Tech Tip: Fenders

Fenders are one of those polarizing bike accessories that many folks just don’t seem to get. They assume that fenders are only for commuters or rando-nerds; no self-respecting gravel or adventure rider could want–or need–the protection fenders offer. Truth be told, I held that same opinion for many years. When I started commuting full-time, I installed fenders on my gravel-turned-commuter bike. I told myself that it was just for the winter, and that I’d take them off when the weather turned nice. Well, summer came ’round, and I didn’t bother to remove the fenders. Guess what? The world didn’t end, riding that bike wasn’t any less enjoyable, and–gasp–my bike stayed cleaner. Who knew, right? Since then, I’ve logged thousands of paved and unpaved miles on fender-equipped bikes.

GRAVELBIKE.com gravel grinder Salsa Vaya Ritchey Classic Logic Lezyne
One of the author’s bikes from his pre-fender days.

Safety First
When selecting fenders, there are several criteria to consider. With most bikes, clearance is the number-one concern. Having adequate clearance between the tire and fender is absolutely paramount for a safe, noise-free ride. Additionally, fenders need to clear the bike’s frame and fork. Factor in fat tires and the stones and branches often found on unpaved roads and you usually end up having to make a compromise in the size of the tire or fender (and sometimes both). The general rule of thumb is that fenders should be at least ten millimeters wider than your tires. Note that metal fenders (more on those later) typically have rolled edges that can reduce the effective width by several millimeters. When in doubt, choose a wider fender or narrower tire.

GRAVELBIKE.com gravel grinder Velo-Orange fender Honjo Berthoud
Rolled edges on Velo-Orange’s 45 mm Facette fenders.

Even with proper clearance between the tire and fender, it’s still possible for a branch or rock to jam the wheel. If this happens on the front wheel, the results can be catastrophic. To help reduce the likelihood of such failures, most manufacturers equip their front fenders with quick-release tabs. These tabs allow the fender’s struts to break free in the event that a foreign object gets caught between the tire and fender. If you choose a fender that isn’t equipped with quick-release tabs, you may want to stay away from knobby tires as those are more likely to kick up rocks or branches.

GRAVELBIKE.com gravel grinder Planet Bike fender Honjo Velo-Orange Berthoud
Planet Bike’s Full ATB fenders feature quick-release mounting tabs.

Metal or Plastic?
Not long ago, metal fenders had a reputation as being expensive and difficult to install. In recent years, however, alloy and steel fenders have enjoyed increased popularity thanks in part to the affordable (and easier-to-install) models from companies such as Handsome Cycles and Velo-Orange. Unlike their fussy predecessors, these new fenders come pre-drilled from the factory, and include all the necessary fittings for headache-free installation.

When it comes to plastic fenders, the term plastic is a bit of a misnomer. Many plastic fenders are actually constructed from a thin strip of metal (usually aluminum) sandwiched between some type of plastic such as polycarbonate. And while 100%-composite fenders are available, they’re head-and-shoulders above the fragile celluloid models from the 1960s and 70s.

So which is better–metal or plastic? It depends. Plastic fenders are less costly, more resistant to dents and dings, and are easier to install for first-timers. Metal fenders provide increased coverage and protection (the rolled edges reduce side-spray) and are often lighter than their plastic counterparts. Because most (front) metal fenders lack quick-release attachments, some consider them less appropriate for off-road use. Having used both types of fenders over the years, I’ve found that stay and bracket design (and proper installation) makes more of a difference than the fender material itself.

More Is Better
Whether you choose metal or plastic fenders, maximize their effectiveness by opting for the longest ones that are appropriate for your intended use and terrain. Shorty fenders might be OK for casual riding, but your feet (and drivetrain) will get soaked by the spray from the front wheel. The longer the fender, the better the coverage, and the less likely you (and your bike) will get wet or dirty.

