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I am looking to buy a hybrid bike for all-around use and several of the models I am looking at come with the Rockshox Paragon air fork. I would appreciate the comfort of well-functioning suspension as I often find myself on bad surfaces (cobblestone with large 20 cm cobbles, accidental pothole hits, unpaved roads, going up and down curbs).

However, Rockshox seems to recommend servicing the fork after every 50 hours of use. I am surprised by this because 50 hours of riding are easily exceeded in 3 months. The service seems costly, not to mention the downtime (leaving the bike at the shop for a couple of days). I researched if I could do the service myself, but it seems like a messy and time consuming affair: still very inconvenient if done with such frequency.

I am surprised by this, since this fork is claimed to be designed for bikes that see everyday use. Now I am wondering if air forks are suitable for daily use at all, or are they really so fragile that they only make sense on weekend bikes? What would be the risk of doing only yearly service, instead of every three months?

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  • My fork served me well for three years of commuting but it is spring driven.
    – nightrider
    Jun 28 at 8:24
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    I also had a spring driven fork on my previous bike, and it worked fine. At one point I serviced it myself, which was quite easy (disassemble, regrease), and it made it work better than when it was new. But servicing these Rockshox air forks seems to be more complicated and messy with oil dripping out ... perhaps I should go for an easier-to-service Suntour spring-driven fork? Better to have a lower-level component that I can maintain than a fancy one that I can't ...
    – DailyRider
    Jun 28 at 8:29
  • Unless you're - wholly reasonably - trying to save money, how could air forks not be suitable for every-day use? Jun 29 at 21:08

2 Answers 2

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First of all, you don't need a suspension fork on a hybrid. Look for a hybrid with a high volume tyre instead. For your example of cobbles see this answer for some research performed by Schwalbe.

This research perfectly matches my real life experience. If i'm looking for comfort over that sort of terrain I would always choose the biggest tyre I can find at the lowest pressure I can. A 65-70mm tyre floats effortlessly over this type of surface.

To answer the point on suspension servicing; the 50 hours is the manufacturer covering themselves for worst case scenario. Very few people stick to the recommended servicing intervals. I have personally ridden an air fork 300 hours between servicing with no ill effects.

Servicing can be expensive, and many (most?) bike shops do not perform suspension services meaning your fork may need to be sent away to a specialist.

For high end forks riders will typically get them serviced once or twice a year. For low to mid range forks it is common for riders to not service them at all. The cost of a couple of services is already the cost of a replacement fork.

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    Whether it's 50 or 300 hours, I'm guessing those do not include the hours you spend with a locked-out air fork (because you're on a smooth surface and don't need suspension); is that right?
    – Sam
    Jun 28 at 9:55
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    Great question Sam (maybe even a question in its own right). Afraid I don't know well enough how the internals of an air fork work to even speculate on the correct answer. It may even vary from fork to fork depending on the lockout mechanism (some lockouts aren't a full lockout, they just make suspension very firm)
    – Andy P
    Jun 28 at 10:19
  • For the surface described in the question, I think suspension might be warranted. Riding over potholes and large cobblestones would likely make at least a few extra cm of squish desirable.
    – MaplePanda
    Jun 28 at 19:36
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    @Sam Let’s just suppose the fork perfectly locks out with zero movement. You’d still want to regularly replace the oil due to oxidation and degradation, and the external seals will degrade with UV and oxygen too. I’d say you can extend service intervals, but not completely ignore them.
    – MaplePanda
    Jun 28 at 19:40
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    @MaplePanda that's the idea. the reality is unless you basically let all the air out of your fork or deliberately ride with all your weight on the front wheel you are lucky to get a few mm of travel on large cobbles. certainly not cm. For me there's a very clear line - if the terrain truly warrants a suspension fork then you should buy a 29er not a hybrid.
    – Andy P
    Jun 28 at 19:42
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Air forks have two kinds of service - a lower leg service and full service. For the purposes of this discussion, consider a full service is something done to fix problems like the fork not holding air, damper not performing or repairing a breakage. A regular full service is common for bikes used for serious mountain biking, often done by sending the fork to a specialist.

A lower leg service is the 50 hour one and often done by the rider. For a serious mountain biker it's just another regular maintenance task, either DIY to taken to the bike shop. The reason to do this service is preventative as well as keeping the shock working properly. Not doing lower leg services at all can lead to expensive damage that effectively writes the fork off. Doing them when specified means the fork will perform well for decades. Spring forks also need a lower leg service for the same reason.

If you look at a fork construction, the stanchions slide into the lower legs. There is a seal with a lubricating ring that keeps the dirt out of the fork and keeps the fork lubricated, reducing stiction (the force needed to get the fork moving) - ideally forks have no stiction. There is usually a bath of a small amount of oil to keep things lubricated in each leg.

If you do not service a fork, two things happen - the lubrication does not get to the ring, and it dries out. This is bad because the fork's performance is severely compromised, and it wears out the surface coating of the stanchion. While very hard, this coating is also very thin. Once worn out, the stanchion quickly wears down and destroys the the seal. The second thing that happens is dirt gets past the seal and mixes with the oil creating a grind paste, wearing the stanchion, destroying the seal.

The service involves removing the lower leg, cleaning everything, replacing the seals if needed, reassembling and adding a small amount (typically 5-50ml) of clean oil with a dab of your favorite fork butter for good measure. Its a 15 minute job for someone who's done it too many times before and has all the right oils and lubes in a well organized workshop.

The question that needs considering is what interval -50 hours, maybe push it out to 100, or 500, what about 1000. I tend to do it when the fork feels it needs it - probably closer to 100 hours. The type of riding makes a difference - sealed roads in dry weather without too much dust you could push it out. Wet or very dry, dusty weather I would not push it too far.

If you lock forks regularly, you really need to keep the servicing going. Few MTB forks true lock with no movement. The small amount a locked fork has concentrates the wear at the mid point of the fork stroke.

@Andy covers the idea that a suspension fork is not the best solution to the problem of cobblestones and pot holes. They are heavy, expensive and require significant maintenance. Talking specifically to Air fork - I suggest they are less suited to commuting than a coil fork, but not because of servicing requirements (which coil fork have the same requirements to keep them performing well), but because they have more things to go wrong. You need to adjust them correctly to get best performance (air pressure, damper settings) or you wasted a whole heap of cash, and they need regular air pressure checks. If the seals go, they need to be stripped and serviced (trust me, you will very quickly get tired of pumping the shock up before every ride).

I might consider one for a commuter - I already do my own fork servicing, have a fork pump and love to play with pressures to see if I can get it better. If I wanted a bike I could ride, doing nothing more than banging some air in the tires and oil on the chain once a month, I would not get one with an air fork.

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