XC Cross Country Mountain Bike Setup for Racing Stem

rdo_stm

Question: How do I setup my XC MTB Cross Country mountain bicycle
stem, I am a beginner and I want to get up to speed fast.

-anonymous rider from CA-

Answer: Everybody’s setups are slightly different based on their body size, gender, equipment, height, weight, riding style, etc. but all the principles (tricks & tips) required to dial in the actual bike, are the same.

So that being said, we begin first with whether or not you will be competing in races, or are more about recreational riding.

This is important because it determines how aggressive your set up will be. Remember you can make adjustments to change your settings, or you can find a happy medium.

The Setup Tradeoff

Ascending:

In order to set up your bike more aggressively for example to climb very steep hills your stem will be slightly longer, the front of your seat titled down more and slid to a more forward setting, thus positioning your body (center of gravity) will be more forward to avoid the front end from rising.

Descending:

This complete opposite of the perfect set up for ascending, is used for agressive descending. While descending tough terrain, you want your stem shorter, the front of your seat pointed slightly higher and slid to a more rear setting so it is easier to position your body (center of gravity) more rearward, thus you can easily get behind the seat and position yourself over the rear tire.

Compromise:

This is the great trade off. I personally enjoy both climbing and descending on trails that are considered very difficult, aggressive cross country riding, bordering on free riding and DH many times.

My personal preference is to set my bike up slightly more aggressively for the downhill portions, while I use my body to greatly compromise on the climbs, as my body position is much more rearward and needs to be moved forward towards the edge of the seat closest to the handlebars.

I suggest, especially for beginners, select a neutral position, until you adapt a bit, have enough experience to actually determine what you prefer, and of course discover the types of trails you enjoy riding.
Let’s start with the stem. These days manufacturers are getting the lengths much better on the bikes they sell, but it is not uncommon to be in the minority and simply end up with a bike that has a stem too long for shorter people, or too short for the very tall, or Clydesdale type.

If it is close, may be give it a test run, but if it isn’t don’t mess around, or you will end up crashing, hurting yourself, and your new shiny bike.

Checking the XC MTB Stem Size on a Cross Country Mountain Bike

A Shorter stem allows you to turn the handlebars faster, making the bike more twitchy.

In turn a longer stem decreases the responsiveness to turn the front end.

Many XC bikes have a very steep head angle of 70+ degrees, making the bike already very responsive to turning, so often a slightly longer stem can counter this while improving your ability to climb the steep stuff.

XC MTB Stem Check Steps:

  • Your seat should be in neutral position in the center
  • Have someone hold the bike in a static position
  • Are you reaching so far forward your chin feels to close to the bars, or it is a strain on your back or just feels awkward
  • The opposite may be true and you are in a very upright position, but the stem might be so short if you are very tall, that when you turn the front end, your elbows are or might hit your rib cage.
  • If the stem is really off, replace it with a shorter or longer size accordingly. This may even be an opportunity to improve its quality if it wasn’t that great, or negotiate a free replacement with your purchase.
  • If it seems like it might right and you want to test it more continue reading.
  • Take the bike outside on the street, ascending and descending.
  • If the stem still feels like it might be close, give it a shot on some mellow dirt fire roads.
  • Finally before a final decision can be made, the seat position must be evaluated, and the seat post angle must be considered if it isn’t a straight post.

XC MTB Stem Purchase:

There are two factors to consider, the length of the stem and the rise. Very short stems are generally more DH oriented, and longer stems are more for XC. These days, an XC stem is preferable due to weight considerations, and your options are aluminum or carbon.

Rise can help keep you more upright, and in a better position for descending, while lower rise and longer length work to keep your weight over the front tire for climbing. This really comes down to preference, but I have always preferred a moderate rise of 10-15 degrees, and at 5’7” I might run a 70mm for my riding style. If I was just going to climb stuff endlessly I might go 10 degrees and 90mm.

Note: Unless you are an experienced rider who knows how they like their setup, lot’s of things need to be adjusted in unisons to get everything dialed perfectly.

Again many bike manufacturers get things close these days, if you are purchasing a new bike form a store they can help, but I have found that you really should be armed with as much knowledge as you can before you let a 16 year old kid tell you how you should set up your $5,000+ XC MTB Race Bike. Even if he is an expert, he may not ride much cross country, or ride the trails you do. It is all about comfort and preference, these are things that allow a rider to excel., while minimizing crashing.

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