beefed up and a decent axle fitted with torsion bar and dampers, Some of the peugeot range would be Ideal for this.

I'm guessing the reason your facing problems is the design looks okay for road use but not robust for what your using it for.

Where is it cracking welds the corners or near axle as the design looks -flimsy in my opinion and could be braced.

Another thought on this that may cure flex and stop bouncing if your not over weight of axle is:-

Phenolic coated 18mm ply with wheels holes cut out and bolted to the lower frame- would take the whip out as a stiffener and also some weigh should stop it bouncing.

Really an engineering company should be able to sort this and I feel that if they were informed of use=Not Fit For Purpose and they should be altering it FREE OR REFUND.

Sounds like avery weak trailer for the job in hand :\ If the trailer is weak enough for welds to break and it has been compromised in that way I dare say even modifying it will not suffice? I suppose you could plate up the broken bits and modify/change the suspension which would not be that difficult...but how far do you go with it really? You might find that even with all these modifications, there will be another weak point on the trailer.

Personally if I bought something sold as "extremely robust construction" I would not be impressed if it fell apart...on what most would not consider as "extreme" terrain.

get a sankey and fit a frame to it. Can't be that difficult surely

Yeah that would be how I would do it!

Went for a sankey trailer and will be modifying it accordingly. The trailer is bombproof, literally I would imagine.

There isn`t a lot to go wrong - see if you can get a spare tyre if it didn`t come with one ( it should undersling at the rear) and assuming you made sure it wasn`t corroded where it might matter before you bought it, make sure its rust proofed as part of the conversion.
Keep the handbrake off even when you are not using it unless for safety reasons, make sure the linkage is lubricated, and make sure the overrun brakes work properly because that is potentially a lot of weight to be following you down a fireroad.

The first thing you need to do is work out your payload, in order to get a spring setup that will give you good travel . I would also suggest large tyres running at relatively low pressure tandem axles would also help to smooth out ride. Go for coil springs with good s/absorbers. If you use leaf springs for the use you have , they will need to be very closely matched to your payload, as its the springs that are transmitting the shock thru to the chassis, and that is whats doing all the damage. Its very common in Australia on badly corrugated bush roads. It also causes very high wear rates in the leaf spring bushes and links on tandem axle set ups , it became very apparent when towing behind range rovers and later coil sprung vehicles , as the early leaf sprung landrovers etc limited the damage due to transmitting thru to the driver!! HTSH