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After the ill-executed (but fun) beach ride a couple weeks ago the Mukluk was in serious need of some work. Specifically, I needed to replace the seized bottom bracket bearings and fix the lower derailleur pulley, and I also wanted to replace the becoming-worn middle chain ring as a bunch of chain suck during the beach ride kept me in the granny gear.
By picking up and assembling some tools (a blind bearing puller and a bearing press assembly) along with the required parts I was able to get all the affected bearings and chainring replaced, and I also swapped out the chain for a standard SRAM PC-991. The Mukluk had come with a KMC Z99 Rust Buster galvanized chain, and while it initially seemed nice I begun wondering if it’s rough surface was contributing to chainring wear.
The replacement chainring is a cheap (~$10) Truvativ ramped 32 tooth steel middle chainring to replace the stock e*thirteen part. While a bit heavier than the alloy model, I suspect that the steel ring will last quite a bit longer than the alloy one did, even when riding in potentially icky conditions. If it doesn’t, at least it was only $10.
A quick ride at River Bends this afternoon ending in rain showed that everything is working nicely, so hopefully everything’s in order for riding the bike as part of a fatbike-only team at tomorrow’s Tree Farm Relay.
Here’s some photos of various steps of this work:
· The e*thirteen bottom bracket after removing the bearings with a blind bearing puller. Conveniently this bottom bracket uses 6806-2RS bearings, the same size as BB30.
· Detail of the 6806-2RS marking on the bearing from the e*thirteen bottom bracket. This one seized up after a ride along the beach and in some fresh lake water.
· KML-brand 6806-2RS bearings to replace the seized bearings in the e*thirteen bottom bracket. These are BB30-size bearings.
· Bearing press made from some eBay-purchased dies, threaded rod, washers, and nuts. Bearings are also shown.
· Home-made bearing press before pushing the BB30 (6806-2RS) bearings into the e*thirteen bottom bracket cups.
· KML 6806-2RS bearings (BB30-size) pressed into e*thirteen bottom bracket cups. This went very smoothly.
· e*thirteen XCX crankset test fit with the newly-installed bearings. Everything aligned nicely.
· Lower SRAM X9 rear derailleur pulley after pressing in a new 626-2RS bearing. This cracked the inner ring of the pully, but appears well seated and spins smoothly so hopefully will remain usable.
· New SRAM PC-991 chain and steel Truvativ Trushift chainring (104 BCD, 32 T) on the e*thirteen crankset.
For reference, here’s the specialized parts that were used:
· e*thirteen Bottom Bracket Bearings: 6806-2RS (Same as BB30)
· SRAM 2011 X9 Lower Derailleur Pulley Bearing: 626-2RS
· BB30 Installation Drivers purchased from eBay seller mtbtools with threaded rod from Mid-States Bolt and Screw.