Mountain Bike Buyer's Guide

Mountain Bike Buyer's Guide

The first critical step in picking the right mountain bike is deciding how and where you plan to ride it. All the trails around Shreveport are XC (cross country) or single track routes. This article is limited only to the key decisions needed for these trails.

Your basic decisions will be:

• Hardtail or Full Suspension
• Wheel size
• Frame material

A hardtail mountain bike has a shock absorbed fork but no other suspension links. The principal advantage to these bikes versus the full suspension bikes is cost. Full suspension bikes can cost 3 times as much. Due to this premium the overwhelming majority of mountain bikes sold are hardtails. Some argument can be made about hardtails’ increased pedaling efficiency, especially during climbs, but that argument loses more steam every year as the active suspension parts of the full suspension bikes improve.

A full suspension mountain bike has both the front and rear wheel motion isolated from shock as the rider engages bumps and other obstacles on the trail. Full suspension bikes provide much better control and comfort than hardtails. Test after test reveal that reduced rider fatigue more than offsets any slight loss of pedaling efficiency. A longer or rougher ride will magnify the fatigue effect. Full suspension bikes put the wheels back on the ground quicker than hardtails so the rider enjoys increased control and confidence.

The shock absorbers in the fork or the rear triangle come in 3 primary designs: elastomeric, coil spring and air spring. These are in order of good, better, best – both in performance and cost. Elastomeric shocks are the lowest cost and offer very little adjustability. A heavier rider may find that he “bottoms out” while a lighter rider may sense too little shock isolation. Coil springs offer better adjustability but are still somewhat limited. Often they can be modified by a certified shop to change the spring rate for a heavier or lighter rider, but the spring rate will still be linear. Incrementally more force will result in proportionally more incremental travel. Control and confidence over big bumps will be compromised. Air sprung shocks contain an air chamber that is pressurized based on the rider weight. You can actually customize the travel of your shock absorbers as you deem fit. Furthermore most air shocks have non-linear air chambers so incremental increases in force will result in less than proportional increases in travel making bottoming out less likely. Some even employ an inertial valve to set threshold levels of force to make the shock move at all. The intent is to increase pedaling efficiency over minor bumps while retaining shock absorption over more significant ones. The better shocks also offer hydraulic dampening which controls the wheel’s rate of return to the ground after a bump.

If that rate is too slow, you may hit the next bump before the wheel has fully extended and experience more impact than you wished. If the rate is too fast you might think you’re on a pogo stick rather than a fully-suspended mountain bike.

Designs of rear suspension are another variable with choices such as Single Pivot, Virtual Pivot Point (VPP), Maestro, Active Braking Pivot (ABP), Instantaneous Pivot Point (IPP) and Future Shock Rear (FSR) suspension. The distinctions of these designs are beyond this document but we would be glad to discuss the pros and cons of each with you in the store.

Wheels come in 3 diameters: 26 inches, 27.5 inches (which is really closer to 28 inches) and 29 inches. The key features effected by wheel size are weight (smaller diameter wheels weigh less), acceleration (smaller diameter wheels accelerate faster since they weigh less), angle of attack (larger diameter wheels have lower angles of attack and thus less impact over bumps on the trail), contact patch (larger diameter wheels have larger patches of the tire in contact with the ground and therefore greater control), strength (smaller diameter wheels are inherently stronger) and manageability (larger diameter wheels may feel gangly to smaller riders while smaller diameter wheels may be dissatisfying to taller riders). Although historically mountain bikes predominantly used 26-inch wheels, bikes with 29-inch wheels now dominate. Bikes with 27.5-inch wheels are somewhat new on the scene and offer many advantages for certain riders. They weigh and accelerate much like 26-inch wheels yet have angles of attact and contact patches very similar to 29-inch wheels. Already 27.5-inch wheels out sell 26-inch wheels. Rider size, weight and riding style will determine which wheel size will be best.

There is no question that carbon is better than aluminum. Design engineers can manipulate tubing shape and characteristics (compliance, stiffness, elasticity, etc.) to achieve the ride quality and performance they desire. Metal tubing is less amenable to such manipulations. Carbon can be designed to nearly eliminate torsional flexure (to increase pedaling efficiency) yet retain mild levels of vertical compliance (ride comfort). Carbon is somewhat lighter but the choice for carbon should be based on its performance advantages other than weight reduction. Carbon’s only drawback is cost – and that’s becoming less and less of an objection each year. The difference between a high quality aluminum bike and a low cost carbon bike is now less than $1000.

Beyond this the more you pay for your bike the better it gets. You can select higher grades of framing material (lighter and stiffer), lower friction and lighter components (wheels, shifters, derailleurs, etc.) and nice accessories (powerful lights, dropper seat posts, computers, etc.).

There’s a lot to be considered. Your best chance at getting it all right is to visit a bike shop with informed staff that can help you identify the best model/size for your specific needs and desired experience. No one does it better than The Bike Pedaler in Shreveport. Please come in and let us prove it to you.