Rear Fender Mount Locations

[BigPoser]

Hi All,

I have a build that I'd like to have the ability to run fenders on, however I've not used fenders or ever built any mounts onto my frames yet. While looking into this, I suspect the best places are on the outsides of the SS just above the dropouts and either at a CS bridge or at the back of the ST above the BB. Is a SS bridge needed and if so, would the mount be horizontal (like a rim brake mount), or vertical?

Thanks in advance!

Brandon

[Andrew R Stewart]

Brandon- Welcome to the world of spray reduction:) A few notes on fender mounts.

Don't end up with the rear fender struts crossing ove/behind a rack's if at all possible. Locating the eyes as far back is a better goal then a forward of the axle location, make sure the fender struts are long enough wherever you place the eyes. Should be obvious but...

SS bridge boss can be either radial to the tire or tangent to it. Radial (boss under the bridge) is a clean look but has less adjustability to fender clearance and requires a hole be made in the fender in just the right spot (I have a short M5 bolt with its head partially ground to a point to act as a spotter poke point when marking that spot).

Chain stay bridge boss nearly always a radial position. If you have horizontally slotted drop outs the fender needs to arc away from the tire as it nears this boss ro allow for the wheel removal. Some people will have the BB end of the fender extend below the BB for more drivetrain protection.

Running fenders often comes with the need for more visibility. I apply reflective tape to the back few inches of my rear fender. But I remove any flap off the rear fender because they often snag on the ground when you roll the bike on its rear wheel, bars pulled way up. Remember that water leaves the tire at a tangent.

I don't like the fenders (including the fashionable hammered AL ones) that only have one pair of struts. Having two pairs of struts for both fenders reduce the wiggling/flopping, rubbing that full length fenders are known for. On the rear fender that second set, running nearly vertically, reduce the stress the seat stay mount point sees. This is one spot poorly mounted single strut fenders can crack at over miles of bouncing up and down over bumps.

1cm of tire/fender clearance is fine if you never ride over road grit or on stone/dirt. I like about 1.5cm of clearance. Andy

[hampco]

Picture below shows the eyelet location at the dropouts that we use here along with use of Sheldon nuts (QBP) and Honjo "L" brackets (Merry Sales, Herse, others); also mounted at the CS bridge. Avoid any tension in an alloy fender as much as possible because tension = cracking. I like the Honjo for performance and clean looks as well as the PDWs mounted as a Honjo; plastic is functional and long-lasting but, you know, plastic-y.

IMG_2231.jpg