Axle load, not tonnage, now decides where cranes can go

The point where a move becomes ‘exceptional’

Almost every country sets a maximum permitted gross vehicle weight for ordinary road transport. Cross it and the move falls under special transport rules: permits, designated routes, restricted driving windows and, in many cases, escort vehicles. For a crane owner that means less freedom to redeploy and more exposure to planning risk.

Gross weight, however, is only the opening question. Regulators are at least as interested in how that weight is spread along the vehicle. A relatively light crane can still be restricted if too much load sits on a single axle, while a heavier machine may travel more easily because its mass is spread efficiently.

Axle load and axle spacing

Axle load is the weight carried by each individual axle, and limits in many countries sit somewhere around 10 to 12 tonnes. Those figures are tied directly to the load-bearing capacity of roads, bridges and other infrastructure. Exceed them and route options narrow — in some cases certain roads are ruled out altogether.

Spacing matters just as much. Regulations assess axles as groups, and where axles sit close together the permitted load per group typically falls. Spread them out and more weight can be carried within the same transport category. The consequence is that two cranes with broadly similar lifting specifications can have very different road access in practice. Spierings says the axle configuration of its five-axle SK1265-AT5 eLift was deliberately optimised on this basis, distributing total weight so the crane sits more comfortably within current transport rules.

Ballast adds to the burden

Transport planning does not end with the crane itself. On many machines the ballast has to travel separately, which means extra vehicle movements, extra permits and greater dependence on third parties within a project schedule. Combined with escort requirements and route restrictions, that turns what looks like a simple relocation into a logistical exercise.

A choice with a long tail

Regulation governing heavy transport is tightening in a number of countries, with weight, axle load and infrastructure condition all playing a larger role in assessments. Spierings frames crane buying as a long-term decision on that basis: a machine designed around efficient weight distribution today is more likely to remain deployable as rules harden.

Its own conclusion is configuration-specific. Where transport restrictions bite, the manufacturer points to a five-axle machine such as the SK1265-AT5 eLift for greater operational freedom; where those restrictions are less critical, the six-axle SK1265-AT6 eLift may be the better fit.

Source: Spierings — Photos: Spierings