Fitting Your Fenders : A Brief Guide

Fitting Your Fenders : A Brief Guide


If you made it to this blog post, chances are you are interested in one of our full coverage fender sets. Sweet! We’re excited to discuss fenders in greater detail so you can be sure to choose the best set for your bike. If you already have a set of our fenders, please use the more detailed instructions available here, and use the below guide for supplemental tips and tricks.

We work incredibly hard to continually improve the design and fit of our fenders, ensuring they are always the best on the market. We created this guide to help answer common (and not so common) questions about proper fit and installation. Please note that while we have tried to be as thorough as possible there is no substitute for the accumulated knowledge of the mechanics at your local bike shop. Remember, if you feel like you're in over your head then go to your local bike shop and have a professional help you select and install your fenders.

Some General Rules of Thumb:

  1. In general, you want your fenders to be at least 10mm wider than the widest tire you're going to ride. This is not a hard and fast rule, especially for road bikes which are going to have much tighter fender tolerances. Aesthetics are a big factor here but so is a good/safe fit. The closer the tire width comes to matching the fender width, the more likely you will have rubbing. Will your 700x38 tires work with our 700x45mm fenders? Yes, this will probably be just fine. What about your 700x42mm tires? Now we are getting close to that 45mm fender width and adequate space between your tire and the fender is in question. If the fender is tightly positioned near the tire, you have very little lateral wiggle room. A minor and hardly noticeable wobble in a tire or a slightly out of true rim will be quickly noticeable as rubbing on your fender.
  2. Disc brakes are almost never a problem. We can work around them (more on this later.)
  3. 700c tires are larger diameter than 650b tires which are larger diameter than 26" tires. 650b fenders will not work with 700c wheels. 650b and 700c fenders will work with 26" wheels but may not follow the wheel diameter closely (so they'll function but look odd.) 700c fenders will work with 650b wheels but may not follow the wheel diameter closely. 
  4. Another word about tire sizes. For smaller width tires (think road and gravel tires,) tire manufacturers use 700c and 650b for diameters and millimeters for the widths. So you'll see tire sizes like 700x38mm or 650bX47mm. For larger tire widths, they switch to inches for some reason and you'll see tire sizes like 29x2.2" or 27.5x2.1". 29" is the same as 700c and 27.5" is the same as 650b. 

Okay, let's dive into clearances and measurements. Finding the perfect fit will ensure maximum splash coverage from the elements and help you have a worry-free ride. 

Minimum Clearances

The first measurements to look at are the areas on your bike’s frame and fork where the tire gets close. You can see the minimum distances you’ll need to have for different sizes of fenders on the chart below. If you are willing to bend the fenders a wee bit, you can probably get by with *slightly* tighter tolerances than what we list here. 

Fender clearance diagram

Chart showing minimum clearances for fender installation

Mounting Points

These are the areas on your bike’s frame and fork where you will need to anchor any full coverage fender. We’ll elaborate on each of these mounting points later in this article.

Fender Placement Guide

Fork Crown Mounting Tips

You will need a hole through your fork crown in the front, back, or both. If you have the option, it is always better to mount the fender front hanger to the front of the fork crown so you have more protection from water spinning up off the front of your tire.

If there is only a hole underneath the fork crown, you can drill a hole in the fender and mount it directly to the underside of the fork. Always use large leather or rubber washers between both the bolt/fender and fender/fork. This will allow you to snug up the bolt connecting the fender to the fork while dampening some of the vibrations that may cause a rattling sound. Note: Any hole added to your fender provides a new stress point and that can increase the chance of breaking.

Front Fork Mounting Tips

Mounting fender stays around a caliper

Bikes With Disc Brakes: Many disc brake calipers on modern bikes are low profile and do not interfere with a fender stay attaching to the eyelet near the dropout. For those that do interfere, you can either space the fender stay out from the eyelet with washers or Presta valve nuts to avoid the brake. You can also use one of our Disc Brake Spacer Sets to do the job.

Using a p clamp to create a fender mounting point

Bikes With Thru-Axles and No Eyelets: P-clamps from your local hardware store can be used around the lower fork stanchions to attach the fenders stays to. **Be sure to check this kind of setup frequently to make sure the p-clamps are solid and not sliding down your fork**

Bikes With Quick Release Skewers and No Eyelets: You can use our handy Eyelet Sets that attach to your quick release skewers. P-clamps (as above) also work and will allow you to remove your wheel more easily. If you are attaching fenders to eyelets that are at the mid-point of the fork you may need to cut down the stays to appropriate length. This is relatively simple and can be done with a hacksaw or even a sturdy bicycle cable-cutting tool. 

Brake Bridge Mounting Tips

If your brake bridge has an eyelet on the bottom rather than a hole that works with our standard rear hanger you can use our special Rear Hanger for Braze-ons Under Brake Bridge to directly bolt to the eyelet. This is preferable to drilling a hole in the fender, which will weaken the structure of the fender.

If your bike does not have a brake bridge it is going to be almost impossible to mount the rear fender. There are a couple of creative solutions we’ve seen but they are going to take some serious DIY spirit and the results may vary. Try these at your own risk! 

  • You can get some aluminum flat bar at the hardware store and cut two pieces to fit on the front and back of your seatstays. Drill a hole in them and use a bolt to sandwich the seatstays and fender hanger between them. You can even coat the aluminum flat stock with PlastiDip or similar coating to protect your frame.
  • You could also do the above with a set of steel core bike levers. Then you’re using a bike tool to create the brake bridge. Kinda cool! 

Rear Dropout Mounting Tips

Bikes with Rear Racks:  Ideally your bicycle will have two sets of eyelets so you can mount your rear rack to one set and your fenders to the other. If you only have one set of eyelets you’ll have to mount the fender brackets to the outside of the rack legs. If you have a PDW Everyday Rack, there are mounting holes for fenders built right into the rack for you to mount your fenders to.

Mounting a fender stay around a brake caliper

Bikes with Disc Brakes: Just as we noted above, many disc brake calipers on modern bikes are low profile and do not interfere with a fender stay attaching to the eyelet near the dropout. For those that do interfere, you can either space the fender stay out from the eyelet with washers or Presta valve nuts to avoid the brake. You can also use one of our Disc Brake Spacer Sets to do the job.

Chain Stay Mounting Tips

Ideally you have a chainstay bridge with a threaded eyelet. If this is the case you will probably want to space the fender out from the chainstay bridge a bit so that the fender fits closely with the curve of the tire. Washers, Presta valve nuts, or one of our Disc Brake Spacers will work well.

attaching fender to brake bridge with one plastic tie

If you have a chainstay bridge with no threaded eyelet you should still be able to run one burly zip tie through the fender and around the bridge without any trouble.

Using two plastic ties to attach fender to chainstay bridge

If you don’t have a chainstay bridge at all you can run two zip ties through the hole in the fender and around each chainstay. Make sure to tighten the zip ties evenly so the fender is centered on the tire.