I live in the mountains at 4,300 feet on the boundary of a national forest, which borders a Yosemite National Park and several designated wilderness areas, I do all day solo rides from my home into this remote country and need to be self sufficient. So far, never had a bike problem I couldn't easily fix and ride out.

However, after 35 years of riding ridged mountain bikes, I have just bought my first bike with suspension. It's a HT with a Fox Rhythm 34 fork, and have some basic questions about field maintenance and repair of these air suspension forks.

How reliable are these forks with regular maintenance? What, if any, spares and tools do I need to carry with me for emergency field repairs? What are their failure typical failure modes? What's likely to break down and what do I need to fix it and ride out?

Not planning to do any overnight trips, just day trips that will start and end at my home. Don't expect to be able to fix a fork damaged in a serious crash.

If you are familiar with a ridged bike then riding home should not be a problem...

If you keep up with the oil and wiper changes which are pretty simple then What you're faced with are pretty catastrophic. You're not going to be carrying around an extra lower or anything extreme like that.

You're hands will thank you!

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I live in the mountains at 4,300 feet on the boundary of a national forest, which borders a Yosemite National Park and several designated wilderness areas, I do all day solo rides from my home into this remote country and need to be self sufficient. So far, never had a bike problem I couldn't easily fix and ride out.

However, after 35 years of riding ridged mountain bikes, I have just bought my first bike with suspension. It's a HT with a Fox Rhythm 34 fork, and have some basic questions about field maintenance and repair of these air suspension forks.

How reliable are these forks with regular maintenance? What, if any, spares and tools do I need to carry with me for emergency field repairs? What are their failure typical failure modes? What's likely to break down and what do I need to fix it and ride out?

Not planning to do any overnight trips, just day trips that will start and end at my home. Don't expect to be able to fix a fork damaged in a serious crash.

There's no "typical failure mode" aside from what happens when you don't maintain the seals and keep fluid fresh and topped up.

Occasional specific models might have a particular recurrent issue, but aside from that, nothing major. Take care of it, and it'll serve you well. Just recognize that you can't ignore it the way you might ignore a rigid fork.

You'll want to carry a shock pump while you're taking the time to get it set up. And maybe on long backcountry rides. I carry a shock pump when I ride, but it has more to do with the fact that I'm frequently leading rides for a youth mtb team, and all sorts of issues crop up. It's been rare that I've needed to use it on my own gear, but I HAVE needed it. Aside from that, there's really nothing you CAN do to it in the field.

 

I would just carry a shock pump and a multitool on very long rides or multiday rides. There is not much you can do trailside if something goes majorly wrong with suspension. Typically modern forks are very reliable with regular oil changes in the lowers. Less frequently you will need to change the dust wipers and rebuld the thing completely.

 

Carrying a tool for every fastener on the bike, tire pump, tire pressure gage, tire tools, spare tire, patch kit, chain tool, and spoke wrench is SOP for any bike. Except for the tire pump, all of this stuff lives in a small under-seat bag, and the tire pump mounts to the frame’s water bottle mounts.

I know that I need to purchase a shock pump to set sag at home, and I will probably carry it with me for the first few rides until I am satisfied that the fork is set up for my trails. Thereafter, assume carrying the shock pump isn’t necessary for an all day ride if the shock is well maintained. True?

Is there any common failure mode that can cause a well maintained fork to suddenly lose all its air pressure? If so, does the shock go flat, preventing the bike from being ridden? If so, is their a field fix that will allow riding the bike home?

An easy half day ride into the back country can turn into a day and a half walk out, which is an inconvenience in the Summer, but nighttime temperatures here are often below freezing in other seasons.

 

Is there any common failure mode that can cause a well maintained fork to suddenly lose all its air pressure? If so, does the shock go flat, preventing the bike from being ridden? If so, is their a field fix that will allow riding the bike home?

No.

 

But you are using the fork brand that prefers the most regular maintenance at the shortest intervals.

The more you learn the better things will go.

 

Thanks you for the link. I also read through the information provided by Fox for this fork, but didn't find the answers to my questions about any sudden failure modes or trailside work arounds.

From my research, I got the impression that the fork will need air added more often and performance will begin to fall off when it needs some attention long before it quits working, but thought it was a good idea to ask the experienced users on the forum. Thanks again for your help.

