Tech Tuesday - Manitou Circus Fork Rebuild

Feb 8, 2011
by Mike Levy  
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:

Views: 24,715    Faves: 123    Comments: 15

Have you done this job? Want to add a tip or hint of your own? Put it down below!

Past Tech Tuesdays:

Technical Tuesday #1 - How to change a tube.
Technical Tuesday #2 - How to set up your SRAM rear derailleur
Technical Tuesday #3 - How to remove and install pedals
Technical Tuesday #4 - How To Bleed Your Avid Elixir Brakes
Technical Tuesday #5 - How To Check And Adjust Your Headset
Technical Tuesday #6 - How To Fix A Broken Chain
Technical Tuesday #7 - Tubeless Conversion
Technical Tuesday #8 - Chain Wear
Technical Tuesday #9 - SRAM Shift Cable Replacement
Technical Tuesday #10 - Removing And Installing a Headset
Technical Tuesday #11 - Chain Lube Explained
Technical Tuesday #12 - RockShox Totem and Lyric Mission Control Damper Mod
Technical Tuesday #13 - Shimano XT Crank and Bottom Bracket Installation
Technical Tuesday #14 - Straightening Your Derailleur Hanger
Technical Tuesday #15 - Setting Up Your Front Derailleur
Technical Tuesday #16 - Setting Up Your Cockpit
Technical Tuesday #17 - Suspension Basics
Technical Tuesday #18 - Adjusting The Fox DHX 5.0
Technical Tuesday #19 - Adjusting The RockShox BoXXer World Cup
Technical Tuesday #20 - Servicing Your Fox Float Shock
Technical Tuesday #21 - Wheel Truing Basics
Technical Tuesday #22 - Shimano Brake Pad Replacement
Technical Tuesday #23 - Shimano brake bleed
Technical Tuesday #24 - Fox Lower Leg Removal And Service
Technical Tuesday #25 - RockShox Motion Control Service
Technical Tuesday #26 - Avid BB7 Cable Disk Brake Setup
Technical Tuesday #28 - Manitou Dorado Fork Rebuild

Visit to see their entire lineup of tools and lubes.


  • + 22
 hahaha french tickler
  • + 9
 This guy knows his stuff. haha he says enough.
Keep up the great work anyway.
Do you reckon you could do a Tech Tuesday on Marzocchi DJ3's??
  • + 21
 You know, it'd be more useful if any of us actually RODE these forks.

