was one of the pioneers of the Plus rim and tire format, and their first rim design, the "Scraper," grew into a range that covers 26, 27.5 and 29-inch wheel formats, in both 40 and 45-millimeter inside-widths. Scraper rims are aluminum, and all are drilled with 32-holes, which are angled in the directions they need to be when laced to a hub. A shallow extrusion helps keep weight to a minimum, while preventing the rim from riding too harshly. WTB is a strong supporter of the UST bead standard. The Scraper's low-profile hooked flanges are designed to interlock with the rectangular UST bead, but will also accept conventional "tubeless ready" tire designs. The rim's drilled spoke bed is heavily reinforced in lieu of eyelets, and inside, the dropped center section is gently profiled to encourage tires to seat up tubeless with minimal fuss.
I was interested in the "narrower," i40 27.5-inch model, because I wanted the option to experiment with tires from 2.5 to 2.8 inches wide. Graciously, WTB built me up a set of wheels using White Industries XMR+ hubs
and Pillar bladed spokes. The complete wheelset weighed 1920 grams, taped and with valves installed, which is a respectable figure for wheels in this category. Weight for the 27.5 Scraper i40 rim is listed at 550 grams (530g in 26" and 555g in 29") and the MSRP is $124.95 per rim in all sizes.
Riding Impressions Scraper i40 Details:
• Use: trail, adventure, back-country touring
• Construction: 40mm inner width, aluminum, pinned joint, 32 "4D" angle-drilled spoke holes, thin-profile extrusion features UST bead-lock flange design.
• Tubeless ready design requires sealing tape
• Sizes: 26 x 40mm, 27.5 x 40mm and 45mm, 29 x 40 and 45mm
• i40 optimized for 2.8" tires, i45 optimized for 3" tires
• Claimed weight: 550g (27.5 x 40mm reviewed)
• MSRP: $124.95 USD
• Contact: WTB
WTB's Scraper i40 rim, with its slim profile and low flanges, seems too lightweight to handle a serious pounding, but I would soon discover my opinion was unfounded. Used in their intended role to support performance Plus-width tires up to 2.8 inches, the 40-millimeter inner width provides a significant degree of lateral support for tires with lightweight casings, like Schwalbe's 2.8-inch Nobby Nic, and other-worldly grip when used with heavier, more aggressive rubber, like the Maxxis 2.8-inch High Roller II. Some of the i40's lateral stability can be attributed to the rim's low flange design - a feature that was originally pioneered by Stan Koziatek to stabilize the bead-seat of tubeless tires, and provided a surprising degree of lateral support.
Installing a tubeless tire on the i40 rim is an easy task. I got some 2.8-inch Schwalbe Nobby Nics aired up first try with a floor pump, but the Maxxis tires would not mount up without a boost pump. My go-to inflation for similar sized tires is 14 psi for the front and 18 psi for the rear tire. At those pressures, there is climbing traction a-plenty and no sense that the tires were wallowing during high-pressure cornering. So far, so good.
A broken carbon rim gave me the opportunity to push WTB's aluminum Plus rim well beyond its intended role. The i40 wheels were installed on a 170mm-travel Pivot Firebird for two months and thrashed on downhill trails. Shod with a 2.5-inch Schwalbe Magic Mary front tire and a similar size Rock Razor in the back, the wide rims did not square off the tread pattern much, while boosting cornering and straight-line grip to a noticeable degree. I expected the rims to last a week before they began to look octagonal from repeated rock strikes, but that did not occur. The rear rim suffered a cosmetic dent in the flange on an infamous rocky descent that also digested a tire, but it still runs true and spoke tension on both wheels has remained consistent.