If you adhere to this advice then your frame should provide you with a large range of adjustment at the seatpost, which is important for finding your optimum mountain bike seat height. It also highlights how crucial sitting on different sizes of your prospective purchase is. The majority of mountain bikes have mm or mm cranks, which do the job perfectly well for most riders. Another important consideration is the top tube length. Together with seat height, stem length and handlebar position, top tube length dictates the comfort and efficiency of your body on the bike.
To confuse matters further, the aspect of top tube length that matters is not the top tube itself, which often slopes, but the reach number. A cross-country rider may prefer a long, stretched-out position, but a beginner who has never taken a bike off-road may want to be more upright for extra comfort, with less weight on their hands and wrists. Find what works best for you, but avoid being too hunched or too stretched out, since this can cause discomfort and back problems.
The cranks or bottom bracket are never situated directly below the saddle, and for good reason. The upshot of this is that you can have two bikes with the same reach that handle differently, due to how they distribute your weight. One of the biggest mistakes made by beginners is to slide the saddle too far back. This is all assuming that the reach is correct for you. As a general rule of thumb, if you drop a plumb line from the centre of the saddle it should cross the chainstays almost exactly half way between the bottom bracket axle and the rear wheel axle.
However, clipless pedals can be more problematic to get right. See what works best for you. This can take a few rides but is worth persevering with — when you hit that sweet spot, draw a line around the cleats for reference when they need replacing. The bikes are usually sized by their wheel diameter, from 12in up to 26in. As with an adult, top tube clearance and reach are very important. Take a look at the controls: can they reach and operate them effectively?
Take a look at the shifters too: are they struggling to push a thumb lever? Gears and cranks are also often overlooked, with a considerable number of bikes sporting adult length cranks and full-sized chainrings.
In other words, you may just need to ride more and do some core muscle training to work things out. Although everyone is different — some folks may have longer legs and a shorter torso, while others may have long arms and short legs — starting with the correct-sized frame allows you to further tune the position using stem, bar, seatpost and saddle tweaks.
The saddle is at the right height when your heel just touches the top of the lower pedal with your leg straight; your crank should be right at the bottom of its stroke. If you have to tilt to one side on the saddle to achieve this position then the saddle is too high. Place your foot on the pedal in the ready-to-pedal position. If your leg was straight with your heel on the pedal it should be slightly bent at the knee in a pedalling position.
As a rule, start with your saddle as level as possible on the top. Some have set-back clamps, others have clamps in line with the top of the post. If you have access to different stem lengths and different shaped handlebars, experiment with different ride positions, adjusting your saddle accordingly.
Arm, leg and torso length will vary between riders of the same height, and body weight distribution can have a major bearing on setup.
How high you have your bars is a function of stack height, steerer tube length and the amount of adjustment spacers on it , stem height and rise, and handlebar rise.
Brake levers and gear shifters can be put in different positions on the bar. On most brakes you can adjust lever reach too, and on some you can adjust the point of contact where the brakes compress the pads.
We know riders who put up with their thumbs rubbing on their gear shifters for years before realising that setting them half an inch further inboard on the bars solves the problem without making them harder to use.
Bar width can be trimmed too: cutting an inch off either end of a handlebar might make a difference to your ride comfort.
Equally, you might benefit from better control with a wider bar. Swivelling bars a few degrees back or forth in the stem can also make a difference.
Tyres: Tyre compounds, as well as pressures, will affect the way a bike feels on the trail. Cleverly treaded dual compound tyres with a high TPI threads per inch carcass construction will generally deform more over rough terrain, and so grip better, without any increase in rolling resistance.
Cheaply made tyres tend to grip less and are more prone to losing traction when under pressure, especially in wet conditions. Find out what grips top our list of favourites here. Saddle: The right sort of surface material and the right sort of padding on a saddle is obviously going to make a huge difference to the way you feel about your bike. Slimline saddles with minimal padding in just the right places are often more comfy than big bouncy affairs, which will often chafe after a while.
Check out our saddle reviews to find the best one for you. But read instructions carefully when it comes to cleat position because poorly positioned cleats can cause problems, especially with knees. Find out which pedals score the highest in our comprehensive mountain bike pedals best list. Your tyres, suspension fork and rear shock effectively provide an adjustable cushion between your bike and the ground. Setting them up properly is crucial to your overall control and comfort.
There is no hard-hitting rule. It is not a good idea to select just one frame size and filter the results by that; select the frame size the brand recommends and also the size above. The thing to bare in mind when going up a frame size his to make sure there is sufficient standover clearance. The internet is only useful if you know where to start.
The problem is that bikes have always been sized by the length of their seat tubes. The modern move away from frame sizes being listed in numbers of inches has been an improvement.
Reach is the distance between the bottom bracket axle and centre of the top of the head tube. See diagram above. Thankfully any bike brand worth its salt includes a reach measurement on the geometry charts of its bikes. Why is reach the vital thing? Because it dictates how the bike actually fits you. It governs if a bike is too cramped or too stretched out for you. And, unlike seat tube length, reach cannot be adjusted for. You can adjust your saddle height up or down to accommodate seat tube length.
Reach cannot be adjusted. A bike with too short a reach will always be too small. Changing stem length will impair how the bike steers and handles. Check out red blob no. Pic from Kona Bikes. What is standover? Standover is arguably a more helpful version of seat tube length sizing. See the pic above. You do need to measure your inside leg though, as this will tell you if the bike has enough standover for you.
The above recommendations may startle some people who are used to traditional advice. Things have changed.
0コメント