The following came about after an email from a confused/frustrated rider. He was having some issues concerning the handlebar height of his bike and was also the victim of some bad riding-advice from arguably the most common source of bad riding-advice: a riding buddy!
This particular rider was setting a bike up for lift accessed/downhill bike-park riding. Though riding bikes that are set up exclusively for downhilling are obviously not what the majority of MTB riders ride, learning how to descend with more control and faster are often the main reasons people seek MTB skills instruction/coaching. Even though the following pertains to downhill oriented riding, the same principles apply in setting up any MTB where having control on descents is a priority and/or necessity.
This rider stated that he had always been mainly an XC rider and had always previously set his bar height slightly lower then his saddle height (probably setting saddle height first in order to get proper leg extension while pedaling). But understanding proper descending position (on this bike his seat would be low and he would be standing when using the bike as intended), this meant that the seat was no longer a good gauge for bar height. He knew that he didn’t want to be reaching out and down too much (getting arms too extended) when the trail got steep, but he also knew that many downhillers were riding flat or nearly flat bars (no or very little rise) in an attempt to keep the bars quite low. He said his friend told him that downhillers do this in order to ride with more weight on the front of the bike. So this is where we’ll pick up the story…
…Bar height is a concern among many riders and setting proper bar height is the first place many riders want to start when setting up a new bike. But what many riders don’t understand is that bike set-up—first and foremost—should about body position and weight placement on the bike. This means maintaining an athletic position so that the body can function optimally in an athletic sense. (And, keep in mind, the focus of this article deals with control oriented riding, or riding MTB’s in tough technical terrain where control is paramount. In other words, riding mountain bikes in the nasty stuff! XC racing or road racing will have more emphasis on pedaling efficiency and power delivery when it comes to bike set-up, over the ability to control or handle the bike.)
First, we have to understand that all movements of the body originate at the core. A rider is in big trouble if the core is not a stable and balanced platform from which these movements can originate. Your body is a kinetic chain; maintaining this position of stability is priority; the position of your bars ultimately will be determined by the position of your body/core.
Now, whether you choose to weight the front of the bike or not (I’m not a big fan of this. Keep reading and see why.), everything needs to start off in a neutral and balanced position (that means a balanced core) with your weight on your legs and off of your hands/arms. Your legs play many important roles in human movement: support the body’s mass, supply balance, and are really are what should be powering and controlling the bike in many situations. (We get way into the how and why of this during instruction). Your arms are great at supplying small and precise movements and manipulations of bike, but not very good at balance and power especially compared to the legs; and, they don’t work well when they are weighted down by your body mass. This all has to come into play when setting the controls for one’s bike.
In regards to weighting the front of the bike, this really should be an adjustment that is made and used only when necessary (usually after you’ve made a mistake–often having your weight too far back–and the front wheel is doing something that you don’t want it to do, probably sliding or pushing). The rider’s default position should start out neutral (weight on feet, balanced over bottom bracket). One reason for this is because you may have to un-weight the front of the bike half way through a corner or a rock garden. When done properly, this is done primarily with the legs (check out this video on the manual, or coaster wheelie). If you do get your weight up onto your hands, it may be very difficult, if not impossible—because your arms really aren’t very strong when it comes to supporting body mass—to then get the weight off of your hands and, thus, off of the front end if the bike…and this, as we all know, could spell disaster! (Imagine a large root or rock ledge half way through the corner but obscured until the last second). Once you commit to weighting the front end of the bike (supporting your mass with your arms; and thus, trying to control your body mass, the mass and movements of the bike, the forces of the trail, etc, with the upper body) you give up your body’s most effective tools in balance and support (your legs), AND you give up your ability to effectively manipulate the bike because your upper body is tied up supporting your mass.
