Creating the best airtight seal
In 2002, after testing hundreds of tyre and rim combinations, Stan discovered a way to create a stronger and more secure airtight seal between the rim and tyre. Stan’s “Bead Socket Technology” design improved the inner shape of the rim and lowered the height. These tubeless rims were easier to inflate and maintained a tight seal during hard cornering and impacts. With a lower profile and less metal needed to create the rim, Stan’s “BST” design also allowed for much lighter rims that were less vulnerable to dents. Competitive racers began winning on Stan’s tubeless rims, often with decals removed to avoid sponsorship conflicts. Stan’s BST rims became available to consumers in 2005 and quickly earned a strong following based on their easy tubeless inflation and light weight.
The challenge of asymmetrical rims
By 2015, Stan’s had introduced an extremely successful carbon XC racing rim designed to absorb radial impacts to roll faster and more comfortably, but changing tyre designs were demanding wider rims for trail bikes. As tyre widths increased, Stan’s partnered with the carbon experts at Ibis Cycles to develop an entirely new asymmetrical tubeless rim design. Asymmetrical rims with offset spoke holes allow for more balanced spoke tension to create stronger overall wheels, but they have traditionally provided poor tubeless performance, being more difficult to inflate, more prone to air loss due to unequal bead retention, and more likely to be dented by impacts. BST-Asymmetric, the technology Stan’s engineers developed for these wider carbon rims, solved all of these problems.
New MK4 series asymmetrical rims
Twenty years of refining tubeless design has led to Stan’s new premium aluminium rims, the MK4 series. The new 6069 alloy MK4 rims feature a welded seam, reinforced spoke bed, and Stan’s latest BST-Asymmetric design for balanced spoke tension, improved spoke angle, and a stronger overall wheel. Stan’s has accomplished this asymmetrical design without compromising their legendary tubeless performance.
Available in three different models based on rim width, MK4 rims offer the most reliable airtight seal on both drive and non-drive-side tire beads, and consistent impact resistance on both sides of the rim. Built for gravel and cross country riding, Crest MK4 rims have an internal width of 25mm with reinforced spoke holes offset by 1.5mm and are optimised for 40mm gravel tyres up to 2.3” mountain tyres. Arch MK4 rims are the most versatile of all Stan’s rims and are ideal for a wide range of trail riding. They have an internal width of 28mm for 2.2-2.5” tires and an offset of 2.5mm.
The legendary Flow rim has earned Downhill World Cup and Enduro World Series wins and is a favourite among gravity and trail riders everywhere. With emphasis on strength and durability, Flow MK4 rims have an internal width of 30mm for 2.3-2.6” tyres.
Offering an asymmetrical design with no compromise in tubeless performance, Stan’s new MK4 rims are the result of twenty years of obsessive dedication to building better rims.
This article is sponsored by Stan's NoTubes