Custom Derby 40i wheels, handbuilt in Colorado, with your choice of hubs from Chris King, DT Swiss, Hope, Industry Nine, Onyx, Project 321, Shimano or White Industries.
27.5" x 40i - for 27-Plus tires and frames
AM, Enduro/DH layup options
- ideal for 2.6 to 3.0 & down to 2.4 tires
Weight +/-10: 510g [All-Mountain]or 570 [Enduro/DH]
Outer width: 45mm, Inner width: 39.5mm, Depth: 34mm
ERD: 540mm, Note: Spoke off-set from rim center: 5mm
29" x 40i - for 29-Plus tires and frames
AM, Enduro/DH layup options
- ideal for 2.6 to 3.0 & up to 3.5 tires
Weight +/-10: 520g [All-Mountain], 565 [Enduro-DH]
Outer width: 45mm, Inner width: 39.5mm, Depth: 31mm
ERD: 582mm, Note: Spoke off-set from rim center: 5mm
- Material: UD carbon-fiber
- Spoke holes - Mountain: 32
- Presta valve hole, required length: 40mm minimum (
Recommended max spoke tension: 125KgF
Recommended rider weight limit: 175 lbs / 90kg for XC rims, 225 lbs 100Kg for AM, 300 lbs 135Kg for Enduro/DH rims
Max tire pressure (mountain): 35 psi (for road use of mountain rims), 22 psi for 2.6 and larger tires. Max for Enduro/DH race/park/shuttle: 30 psi, ProCore max pressure: 70 psi, 4.5-bar
- Tire pressure to seat beads of most new tires, with soapy water or bead seating lubricant: 35 to 40 psi for mountain rims
- Tubeless rim tape maximum width: 18mm or ¾ inch for 30i and 35i rims; 25mm or 1 inch for 40i and 45i rims; Only tape within the center channel, do not taping over the bead seats, for best results.
AM (All-Mountain) layup Derby rims are for technical trail medium size knob tires under 800 grams, except if plus size for technically difficult trails and where climbing wheel weight and rear tire rolling ease is as important as descending control, through rocks or roots with rare in-trail small drops less than 2 foot vertical. Free-ride larger drops and stunts and Enduro-DH high speeds are not AM technical trail conditions, for such extreme riding DH (Enduro/DH and Downhill) layup rims are required for shuttle and DH park and for the rear wheel for Enduro-DH racing and similar descending high speeds.
DH (Downhill, Enduro/DH) layup Derby rims are for maximum durability under the hardest riding conditions for any weight rider of extremely rocky trails. "DH" Derby rims are required for DH bikes, and required for at least the rear wheel of Enduro bikes for Enduro/DH racing and similar high speed descending uses. Also DH layup Derby rims are required for tandem mountain bikes, and mountain E-bikes, and riders over about 250 lbs.
Rider weight is almost not a factor for durability. Sharp rock hits and suspension bottoming loads focus more than 1000 lbs of acute input causing flex to a rim. Aluminum rims could bend or dent from sharp or heavy hits, but carbon-fiber will flex. And excessive flex and repeated excessive flex damage carbon rims. Usually excessive flex causes internal damage at first, called "micro-fracture", where the actual carbon fibers split microscopically. Additional excessive and normally intended flex will open the internal fracture further, until the internal layers separate enough to become unable to support intended loads, and many months later after the initial excessive hit flex the rim wall collapses showing as a surface crack.
Derby Rims are not for weight weenies. These very wide trail rims are for high performance bike handling, improving the performance of nearly any trail tire. The AM rims are about 0.75 lb, about 300 grams lighter per set than an equivalent width aluminum rim. This is a huge weight improvement in rolling weight. With wide Derby Rims there are additional effective ways to reduce weight. Some examples: Wide rims with smaller tires have more traction and cornering grip than a high volume tire with bigger knobs on narrow 25 mm internal width rims. And Sapim CX-Ray spokes drop about 100 grams compared to common double-butted spokes.