Brucey wrote:One stay on the front mudguard? Not as bad as one stay at the rear but still pretty hopeless.
I think SKS mudguards with ESC stays are an exception to that rule. I've recently fitted my MTB with SKS mudguards which use a single ESC stay on the front mudguard, and my experience so far is that for very wide mudguards
, e.g. 65mm, they are much better than the standard double stays supplied with other SKS/Bluemels mudguards. In particular the combined mudguard and stay is much more rigid. I should add that I have fitted the rear mudguard to the front for the reasons given by other posters above, so I have a single stay behind the fork crown plus a 'front' stay ahead of the fork crown, but when I was experimenting with fitting the mudguard I came to the conclusion that the front stay did not make a significant difference to the rigidity of the rear part of the mudguard behind the fork crown.
Brucey wrote:Another factor which is often overlooked is the importance of tyre design in how (and how much) crud flies off them and the mudguards have to deal with. Wide tyres with tread on throw lots of crud off and skinnier, smoother tyres throw less. The main thing that is an exception to this is the amount of crud thrown out of the front wheel forwards. This also seems to vary with wheel diameter, the speed at which you ride, and the consistency of the crud on the road. So a certain speeds water comes out forwards, but at another slightly different speed it might be mud instead.
I think a major factor in how much spray and muck comes off the top of the tyre and is not blocked by the end of the front mudguard is the amount of clearance between the mudguard and tyre. The centrifugal spray is projected forwards at a tangent to the tyre. If the mudguard is very/too close to the tyre and ends at the 12 o'clock position, it will not only limit the amount that is sprayed off but crucially will also only allow it to be sprayed horizontally or downwards. Conversely, with a large tyre/mudguard gap the spray projected from the tyre around the 11 o'clock position will pass under the tip of the mudguard and will have an upwards trajectory. Consequently at speed, such as going downhill, the spray will result in muddy deposits not only on fork crown mounted lights as in the OP's case, but also on the rider's clothes. I found this out the hard way and realised the wisdom of reohn2's set up. Hence my MTB now sports a rear mudguard on the front.
With regard to the suggestion above of extending the rear mudguard below the bottom bracket, I cannot see that there would be any benefit.
However, I have a Hebie Chainglider and there is muddy spatter on the plastic cover over both the top and bottom chain runs immediately adjacent to the tyre. Muddy water is clearly being thrown off the side of the tyre down onto the chain/Chainglider and chain stay at that point. Because of that, I think there would be benefit if the rear mudguard profile several inches above the chain stays was a full semi-circle to provide better side coverage (or if some kind of screen could be affixed on the drive side similar to an old style dress guard).