Single Axle Caravans


The Hublock disc and stand replaces one of the caravan wheels and can be fitted nearside or offside for your convenience.

Four security bolts are used to lock the JSB Hublock to the brake hub housing on both four stud and five stud hubs.

One hole is omitted on the five stud Hublock (see picture).

Always follow the caravan manufacturer's instructions when jacking up the caravan and use a mechanical jack, hydraulic jack or trolley jack to remove the wheel. Slacken the fixing bolts before you jack up the caravan.

When the caravan is raised remove the fixing bolts to remove the caravan wheel, a wheel guide/guides can be used to take the weight off the wheel.

With the wheel removed and the wheel guide/guides in place slide the stand into position followed by the hublock.

Fit two security bolts hand tight only to hold the hublock and stand in position, before removing the wheel guide/guides and fit the remaining security bolts.

Lower the caravan using the jack and place a spacer (10mm marine ply 150mm x 400mm) under the stand.

At this point the caravan can be checked for level (side to side) and addition spacers can be added as required.

When the caravan is lowered and level, the security bolts can be tightened to the correct tension using a torque wrench.

Twin Axle Caravans

Two units are fitted using the same procedures as for single axle caravans, however both units must be fitted on the same side.

The JSB Hublock does not have alignment problems often associated with wheel locking devices.

Other users of the JSB Hublock

The JSB Hublock has been fitted on Motorhomes, Trailer Tents, Box Trailers, and Trailers for RIBS, Motor Launches, Speedboats, Motor Vehicles, Industrial Plant, Farm Equipment etc.

Any trailer with Alko hub assembies and the following wheel centres:-

Four holes M12 x 1.5 on 100mm PCD. 

Five holes M12 x 1.5 on 112mm PCD.

Other sizes may be supplied to special order if not available from stock.

If you use CASSOA registered caravan sites and storage sites you may feel your caravan is secure, however the responsibility will always fall on your insurance should the caravan be stolen. We recommend you carry out your own assessment of the sites security, and if in doubt fit the JSB Hublock in addition to the wheel clamp and hitch lock specified by your insurance provider.

Because the JSB Hublock is fitted to the caravan/trailer hub assembly it does not need to be changed every time you change your caravan.

Only if you change from 4 stud to 5 stud hubs (or visa versa) would you need a new Hublock disc.

The stands are pre-drilled to suit 4 stud and 5 stud hubs, whilst the security bolts are the same.


The security bolts have a separate hardened anti-drill head, it's narrow groove key pattern with unlimited combinations prevents key duplication.

A nylon key pouch is available for key storage and helps prevent misplaced keys.

A computerised key registration and replacement program is in place.


Replacement keys:

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© Kenneth Johnson