We’ve covered the basics of fork set up, spring rate and damping adjustments, but getting this right isn’t worth a whole heap of beans if it stops working after a couple of rides. If that sounds a bit extreme, believe us when we say we know several species of forks that won’t be at all happy after a long winter weekend of riding.
Here’s our guide to the basics of looking after your forks, what you can do with regular servicing and when to treat your forks to a specialist suspension service.Before we go any further a word of warning:
I thought this was going to be a lovely, easy “hey look kids, anyone can maintain their forks” sort of feature when I started writing it sometime Friday morning.
For once I even had all the gear I needed to do the job and illustrate it properly. An hour into painstakingly stripping down the Fox forks, I find out that because of a cunning pop out seal housing, they don’t need stripping regularly at all. This is yet another point in their favour as forks, but boy was it irritating at the time. So I think ‘I’ll whip those Duke’s off a test bike’. But oh no, they don’t recommend you pull them apart at home so they don’t list the amount or weight of oil you need to refill them correctly. I can’t be arsed to try and judge how much I’ve lost when I drain them and top them up again, so I move onto a set of Pace’s. Because I’ve lent someone my circlip pliers, I end up jamming a bradawl into my thumb-end trying to remove a circlip which, by the time I’ve wounded myself, I’m not even sure I have to remove anymore.
I end up stripping down a pair of Judy SL’s.
In short what was supposedly a simple wipe, unbolt, wipe some more, squirt a bit of oil in and stick back together job turned into a monumental nightmare. If you’re at all squeamish about maintenance ask someone who knows what they’re doing, or just get some rigid forks. I know I’m certainly very, very tempted.
That’s made me feel better, now on with the feature 🙂Every ride
The worst enemy of plastic seals and smooth sliders is gritty sand. Scratches on the stanchions (the inner legs that the outer legs slide on) or damage to the seals can stop the fork from moving smoothly and also lets more filth in or out, making things worse in double quick time. Leaving water or mud to sit on the sliders and seals also causes corrosion damage.
This is why it makes sense to wipe your forks clean after every ride. A quick rinse with a low pressure garden hose or water and soft brush will get the worst off, then use a soft rag or cloth to wipe off the rest of the muck. Make sure you clean around the seal thoroughly but without pushing any filth further in.
If the forks use protective boots make sure you ‘unplug’ them and then slide them up to clean any crud out from underneath. Otherwise the boots will actually hold corrosive filth against the seals in between rides which defeats the whole point.
In winter or wet conditions, a smear of fork oil or light lube (but not one like GT85 or WD40 that will dissolve grease) helps keep the fork running smoothly and sensitively. Don’t try this if you’re riding in dusty conditions though as it’s more likely to attract and collect dust.
Once you’ve wiped clean, give the fork a couple of pushes up and down (or ‘cycles’). If it seems smooth and happy then it should be fine for the next ride, so you can go put the kettle on. If it grinds, sticks or generally feels unwell then you may as well put the kettle on anyway and get some biscuits for moral support, as it’s on to the next stage of servicing.Strip and lube
If the fork feels gritty or notchy chances are it’s filled with a grinding paste of old lube and anything else it’s picked up from the trail. You need to get that out and replace it with fresh lube. If there’s wobble in the fork that isn’t caused by the headset, brake or the wheel you’ll also need to replace the bushings.WARNING: Don’t start undoing anything until you’ve released any air pressure – positive or negative – from air forks though. We’ve seen some serious scars on people who’ve had forks blow apart in their face, so check and double check that all air springs are empty.
You’ll also need a clean area to put the forks parts on and enough time to do job the properly (with a decent margin to allow for unexpected complications). Make sure you’ve got any suspension oil, lubricating fluid (plus graded syringe or measuring cup to get the right amount) or grease you’ll need to put the fork back together again too.
Getting the forks apart depends on the model. Most rely on bolts that stick out of the bottom of the fork (or are hidden up inside on Marzocchis). Others have bolts that can only be accessed from the inside after you’ve removed the internals. Before you take a spanner or Allen key to anything check with your fork manual.
