Homework Done

Whenever you switch a part on your bike, it’s important to do your homework. A coworker of mine once wanted to change the stem on his bike. He got one, went on the put it on the bike, only to realize that his handlebar wouldn’t fit. He had purchased a stem with a 31.8mm clamp. Unfortunately, his bike was equipped with a 35mm handlebar. It’d be easy to laugh and say what a noob. But we can’t all be experts in everything. I’m certainly not. After several winters of riding my fat bike, the axle of my crankset has worn where the bearings are seated. Without tightening the pre-load adjuster, there was noticeable play. A tightened pre-load adjuster doesn’t remove that play; it only hides it while the bike is in the work stand. The play is still there under every pedal stroke and will only worsen over time. It will also lead to premature bottom bracket failure. It was therefore time to replace the axle. Because I chose a SRAM XX1 carbon crankset at the time, a simple axle change isn’t possible. The axle and the non-drive side crank arm form an inseparable unit.

So, I started to look for a new set of cranks. I would have loved to purchase a bling set of cranks with gold anodization. Leonardi offers their Capo cranks like that. Ignite Components has the Catalyst fat-bike cranks that can be made in any color. Leonardi doesn’t currently offer fat-bike axles for their Capo cranks and Ignite only offers one Q-factor that is too narrow for my Snakedriver. So, I had to keep doing more homework. Homework is necessary for any crankset purchase no matter the type of bike. There are axle diameters, axle lengths, chain lines, Q-factor, and chain stay clearances to consider.

I immediately started looking at Race Face. Their Cinch-type cranksets come in a lot of flavors, and there’s a wide range of axles available. First, I looked if all the numbers would match up for the Next SL carbon cranks. But they didn’t. The numbers would have lined up for Race Face’s other carbon crank, the Next R. But this crank was a little busy on the logos. I never cared for the huge “XX” on my old SRAM cranks. I wanted something with no or at least small logos. It just happened that Race Face released a new Turbine aluminum crankset in a modern remake of the legendary Turbine LP cranks (photos below). I studied the drawing, punched the numbers, and came to the conclusion that this was the perfect one. The Q-factor of 208mm with an RF169 spindle is 5mm wider than SRAM’s XX1 Eagle DUB SL crankset. The SRAM cranks were a little tight on my frame and only left 2-3mm clearance to the chain stays. 2.8mm more clearance felt right. The RF169 spindle is for fat bikes with 4” tires and a 170/177 rear axle. My Snakedriver, however, runs 4.5” tires and is equipped with a 197mm wide rear hub. To get the chain line right, a Boost chainring with a 3-4mm offset needs to be flipped. The Cinch system, thankfully, lets you do that.

Speaking of flipping a Boost chainring, when it is oval, it’s also necessary to rotate it once flipped. I took a piece of paper, installed the chainring the way it is intended, drew the outline of the ring onto the paper, marked the direction of the crank, then flipped the ring and rotated it until it matched the outline on the paper. Lastly, it came to figuring out the right axle spacers and mounting them. Fortunately, I had plenty of 30mm axle spacers at various widths. I also had two different Chris King BB fits kits on hand. First, I popped in the plastic BB sleeves with the thicker shoulder and used a 6mm spacer on the drive side. This would have worked, although the drive-side crank was a little closer to the chain stay than the crank on the non-drive side. So, I exchanged the BB sleeves for the ones with the thin shoulder and corrected with a wider spacer. This equalized the clearance between the cranks and the chain stays. Lastly, I needed to find the right spacer to fill the gap on the non-drive side. A 2.5mm wide spacer did just that.

With an all-new drivetrain, the Snakedriver is ready for winter if winter will show up. There are two more updates scheduled already. First, a Prologo Scratch NDR saddle once it hits the store shelves. And secondly, a user-serviceable dropper post to replace the Thomson Covert seat post. The Wolf Tooth Resolve dropper post may be a contender.