Harry Orr explains why less isn’t always more when it comes to weight as he looks at the risk vs reward of dropping grams.
A WEIGHT-WEENIE IS
someone who strongly considers the weight of a mountain bike or its components with every purchase decision they make. Those on the extreme end of the spectrum regard weight as the highest priority, while moderate weight-weenies may consider weight after durability and capability. A smart weight-weenie uses critical thought and advice from experienced riders to assess the risk to reward ratio when reducing the weight of their mountain bike.
WHY WEIGHT?
Why is weight the most analysed aspect of the bicycle? For two main reasons.
Cyclists believe that less is more. But more of what, more speed or more problems? Weight is (unfortunately) very easy to quantify. Simply hang the bike on a scale and see a two-digit number.
Lower bike weight can certainly increase your riding speed, especially uphill, but also means more problems, more maintenance, more waste, more risk and more fatigue… which sounds like it could mean less speed in reality.
Ironically more important aspects such as geometry or suspension dynamics require lots of numbers in tables and graphs to quantify, making weight an easier go-to unit of comparison in the bike shop and the coffee shop – one that often leads to poor purchase decisions.
So, let’s become smart weight-weenies and assess at the components of a mountain bike by thinking critically about where reducing weight makes most sense for our riding style.
RISK VS REWARD
Every decision involves a tradeoff, and therein lies the safe balance of risk and reward which we hope to achieve. Various rider profiles will have different goals, so we’ll speak for the biggest group of mountain bikers in South Africa – the endurance ‘weekend warriors’ who may train two or three times per week in preparation for single- or multi-day events
bi-annually. Those who most of all enjoy the fresh air, the trails and the benefits of staying healthy.
FRAME
A lighter frame is not an upgrade decision but the main purchase decision. All other components will wear out or be upgraded over the lifetime of the frame, which is generally 5-10 years for performance mountain bikes.
In a previous article about mountain bike geometry (Autumn 2021 issue) we discussed the concept of rotational, unsprung and sprung weight, by identifying how components move while you ride. Do they spin fast, move up and down, or stay calmly suspended above the suspension? As example in a full suspension bike, the rear triangle moves up and down over bumps, but the main frame triangle stays calm, sprung between front and rear suspension, just as a passenger in a vehicle is isolated from an uneven road.
When bike shopping, we usually lift the bike to feel its (static) weight and often put too much emphasis on this basic assessment. Knowing that the bike frame is mostly sprung weight, it wouldn’t be smart to save weight here first.
Before deciding on a carbon vs alloy frame, choose the right frame geometry for your riding style. Consider geometry numbers such as stack and reach, head and seat tube angles and suspension travel, before frame weight.
WHEELS
Reducing weight in wheels is (usually) a smart move. They make a big difference to your riding experience because they spin and move up and down over bumps (rotational and unsprung weight). But there’s an important risk vs reward trade-off here. Heavy or aggressive riders need stronger wheels with more spokes (eg, 32). Lighter, less aggressive riders can upgrade to lighter wheels with fewer/thinner spokes (eg, 28) without durability issues.
MTB wheels and tyres are a system that must be paired well. Bigger volume tyres are becoming the norm for XC/marathon events and require wider tubeless specific rims to prevent ‘burping’. This could result in a wheel upgrade to heavier rims. For example, upgrading from 23mm to 30mm (inner width) rims will be safer, faster and more fun for riders who play on the trails. This is where carbon comes in. Carbon has allowed wider rims to be as light as narrow alloy ones, while being just as strong, so they’re a great upgrade, as long as the hubs are worthy…
My number 1 upgrade tip for wheels (described in the Summer 2021 issue) was about hubs. High-quality hubs aren’t much lighter than generic ones but have vastly improved performance and durability. So always choose wheels with high-quality hubs and then
upgrade your rims and spokes over time to match your tyre choice and riding style.
TYRES
Tyres are a lot more important than most riders realise. But if you consider that they’re the only part of the entire bike that touches the ground, then they’re fully responsible for acceleration, braking and cornering by keeping us rolling safely. However, many brands ‘cheat’ with tyres to win the sale. They often specify very light (sometimes nontubeless) tyres on mountain bikes to reduce the data sheet weight and win customers in the ‘shop floor weight test’.
For any mountain biking other than riding gravel roads (there are now gravel bikes for that) upgrading tyres can mean heavier tyres with reinforced sidewalls. Tubeless tyres have saved us from trail-side frustration, but tyres without reinforced sidewalls can suffer cuts too big for sealant and plugs to repair. Reinforced tyres also allow lower tyre pressures for more grip, comfort and therefore speed.