Make sure you have something ready to collect any oil that may come out when you undo an oil bath fork, as well as kitchen towel or an old rag to soak up the inevitable spillage. Remember to remove the brakes from the forks too, otherwise you’ll suddenly find them dangling on a cable or hose while you’re trying to juggle a tub of old oil and the rest of the bike.
Once you’ve undone the bolts, slide the forks apart gently. You may get some resistance from the seals as they pull apart, but just wiggle the lower legs slightly and they should pop off without a problem. Start by cleaning the inside of the lower legs with a twisted cloth. Don’t use paper towels or anything that will fall apart and stick inside. Clean carefully around the seals and top lip of the fork, checking for any scratches, or nicks out of the seals and use a bike light or torch to check that you’ve got all the old filth out.
If you’ve got an air fork, clean gently around all the plunger and seal sections and wipe the inside or the air chamber. Again make sure you use a rag that isn’t going to get stuck down there! For coil forks without an oil bath you’ll need to check how clean the grease is on the coil itself and inside the leg. If it looks at all grotty then clean it off completely with a degreaser, but make sure you wipe all the degreaser off with a rag as it can damage seals and plastic innards.Now remove the top cap from the spring side/s of the fork. Again go carefully and make sure any spanner you use is a good tight fit, as an old pair of pliers or mole grips will often mangle soft top caps. Once that’s off, pour out any old oil that is lurking in there. You can generally just fish out the spring internals from the top, or push them up from the far end with the carrier rod at the base of the inner leg. Try and lay them out in the order they appeared or at least make a note of how they fit together.Damping
You’ll notice we’ve just talked about the spring side of things so far. For open bath forks when you dismember them you’ll need to change the oil anyway, and that’s generally the only maintenance needed apart from seal checks. On forks with a separate damping cartridge, servicing depends entirely on the model. Some can be disassembled, re-oiled and rebuilt relatively easily, others are definitely best left to the manufacturer or an authorised service centre. Check with your manual, the manufacturers website or the shop you bought them from before you tinker.Seal culling
If you’ve noticed anything looking worn or damaged order yourself a replacement before the wear starts to spread to more parts. If you’re down to your last bit of grease, fluid or oil when you rebuild the fork, make sure you order that too – as local shops can’t be relied upon to carry every possible suspension component or spare.
While the fork is clean make a quick check all round the structure for cracks or paint flaking, which can show fatigue. On forks with bolted crowns or braces check that everything is done up to manufacturers specifications.Rebuilding
Rebuilding is pretty much a case of reversing the above procedures, but you’ll often find things more difficult going back in than coming out. Never force anything, just try a gentle wobble and a dab of fork fluid or grease on stubborn sticking points.
Greased forks generally just need plenty of suspension-friendly, low stiction plastic safe grease on all parts and as such are the easiest to strip and clean. However, you need to be totally accurate with replacing oil in air forks or anything with oil bath lubrication. Changing the amount of fluid or its weight can cause big changes, from altered damping performance to complete hydraulic lock. Some forks also enjoy a small amount of suspension fluid being added on top of air pistons to lube them, while others hate it. Again check manuals and manufacturers.
Continue to re-assemble the fork carefully until it’s all back together and then check that it’s all operating smoothly before you go charging headlong down your local hill. If you’ve re-assembled the fork incorrectly you won’t be able to claim on warranty if you destroy it or yourself.
Now it’s just a case of riding it round until if feels horrible again and repeating the whole process – but at least it should be easier the next time!Where to look for more information
Different forks have widely different servicing needs and particular techniques and where and how you ride them. Trial and error is a fine technique in some circumstances, but when you’re dealing with delicate and easily damaged fork sliders, seals and valving set ups then use someone else’s experience wherever possible. Obviously the fork manufacturer should be the first port of call. The BIKEmagic forum can often be helpful, but there’s also a specialist fork tweaking forum on the Angry Asian website. Specialist fork tuners like TFTunedshox , CVI or Mojo, make a living out of suspension tuning and have got far more experience and know-how than most.