Installing drive-in racking is several times more demanding than standard selective racking. The forklift travels inside the lane with minimal side clearance — any deviation in verticality or unevenness in the guide rails means a risk of collision and damage to the entire section.
Key Differences from Selective Racking
With selective racking, beams are simply hooked into the upright perforations and secured with a locking pin. The verticality tolerance is H/1000 and anchoring typically requires 2 anchors per base plate. With drive-in, everything is stricter — verticality tolerance is H/750, bolted consoles with guide rails replace standard beams, and anchoring must be more robust due to higher overturning moments.
In the Stow drive-in system, consoles (DNSL/R) are hung into perforations and bolted — each standard console takes 2x BOSP 10x25 bolts on the first two uprights, 1x on the rest. The top beam is always bolted with 8x BOSP 10x25 and is critical to the stability of the entire structure.
Installation Procedure
Before installation begins, the floor flatness is always surveyed. Deviations exceeding +/-3 mm/2 m at anchoring points are a problem and must be resolved beforehand. The concrete must be at least C25/30 and anchor points must not fall on expansion joints.
Floor-mounted guide rails are installed first, as they define the lane centreline. Rear frames follow — installation always proceeds from the back wall towards the entry. Verticality is checked in two axes, anchoring is torqued (Stow ANEX 12x100, typically 2 anchors per base plate in practice). Rear frames must be perfectly aligned — this is verified with a string line across the entire row.
The most critical phase is fitting the consoles and guide rails. Rails are hung on consoles in the upright slots and must be precisely level. The height difference between rails in the same lane must be minimal — uneven rails mean the pallet “rides uphill”, the forklift has to exert greater forces, and there is a risk of collision with the structure. After fitting, alignment is checked with a string line along the full length of the lane. For the Mecalux Pallet Shuttle system, the rails are CSM-CI profile (Z-profile, 2.5 mm) with a tolerance on the distance between rails of +/-0 to +2 mm per 1000 mm — extremely tight.
After the front frames with forklift entry guides are installed, the top bracing and wind bracing are fitted. This must be completed before removing temporary supports — without the top bracing, the racking has no longitudinal stability.
The final check includes measuring the verticality of every frame in 2 axes, lane levelness, anchor pull-out tests, and inspection of all locking pins and end stops. Every lane must be test-driven by a forklift.
Common Problems from Practice
Installing without a prior floor survey is the most expensive mistake — deviations are only discovered after installation and corrections are costly. Installing from the front instead of the back means rear frames become poorly accessible for anchoring and alignment. Inconsistent rail height within a lane leads to unstable pallets. And in shuttle systems, rail alignment is the most common cause of complaints — according to the Stow manual, it is problem number one.
Shuttle = Drive-In + Rails
Shuttle systems share the same load-bearing structure as drive-in, but with added rails for the automatic carrier. Rail installation is the main time driver — with Mecalux, this means brackets, shims, joints and reinforcements, i.e. 20-40+ bolts per lane side per level. Total time for a rail-equipped lane is 3-5x higher than for a standard drive-in bay.
FAQ
Is a special floor required?
Quality concrete C25/30, flatness +/-3 mm/2 m, no expansion joints at anchoring points.
What to do if a guide rail is damaged?
Immediately take the lane out of service and replace the rail. Operating on a damaged rail is prohibited — the pallet can fall.
JTB STORAGE installs drive-in and shuttle systems for Stow, Mecalux, Dexion and other manufacturers across Europe. Contact us for a quote.