So, you’ve bought a new mountain bike and it’s got the latest rear shock on it, with all kinds of letters and numbers after its name, and an RRP that would make you wince if you had to buy it aftermarket. That means your bike is going to work perfectly, right?
Wrong. What most people don’t realise is that the shock probably has a broad tune inside it that's designed to suit a wide range of riders, of different sizes, weights and riding styles. Almost a jack of all trades in shock absorber form. And like a jack of all trades, it may be master of none.
Companies like RockShox and Fox Racing Shox now offer a range of base shock tunes, which are designed to extract maximum performance from particular suspension designs and models of bike. Custom valving for a more specific feel is sometimes available too, depending on the shock.
But a bike company's idea of how a bike should feel may not match up to your own preferences. On the shop floor, a linear suspension curve feels plush, and plenty of low-speed compression damping gives a bob-free test ride. But out on the trail, more aggressive riders are likely to regularly bottom-out, and excess compression damping can choke the suspension and give a rough ride over smaller bumps.
If your new bike isn't giving you the ride you'd like, don't go straight out and spend a massive amount on component upgrades or a new shock – you could achieve a lot more by getting your existing damper tuned up. Custom tuning generally costs around £150 and it's one of the best ways of increasing your bike’s performance without spending a serious amount on something new and shiny. I've had some of my best rides on bikes with cheap shocks that have been tuned to the application (ie. the type of riding) and to myself as a rider.
Shimmy Shimmy Ya
I'm part of Mountain Biking UK's product testing Wrecking Crew and we've spent a lot of time with SRAM over the past year, working with our trail bikes and the new RockShox Monarch Plus shock to get the exact performance we were after. I first had a Monarch Plus bolted into my Devinci Dixon long-term test bike back in June while out in Les Gets, France. Since then I've worked with Torben and Danny, RockShox's elite suspension fettlers for Europe, to achieve the perfect tune for my downhill-orientated riding style.
Jake has swapped the Fox RP23 shock that came with his Devinci Dixon for a RockShox Monarch Plus RT3 that's now been tuned to suit his aggressive riding style
What I wanted was a shock that gives loads of support throughout its stroke, so the bike doesn't wallow or blow through its travel, but one that'll still deliver full travel when needed. Essentially, I wanted a coil shock feeling, but with a more progressive leverage curve.
Basic tuning of the Monarch Plus is done by altering the internal shim stacks. These piles of thin shims – basically, washers – sit either side of the main piston and determine the rebound and compression characteristics of the shock. By altering the size of the shims, oil is made to flow through the shock in a different way and this either slows down or speeds up its movement as it's compressed (when the wheels hit a bump) and then re-extends.
We decided to stick with the stock rebound damping and concentrate on adjusting the compression stack to extract maximum performance from my Monarch Plus. We also made the air chamber of the shock smaller, to create more ramp-up towards the end of the travel. It's possible to tune the Monarch Plus's internal floating piston arrangement too, using different air pressures, but this wasn’t something we needed to change for the Dixon.
The Monarch Plus shim stacks laid out, with the rebound and compression shims on either side of the piston head
So, could we notice the changes we'd made? Undoubtedly. Although the tune that we had done for our super-hard riding wouldn’t be perfect for everyone, it's massively improved the bike’s handling over some serious terrain.
When sending your shock off to be tuned, be sure to let the tuners know your weight, riding style and what kind of trails you ride, as well as the bike the shock is going on. Chances are, it’ll be some of the best money you’ll spend in terms of bang-for-your-buck ride improvement.
Check out our image gallery to see the SRAM shock tuning team in action.