Yes, the MRP Cage Guard is just a tiny piece of plastic. But for its truly affordable price, it could just mean the difference between an expensive derailleur replacement or just a few scrapes. Call it a $30 low-level insurance policy against smashed derailleur cages.
Well now, MRP has a new Cage Guard to protect the latest 12-speed Shimano mountain bike derailleurs, too. The Shimano XTR & XT mechanical derailleurs aren’t nearly as expensive as AXS, but this could still save you some money if you ride rocky trails!
MRP Cage Guard protects Shimano 12-speed MTB derailleurs
Just a few months ago MRP introduced a tiny bolt-on Delrin plastic skid plate for SRAM’s wildly expensive electronic derailleurs, which can cost as much as $650/700€. A mechanical Shimano XTR derailleur is cheap in comparison at $260 /265€. But they’re still an expensive piece kit that I worry about thrashing through rough rock gardens. I know that I broke the cage off an XT derailleur that cost half as much as XTR when it got hung up on a rock, and its replacement still hurt my wallet.
But why?
Modern 1x MTB drivetrains with huge cassette spreads mean really long derailleur cages that get perilously close to the ground, even on 29ers. Pretty much every current mountain bike derailleur I own has scrapes on its cage around the lower pulley. For the alloy cages, it’s mostly cosmetic damage. But every gouge tells the story of a derailleur cage that got momentarily hung up on a rock, maybe a derailleur or hanger slightly bent, and was moments away from getting ripped off. Then, with carbon cages like on XTR (see below), each of those impacts and scrapes risks delaminating carbon fibers, that will eventually splinter and fail.
Cages are a pretty common MTB failure point, and MRP’s little plastic skid plate aims to lessen that routine damage without costing an arm and a leg. And while it’s not crazy expensive to replace the cage on a mechanical derailleur, it still means time you won’t be riding your bike and searching for a replacement.
Think of it as a classic low-friction MRP bash guard for your derailleur cage instead of your chainring.
I don’t know how many broken derailleurs an 8g piece of MRP thermoplastic could save, but it’s probably quite a few.
MRP Cage Guard – Pricing, Shimano compatibility & availability
The tiny Delrin plastic MRP Cage Guard sells for $30, direct from Mountain Racing Products. MRP machines them in-house in Grand Junction, Colorado to fit mechanical 12-speed Shimano mountain bike derailleurs.
Officially, MRP says the XTR 9100 model is compatible with the carbon cage of M9100 derailleurs (all cage lengths). Plus, there’s a separate XT 8100 model, compatible with the aluminum cages of M8100 derailleurs (all cage lengths). They have not confirmed yet, but the XT model is likely also compatible with alloy cage SLX M7100 & Deore M6100 12-speed derailleurs. Of note, it is NOT compatible with the XT M8130 LinkGlide 11sp derailleur.
SRAM T-Type guards are still also available. Then, we wouldn’t be surprised to see another Cage Guard option once rumored XTR Di2 drops this spring/summer.
All MRP Cage Guards feature a crud-clearing hook that extends towards the pulley. And all come with an extended stainless steel bolt to easily install it over your cage.