 

I've never had a fork actually break on the trail. Its usually a gradual decline in performance, or a slow leak that progresses into a big leak over quite some time. I havent been caught off guard or anything.

 

Thanks. That's what I was hoping to hear.

 

On the trail, without a pump...

NEVER try to let "just a bit" of air out of a shock.

 

Thanks. I can see how that might lead to a problem. Think you have identified one of those sudden failure modes I was wondering about.

If all the air in the shock was lost, would the shock go flat, sag its full travel?

 

I've never heard of an air spring failing on the trail. I guess it could if the fork went without regular service on a regular recommended basis. But you know, a coil in that fork instead of an air spring would make your bike bomb-proof!

 

Good, that's what I want to hear.

Mike J. In post #11 identified an operator error that could lead to a sudden failure. I could see that happening.

A failure of a single component, like the shrader valve for example, seems like it might have the potential to cause a sudden failure, but that possibility seems remote.

Here, "sudden failure" is anything that could cause the shock to loose its air within a long day of riding.

 

Air suspension is so much more reliable than it was in the early days. You have a much higher chance of breaking a chain, rim, or frame than a piece of suspension (assuming it is reasonably well maintained)

 

That's good because I have never broken a chain, rim, or frame. Had a LOT of flat tires though, so view air-filled components with suspicion.

Suspension was just becoming available for mountain bikes when I was shopping for my previous bike. It seemed a bit rube goldberg, so I passed on it to give the technology a chance to mature, didn't intend to wait this long to try it though. Needing to carry two different types of pumps on the new bike is not a plus.

 

Loosing air is about the only issue you're likely to have on a properly assembled high-quality air fork. And that's not very likely. They really are far more reliable that you might expect them to be.

If you want no-question total reliability the best option is a fork with a metal spring in it. Little more weight but even if it's worn or filthy inside it'll still work.

 

I've seen *one* modern air sprung fork failure in a heck of a lot of riding. Location was Moab, specifically Porcupine Rim, and the failure was one of my group had the compression circuit die. He didn't even notice until we hit the bottom parking lot and he tried to lock out the fork for the ride into town. We're talking about someone who is a highly aggressive rider/enduro racer here, someone who is genuinely hard on equipment.

New forks are amazingly reliable, as others have said. The Yari on my bike needed air once last season, after six months. I just check sag before riding and off I go. Follow the service schedule, keep an eye on pressure, and you should be golden.

And as far as any trailside repairs, don't. If you open up the fork and introduce dirt into the lowers, it can be murder on the upper stanchions and lower internals.

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Another option is to ditch the air fork and go with a coil fork!

Or ditch all modern technology and ride a full rigid single speed with cable actuated brakes. Then carry brake and shifter cables, tube, spare chain link and a few tools......then go ride.

No one can predict with 100% certainty when a failure will happen. It’s all about mitigation of risk within our own usage spectrum.

 

Or ditch all modern technology and ride a full rigid single speed with cable actuated brakes. Then carry brake and shifter cables, tube, spare chain link and a few tools......then go ride.
.

Thank you, but I have been riding a bike like this for 35 years. My questions are about modern air suspension forks.

1. What are their typical failure modes? What goes wrong with them? How does it effect riding the bike?

2. What, if anything, can be done to temporarily fix the problem trailside? Are there any trailside work arounds? For example, a tear in the sidewall of a tubed tire can't be fixed, but many people have managed to ride home by constructing a temporary boot from a dollar bill and some duct tape. Are there any similar trailside work arounds for suspension forks?

Here's what I have learned from this thread so far. Modern air suspension forks tend to be very reliable if given the manufacturer's recomended maintenance, much more so than tires.

When they fail, they typically fail gradually, not suddenly and catastrophically. The fork just begins to need air added more often than it did initially, giving ample warning that the fork needs attention.

If all the air was lost for any reason, the fork would collapse, lowering the front end and the bottom bracket, but the bike would probably still be rideable to some extent. It's not clear to me whether anyone has actually experienced a fork collapse and has confirmed the bike would be rideable though. Can anyone confirm it?

2. No one has any suggestions for trailside repairs or temporary work arounds. Perhaps because fork failures are so rare that no one has experienced a trailside failure requiring a work around.

Still, it seems that operator error (post # 11), or failure of a single fork component, such as the shrader valve, or a failure of the shock pump could cause all the air in the fork to be lost and the fork to collapse trailside.