If you find that your front fender isn’t giving you all the protection you’d like, don’t fret–there are ways to improve its coverage. The most common method to improve a fender’s coverage is by adding a mudflap. If you’re the crafty type, you can make your own mudflap out of rubber stair tread material, or if you prefer to go the ready-made route, they’re available from companies such as Planet Bike.

When dialing in your front fender’s position, pay careful attention to ground clearance. A fender that’s too low can easily get caught on obstacles or curbs. This can damage the fender, or worse–lead to a crash. This is one area where flexible mudflaps are preferred, as they can safely bend if they catch on something. Also be sure to check clearance between your shoe and the front fender when the wheel is turned. This interference–known as toe clip overlap–is more common on smaller bikes, but can sometimes occur on larger bikes with short front-centers.

If there’s one drawback to longer fenders, it’s that they sometimes need additional struts or reinforcement to prevent unwanted flex. The added flex is rarely an issue with the rear fender (because it’s anchored at three points), but very long front fenders (regardless of whether they’re made from plastic or metal) often benefit from an extra set of stays. In the case of metal fenders, the process is as simple as drilling one or two holes and bolting on the second pair of stays.

GRAVELBIKE.com gravel grinder Velo-Orange Salsa Vaya Front Range Colorado
Velo-Orange 52 mm Zeppelin fender with a second set of stays added by the author.

Hints & Tips
If you’re installing fenders yourself, take time to read the instructions. Still confused? Check out these tutorials from Jitensha Studio, Rivendell, and Velo-Orange.

Lubricate all fittings’ threads to prevent them from seizing up. Stainless steel hardware is less likely to rust, but greasing the threads is cheap insurance against future headaches.

Check the fenders before each ride to ensure that hardware is tight and in good condition. Rattling or other noises are usually an indication that something has come loose. If this persists, you may need to add lock washers or threadlocker (such as purple or blue Loctite).

It may seem like a lot of work, but once you get everything dialed in, fenders don’t require much attention. After your first wet ride with fenders, you’ll wonder why you didn’t install them sooner. Your bike will stay cleaner, your drivetrain will last longer (and run smoother), and you’ll spend more time riding instead of cleaning or maintaining your bike.

Special thanks to Handsome Cycles, Planet Bike, and Velo-Orange for their assistance with this article. They provided product samples for this article, but offered no other form of compensation in exchange for editorial coverage.

4 thoughts on “Tech Tip: Fenders

  1. I appreciate that you are encouraging broader use of fenders for more types of riding. It certainly does help with grit and longevity. I would add a couple more thoughts from my limited experience which may be of interest in rougher gravel situations. To be fair, it hasn’t been that long that any variety of wide options has been available for 700/622/29er situations.

    One real benefit of plastic fenders is that not only are they more easily repaired in the field with duct tape, but they are far quieter than metal fenders. They will not rattle nearly as much, and small bits will only result in a tapping sound, whereas metal can result in a shrill tin-roof sound and can rattle if not completely secured every which way. You don’t want to have a ride ruined by the sonic equivalent of Chinese water torture.

    Also, in either case, I have found that the weakest link in terms of contact points is the bridge between the seat stays. Velo Orange rightly advocates the traditional downward-facing mounting braze-on its frames include, but most of us must instead deal with those sub-optimal adapter brackets, which can break or loosen and rattle. Of course, if you drill through, the bolt can break through too. Ideally, companies offering frames would include a short section of curved, predrilled reinforcing material.

    When racks are used with fenders, it’s nice to be able to take advantage of eyelets there too, another nice detail again that Velo Orange attends too.

    Lastly, it can be tempting to swap fenders around from one bike to another, but this has never worked out too well for me. The contact points may be slightly different, and some contact point will weaken with multiple installations. Better to just spring for the widest pair you are likely to need on each bike.

    Recently I picked up a Brodie Argus, similar to your Vaya, perhaps a bit stouter, but I haven’t installed fenders yet. It may need those black hammered numbers! Thanks for your balanced reportage.

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