Sourcing fat bike fenders is a difficult task if you don’t know where to look. The good news is that a few off-the-shelf and custom fender options have recently been made available. I won’t be covering the nuances of fenders in this article, so please start with my comprehensive fender resource to understand everything there is to know about fenders.
Before I take you through the available fender options, here’s some info specific to fat bike fenders:
Fenders are measured on the outside (not the inside) so a good rule is to subtract 10mm off the fender width to determine the maximum tyre clearance. You’ll ideally need a 20mm gap between the top of your tyre and fender, and about 5mm on either side of the struts. For example, a 75mm (3.00″) wide fender will comfortably clear a 65mm (2.60″) wide tyre. That said, manufacturers are usually very conservative with the maximum tyre clearances they recommend. You can often stretch the maximum tyre clearance to match the fender width, provided the struts allow it. A small bend to the strut near the tyre may be required.
Front Derailleur Clearance
The only other thing to know about fat bike fenders is that they can sometimes inhibit the action of a front derailleur. To get around this, you can use a Dremel to cut a small section of the fender off near the chainstay.
You’ll be surprised how much terrain you can cover without your fat bike fenders clogging. I normally hit sticky mud just 2-3 times per year (travelling off-road fulltime), but some regions of the world are notorious for their sticky mud. It’s probably best to leave the fenders at home if you’re expecting rain and clay/volcanic mud!
An issue not often discussed is what happens when a stick jams in your front fender. The worst case scenario is that you will be promptly thrown over your handlebars, and your bike will suffer a lot of front end damage (photo). I don’t mean to scare you, and not everyone rides on roads and trails with stick debris, but this is worth keeping in mind. The SKS-brand fenders are the only model listed here that have quick-release lower mounts to pop the fender open if something jams. This is one reason why SKS models are my pick of the bunch.
Right, let’s take a close look at the fat bike fenders available.
Honjo H95 Fenders – 65mm Wide
The fanciest fenders for mid-fat tires have got to be Honjo H-95s. As the struts go over the top of these aluminium fenders they get tyre clearance far beyond the 2.20″ maximum they recommend. For example, the Honjo H95 mudguards fitted to the Ahearne Outback above are comfortably wrapped around Schwalbe G-One 27.5 x 2.80″ tyres, but other riders have even squeezed in 3.00″ rubber. You can get these in 27.5″ or 29″ lengths (polished silver) for US $145.
Planet Bike Cascadia ALX 65 Fenders – 65mm Wide
The Cascadia ALX aluminium fenders have been a popular option for touring bikes for quite some time. These are some of the longest fenders available too because they’ve been designed around a 29er wheel diameter. Planet Bike recommends a 2.00″ maximum tyre, but many have managed to squeeze in 2.40″ provided you mount the fenders high. You can find these fenders in black or silver for US $70, and it’s handy to know that mounting hardware is available aftermarket too.
Sim Works Flat 65 Fenders – 65mm Wide
The Sim Works Flat 65 fenders are actually re-branded Honjo H-95 aluminium ‘guards. With an extra bend made to the strut near the tyres, they will even clear a 3.00″ tyre (see Stephanie’s Surly Wednesday in detail HERE). They’re available in polished silver (US $135) or black (US $151), a colour that’s unique to Sim Works.
SKS P65 Fenders – 65mm Wide
For a long time, SKS has been making these wide mudguards for 26″ mountain bike wheels. You can find the P65 fenders matched to 2.40″ tyres on many touring and electric bikes include the KOGA WorldTraveller Signature builds. The main downside to this option is that they’re a little bit short when paired to a 29er wheel. The SKS P65s are available in black or silver for US $49 on Amazon.
SKS Bluemels 75 U Fenders – 75mm Wide
SKS released these off-road fenders in late-2018. Officially they’re good for 2.60″ but we know that the combination between flatter-profile ‘guards and bent fender struts should suit even wider tyres – 3.00″ are theoretically be a breeze. You can get SKS Bluemels 75 in matte black for US $75 on Amazon.
Honjo H101 Fenders – 78mm Wide
Coming soon from Honjo is the new H101 model. Honjo says it’s designed to clear 2.30″ tyres but given the flat profile and strut design, there should be no reason why you can’t squeeze in 3.00″ rubber too. Honjo will make these in two lengths; one to suit 27.5″ and a longer version for 29″.
Wald Balloon 962 Fenders – 81mm Wide
These wide Wald fenders were originally designed for lowriders and cruisers, but they tend to make a great fender for off-road tread too. Chip from Whatbars.com has his wrapped around some 26 x 3.00″ tires. You can get the 962s in black or chrome for just US $34 on Amazon.
Surface604 Fat Bike Fenders – 120mm Wide
These are the only off-the-shelf fat bike fenders available. They’ve been designed specifically to suit a Surface 604 fat bike but should be adjustable enough to suit most bikes with tyres 4.50″ wide or less. You can get them in black for US $119.
Kelpie Cycles Titanium Fenders – Custom
Kelpie Cycles are one of the only companies that make hammer-rolled titanium fenders. They can whip them up in any width and length you desire – check out the 36er fenders found on this Black Sheep cruiser!
MK Wooden Fenders – Custom
MK Fenders are hyper-customizable wooden fenders made in Iowa, USA. You can choose the wheel size, fender length, fender width, wood type and colour inlay. The base price is US $200, but they can be optioned-out to over US $400.
Woody’s Wooden Fenders – Custom
Woody’s Fenders of Oregon, USA make fenders that are works of art. They’re available in a number of shape profiles and wood patterns (you’ve got to check out the options on the website!). The built-and-ready fenders start from US $120, but expect a full custom set to be north of US $250.
DIY Modified Fat Bike Fenders
You can make your own fat bike fenders by slicing a set of off-the-shelf fenders in half (Planet Bike Cascadia are popular), widening them with a 3.00″ strip of aluminium and attaching it all back together with rivets. There are a few good tutorials floating around online to complete this hack. The other popular DIY option is to source some ‘trials motorbike’ fenders and match them to some bicycle fender hardware.