Tips for Measuring Pannier Hook Size ‒ for Lone Peak Panniers Only

  • How can I measure my rack to see whether I need 8mm or 10mm TOP hooks On MY LONE PEAK PANNIERS? . . .  Measure where the top rail is circled in the rack pictured below.  That is where the hooks will attach.  In most cases, the top rail of your bike rack will be either 8 millimeters or 10 millimeters in diameter — or the standard equivalents — 8mm is approximately 5/16 inches, and 10mm is approximately 3/8 inches.  The difference between the two sizes is about 2mm or 1/16th of an inch.  Of course, the easiest way to measure is with a nice set of metric or standard dial gauge calipers.  But if you don’t have the calipers, here are some other ideas that may help . . . If you don’t have a ruler or tape measure handy, 8mm rails are about the same diameter as one of those very common white round plastic Bic pens with a push-on cap.  10mm rails are about the same diameter as a AAA Duracell battery.  Because of differences in manufacturer’s tolerances, and because rack rails are made in standard and metric diameters, don’t expect your rails to measure EXACTLY 8mm or 10mm.  An easy way to get an accurate measurement is to use an adjustable (crescent) wrench as a caliper.  Dial the adjustable wrench down until it fits tightly to the rack rail.  Without touching the adjustment mechanism pull the wrench off of the rail.  Measure the gap in the wrench with a metric or standard ruler or tape measure.  It should be close to one of the above values.  Another easy method . . . many cyclists have 8mm and 10mm open end wrenches in their bicycle repair kits.  Try slipping an 8mm or 10mm wrench over your rack rails to see which size is a close fit.  An 8mm wrench may, or may not, fit over an 8mm or 5/16 inch rail.  If it does not fit, it will be very close.  It will be the same with 10mm or 3/8 inch rails – the wrench will fit or be very close.  Note: Although the hooks are VERY strong, they are also just flexible enough to handle the differences in tolerances mentioned above, and will fit nicely with the above size variations..  Please email Wayne at or call me at 1-800-747-0588 if all I did was confuse you with my explanation.