The only time I ever been unable to fix a problem trailside and had to walk home was when I couldn't reinflate a repaired tire because the tire pump failed catastrophically during the repair, so have learned to be wary of anything that requires air pressure to function.

Thanks again to everyone for your help answering these questions.

 

If your air fork were to unexpectedly collapse -- and it won't -- you could still ride your bike out.
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As stated (many times!) it's extremely unlikely for it to fail if properly maintained. Go ride your bike and enjoy your new fork!

Regarding what to expect in the unlikely event it DOES fail...Just let all the air out of it and ride it around the driveway a little (be gentle with it!). This will probably give you a feel for what it's like to ride your bike with no air in fork.

 

You could get a coil fork. If your damper fails on you, you still have the spring to keep you upright... and with coil you don’t worry about leaky air..


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You could get a coil fork. If your damper fails on you, you still have the spring to keep you upright... and with coil you don't worry about leaky air..

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Yes, that's an advantage of coil springs. At one time, they had a substantial weight disadvantage though. Is that still true?

My old bike has a ridged fork, which is very light, very simple, and very reliable. I chose an air suspension fork for my new bike for its performance advantages, assuming it would be reliable enough despite its added complexity, and the responses here are validating that assumption.

Now, trying to determine what additional tools and spares to take along to ensure that I can handle whatever suspension problems might come up in the back country in Winter. My approach is to make sure I have everything I need and nothing I don't. A person who trucks his bike to nearby parks on Saturday morning and rides familiar trails with his buddies for a few hours might have much different needs.

 

It's also worth noting that there's a significant gap between air and coil options.

The absolute lowest end xc/trail forks are coil. Then you hit a sort of a quality threshhold and then they all become air sprung. Period.

You don't start seeing quality coil spring forks again until you get into longer travel stuff. The MRP Ribbon has adjustable travel and can be had in coil at shorter travel than most (140mm), but with that said, in my conversations with MRP, they recommend air for hardtails, and say that the "feel" of coil doesn't really start to shine over air until you hit about 150mm of travel, anyway. So, for my hardtail with 140mm Ribbon, I bought the air spring version.

And fwiw, this is the bike I'll be choosing for the vast majority of my bikepacking trips. I probably won't be doing many trips longer than weekend stuff, but I have no hesitation whatsoever of using an air spring fork for that sort of thing.

 

2017 SID RLC, air spring failed, shock dropped to bottom of travel. 2017 reba, air spring failed, let air pack into lowers so it turns rigid. Fox 34 poor assembly from factory, too much grease in air spring caused it to drop to bottom of travel. Lefty 2.0 air spring failure, dropped to bottom of the travel.

All 3 of these brands had the exact same failure, positive to negative air equalization . Fox and cannondale had issues with too much grease in them. I'm not sure why the rockshox do what they did. The SID broke on a bike vacation. I was probably 3 hours into a ride at Santos. It was Florida the trails are easy. I had to call SRAM and get them to send me warranty parts to a shop where I was.

Most shocks are darn good, for how much abuse they take and how light they are. I would just be prepared that anything can fail at anytime. All of the failures I had allowed the bike to be ridden out. Although the fox and the lefty the fork was slammed to the bottom.

 

2017 SID RLC, air spring failed, shock dropped to bottom of travel. 2017 reba, air spring failed, let air pack into lowers so it turns rigid. Fox 34 poor assembly from factory, too much grease in air spring caused it to drop to bottom of travel. Lefty 2.0 air spring failure, dropped to bottom of the travel.

All 3 of these brands had the exact same failure, positive to negative air equalization . Fox and cannondale had issues with too much grease in them. I'm not sure why the rockshox do what they did. The SID broke on a bike vacation. I was probably 3 hours into a ride at Santos. It was Florida the trails are easy. I had to call SRAM and get them to send me warranty parts to a shop where I was.

Most shocks are darn good, for how much abuse they take and how light they are. I would just be prepared that anything can fail at anytime. All of the failures I had allowed the bike to be ridden out. Although the fox and the lefty the fork was slammed to the bottom.

Thank you. Your first hand experience with air-suspension fork failures is very helpful.

I believe the Fox 34 on my new bike should be reasonably reliable, but like everything else on the bike it will eventually fail, so I want to be prepared to deal with it on the trail if possible, just as I am prepared to fix a flat tire or work around a broken derailleur.

