Which Bolts Should I Check Before Riding? [Quick Question]

The Quick Question series answers your MTB repair questions. Do you have a quick question about mountain bike repair? 🤔 Email [email protected] and we’ll do our best to answer it!

It’s common to blame the chef or the restaurant when your gut gurgles painfully after a meal, but are you sure you soaped your hands just before digging in? Could it have been something you ate earlier or the ice cream stop that followed? A food allergy perhaps?

Our fingers start their pointing when things go awry, and often for good reason. However, there are instances when a little effort on our part could prevent a catastrophe altogether, no matter the culpable party. Today’s quick question is aimed at preventing trail mishaps that can occur when a mechanic forgets to tighten up all the bits and bobbins. “Which bolts should I check after picking my bike up from the bike shop?”

Whether your mechanic is in the mirror or in the shop six doors down, you likely feel that you can trust them. They always get you rolling quickly, and have saved more than one fun weekend from the chaos that followed a weeknight OTB. Those trusted hands can be hurried, and occasionally miss a bolt here or there, so it’s always a good idea to check a few things before hopping back in the saddle. Mechanics are overworked and rushed in some shops today, making it all the more possible that they might miss little things. “I coulda sworn I tightened your handlebar clamp.”

The easiest way to remember which bolts to check is to ponder this question: “which components do I really not want to fall off my bike?” The ones you’re attached to might come to mind. Checking that your stem and steerer tube fasteners are tight will prevent one nasty accident. Then, double-check that the pinch bolts or central spline-tightener on your cranks are done up properly. Maybe even grab a torque wrench to ensure that all of these threads are genuinely tight enough.

After confirming that my hands and feet won’t flop off along with their associated components, I check the front and rear axle. A loose axle won’t often result in a wheel flying past you on the trail, but if it starts to slide out of place there can be a good amount of damage done before you get the bike stopped. While you can go over every fastener on the bike, the last spots you’ll want to check for sure are the specific components that the mechanic worked on or inspected. With the touchpoints, wheels, and recently serviced parts battened down, anything else that’s not quite tight can likely be sorted if it rattles loose.

I am my bike mechanic, and I make plenty of mistakes, so I try to check over every test bike I receive to catch the blunders of my fellow humans with wrenches. Sometimes I forget, or simply hope that everything was done right. I received a test bike in the morning a few weeks back and slammed it together for a lunch ride that afternoon. I was in a hurry to build it between completing another project and getting home for a kneepads-still-on interview directly after the ride. I pedaled up the singletrack feeling pretty stoked on my rapid-fire suspension settings, and ready to see how it rolled on the coming descent.

Since this was my first date with that particular bike I decided not to push too hard down the first half of the rough descent, opening it up more and more as I coasted along. At the midpoint of the trail there’s a gap jump that stretches about two bikes lengths, with maybe a meter of drop between takeoff and landing. I typically take the B-line for the first date, but the suspension felt nearly dialed so I popped the gap and was again surprised that my “by-feel” suspension settings were fairly close to where they needed to be. That’s not always the case on a 170mm bike with unfamiliar squishy bits.

Further down the track, there are several other janky drops and hip jumps, and I noticed that the bike was feeling better the more I let off the brakes. I decided to give it full steam off a nasty belly-button-high kicker that spits you onto the takeoff of a smaller gap jump. I sent that boulder kicker higher than I had before, and when I landed a spooky ratcheting sound gurgled from the frame. I knew something was wrong, and my body position felt way off, but I had no time to think as I had to negotiate the following gap and locate the softest place to crash. I have broken a few frames in similar scenarios, and by now my brain knows not to bother with the bike until all motion has ceased.

Thanks to the magic of powerful brakes, and a flat passage between the trees, I managed to halt the horse without a dismount. I looked toward the bottom bracket to find my feet, pedals, and crank arms all hanging down in the same direction. Had I broken the crank spindle? I tried to coast the remaining meters of trail with the cranks together like this and quickly remembered that you can’t turn or ride past rocks with both pedals hanging at six o’clock. It was time to walk to a sunny spot and determine the next steps.

After sending a photo of the mishap to all of my colleagues, I pulled on the Shimano XT cranks to find that they were laterally tight. The preload cap was so tight I couldn’t tighten or loosen it. I then noticed that the plastic tab Shimano places between the two pinch bolts to prevent the crank from falling off had flopped open. I checked the pinch bolts with my multi-tool to find that both were about as loose as they could be without falling out. So loose in fact that they had allowed the splines that keep the non-drive-side crank arm in place to slip past one another with the force of that landing.

Since the pinch bolts were baggy, and the preload tight, I grabbed both crank arms and clunk-clunk-clunked them back to their intended positions. I then cinched the pinch bolts until my hand hurt and headed up the next long climb to descent toward home, just barely making it to my next appointment. I feel fortunate this mess didn’t happen on a different piece of the trail, and I won’t be skipping these few bolt check steps on future test bikes.

Here’s a quick list of bolts to check for readers who like quick checklists.

• Stem, steerer tube bolts, and headset preload
• Crank fasteners and pedals
• Front and rear axles
• Any areas the mechanic recently worked on or inspected
• Extra credit: every other fastener, with a torque wrench