In reality, the only way to truly know how a mountain- bike tyre will handle is to ride it over a few days. But there’s some sound theory on profile, volume, tread pattern and knob locations. Here are a few pointers to help predict how a tyre will behave. - By Neil Gardiner

A narrower tyre cuts into the loose surfaces to get to the grippy stuff.
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Long knobs positioned lengthwise cut into the looser, loamier surfaces.

Closely positioned centre knobs generally ensure lower rolling resistance – a flatter contact point on the trail.

In most conditions, higher-volume (or fatter) tyres offer better rolling resistance grip, as well as puncture resistance.

Closely-packed knobs featuring grooves provide more edges for grip – these knobs suit hardpack, but wear more quickly.

Wider gaps between knobs typically shed dirt and mud more effectively, but increase rolling resistance.

A sloping leading edge in the centre row of knobs results in lower rolling resistance.


Square knobs tend to ‘float’ on top of the looser surfaces – they’re more suited to gravel and loamy soil than other shapes are.

Higher-profile knobs on the edges cut into the trail, seeking the grippier layers underneath – though ‘breakaway’ can occur suddenly.

Stiffer sidewalls will hold the tyre’s shape better – remember that deformation of the profile causes loss of traction.

Billy Kanzler of Colnago America explains the benefits of disc brake road bikes and why Colnago designed the C59 disc road bike.

Always toss your valve-caps away as soon as you change a tyre? Here are nine reasons why you shouldn’t. – By the Bicycling Editors

1. They protect fragile presta valves from damage from rocks and branches.

2. They stop dirt and moisture from collecting around the head of the valve that can lead to jamming and seizing, especially in wet weather.

3. Presta valves include a rubber seal that perishes when exposed to air. Keeping the valve cap on increases the life span of the valve.

4. On tubeless MTB tyres, you rarely change the valve since it’s not connected to a tube. This makes preservation of the valve even more important. Replacing a valve on a tubeless system is frustrating since it’s often the last place you look for a leak.

5. Without the valve cap, dirt collects around the head of the valve and gets pushed into the valve unit during inflation. Dirt can wedge in the seal and can cause annoying slow punctures.

6. Schrader valves have large openings that allow for even more dirt to collect inside the valve unit if the valve caps aren’t used.

7. Pro teams don’t use valve covers because they have the benefit of back-up spares and full-time mechanics.

8. Valve covers can add bling to your bike. Colour co-ordinate your valve covers with your bike. There are plenty of unique, designer valve covers on the market that add a touch of fun to your steed, including LED versions.

9. When storing a tube, the valve caps protect the rest of the tube from being punctured by the presta valve when its folded up.

Choose the right  shades for your style. - By Emily Furia

Full-rim

Blocks dust and wind
Great for Prescription lens wearers, Hout Bay residents, Mark Cavendish
Not for Off-road riding

Half-rim

Vents perspiration, signals dedication
Great for Intervals, long rides, coffee shop posing
Not for Distinguishing yourself from the pack

Rimless

Optimum visibility
Great for Triathletes, hardcore commuters
Not for Coffee-shop rides, fashion mavens

Oversized

Screams star power
Great for Hipsters, Sandton housewives, Khanyi Mbau
Not for Weight weenies, interval workouts

Yellow lens

Brightens low-light conditions
Great for Mountain ­bikers, city-dwellers
Not for Fair-weather riders, the demure

Polarised lens

Cuts glare from ­pavement, water, clouds
Great  for Century riders, coastal residents
Not for Cash-strapped cyclists, retrogrouches

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Five ways to manage inflation. - By Tori Bortman

Whether it’s your first or 50th time using a floor pump, this basic piece of equipment can sometimes be downright frustrating – even though you’re doing every­thing right. Or are you? Try these tweaks to your tyre-pumping routine, to make the difference between blowing your gasket and inflating your tube.

