Giles Pargiter wrote:I think it is very much a "courses your bicycle is going over" question.
The bike I most often use across the hills round here is configured very similarly to Andrew_s's. However if I had a rear mudflap, let alone one that long, it would very quickly be disasterous. I need to be able to easily wheel the bike on its rear wheel so that I can traverse places like narrow bridges etc. the width of my shoulders and hips. Doing that the flap will either get ripped off when I tread on it, very likely wrecking the mudguard and causing me to overbalance or else trapped under the wheel - pretty much same result. The front one got ripped off by a sheepdog a number of months ago, this saved it getting ripped off on a step - like a kerb.
So highly desirable for following riders and to keep your chainset and feet dry, but I find, not really practicable.
Front m/flap made from a piece of old truck or car inner tube just a bit wider than the mudguard and to within 50mm of the ground is extremely practical and durable,and flexible enough not break when descending upto 300mm drop offs,it keeps feet and bike totally clean.
Yesterday out on the MTB(with full m/guards and front flap)I rode through a 75 to 100mm deep stream for over 400m without so much as a drop of water on me both feet totally dry.
I take your point about rear m/flaps they can get in the way as you say when wheeling the bike on the rear wheel.they do protect riders behind though and if I were riding in a group regularly I'd fit one but as I don't have small deflector fitted to the rear to stop muddy wet spray getting all over me and the bike.On the Vaya the rear deflector sticks out from the rear m/g about 50cm and all it needs,on the mtb it's a purpose made one that sticks out 10cm
Some upthread mentions m/guard not being long enough,SKS Longboards address the issue,though they're only available in 35 and 45 mm widths and the range needs a 52mm width adding for wider tyres