Q: I just installed a new cassette on my bike, but now my bike shifts worse than ever. What am I
A: This is a much more common problem than many realize. There are a few reasons that a new cassette could be offering less-than-ideal gear changes. First is that they might be sitting in a different position on the hub body than the old one. This can even be true if they are “the same on the label.” Just a few millimeters is all it takes to throw the shifting off, so verify that the limit screws are set to the new cassette. Now with the new limit-screw position you will need to adjust the cable tension. If it’s electronic, you may need to change the micro-adjust position.
If that does not remedy the problem, then you may have a much larger issue than you realized. As a cassette is used, it wears with the chain, also known as “chain stretch.” This also leads to the worn chainrings. The cassette, chain and rings wear together, and if the chain is too worn, it shouldn’t be used with a new cassette or chainrings. In reality, the three are now a permanent set and cannot be mixed with any others. They are worn out of spec, so if one is being replaced, the rest will need replacing, too.
As I have mentioned in the past, this is the importance of chain lube and regular maintenance. I would say that 70 percent of bikes that are having shifting problems have a worn-out chain. Park Tool and Unior both make a chain checker that I recommend. This tool can help in ensuring you don’t ride the components too long and wearing them out of the ability to reuse them.
Let’s say you get it working and it shifts good enough, the worn-out components will accelerate the wear of the new component, so don’t expect it to last anywhere as long as it should. It can also be dangerous, as the worn chain may not lock into the gears on the cassette the same and jump the teeth when under a heavy load. This could send the rider’s momentum forward, risking an over-the-bars incident, or I’ve even seen riders smash their face on the stem or bars.
If you are not sure which of these might be your case, then head to a local shop you trust and have a professional access the situation. Your drivetrain is one of the most important aspects of enjoying the bike, so don’t leave it to risk or mistake.
Q: I read your July tips and have been making a few changes to my position and setup. I am still having problems with my hands and feet going numb. What else should I consider?
A: As I mentioned in the July issue, most people do not prioritize leg position, but instead jump straight to reach and body position. Saddle position and cleat position are always the priority. In my years of helping people, one of the biggest problems is shoe size, which leads to cleat-position problems.
“The cassette, chain and rings wear together, and if the chain is too worn, it should be used with a new cassette or chainrings. In reality, the three are now a permanent set and cannot be mixed with any others.”
Many riders have the incorrect-size shoes (normally too big). This means the position where the cleat attaches is too far forward. This can make it very difficult to get the cleat in the correct position under the foot. It also means that under load and efforts, the foot can move in the shoe, changing the relative relationship the cleat has with the foot.
I would first and foremost make sure you have the correct-size shoe. This can be hard to tell when trying shoes on, because most are using stiff and lightweight materials that are restricting. This is even truer when they are new and have not had time to wear in.
If you feel like the shoe you have is correct, then positioning the cleat and using the correct cleat is next. Many
times I will see that the position of the cleat is correct, but they have too much or too little float. Too much float is less impactful on comfort and performance, but has the most effect when you are tired.
My last tip is to only make one change and stick with it for at least 5 to 10 rides. It will take your body some time to reset. The exception is if you have immediate pain or extreme discomfort. Make sure you record your changes and document the original position and hardware before making the changes. If none of this seems to do the trick, it’s time to visit a fitter that can analyze your specific needs and issues. They can target your problematic issues, and only there would I consider changing multiple things at once.