When your shocks failed and you were you were able to ride the bike out, what was the terrain like? I do almost all of my riding in the steep, rocky, remote terrain near my mountain home. Do you think a collapsed fork would be rideable for half a day in such terrain?

Do you know of any practical, temporary, trailside fixes that would make an air-suspension fork more rideable for the 1/2 day it might take me to ride out?

 

Hey, I've heard of guys stuff a torn tire with leaves so they could ride out. Why not stuff your flat air fork with leaves?

 

Why not stuff your flat air fork with leaves?

Firstly, you'd need to carry the tools to open the fork, but more importantly any junk you stuff into the air chamber is likely to scratch the walls and knacker it.

I visited my garage to look at my fork and consider whether a support wedge could be fashioned. Said wedge would go between the fork's bridge and the underside of the crown..

The bridge of a fork is not designed to take anything like that amount of load and would almost certainly break. Even if it didn't fail at the time, I wouldn't want to ride that fork again.

None of the 17 people who have responded to this post so far have offered a simple, practical, temporary trailside fix yet...

I know, weird eh?

 

If you want to make your fork a rigid fork -you may need to do some at-home MacGyvering.

Let the air out of your fork and devise a way to hold the fork in full extended position by way of no internals.

I haven't torn a fork apart. Maybe you should look up the fork diagrams to understand what is happening internally.

Maybe you can carry a large socket and/or large Crescent wrench to remove the top cap. Then insert a length of PVC pipe and reinstall the fork cap.
I have no idea if that will work.

Sometimes when a question doesn't seem to have an answer by others we need to make up our own answer, as in -if nobody can tell you how to fix a fork on the side of the trail then you will probably have to be the innovator and let US know how to fix it.

I'd encourage you to let the air out then take your bike for a ride. You will truly know if the bike is rideable. If so, you'll learn what the limitations will be.

How do you intend to repair a broken pedal spindle?
How do you intend to repair a broken crank arm?
Broken brake lever?
Severed brake line?
Handlebar?

 

If you want to make your fork a rigid fork -you may need to do some at-home MacGyvering.

Let the air out of your fork and devise a way to hold the fork in full extended position by way of no internals.

I haven't torn a fork apart. Maybe you should look up the fork diagrams to understand what is happening internally.

Maybe you can carry a large socket and/or large Crescent wrench to remove the top cap. Then insert a length of PVC pipe and reinstall the fork cap.
I have no idea if that will work.

Sometimes when a question doesn't seem to have an answer by others we need to make up our own answer, as in -if nobody can tell you how to fix a fork on the side of the trail then you will probably have to be the innovator and let US know how to fix it.

I'd encourage you to let the air out then take your bike for a ride. You will truly know if the bike is rideable. If so, you'll learn what the limitations will be.

How do you intend to repair a broken pedal spindle?
How do you intend to repair a broken crank arm?
Broken brake lever?
Severed brake line?
Handlebar?

I kind of hate to advance this conversation for fear of Pig and Harold stoning me but I have to admit a couple days ago I visited my garage to look at my fork and consider whether a support wedge could be fashioned. Said wedge would go between the fork's bridge and the underside of the crown, separating them and keeping the fork from compressing.

Kickstarter, anyone? We could become millionaires, I tell ya!
=sParty

 

Modern forks are extremely reliable. If they do fail it's usually a slow air leak and are still rideable.
Do not put modify your fork internally and especially do not put PVC in the air chamber.

Get a quality brand suspension fork and don't worry about it. It has about the same chance of a complete failure as your frame does.

For backpacking tool, maybe an emergency air pump, but doing anything more trailside is not feasible. Just like everything else, make sure it's bolts are torqued to spec and it's funtioning properly before you embark.

 

I looked “curmudgeon” up in the dictionary. There I found a picture of a pig wearing sunglasses.
=sParty

 

If the air chamber cannot hold air anymore, maybe it can host a suitably sized stick. All you need is the correct wrench for the air cap.

 

Ya know, I could just see that stick idea going terribly wrong. Hitting a bump with a solid object in there might develop enough force to violently eject the top cap.

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One thing is for certain, you do take an idea and run with it until there is nowhere else to run.

Glad you found a resolution.

 

This thread should not exist.

 

Same thing can be said for many if not most other threads on MTBR.
Some of us are having fun with this, Jayem. You needn't feel obliged to click again.
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