We’re not all tough enough to run a single chainring on our trail bikes, so in light of this MRP have designed a new chain guide for the current crop of two-ring, 10-speed mountain cranks.
MRP say they’ve been working on the new 2x guide for two years. It utilizes their patented removable skid plate and introduces a new patent-pending dual pulley tensioning system in a truly lightweight package.
The 2x guide has been brought to market with SRAM specifically for their 2x10 double cranks, and will also be sold as the Truvativ branded X-Guide. However, MRP’s version also works with nine-speed twin-ring systems – its thinner back plate relies on a spacer that allows for chainline adjustment and the subsequent ability to configure a triple crankset as a double.
The 2x's dual guide pulley system; the chain switches pulleys depending on its chainring position
“When SRAM introduced the XX groupset we were intrigued because it gave us some new challenges,” Paul Aieta, MRP’s marketing manager, told BikeRadar. “We had to look at chain management in a new way for several reasons: [the XX crank wouldn't allow a] crank mounted bashguard, the different chainring combinations, and the slightly different chainlines.
"So, our LRP product wasn’t immediately adaptable to the XX crank, because there was no clean way to add an outer capture ring or bashguard to the crank. We also new that the XX rider was going to be very weight sensitive, because of the nature of that group.”
The 2x forgoes an outer capture guard on the crankset, instead relying on the front derailleur and lower pulley assembly to retain the chain. The integrated skid plate eliminates the need for a bashguard to protect the chainrings from impacts, further reducing system weight. However, gram counters can remove the skid plate to save an extra 43g.
The dual pulley tensioning system is said to properly tension the chain in both rings. MRP say the twin pulleys reduce drag and noise, and offer smooth, secure back pedaling, when compared to other single pulley or roller designs. A raised top fin profile prevents the chain from dropping to the bottom bracket shell.
MRP will offer the 2x in ISCG, ISCG-05 and bottom bracket mount versions, which will be available in black or white, and cost US$150. They claim the following system weights: 36-38T w/ skid guard – 130g; 39-42T w/ skid guard – 144g (both weights represent ISCG05 models).