You also will have to adjust lean angles through corners, perhaps dodge trees, etc., and the arms are only able to provide adjustments and manipulations effectively if they are NOT weighted down by the body’s mass. Try this: stand straddling your bike with your feet on the ground. [good example of this exercise at 2:32 of this video]. Now, get all your weight up on your hands and the bars. Get up on the very tips of the front of your shoes/toes so as much weight as possible is on your hands. Now try to make small, micro-adjustments and manipulations of the bars/bike with all your body mass supported on your hands. Notice how this is tough to do: the movements are large and not very precise. (Not to mention, this is tiring and one will fatigue real quick if this is the position that they ride in). Now, simply put ALL of your weight back onto your feet. Now try to make those same micro-adjustments and precise movements with your arms/hands/bars. Notice how much more control you have of these precise movements and subtle manipulations (and how this is way less tiring!). This is how your body is meant to work: mass supported, balanced, and transported by the lower body, thus, freeing the upper body to perform other tasks.
Again, weighting the front end should be an adjustment, not a default position or a riding style…and should be used as sparingly as possible.
I’ve heard many riders in both MTB and motocross proclaim that they ride with a lot of weight on the front of the bike. Studying their riding styles, watching video, etc, I can emphatically say that this is not what they are doing. There are exceptions to every rule and always are a few outliers, however, ALL of these top riders are remaining centered and neutral—with their mass supported by their legs—the majority of the time.
To provide proper position—and a balanced and stable core—your limbs basically have to be half way through a squat and half way through a push-up, with ALL your weight on your feet. This is the athletic position of the human body and MTB is an athletic endeavor. You now have supplied maximum range of motion, in any direction, from all of your limbs and your core is properly “suspended”. From this position, you are able to react, pro-act, etc, with movement in any direction. Any decent motocross school and/or decent MTB skills instruction should teach this (this is also body movement 101).
And that takes us back to bar height and bar position: bars too far forward (too low–away from you) means giving up the bend in your arms (range of motion) and your weight will end up tossed (bucked) forward onto your hands (example: if your arms are already straight, and your front wheel has to drop a foot, your core is going to have to go forward with the bike as the front end drops and your weight will be thrown onto your hands). Bad news… Bars too high and your arms will be all cramped up/bunched up in your chest and you won’t be able to manipulate the bike effectively, thus you’ll start to lean back to get your arms in a better position and then you’ll be too far off the back, giving up the balanced, stable, and neutral position (this is one reason why you shouldn’t lean back on descents, but instead stay neutral by continuing to keep your weight on our feet and over the bottom bracket). Muscles function best (strength, reaction time, balance) when the muscle belly is half contracted…this is another reason why the half push-up, half squat is the most effective athletic position for the human body (Think: tennis player, baseball shortstop, middle linebacker, etc…)
So, wherever your bars end up when you’re in this position…that is the proper bar height.
I’m sure you noticed that I haven’t given you an exact measurement or number on that bar height! Obviously, they can’t be perfect all the time because you should have a dynamic relationship with your bike: your core should remain stable and static while your bike will move—often quite a bit—underneath you: on super-steep descents, they may be a bit too low; on a fairly flat track they may be a bit too high. There’s nothing wrong with making height adjustments depending on where and what you’re riding; the difference between even 5 mm can really be felt if you’re in tune with your bike; 15, 20 mm’s is a huge difference. Play around with the spacer stack height of your stem. I always start out with at least 25 mm of spacers, that way, I have plenty of room to move the bars up and down when necessary.
So, really, it doesn’t START at the bars, but it’s more like where do the bars END UP when your body is properly positioned on the bike? That is the optimal bar height.
Many riders also believe that if the bars are set-up to descend well, then they are too high for effective climbing. Not true. Proper climbing depends, again, on core position, not bar height or where a rider’s hands are located. I will admit that sometimes, at proper descending bar height, the cockpit starts to feel a bit cramped on long climbs, but the bar height shouldn’t drastically hinder one’s ability to climb. Again, adjustments can be made depending on what a rider’s priorities are. Having a travel adjustment on the fork is a great way to drop the front of the bike, lower the bars on long climbs and help out in the comfort department. I love this option on front suspension, especially with a longer travel bikes.