Last updated: February 1st, 2023
As a new cyclist, fenders puzzled me.
Some bikes include them. Some bikes don’t. And most bike shops have half a wall covered in aftermarket fenders.
What gives? They’re so useful that shops stocks dozens…yet they’re not always installed off the rack?
With experience, I found that it depends not just on the type of bike you ride, but on the terrain and conditions and practical purposes you use it for.
When your bike does & doesn’t need fenders
If you ride on pavement, then you need fenders to keep yourself clean and to protect your bicycle from grime and dings. Even in dry climates, fenders will block spray from run-off or spills, and stop pebbles from damaging your frame. Avoid fenders off-road because of the risk of trapping debris against the wheel. Most also lack clearance for mud or snow.
However, mountain bikers should consider a frame guard. It’s effectively a miniature fender that mounts to the crown of the fork. Its small size and ample clearance avoid those dangers.
The two ways bicycle fenders help
There are two major reasons to put fenders on a bike: to protect yourself and to protect your bike.
1. Keep you clean and dry
The most practical reason to use fenders is to avoid getting wet and dirty. Pretty obvious!
What if you don’t live in a rainy climate, or you never ride on rainy days? Fenders still make sense. Roads stay wet long after the rain stops—not to mention irrigation run-off and the like. You’ll almost certainly ride on wet ground at some point.
What’s more, the wheel spray from wet streets isn’t just pure rainwater. It’s a mix of dirt and oil and any number of nasty things that nobody wants to be covered in.
Fenders, of course, block all the above. And the farther they wrap around your wheels, the more effective they are.
2. Protect your frame and drivetrain
In wet conditions, fenders reduce the amount of grime that gets flung onto your drivetrain. That means more precise shifting and lower maintenance in general.
In all conditions, fenders also deflect tiny pebbles and stone chips. Your tires often pick these up and fling them at your frame. Serious damage is unlikely, but we might as well prevent what we can!
Two common issues with fenders
For all their practicality, fenders aren’t universally appropriate. They’re best avoided when you’re riding amid heavy brush or debris, and they’re difficult (if still possible) to install on certain bicycles.
1. Catching debris can be dangerous
Fenders are useful for urban riding precisely because they wrap around your wheels. But that coverage also makes it easy to pick up brush when you’re riding off-road. The tangled brush can break fender parts, bust spokes, or even bring the wheel to a sudden stop (potentially causing a crash).
That’s a bigger concern in the front wheel, since locking up the front wheel practically guarantees you’ll go over the handlebars. It’s exactly the same effect as applying too much front brake at the wrong time.
With that in mind, many fender manufacturers use a quick-release front mount. It’s not for installation and removal, but for fail-safe release that minimizes this danger. To be clear, that’s strictly a safety feature, not an endorsement for off-road use!
2. Not always easy to mount
Mounting fenders is usually a one-time effort. And that’s good, because certain bicycle and fender combinations can…challenge one’s patience.
It’s notoriously hard to mount fenders to racing-oriented road bikes, since they often lack mounting eyelets. Clip-on fenders are an easy solution, but their coverage is limited. There are workarounds with alternative hardware (like “p-clamps”) but the result isn’t exactly elegant.
Tire clearance may also be a problem in two scenarios.
For racing-style road bikes (as mentioned above), the frames rarely clear more than a narrow racing tire. There’s just no space for a safe fender-tire clearance gap, let alone the fender itself. Partial-coverage fenders that stop before the frame are a good alternative.
The other tire clearance challenge is on off-road bikes. While they usually have ample clearance, it’s often impossible to find fenders wide enough to clear fat, knobby tires while leaving room for mud.
Tip: if you find yourself frequently installing and removing fenders due to terrain/safety reasons, then it’s probably time to think about a second bike. The cost is nothing to sneeze at, but the convenience (and fun!) of two purpose-built bikes is easy to justify, if your budget permits.
These bikes almost always need fenders
Fenders are almost always a good idea for casual, everyday use. If you cycle to work, or do errands by bike, then they’re practically guaranteed to make life a little better.
City and commuter bikes are for daily transportation, so it’s important to be prepared for wet conditions. Outside of a desert climate, at least occasionally wet pavement is inevitable. With fenders, you’ll be well equipped to get around and get stuff done without becoming soaked and dirty.
City bikes quite often do include fenders off the rack. But if your doesn’t, or if you’re using (for instance) a hybrid bike for commuting, then it’s a worthwhile upgrade.
This also applies to anything you’re using as a city/commute bike.
Whether it’s a mountain, road, gravel, cyclocross, or other style of bicycle, the key is that it’s used on pavement for non-racing purposes. Now, the frame design and suspension (if any) affect your fender options, so we’ll revisit that a bit later.
