Coil Versus Air: The Great Debate

The move from coil to air shocks was a swift one when it came to light-weight cross country riding and the needs to shed grams, but with the emergence of more trail orientated riding and Enduro, the trend is starting to head back the other way. So why choose an air shock? Why choose a coil shock? We take a good hard look at the topic that may divide riders and give you our take on what squish should go where…

Back when mountain bikes only just started getting suspension and bar widths were still sub-700mm, all suspension was heavy. Coil sprung systems performed well but were markedly heavier than most riders wanted, so the air revolution began. The average coil shock would weigh in at nearly a kilo and dropping the weight to 250-300g with some air shocks, certainly made plain old fashion good sense. With the rise of enduro and all-mountain trail riding and the addition of lower gear ratios, the emphasis is no longer on how light you can get your bike; rather how hard will it pin down the trail and can you ride it back up again.

Air Shocks are still great for hitting gravity trails and boosting

With the change in focus for many riders, it only makes sense that coil shocks have started making a come back in a big way; is this the beginning of the end for air shocks? The simple answer is a hard and fast no, after all, last I checked air is pretty damn light and steel is not. Both suspension systems have their benefits and like many components that adorn our bikes, it’s going to come down to ride style, terrain, discipline and rider preference.

The Benefits of Air Shocks

Air shocks are not just simply lighter shocks and they are not just simply for cross-country riding or lighter riding. Air shocks can perform in the gnarliest conditions and are even being used on the World Cup DH circuit. The biggest benefit of air shocks is the shear tune-ability of the shock, no longer do you have to change a spring when you change rider weight, you can simply alter the air pressure to alter the sag, ride characteristics and responsiveness of the shock. The ease of adjustment of rebound, high speed compression, low speed compression and differing damper settings makes an air shock an appetizing dish on any riders menu.

The air spring in most modern shocks is also progressive as opposed to the linear spring rate of coil shocks, what does this mean? A linear shock may take say 200kg of pressure to compress through half of it’s travel, so would then hypothetically need 400kgs of pressure to reach the full extent of it’s travel; meaning that the spring compresses at exactly the same rate. A progressive air spring will need more pressure to compress the deeper it goes in it’s travel, for instance it may need 200kg of pressure to compress half of it’s travel but need hypothetically 600kg of pressure to compress 100% of it’s travel; meaning that the further it goes into it’s travel the harder it will be to compress. Air shocks are progressive in nature, and the addition or subtraction of volume spacers can make them more or less progressive.

When Coil Prevails

Coil shocks have been slapped on DH bikes since the beginning of the discipline and there has been a great load of success with coil sprung suspension. Is this the only place for them? Before we delve into that question lets take a good hard look at the pros and cons of Coil suspension systems.

Whilst coil might be heavier it also offers less resistance and greater tracking which translates into greater traction. Greater small bump sensitivity can be attributed to less resistance than air shocks and boosts grip on the trail. The lack of air shaft means that as the shock heats up the performance is not effected, so on long descents coil will keep performing the same all day long.

The downside to coil shocks is the weight, coming in 300-400g more than most air shocks; this might scare off the weight sensitive riders but lets be honest they probably don’t need a coil anyway. The other downside is the lack or progression and lack of adjustment when compared to an air shock; that being said most new coil shocks are being produced with more and more adjust-ability. Every rider will need a different spring depending on the rider weight so there are also some added costs there, but once you have the right spring, it can be a set and forget routine sometimes.

Which one suits me?

If you find yourself asking which shock is best for you, air or coil, then you must be riding some decent gravity trails. If you ride trails with not many features, a distinct lack of steeps and are as smooth as a dirt footpath…. then you should probably just stay with air and forget about, you’re probably over-biked already. If you are riding ‘Enduro’ or DH trails then a coil shock is definitely worth considering, especially if you are a heavy rider and like to hit big jumps and gnarly rock gardens.

Coil shocks are great for getting rowdy

Like anything in mountain biking, it all comes down to rider preference. The modern air shocks with piggy back systems are super capable suspension systems and some riders absolutely love the tune-ability of these shocks. Whilst the coil systems are getting lighter and lighter, the performance and adjust-ability is certainly there with the high end coil shocks. You need to ask yourself what trails you will be riding, what benefits you are looking for and what are you willing to sacrifice, weight, performance or versatility?

The Bottom Line

The bottom line is that both systems have benefits and both systems have weaknesses, it’s about what works best for your riding style and frame setup. If you are riding heavy trails with plenty of challenges then it’s worth considering which one will benefit you most. For us here at Brakes Wide Open it’s not a clear cut decision as we ride bikes with both systems, but we do love a coil shock!

If you are looking at changing up your suspension then do some research, consider your needs and if possible try out a coil shock if you know someone of a similar weight with the same bike!

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