Off-Road sidecar build

Not the normal type of vehicle that JA4x4 work on, but we can’t resist a challenge- so when one of our customers asked us if we could build an off-road sidecar so that they can go to winter rallies in the snow, we had to say yes!

(Please click on any image to see full sized version)

We picked up  his wrecked old tub frame complete with suspension and a wheel/mudguard

Velorex frame

Not a lot to work with and some pretty rotten metal, but it’s a start and a shape to work with


Looking at the original frame, it was fairly obvious that the metal wasn’t in great condition…..being used to building and working on Land Rovers, we also didn’t think it was  nearly strong enough for the purpose eitherOriginal Velorex frame with brackets ground offWe put the bike (a BMWR1100GS) with the Velorex frame up on our bike ramp and matched it up, to see how it would look and to get a ‘feel’ for how much more space we’d need to create to form a nice stable luggage platform, capable of winter and off-road travel with a lot of kit on board

Original Velorex subframe offered up to the bike to get an idea of measurementsIt’s fairly obvious that it needed to be wider than the Velorex frame, by about 40cm in fact

We also didn’t trust the 15mm diameter Velorex axle, OR the rather flimsy feeling suspension tower it was mounted in…….or for that matter, the rather puny looking shock absorber it was equipped with.

Designed originally to be fitted to a 350cc Enfield or a bike of similar size, we were attempting to build it on to an 1100 cc off road beast of a bike that would be taken off road and also be carrying a LOT of equipment.


For a normal sidecar, many people have 3 mounting points, but as this rig is going to be going off-road and needs to be heavy duty, we decided that 5 points would be better.

To accomplish this, we needed to build a subframe on the bike – this is the mounting point on the right hand side of the bike (UK law says that this age of bike has to have any sidecar mounted on the left hand side) to support the subframe.

The drawn-in yellow lines are where we planned to take bars across to the other side

(as with most projects, this of course changed as we developed the ideas!)

How we intended to make the cross-body bracing for the subframe

On the left hand side, we mounted a length of angle iron as part of the subframe….as the outfit will have three wheels, there’s no need for a centre or side stand, so we were able to use these very strong mounting points

Lower front bar mounting point, welded on to 10mm steel plate flangeFront lower mount, on to angle iron subframe

Centre stand mounting positionCentre lower mount point, only lined up with a bar to the centre stand attachment locations here.

Attachment bar for the rear lower mountRear lower mount point (welding not tidied up yet!)

Front top mounting arm fittedThe front top mount point was fairly easy- We went from the crash bar mounting hole outwards, and welded a plate on to go up to the front ‘beak’ subframe to stop the assembly from twisting

For the rear top mount, we decided to go onto the frame itself.

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