Got ya. Been there, ate that! I should have paid more attention to one of Andre's post when he had his doubts on wheather the chainglider would work in Dan,s inviro..
Mmm. Hebie Chaingliders are made in several specific sizes matched to particular chainrings of 38, 42 and 44 teeth at the front, and to particular hub gearboxes at the back, again with particular tooth counts. If used as intended, they seal well.
Revelo fitted a Chainglider intended for one size of chainring to an entirely wrong-size chainring. In his installation the seals on the Chainglider get no chance to work. The photographs he published before his tour showed there are huge holes for the dust to pour into the Chainglider. The lube he adds, far from helping, disastrously combines with the dust to form a grinding paste. In such an installation, who would be surprised that the Chainglider doesn't work, and is abraded?
We don't know whether on Revelo's roads a properly fitted Chainglider will keep the dust out. I have substantial experience (admittedly in trucks rather than on bikes) on dirt roads in Africa, Australia and South America, and have been on dirt roads in the States and Asia as well. I suspect that a proper Chainglider installation on Revelo's bike will a) keep the worst of the dust off the chain, b) reduce maintenance to some longer period than daily, c) be cleaner and d) not abrade the Chainglider so fast or perhaps at all. That is not to say that the Chainglider on Revelo's roads will be immune to abrasion as appears to be the case on my roads, where the inside of my Chainglider after several thousand kilometres is unmarked. I suspect that over a period of years the grinding paste of dust and oil will grind away the Chainglider if used in constant heavy dust or sand. But if the Chainglider saves daily maintenance, so what? For around 35 Euro you can consider it a consumable component and buy a new one every second or third time you buy tires or a chain and feel no pain.
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The argument in Dan's case was entirely different. The Chainglider is pretty closely fitted, so closely in fact that the whole thing doesn't rattle like a machinegun when you pedal only because it is made from a flexible, sound-deadening material, which works brilliantly, as you can conclude for yourself from the absence of complaints about noise. But that close fit, out on Dan's playa, could be a disadvantage. Dan has given a frightening description of this dust a) getting everywhere and b) turning to concrete in the presence of water. On the playa it apparently rains heavily every day. Because of the tight fit of the Chainglider, even a little concrete in it could immobilize the chain, and with it the bike. Now, I don't think this will happen, because the close fit of the Chainglider also keeps out water, but caution suggests Dan conducts a more controlled experiment in a less life-threatening milieu before he makes so radical a change to equipment proven in previous expeditions to work.
So. On Dan's playa, the consideration isn't a grinding paste of dust and oil possibly wearing away the Chainglider (of which there is zero evidence I know of on any properly fitted Chainglider -- at this point it's all speculation), but about concrete making the bike inoperable in a hostile environment.
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What it comes down to, Tom, is that everyone with a properly fitted Chainglider recommends it. The only caveats -- more like cavils really -- arise from a Chainglider so improperly fitted as to obviate its design purpose -- and from Dan's insane desire for self-flagellation in an impossible desert.
If you're going to fit the thing properly, if you aren't going to ride it in dust that turns to concrete, go ahead and fit it. You won't be sorry.