Fenders are prudent if your folding bike serves everyday purposes—in other words, if it’s used as a city/commuter bike. Seeing as folding bikes aren’t made for rough or competitive riding in the first place, this covers just about all of them.
And many folding bikes do indeed include stock fenders, which is helpful since their small wheels mean limited aftermarket options.
Road, cyclocross & gravel bikes (for non-competitive paved rides)
If you’re not racing, and your terrain isn’t covered in rocks or brush, then fenders aren’t a bad idea.
Whether they’re necessary usually comes down to what attire you ride in. For casual clothing that you’d prefer to keep dry and clean, they’re a no-brainer.
Forget fenders on these bikes
This site focuses on the utilitarian sorts of riding described above. But there’s a whole lot more to cycling, of course. And fenders generally get less useful as you venture farther from transportation and further into sport.
Here’s what I mean.
Road bikes (when racing)
If you’re considering racing (or intense club/training rides) on your road bike, then fenders are unnecessary and often not even permitted.
Unnecessary, because there’s no need to keep dedicated cycling attire clean and dry. You’ll also want to avoid any excess weight.
Probably not permitted, because race rules typically forbid accessories, especially large ones with the potential to tangle up others’ wheels when riding in a tight pack. This varies, of course, but is important to verify with the event’s organizers.
Gravel and cyclocross bikes (off road)
Rocks and brush are inevitable in your gravel or cyclocross bike’s native, unpaved habitat.
Rocks make a racket as they ricochet through fenders—especially metal ones—and brush risks getting caught up between your spokes and fender stays. Deep mud will also cause clearance issues with knobby cyclocross tires.
This isn’t a problem on gentle dirt roads or well-groomed paths, but you should skip the fenders in less hospitable conditions.
Besides the debris and mud issues mentioned above, mountain bikes also have suspension. And when wheels can travel up/down independent of the frame, fenders will get bounced around like nobody’s business. They’ll drag and catch, creating obnoxious noises (if not safety hazards), so they’re simply out of place for mountain biking.
With that said, mountain bikers often use small front mudguards to block spray from their faces. This is a scaled-down piece of plastic that usually attaches to the fork crown, and is small and stiff enough to stay in place despite aggressive riding.
Likewise, MTB riders may install a downtube frame guard to block large rock impacts. This is particularly important on a carbon frame, which can’t generally withstand impact as well as a metal frame can.
Mucky Nutz is one of the older and more popular brands of both.
Need fenders? Start with these!
If you’re thinking fenders would make life easier, then I have two general recommendations.
First, check with your bike manufacturer for model-specific OEM fenders. Some brands offer fenders that are not only color-matched to your bicycle’s paint, but have hardware specifically designed to fit with minimal fuss. These are usually metal, which does have the drawback of noise from gravel/stones, but the tradeoff is easy installation and a precise fit.
Second, if OEM fenders aren’t available, then opt for plastic fenders like the SKS Chromoplastic Longboard. The exact model will have a name like P50 or B65, where the number is at least 7-8 greater than your tire’s width in millimeters. For instance, their P50 fender would accommodate a tire up to about 43 mm wide.
(That’s just a guideline, so always defer to the manufacturer for a safe fit. Contact them directly if in doubt, or simply check with a local bike shop.)
Well, metal fenders can look terrific, but they’re noisy when debris bounces off the wheels. They’re also a little harder to manipulate when they don’t fit your bike quite perfectly. (That’s often necessary for aftermarket fenders, hence my earlier suggestion to use OEM fenders if possible).
If your bike doesn’t have fender eyelets, then there are at least two options. One is to use conventional fenders, as mentioned above, with P-clamps attached to the frame near the axle. It’s a bit unsightly, but functional.
If that won’t work—or if there are problems mounting the front fender to the fork—then it’s the SKS Raceblade to the rescue. These are quick-on, quick-off fenders made to work around limited mounting options. They won’t have the same full coverage or solid fit as regular fenders, but they’re often the easiest (or only) option.
Rain gear is the other half of the equation
Even with fenders, you’ll want to wear proper rain gear. Blocking tire spray is helpful, but most of the water comes from above!
Cycling ponchos are a simple and (potentially) cheap solution that’s more breathable than any—yes, any—rain jacket on the market.
You may still need a rain jacket and even over-pants for strong winds or extended rides, however.
Have a look at my guide to rain gear for city cycling for a closer look at rainwear options.
Finally, remember that even full-coverage fenders can’t protect your feet and perhaps shins from 100% of tire spray. If the ground is wet, then the best shoes/boots for cycling are the same ones you’d use for a rainy walk.