Not only does Manitou make a decent MTB fork, but you have to check out Manitou’s line-up of ISX dampers. I was lucky enough to get my hands on an ISX-6 and I must say it shows some promise to be a great damper. Out of the box it has all the things I need and want in a damper and none of the things I don’t need – kinda like it was custom made for me! Anyhow, the Manitou ISX-6 (MSRP $609) is made for those who fall into the all-mountain to gravity range of riders where weight is not too much of an issue (my 190 x 50mm unit weighs 418grams with spacers). Even at that weight it’s still as light if not lighter than some of its direct competitors.
The Manitou ISX-6 rear shock comes with independent high and low speed compression dampening adjustments, rebound adjustment, volume control (which controls spring rate near the end of travel), and spring rate (air pressure). These are all the controls you need for everything from stuttery, rutted, rocky trails to big drops that would normally cause your bike’s rear end to bottom out.
Installing this unit on the bike really should be done by a person who knows what they are doing, mainly because you need to know which adapters are required for your bike (all shocks are sold without adapters). Once you or your mechanic install the correct mounting hardware, you’re ready to get busy setting up the damper.
First things first: set the sag by following the instructions supplied with the shock. The instructions are very specific and require you to set the shock by adding air into the reservoir first (red cap). Pump that side up to at least 150psi to start. Next, make sure the high and low speed circuits are fully open as you add air into the main chamber. Adjust sag by adding or taking away pressure from the main air spring (black cap). Although this part sounds complicated, Manitou includes a handy measurement chart for dialing sag in exactly. Serious riders know that sag measurement is critical for optimizing travel path and positioning and once you have it dialed in correctly, it’s nirvana.
After setting the sag I worked on adjusting compression. To be honest I found the compression settings a bit difficult – I ended up with the high speed compression (black knob) 3 clicks from full on and then fiddled with the low speed compression (red knob) only. My goal in setting high speed compression is to find the point where coming off a drop won’t cause the wheel to blow through its travel too quickly. For the low speed compression setting, I found the point where there was as little pedal bob as possible when sitting and pedaling.
Once the compression was set, I worked on rebound (blue knob) to find the point where bumps don’t buck me off the saddle. During ride one I played with the rebound – two clicks +/- here and there – until I found the perfect setting. With the ISX-6 dialed in I could launch off drops with a controlled compression and even return without overshooting or bouncing too much.
The final control is the volume control which controls the shock at the end of its stroke. There are four settings and I ended up at the 3rd setting which ramps up spring rate for the 6+ foot drops I was taking.
On the trails I felt confident with the ISX-6 controlling the rear suspension. I found on fast descents and hitting multiple roots and drops that the rear end of the bike was far more stable than with my previous shock.
At this point I’d like to pause and offer a brief physics lesson. If you consider the saddle as a level or a gauge of how your bike is tracking, when the saddle goes up on a bump this means the suspension is working but not fast enough (my old shock did this). The transfer of energy is not complete and the wheel is following the disturbance and forcing the bike to move instead than the shock. This can also be an indicator that you are near the limit of the shock’s travel.
With the ISX-6 I noticed far less bike movement and the saddle was more stable than with my previous set-up. This made a big difference in the overall ride quality for me – more plush, yet fully under control without that wallowy feeling.
Taking the ISX-6 to the limit, I hit a few of my favorite rock garden waterfalls. These sections are 50 foot long steep descents of just rock and trees where you have to change direction at least 4 times as you thread yourself between some large trunks. This can be a daunting task, but with the help of superb ISX-6 enabled tracking in the rear it was a piece of cake with tons of control. These sections are great at measuring wheel control and the ISX-6 passed with flying colors!
All in all, the ISX-6 is a decent shock with great small and large bump compliance. It’s light enough for long leg trail bikes and tough enough to take bigger hits and thread rough terrain. Many thanks to the folks at Manitou for tuning tips to unlock this shock’s potential!