Swapping out your bar and stem is one of the quickest, easiest and most cost-effective ways to upgrade your bike. It’s also an easy way to customize your fit for both control and efficiency. However, swapping these components is not as simple as slapping them on and tightening the bolts. There is a step-by-step process, and we’re going to show it to you as we install this 35-millimeter Renthal Fatbar Lite and Apex stem combo on our Pivot Firebird.
For this job we will need a set of Allen wrenches and a ruler. We like to use the PrestaFlator torque keys, because they deliver precise torque to the bolts we’re working with. They are preset to the most common torque ratings and come with nearly any bit size you could possibly need.
We’re installing a Renthal Fatbar Light handlebar, an Apex stem and a pair of Lock-On Super Comfort grips. The bar and stem are the newest 35-millimeter clamp version, which is said to deliver optimized stiffness and weight. The grips are the softest ones Renthal makes, but they have several different compounds if you prefer something that will last longer.
Begin by removing the front wheel. While this is not 100 percent necessary, it will make the next few steps easier.
Remove the stem faceplate bolts to free the handlebar. You would not want to loosen bolts with a torque wrench, but these PrestaFlator torque keys are designed differently
You can use them to not only precisely torque bolts down, but also remove them without taking them out of tune. You can use the same tool to loosen brake and shifter mount bolts.
With the bar removed, it will be easy to remove the grips, shifters and brake levers without having to fight the cable length during the process.
Loosen, but do not remove, the steerer clamp-stem bolts. This will free the stem. Once loose, slide the stem off and set it aside.
While removing the stem, be sure to support the fork so it doesn’t come crashing down on the garage floor. To be sure, you can thread the top cap back in to keep the steerer tube in place in case the fork wants to commit bike-stand suicide.
Stem length is measured from the center of the steerer-tube clamp to the center of the handlebar. This shorty Renthal Apex stem is 45 millimeters and will quicken the handling slightly compared to the stock 50-millimeter stem.
Slide the new stem on the steerer tube with the appropriate number of headset spacers. The bottom of the steerer tube should be slightly below the top of the stem, but not so much that it’s below the level of the top stem- clamp bolt.
If your steerer tube is too long, the top cap will bind as you tighten it and will not preload the headset bearings properly. If this is the case, you can either take the fork to a shop to trim the length of the steerer tube, or simply add an additional spacer on top of the stem to allow the top cap to tighten properly.
The Apex stem has a special two-piece faceplate that must be slid on the bar carefully. Be sure each piece is right side up, and slide the pieces on from the side, being careful not to mar the graphics on the bar.
With the bar still off the bike, take time to slide the controls and grips back onto the bar. They don’t need to be tightened yet; it’s simply easier to do this before you mount the bar to the stem.
All stem faceplate bolts should be evenly torqued, but some have a very specific order in which this must be performed. This Apex stem is designed to have the bottom bolts tightened all the way first until the bottom clamps are bottomed out at 5 newton meters.
We will tighten the top bolts down to fix the bar in place in a little while, but for now, leave them loose.
Now, take the bike out of the stand and put the bike on the ground. It’s much easier to make the final cockpit adjustments with the wheels level.
First, center the handlebar in the clamps by gently sliding the bar so the markings are even on both sides. Then, rotate the bar to your desired position. We like a neutral position, with the sweep of the bar coming straight back or slightly up and back.
Since the bike is on the ground, it’s a good time to double-check the headset is snug. With the front brake applied, rock the front end back and forth. If the headset is tight, it should be snug but not bind while steering. If you feel a knocking, you may need to add another spacer or trim down the steerer tube.
Tighten the grips into place. Remember that these small lock-on bolts are very low torque. Follow the torque ratings closely or risk a stripped out bolt head later.
With the bar properly positioned, tighten the faceplate to the recommended torque. Our Renthal stem required 5 newton meters on all bolts.
Now it’s time to set up the rest of the controls. We like to scoot the brake levers in slightly to ensure our fingers hit the hook of the brake levers for the most leverage. This is usually about 1 inch, or 25 millimeters, in from the grip. We like to use a ruler to ensure they are even on both sides.
Now, sight the level of the levers from behind the bike, ensuring they are even, and tighten the bolts down. This is another low- torque set of bolts that are best tightened with a torque wrench.
Finally, it’s time to tighten the stem down to the steerer tube. It’s often difficult to get the stem straight the first try. We recommend using the front wheel or front axle as a guide, and then torquing the bolts down. Once you feel it’s straight, take the bike for a quick spin around the block. You may feel right away the stem is crooked. If that’s the case, loosen the bolts, re-align and try it again. Once you’re satisfied, it’s time to go hit the trails.
THERE ARE SO MANY WAYS TO GET MOUNTAIN BIKE ACTION
Mountain Bike Action is a monthly magazine devoted to all things mountain biking (yes, that’s 12 times a year because we never take a month off of mountain biking). It has been around since 1986 and we’re still having fun. S