11 January, 2017

Re-Radiusing Fenders

by Igor

Chances are, you don't need to re-radius your fender if you choose the proper width relative to your tire size. Alas, we do not offer a 45mm 26" fenderset. Yet. So for those of you with 26" wheels with 1.5" tires, our 650bx45mm hammered fenders can be re-radiused to match the curve of a 26" wheel.

As a reference, here is what how a 650bx45mm hammmered fender sits over a 26" wheel with 1.5" tires. The subject is Adrian's 26" Campeur, in case you were wondering.
Before
And here it is after some massaging. Notice that the fender is only attached at the seatstay and chainstay bridges, and has a smooth line that follows the curvature of the tire. Once this "fender-zen" is achieved, your fenders will live long and fruitful lives free of stress risers.
After
First, here is what not to do:

Do not bend the fender by grasping on the ends and squeezing. You will kink your fender, and it will be extremely difficult to fix. Rather, you need to work the fender bit by bit until the fender matches the curvature of the tire.

To decrease the radius of the fender, you will need to increase the width. Since I am using an aluminum alloy fender set, I just use my hands to depress the middle and pull the outer edges. I have heard of others using a tennis ball, but since 1) I don't play tennis and 2) the yellow fuzz is bad for a dog's digestion tract, I simply do not own a tennis ball. 
Decreasing radius
You don't need to do a lot at a time. Little bits over the length of the fender can decrease the radius enough to work. With the wheel in the dropouts, simply mock it up and adjust as necessary. Conversely, if you need to increase the radius, squeeze the edges together.
Increasing radius by squeezing
With the proliferation of off-road touring and gravel/all-road/any-road/road-plus/adventure/quiver-killer bikes, we have started including a pair reinforcement plates in all of our alloy fender sets. Just peel and stick it under the screw during installation - one under the seatstay bridge and one under the fork crown.


Here's the final result:

We'll probably bring in some fenders for the narrower 26" crowd. What other sizes would you like to see?

22 comments:

zybariver said...

Definitely need fenders to cover 650B +/-50mm tires. It would be nice if these were simple rounded profile to better complement modern frames/builds. Also please in black/noir/schwarz!

Grego said...

Thanks for this article. I'd like to see the fender reinforcement plates and some extra-low-and-smooth-profile hardware available for separate sale. Perhaps a countersunk bolt (sunk into the reinforcement plate)?

geoff_tewierik said...

Still hunting for 700C x 60mm noir metal fenders (hammered or fluted, no issue) that have long coverage for both front and back, think SKS Longboards in length.

Hi-Fi-sh said...

26"x65mm mtb style low height fenders

scottg said...

Looking at the very cool inside pattern on the fender,
how about some inside out fenders ?

Harry said...

+1 for this

Coline said...

Priceless, ugly fender lines ruin look of a bike.

Second the countersunk reinforcement plate idea.

Vincent said...

Hah...How timely! Just the info I needed to help finish off a Bridgestone XO build. Thanks!

Anonymous said...

Ooh! How about 650b fenders wide enough for 47-48mm tires?

Don said...

The inclusion of a set of reinforcement plates is a terrific addition. I have had to fashion makeshift reinforcement out of all sorts of things, but those look really handy and sensible. I have never seen changing the radius of a fender addressed anywhere, and it's the kind of thing you learn once and are glad you did. And it is definitely fender season. Thanks!

Then there's that situation where the fender is a little too wide for a unicrown fork and you have to compromise your aesthetics with the mushed look. A good argument for those VO fork crowns.

lenamarianne said...

so that a campeur with 26 tires?.....nice....

Morlamweb said...

How about 26 inch x 60 mm fenders that are the same length as the 650B fenders? Judging by that photo, the re-radiused 650B fenders provide about as much coverage as my current VO 26 in x 60 mm fenders + mudflaps. According to the store, the 650b fenders are 10 cm longer than the 26 inch ones. Longer 26-inch fenders would encourage me to buy a new set of fenders.

Tony Hunt said...

I currently run your 26"x60 alloy fenders on 26"x1.8 tires. The clearances are great but what I'd love to see is something in the 26"x58-62 range with more wrap - to catch more crap. Maybe fluted?!

Tony Hunt said...

Oooh ooh - Also what Morlamweb said about more length

Anonymous said...

You may have wanted to mention that this is only going to work on metal fenders. I can imagine some poor soul out there trying to bender their plastic fenders.

Anonymous said...

I'm looking for a fluted alu.fender that will caress the 26x1.75s on my Atlantis. Currently using SKS Longboards which are acceptable but a proper fitting alu requiring minimal adjustments would be the bomb. Cheers.

Anonymous said...

Add another vote for a Hammered aluminum fender to fit the Atlantis in the 40mm-45MM range, these would probably be popular for owners of LHT's and other bikes now that manufacturers are starting to vary wheel size to frame size. 50MM fenders are great for Cruzers or really fat tires, but a middle width 26' would be appreciated. - Mas

Anonymous said...

Another vote here for wider fenders for 650b. At least wide enough to accommodate up to 48mm tires.

Unknown said...

A well written article. The reinforced plate is an great product and needed when installing fenders.

somervillain said...

Great article-- looks eerily like a photo set of instructions I made a few years ago to re-radius fenders :-)

https://www.flickr.com/photos/7516215@N03/albums/72157633821482372

I like the idea of a pre-bent reinforcement plate. I've been doing that on all my builds.

Sukho Viboolsittiseri said...

To the guys wanting fenders wide enough for 650bx47-48, VO's 26"×60 works PERFECTLY. No fuss no muss. My frame was designed with proper clearances, but should still work nicely if you frame can handle it.

Anonymous said...

if possible, i'd be interested in a 55mm or more hammered finish for 26"; i've got a pair of rat trap pass tires that according to specifications, don't reliably fit under any fender with significant side coverage (honjo being the one very expensive solution).