Instinct
To position the valve stem at 6 o’clock when inflating.
Instead
Try 12 o’clock. You’ll have better control while getting the pump head or inflator on and off.
[Some pump-head levers push down to clamp; others pull up. Know yours. If you force it while in the clamped position, you can quickly ruin seals.]

Instinct
To hold the wheel (off the bike) with one hand and pump with the other
Instead
Lean the wheel against something — your leg, a wall. Using both hands to engage the entire stroke of the pump is twice as effective.
[Keep seals fresh and decrease friction by wiping the plunger with a thin layer of light oil every so often.]

Instinct
To assume that the washer on the valve of a new tube needs to be there
Instead
It’s there to stabilise the stem, but if it’s too tight it can rip the stem from the tube. Too loose, and it’ll rattle while you pedal. Ditch it when using a floor pump.

Instinct
To push down on the tyre when the valve recesses into the rim
Instead
Pinch the sidewalls together above the valve stem to stabilise the stem and make attaching your pump easier.

Instinct
To yank off the pump head once you’ve reached your desired psi
Instead
Place both thumbs under the mouth of the pump head, fingernails facing the rim, and push it straight off the valve in one quick motion.
[For a better fit between a new pump head and the stem, turn the mouth of the head counterclockwise, between a quarter and half a turn.]

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How to find the right frame and make adjustments for endless comfort.  - By Joe Lindsey

While there is no universal method for fitting a bicycle to the rider, fit theories do agree on most things, and proper training and equipment help bike-shop workers and fitters do their job consistently well. You’ll have an easier time shopping if you know a few benchmark measurements.

Start with figuring your frame size and seat height, and then, when you have the bike, determine your proper cleat placement, saddle position and handlebar reach, in that order. These are just a guide, it is advised to get a proper bike-fit done by a professional.

Reach to Handlebar
This is the most variable of all measurements, as it depends greatly on your flexibility. You want a slight angle at the elbow when your hands are on the hoods or drops, but you shouldn’t force yourself to bend double to get it. On a new bike, ask the shop to leave the steerer tube long and add 2 inches of spacers under the stem. Move the spacers above or below the stem to fine-tune your fit, and have the shop cut the steerer later, if needed.

Frame Size
In socks, place a thin hardcover book, spine up, between your legs with about the same upward pressure a saddle produces. Measure your inseam, from the book’s spine to the floor, in centimeters. Multiply that number by 0.65; the result is your approximate road frame size. For example, 81cm x 0.65 = 52.65-a 52 or 53cm frame (sizes are the seat-tube length). Note that compact sizing uses a virtual seat-tube length, so don’t go by the stated size unless it has the same virtual size. To convert to inch sizing, divide by 2.54. For mountain bikes, subtract 10-12cm from your road size.

Saddle Position
The front of your forward knee should be directly over the ball of your foot when the pedal is at the 3 o’clock position. Check this with a plumb line. If the line doesn’t pass the front of the pedal axle, move your seat forward or back on the rails until it does. Your seat should be level, or point at most a couple of degrees up or down. Check it with a carpenter’s level.

Seat Height
Your knee should have a slight bend in it at the bottom of your pedal stroke. (The bottom is when the crankarm is parallel to the seat tube, not perpendicular to the ground.) To check this, in cycling shoes, pedal unclipped with your heels on the pedals. You should barely maintain contact with the pedal at the bottom of the stroke, without rocking your pelvis. Measure the distance between the bottom bracket and the top of the seat. This is your seat height. It should be very close to the product of your inseam (in centimeters) multiplied by 0.883.

Cleat Placement
Mount your cleats on your shoes so that the ball of your foot is directly over the pedal spindle for maximum power transfer. Unless you have an unusual stride or stance (splayfoot, etc.), point the tips of the cleats at the tips of the shoes for a neutral pedaling stance to start out. Pay attention to your pedaling style on the first couple of rides and adjust as needed-this is one place where professional fit advice may be worth the cost to help avoid injury.