How To Change Your Threadless Bike Stem
Fit adjustment and weight savings are the two most common reasons for installing a new stem. Swap in a super light stem to shave grams, or change stem length to achieve a more comfortable riding position, by either lengthening or shortening the distance you must reach to grasp your handlebars. Just remember, that it’s best to consult a fit specialist before changing your bike’s stem length.
Here are step-by-step instructions for installing a new stem. The only tools you’ll need are a set of Allen wrenches.
1. Remove your handlebars from your old stem, using the correct sized Allen wrench to loosen the face plate bolts in the front of your stem. Hold your bars when removing the last bolt, otherwise they will fall. Once all the bolts are removed, let you handlebars dangle in front of the stem.
2. Using the correct sized Allen wrench, remove the stem. Start by first loosening (not fully removing) the stem clamp bolts. Next, loosen the top cap bolt, and remove the top cap as well as any spacers. Now slide the stem off your bike.
3. Next, slide on the new stem and any spacers you removed. Don’t worry about alignment yet, but do remember that when putting the spacers back, leave at least a 3mm gap to allow room for the top cap to be put back on.
4. Put the top cap back on, hand tightening the bolt until it’s slightly snug. Also, snug one stem clamp bolt just to keep things from moving around too much.
5. Remove the face plate from the new stem and put the handlebars back in place. Snug, but don’t tighten the face plate bolts, then center the handlebars inside the stem. In some cases, there will be indicator marks on the bars showing their center point. Once centered, tighten the face plate bolts, being mindful that you must tighten these bolts incrementally so that they cinch equally. You’ll know you’ve done it right if the gap between the face plate and the stem is equal on the top and bottom.
6. Next, fine-tune headset adjustment. Start by removing your bike from the work stand, if you are using one. Then loosen the stem bolts and line up the stem with the front wheel. Now tighten the stem cap bolt, then one of the stem bolts.
7. Hold your front brake and rock the bike back and forth, while at the same time, placing your finger at the intersection of the top tube and head tube, to see if you feel any movement. If you do feel movement, the headset is loose and you need to tighten the stem cap bolt more. To do this, loosen the stem bolt, and then tighten down the stem cap bolt about a quarter turn. Again, make sure everything is lined up properly, then tighten stem bolt again and repeat the rocking test. If the movement is gone, do one final test by picking up the bike and making sure that the handlebars turn freely with no friction. If the bars feel too tight, slightly loosen the stem cap and check again.
8. Once everything is lined up and properly tightened, make sure your handlebars are angled correctly. To do this, slightly loosen the face plate bolts until the handlebars will rotate up and down. Now move them into your preferred riding position. Some cyclists favor a low angle position because it’s more aero. Others prefer an upright position for increased comfort.
If you have any questions about installing a threadless stem, call the Performance Bicycle Spin Doctor product support line at 1-800-553-TECH. Happy riding.Bike Parts and Components