Air Or Coil?  And What's The Difference?

Air Or Coil? And What's The Difference?

Air or Coil Shock?

Over the past few years and following in the footsteps of the growth of Enduro racing we’ve seen an increase in the number of coil shocks around on Enduro and Trail Bikes.

Is it as simple as Air shocks are lighter and Coil shocks are more hardcore?  Let’s take a brief look and see if we can debunk some of the noise.



Let’s take a look at the pros and cons of Air Shocks to begin with.

The big plus with an air shock is it’s tuneability. If you like to change your setup and/or carry extra gear for long rides, you may need the adjustability to tune your spring rate or progression. This can be done fairly easily with the addition/reduction of volume spacers and fine tuning the air pressures. 

They are also lighter than their coil adversary, making them ideal for races/riding with lots of pedalling/climbing or with less big hits and more smooth terrain.

On the downside they require more seals. This creates friction. Friction is bad! It means less sensitivity and it generates heat. Air also expands and contracts in temperature changes.

Interestingly enough, as pointed out by Jesse Mellamed this weekend at Zermatt, at altitude the fact they have air in them means that they may perform slightly less consistently (think about how cold it is at the top - so oil is thicker and air pressure drops - and then the shock heats up on the long decent to a warmer climate lower down - oil is now thinner and air pressure increases), so bear that in mind if you’re planning some big alpine riding.

Another factor leading to more heat build up on an air shock, often overlooked, is the insulation the air spring provides. Think of it a bit like double glazing – the air sleeve is holding a pocket of air around a large proportion of the dampers surface area, reducing the transfer of heat to the atmosphere.



Coil Shocks for the win?

Simplicity is always good right?  Well a coil shock offers fairly straightforward setup, you just need to find the right spring for your weight, riding style and bike, then it’s kind of fit and forget territory (as long as you don’t add/subtract too much riding weight for long/short rides).  One of the often-overlooked advantages of coil shocks is their improved feel over small bumps, less seals means less friction. This increases grip and ensures the rear wheel holds the ground better for improved control.

photo credit - Sarah Barrett Photography

As there are less seals and the damper has more cooling surface area, the coil works better in longer descents as it manages heat better. And, within the operating temperature of a shock, a coil spring will remain consistent regardless of temperature. There’s also less to go wrong – coil springs rarely fail and, other than cleaning, don’t require servicing or regular replacement.

On the downside, coil shocks are heavier. Although that being said, most enduro tracks these days are akin to old school downhill tracks, so the added grip and reliability of coil could outweigh the weight!

Depending on your bike, fitting a different spring rate may be time consuming. And most importantly, the linear rate of a conventional coil spring may not work for bikes with a linear leverage curve. However, we’re seeing more progressive coil springs and bottom out control systems becoming available, with more on the way – watch this space!



In Conclusion

Many publications have run side by side testing and all have slightly differing results, but the consensus we found whilst researching this, was that the coil shock was better on gnarly and/or long descents, and in conditions where grip levels were low, and gave the rider less fatigue on rough terrain. But, in high grip conditions, did sometimes leave them slightly short on feel, whilst the air shock gave more feedback to the rider, afforded them more tweaks to fine tune the feel and allowed them increased bottoming resistance that couldn’t be achieved by a coil spring (pre-progressive spring availability).

photo credit - Sarah Barrett Photography

So in conclusion, we’d recommend speaking to us first.  We can discuss your riding style, typical terrain and bike setup and help you pick the shock which will work best for you.  We carry a great mix of Coil and Air shocks as well as upgrade parts from the likes of Ohlins, Cane Creek, Fox, MarzocchiMRP and Rockshox  Having worked with hundreds (if not thousands) of riders over the years, we’ve seen our fair share of riding styles and with our data logging equipment we’ve mapped the setups of multiple bike setup variations, to help us fine tune your ride.  On all shocks we sell we fully strip & tune your chosen shock to get you out riding with confidence and style.

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