Rear fender needed with rack?

My commuter has a rear rack I just installed, which usually has a bag strapped to it, so I *assume* I don't need to install a rear fender for rain riding. Am I wrong? Do rear wheels tend to fling water all the way around and forward toward the seat tube/feet?

And my front fender (a Planet Bike Freddy Fender) - even with the integrated mudflap - doesn't really pass far enough down my wheel to keep water from spraying the bottom bracket. It does protect my face, and crotch, I guess. Do folks usually rig longer mudflaps or just let the bottom bracket get wet and overhaul it a couple times a year?

If your rack has a flat top, it'll probably do the trick.
I wouldn't worry about your bottom bracket shell being sprayed. I'm not sure that the flung water is able to make direct contact with the BB "seals". My current commuter BB has survived hundreds of showers and is still smooth.

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"All that we see and seem is but a dream, within a dream..."

I tried just a rack on my MB, and my back ended up pretty wet. I bought a small extension fender that bolts on the back of the rack. It is about 6" long. I don't remember the brand though. If you want it, pm me.

That has kept me dry now.

I used a front fender that did the same thing. I am not too worried about the BB. I will just rebuild it when it warms up. It would probably need it anyway.

I may have answered my own question the other day. I rode on very wet roads while it was not (during the ride) raining and found the BACKS of my legs getting wet from my rear tire flinging water *forward*, due to there being no rear fender. The luggage rack kept most water off my back but apparently some water is still on the tires at the top where the tire is rotating forward.

Curiously, the front wheel can fling water forward as well if you're riding with the wind instead of into it. I always thought wheels only spun water off one spot (the spot touching the road).