The only time I’d suggest saving weight on tyres is if you enjoy the geometry and comfort of a longer travel trail bike, but don’t need the big knobbly tyres for your local smooth trails. Then certainly some lower profile XC tyres (with reinforcement) will allow you to carry more speed on smooth terrain and climb the hills with less effort.
BRAKES
Saving weight on brakes is not smart. To go faster you need more confidence in your brakes, period. So generally, a brake upgrade won’t lower your bike’s weight, unless you go super fancy.
Four-piston callipers weigh more than two-piston callipers that are usually stock on XC bikes, but the increased stopping power of stronger brakes (and bigger rotors) can often add more speed to your ride than going from an alloy to carbon frame for example.
If you’re an extreme weightweenie, you can switch out a few steel bolts with titanium ones, such as rotor bolts and brake lever clamps. But those are expensive marginal gains. Rather buy new brake pads and ensure the braking system is well bled for a sharp and consistent lever feel.
DRIVETRAIN
There is a lot of hype around fancy groupsets with exotic materials and flashy graphics costing a lot more money than mid-range groupsets. But the gains are more about improved ‘shift feel’ than speed and weight benefit. Except for two main components, the cassette and crankset. Not coincidentally, they’re also the two components that spin while you ride (rotational weight) and the heaviest items of a groupset. Making them low-hanging fruit for smart weight-weenies.
The cassette is also unsprung weight, moving up and down over each bump, whereas the crankset is central on the suspended main frame. Switching from an entry level cassette to a top-tier option can save almost 300g! Way more effective than a 300g saving on components that don’t spin or bounce.
SUSPENSION FORKS
Can you save weight on suspension? Yes. Is it smart? Mostly, yes. Often mid- and even upper-tier mountain bikes come with suspension that looks just like the fancy stuff on the outside, but inside there’s a lot of unseen added weight. So, upgrading the stock fork will certainly improve ride feel and confidence while also dropping weight.
Fox adapted its 34 trail fork with lighter stepped lowers for the new genre of ‘down-country’ bikes. That saves about 200g over the regular version, which is significant because the fork is moving constantly while riding, and there is no safety risk to the lower weight.
It’s possible to save even more weight by changing to a skinny tubed XC fork such as the Rockshox SID or Fox 32, but that wouldn’t be smart for riders who enjoy jumping or rock gardens, because the flex makes steering less accurate and lowers rider confidence, therefore reducing speed.
SADDLE & SEATPOST
Which is better, a super light carbon seatpost of 200g or a dropper seatpost of 600g? 400g is a huge difference, but the dropper post will add more speed, fun and safety to any mountain bike. Recently a few brands have developed lighter dropper posts, which make sense for XC riders who only need a short drop of 100mm for example. But for playful riders, the more drop the better!
Saddles are a counter intuitive component of the bicycle, since many beginner riders
assume that bigger, more padded saddles are more comfortable, but generally the opposite is true. Therefore saving weight with a minimally padded saddle that matches the width of your ‘sit bones’ (get a proper fit done at good bike shops) is a smart weight-weenie move.
HANDLEBAR & STEM
The handlebar can also be low-hanging fruit for weightweenies, except if they choose
a narrower bar to achieve that saving. MTB handlebars have become a lot wider in the last
decade, from 56cm to 76cm, an extra 10cm each side!
Some bike brands take shortcuts with handlebars because customers don’t bother weighing them. So, upgrading to a high-quality alloy or carbon bar is smart, as long as they’re from a
reputable brand in a suitable width for your body and riding style.
Mountain bike stems have done the opposite of handlebars, they’ve halved in length over the last decade, from 10cm to 5cm on average, meaning there’s less weight savings to be had with stems.
Yet weight-weenies often choose to switch the standard steel bolts to titanium ones. This is a high-risk-low-reward decision because a stem bolt failure can lead to serious injury, so be smart about this one. Titanium is not as strong as steel and not all titanium bolts are created equal. Rather look to non-critical components to save weight with titanium hardware.
SPARE & TOOLS
Carrying spares and tools on your body and bike often feels like a waste because we usually don’t need them. And when we do, there’s usually one guy in the group who always has a spare tube and pump to help us out, so let him suffer and enjoy your weight-weenie bliss! But seriously, tool technology has become very smart and well-integrated into modern mountain bikes, so there are no excuses to rely on others any more. Visit your local
bike store to see what cool (but functional) tools are available to fit into the empty spaces of your bike. You may be surprised to achieve significant weight savings from your current saddle bag or hydration pack stash.
AT A GLANCE
Smart weightweenie:
Wheels
Saddles
Cassette
Crankset
Handlebars
Tools
Suspension
Risky weightweenie:
Tyres
Brakes
Stem bolts
Seatpost
Frame
