EXT has launched a lighter coil spring, the Superlight V2. It fits the Italian brand's Arma and Storia dampers and is compatible with other manufacturers' shocks using adapters. Depending on spring rate, the V2 springs are claimed to be lighter by "up to 30% compared with previous EXT Superlight springs and other competitor products". However, using numbers from a table they provided (below), the V2 spring works out to be between 9% and 23% lighter than the unnamed competitor(s) in this comparison. That's a 33-80g absolute weight difference - not something to write home about, but nice to have if you're after a new spring anyway.
Superlight V2 Coil Spring Details
• Claimed to be up to 30% lighter than competitor springs in some configurations.
• Two length options: up to 65mm or up to 75mm stroke.
• Spring rates: 225 to 600 lb/in (75mm) and 325 to 800 lb/in (65mm).
• 25 lb/in spring rate increments.
• +/- 3% spring rate tolerance.
• 109€ + VAT
When asked how the weight savings were achieved, EXT were tight-lipped about the material composition but say the steel alloy contains a higher percentage of Vanadium. "The capacity to make lighter springs is due to the possibility to apply higher stress on the material," EXT's Technical Director, Franco Fratton said. "This allows a different design with a smaller coil diameter and shorter material for a given spring rate and travel, which finally results in lower weight."
EXT say they're able to save weight without compromising on safety, lifespan or resistance to cracking.
*Springs over 600lbs/in are not compatible with ARMA V3, STORIA V2, ARMA V2 and previous Storia and Arma models. Springs over 600lbs/in must be assembled with a reinforced abutment.
The springs are available in two lengths to suit shocks up to 65mm stroke or up to 75mm stroke. The travel of the spring is built to closely match that of the shock in order to avoid wasting material to provide extra travel that's not needed. As a result, it's important not to preload the spring more than 2mm to avoid the coil binding before reaching full travel on the damper. (Preloading a coil more than about one full turn is usually a bad idea anyway
They're available in a wide range of spring rates (stiffness), from 225 to 600 lb/in for the 75mm length and 325 to 800 lb/in for the 65mm length. The gaps between spring rates remain nice and small, at 25 lb/in throughout most of the range, increasing to 50 lb/in gaps above 600 lb/in. That means the steps between spring rate options are as low as 4.3% and no higher than 11%, depending on the starting spring rate.
The V2 springs will become standard on future Storia and Arma shocks and are available through EXT's website at a cost of 109€ + VAT.