How about doing Marzocchi Dirt Jumpers, Fox 36's, or an Argyle? I'm all for Tech Tuesday, but it seems a bit pointless when the only people riding them atm are people who don't service their own stuff i.e. Sponsored riders.
  • + 24
 you should ride this fork i got one and they are so good. cheaper than the base model argyle and lighter with the same adjustments (+ lockout ) than the rct. i cant see how this fork will not take off.
and trust me im not a sponsored rider and i do service my own gear
  • + 7
 don't forget to mention the reverse arch feels so nice
  • + 6
 I think a Marzocchi fork rebuild would be a good tech tuesday as a vast majority of riders use them.
  • - 2
 i agree with shred. the amount of people who have these forks are low.
  • + 1
  • - 5
flag pperini (Feb 8, 2011 at 10:01) (Below Threshold)
 i dont want to be rude or not greatful for the tech tuesdays...but i see all the time people asking for fork rebuild videos from boxxers and totem and 888, 40s...and this is already the second tech tuesday with exactly the brand that almost anyone have..i mean no disrespekt to manitou, but comon......u know what i wanna say....nice video anyway
  • + 5
 marzocchi forts are easy as to take a apart you just need to take your time and rember were everything goes back togeather same with rockshox aswell although i didnt want to touch the damper on the rockshox
  • + 11
 maybe cos more and more people are getting manitou's ? I'm getting a circus expert for my bike, and I'm probably gonna get a Dorado if I get a DH bike Smile
  • + 0
 do a tech tuesday argyle! thats prolly the most popular fork on the market
  • + 2
 mikes changed loads Razz
  • + 10
 You guys are noobs. Circus's are quite amazing. I want some myself.
  • + 8
 they pretty damn cheap on CRC!
  • - 11
flag STP977 (Feb 8, 2011 at 12:42) (Below Threshold)
 Marz dj1 more popular dj fork then circus
  • + 4
 i have circus's there awesom and at a good price!
and yeh but how many years have dj1's been going now?
and i actually doubt it, i dont realy know many people who are runing dj1's right now
  • + 4
 i have a dj1 and it sucks. it blew out. im getting an argyle now.
  • + 1
 yeah its all prefrence but honestly i liked my dj 1 over my argyle and never had problems and im going to enjoy my circus just like i enjoyed my sherman flick back in 2005 the reverse arch kills all other companies in my opinion
  • + 2
 hardly anyone has mz's now compared to fox's argyles or circus'
  • - 2
 when he says the fork needs to be serviced every 20 hrs, does he mean 20 hrs of riding or 20 actual hours?
  • + 13
 lol bisk what? When I snapped my gold label fork a while back i recieved a fixed fork a week after sending it off. I now run a circus, so clearly not everyone stays clear of them. In terms of price and performance, manitou are onto a definate win with this fork in the dj area.
  • + 7
 Austin, as outlined above, 5wt Suspension Fluid for the Damper, 5wt40 "Full Synthetic" fluid for the lowers. A Full Synthetic Motor oil works great in semi-bath type systems as it is designed to resist 'shearing forces' rather than a damper fluid which is generally designed to resist 'cavitation' (Aeration of the damping fluid). You can use a damper fluid in your lowers if you want, but you'll likely find it will degrade rapidly and become notchy-feeling sooner than a full synthetic. It's all about having the right ingredients in your kitchen!
  • + 1
 fair enough. I have a gold-label so my fork is much less sophisticated than the circus
  • + 5
 Everybody is hating on how this is a pointless video.. Just wait til more people have the Circus and this will be like the number one viewed video on how to service one. Not pointless.
  • + 6
 manitou again!!! i like it !!
  • - 11
flag bigburd (Feb 8, 2011 at 9:33) (Below Threshold)
 Why don't they show you servicing for forks that people actually own? out of maybe 100 plus riders I know not one of them has manitous
  • + 6
 here, in germany much of my friends ride dorados or travis forks. Wink
  • + 1
 Why would they do one about argyles ? I think there is a manual on taking it apart in the owner's manual or somewhere on their site. And i think it was about all RS forks. And what would happen if I dont do this every 20 hours of riding ? The damping systems are gonna bug?
  • + 5
 pleeeeease do a how to for fox 36 floats!
  • + 0
 Please do Argyle 409s
  • - 16
flag ryan-irvine (Feb 8, 2011 at 2:18) (Below Threshold)
 You'd think so eh. I've never even seen anyone riding that fork. Must be usefull for about 3 people world wide. Guess it's just easy marketing.
  • + 3
 marco-djer: check out rockshox website, they have great service manuals to check before getting into it
  • + 13
 why does everyone think no one rides this fork,
  • - 4
flag bisk (Feb 8, 2011 at 5:43) (Below Threshold)
 manitou support is shite in the UK, so as a rule of thumb, everyone stays well clear of them. so most of the guys assuming nobody uses them will be UK riders
  • + 1
 There is a video on pinkbike to show how to lower them... The easiest fork to lower.
  • + 3
 This fork is hardcore I seen what Mike Mongomery could do with it on a friggin hardtail so awesome
  • + 1
 Are you guys ever going to do a Fox DHX RC4 rebuild on tech tuesdays?? I would really appreciate some help, because I have no idea where to start!! lol
  • + 4
 get it to your bikeshop and they will do it for you Wink if you have no idea.
  • + 4
 its pretty easy. Just take it apart slowly remembering what order, or write down what order. then If you get stuck you can google it and it will come up with instructions how to re-build
  • - 1
 yea not to be a downer here but id really like to see a tech tuesday on a marzocchi 66, 888 or at least a 55. most people dont go out and buy a manitou dourado for there normal trail riding so it would be nice to see a video the at least was on a boxxer, 66, 888, argyle or a DJ
  • + 1
 I want to know how hard it is to lower these and if it's possible to go any below 80mm. I would like to go to 70 or even 60mm.
  • + 3
 please do how to for last gen Boxxer Team!
  • + 0
 Very cool, well given instructions, right up until he tells you to tighten the rebound knob CLOCKWISE to re-assemble, he should have said COUNTER Clockwise.
  • - 1
 Just depends on your perspective Smile
  • + 1
 Did someone make a video to how to lower them? cuz I don't know where to put the spacers?
  • + 2
 no 'how to lower a circus' video?
  • + 2
 yea marz rebuilt i got the 66 ata let get it done......
  • + 2
 Great vid! Next time Sektor Coil please....
  • + 1
 how bout pikes 454 dual air
  • + 1
 what about a video für the RS argyle?!
  • + 1
 i have to replace my uppers any tips
  • + 1
 Where can i get a circus?
crc has just 130mm and black 80mm
  • - 1
 every 20 hrs??
  • - 2
 my thoughts exactly^^ :S ....
  • + 0
 same for marzochis roughtly...
  • - 1
 So that'd mean i'd have to service my fork every 5 days of riding? Yeah nah. Flag.
  • - 3
 Fox recommend every 30 hours for the 36 and 100 hours for the 40, 32s and air shocks. I don't know who would do the 20 and 30 hourly oil changes - imagine how much oil you'd go through.
  • - 3
 Well i've done at least 100 hours on my Float 36s and they're still going hard.
  • + 4
 they mean hours of actual riding not time on the bike you know , think about how long your regular tracks are in mins
  • + 4
 Guys, guys, guys. Listen to BigBurd. A lot of smaller-sized forks on the market are 'reccomended' at 20hr service interval for INSPECTION AND CLEANING of the outer casting or lowers. This doesn't mean mandatory overhaul of the entire fork, and it obviously could not be in real-time. It's about accumulated operation time. It's just a reccomendation for top performance...
  • + 1
 The Fox hours I quoted are for oil changes.
  • - 3
 arn't you supposed to use 5w suspension oil... not 5w40 motor oil...
  • + 2
 5w40 is for lubrication... 5w is for damping....
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