In this week's Tech Tuesday we take a closer look at rebuilding Manitou's Circus fork. Inside you can watch a great How-To video and read up on some helpful pointers.
The dirt jump oriented Circus fork is a new addition to the Manitou lineup, but there are many already out in the field being pushed hard. If you've already got a Circus mounted to the front of your bike, this is a great Tech Tuesday for you to reference when the time comes to give it some love. If not, many of these same steps and principles can still be applied to other Manitou forks. Watch, learn, and you'll know what to do the next time your fork's service interval comes up. Manitou recommends removing the Circus' lowers for a cleaning and re-lubing once every 20 hours of use, but you may want to do it more often if you ride in nasty conditions or make a habit of hosing your bike off often. Damper service needs to be performed less often, only about once per year. Some pointers before you begin...
• While everyone has to start somewhere, and this isn't the most technically demanding job, it still isn't for everybody. If you have some doubts about being able to get it done, don't start. Likewise, you need every single tool listed below to do this task - no substitutes. If your fork needs some love but you don't feel up to the task, take it to your local shop to have the work done by the pros.
• Anytime that you are dealing with suspension, you need to be aware that there may be residual pressure within... even if you've let out all of the air. Take your time and wear eye protection to prevent injury.
• As always, clean your work area before beginning this job. An organized work area is an efficient work area and you'll be less likely to lose parts.
• Be sure to write down both your rebound and compression damping settings, as well as your air pressure, before taking things apart. This will save you setup time once you have the fork back on your bike.
• Clean around the fork seals very thoroughly before removing the lowers. This will lessen the chance of dirt and grime getting into the lowers when you slide them off of the stanchion tubes.
• This is very important
- too much damping oil in the fork will prevent it from attaining full travel and possibly damage the internals. Too little oil and your fork will suffer from inconsistent damping... get it right! Stoking the damper rod and rotating the leg while draining the oil will help to empty the leg.
• Likewise, it is important to never exceed 16cc's of lubrication oil in each leg. Too much oil can prevent full travel and cause oil seepage at the seals.
• Take a few minutes when you have the fork apart to inspect the seals, stanchions, and internals for any damage that may be present.
• Stroking the damper rod while adding new oil will let it flow into the damper and is vital to attaining the correct oil height.
• Be sure to double check any and all bolts on the fork once you have everything back together and it on your bike. This includes crown bolts, caliper and axle bolts, and even the bolts holding on the leg guards.A note about fork oil
: The oil used for damping has very different demands than the oil that is best used for lubrication. The damping oil, in this case it is a 5w fluid, is designed to resist cavitation (foaming
) as the piston and internals travel though it at a high rate of speed. Cavitation can cause inconsistent damping as the damper now has to deal with air in the oil. Lubrication oils, such as the the 5w full synthetic recommended in the Circus, are made to resist shearing forces and let the parts slide as smoothly as possible. Yes, you can use damping oil for lubrication. No, it won't work as good. Take the time to use the right oil in the right places.If you've never worked on your Circus before
, you'll be doing yourself a big favor by taking a few minutes to read the manual found on the Manitou support page
before watching the video below. Better yet, print it out and have it on hand in case you get lost. Even if you've done this job numerous times, it doesn't hurt to refresh your memory.What's needed: 2mm and 8mm hex keys
, 12/20/24mm sockets and wrench, adjustable wrench
, French tickler
, shock pump, 5w suspension fluid, 5w full synthetic semi-bath fluid (full synthetic 5w40 motor oil
), drain tank (for old oil
), eye protection and nitrile gloves
.Learn how to rebuild your Manitou Circus: