

DEFENDER iGlow
Topeak Defender iGLOW Fender
Hot
- Rubber backing on seatpost strap keeps fender from shifting off center
- Fender angle and position adjustable
- Kept my backend dry
- Sleek enough for a road bike
- Built-in rear and top lighting with flash and constant setting
Not
- Takes time to put on
- Light not bright enough to be visible as a daytime running light
- Not rechargeable battery
- Two pivot adjustments require different size Allen keys

Planet Bike Big Buck Fender
Hot
- Fender angle and position adjustable
- Easy on/off
- Fits wheels 3-5” wide
- Keeps majority of splash off your backend
- Economically priced
Not
- None
Price: $39.95 (Topeak); $28 (Planet Bike)
Avalibility: Online, Retail
How obtained: Company Sample (Topeak); Purchased (Planet Bike)
RBR advertiser: No
Max tire size: 700x25c (Topeak); 5” (Planet Bike)
Weight: 179g (Topeak); 95g (Planet Bike)
Seatpost diameter max– fits all standard seatposts, not suited for aero seatpost
Dimensions: 22”x 2.3” x 1.5” (Topeak); 22” x 4.5” (Planet Bike)
Keep Your Backside Dry While on the Road
Last week Jim Langley’s article on “Top Tips for Road Cycling in the Rain” was perfect timing as I have been testing a couple of rear fenders. Chicagoland has had a cold and rainy Spring requiring us to ride in less than ideal conditions. Fenders are nice no matter what bike you’re on as it prevents spray from coating your backside, plus it reduces rooster tails affecting riders behind you.
I own several types of bikes from road to cross to fattie. In this review I’m covering a couple of rear fenders that work on a variety of tire sizes. The Topeak Defender iGlow is ideal for road and commuter bikes and the Planet Bike Big Buck which works great on wider tires including a fattie. While these companies and others offer downtube and front fenders, I’m just focusing on rear models.
Topeak Defender iGLOW Fender
I reached out to Topeak for this fender to test because of the built-in lighting along the top of the fender and at the end. What a great idea for commuters or roadies who get stuck riding in low light or dark conditions. You never have to forget to bring a light. The fender uses a 0.5W red LED. Using a conversion table, I found on the web, 0.5 watts equates to 45 lumens. This is standard for many commuter rear lights. Unfortunately, the light was not bright enough for a daytime running light but works fine in low light and dark settings. With today’s distracted drivers a daytime running light is necessary, so in this case I had to run an additional rear light on sunny days.
The light has a contestant and blinking mode and according to Topeak the battery life is 50 hours for the constant setting and 100 hours for blinking. It uses two CR2032 batteries, which come with the fender. I’d have preferred a rechargeable battery both for environmental reasons and you’re less likely to run out of a charge. Without a battery life indicator, you need to make a guessamate when to change the batteries instead of just plugging it in when you think it needs recharging.

Rear and top light for added safety
I immediately liked the sleek design as it wouldn’t cause too much drag on a spirited group ride. I also liked that Topeak thought out of the box when they designed the seatpost mount. First, the strap that goes around the seatpost has a rubber backing which helps to keep the fender in place. It does not slide down on the seatpost and rarely moves off center. Second, they redesigned how the strap is tightened down on the seatpost. The yellow peg gets pushed up and the strap feeds through a slot, then turn the peg to tighten and lock the strap tight into place. I really liked the concept, but It was a bit cumbersome to attach. If you are leaving the fender on all the time, this design is fantastic. But if you are moving it from bike to bike, or removing it when not needed, reinstallation takes some time.

Fender pivots at two points
The fender is also designed with two pivot points for maximum adjustability. You can adjust the angle and position of the fender to provide the coverage you need. The problem is you need an Allen key to adjust the angle. The pivot closest to the seatpost uses a 5mm Allen key, whereas the fender pivot uses a 2.5mm Allen key (2.5mm Allen key is supplied). If you aren’t switching bikes or need to adjust while riding then this is a moot point, but if you want to make any adjustments, you’ll need to carry a multi tool or two Allen keys with you.
I tested the fender on my road bike with 700x25c tires and it worked great. My bottom stayed dry and it minimized spray to the riders behind me. The fender is made of injected high-impact resistant plastic and according to Topeak the high polished underside prevents dirt buildup. I didn’t test this feature as the roads I ride on do not kick up that much debris.
Topeak offers a 2-year warranty on their fenders.
Rear Fender for your Fattie Trail Adventures
I’ll take the fattie out in any kind of weather…snow, rain or sun. It’s just a fun bike for hitting the trails. Finding a good fender that keeps you dry when those 4.5”+ tires kick up water and mud can be difficult. Back in February I came across Planet Bike at CABDA Midwest. The Madison, WI based company had a lot of interesting products at good price points. What also intrigued me was their advocacy work. Since 1997, they have awarded over $2 million dollars plus over 4,000 products to domestic and international grassroots groups making a difference in their local communities.
After chatting with the reps at the booth, they gave me some lights to test, which I’ll cover in a future review, and I purchased their Big Buck rear fender. At a $28 price tag, it is well made and looked to be better than the fender I was currently using.


Installation/removal of the fender was fast and easy with a standard quick release locking lever. There was no assembly and the Big Buck has one pivot point which is easily adjusted without tools, just a knob. The other day I tested it in 20mph winds with gusts over 30mph. The fender stayed in place and barely moved off center with the cross winds.
The Big Buck fits more than just a fattie. It fits wheel sizes 26”, 650b, 29” and 700c and tires 3-5” wide. And for such a large fender it only weighs 220 grams. Planet Bike also offers front and downtube fenders which I am thinking of adding to my fat bike in the future.
Planet Bike offers a limited lifetime warranty on their fender.
Transporting Bikes with Rear Fenders
If you use a roof or rear rack to transport you bikes, for either brand it’s recommended to remove the rear fender as it can move or break at high speeds.
Bottom Line
Fenders are an inexpensive way to keep you drier on rainy days or riding through mud. Here are two fenders that will do the job nicely. Topeak Defender iGlow is perfect for your road or commuter bike and Planet Bike is a great option for your larger tire bike like a fattie. Both attach to your seatpost and use a quick release latch. So don’t let the wet weather keep you off your bike, just get yourself some fenders.
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