More years ago than I care to admit, when I was a Penniless Student Oaf, there was a company called Vivo Sport and they made a thing called the Grunge Guard. It was a (patented!) rubber boot that completely enclosed a bicycle's rear derailleur from hanger bolt to tensioner pivot, and was supposed to keep out the mud and SKOG that the rear mech would pick up from mountain biking (or commuting, or any kind of riding in Britain, really). I bought one and over the months I found it did an excellent job of 1) not quite keeping all the grunge out of the parallelogram, and 2) not quite letting it drain out again. Of course, as a bicycle mechanic I should have known better than to just leave it in place and never check it, though I can't really believe I would have done that. I was probably too busy with exams.
The long and short of it was that my fancy* Shimano derailleur wore out much too quickly; I moved on to better† things, and I think I threw that rubber boot in the bucket.
Having recently splurged on a new SMC that has, thankfully, solved¥ the brake problems that sidelined my bike for so long, and having seen the utter mank in the old SMC when I took it to bits, I got to wondering how I might prevent it rusting all over again. The late, great bicycle designer, Mike Burrows, described how bearings in hubs and pedals and cranks tended to wear out owing to an "excess of environment" – which is exactly what the Grunge Guard sought to ameliorate. So I look at my shiny new SMC and I think, "y'know, that little rubber boot is the only protection the plunger and piston have against everything they'll encounter", and "why didn't Honda include a bleed nipple at the piston end?" and "why isn't all this made of out of stainless steel?" and "why is no-one making a pattern part?". I look at the old SMC, with its rubber boot now more than a little loose at the seams, and I think "well, quite".
It occurred to me that perhaps what the SMC needs is its own little mudguard, not so much a larger all-enclosing Grunge Guard but kind of two-thirds of one. Something flexible and specifically shaped but free draining. Did anyone ever try making one? I never saw it mentioned anywhere, so I went prototyping yesterday with chopped up inner tube. I freely admit I'm either reinventing the wheel or, as a complete newbie who thinks she knows better, inventing a solution to which there is no particular problem – except to say that it's blindingly obvious that a) the SMC is a bit of a long term liability, and b) after 45,000 miles (and more importantly perhaps, many years) of unknown quality, my bike's SMC piston was so very nearly completely seized I'm amazed the bike got through its MOT test last year (a month or so before I bought it). I'll post the evidence on my other thead in due course, just for the heck of it.
Perhaps I am inventing a solution no-one needs, and that the best option is to inject silicone grease into the boot using a blunt needle. Seems a fine and dandy idea as long as it doesn't ultimately cause moisture to gather where it can't drain out.
* insofar as my PSO status allowed
† much
¥ grateful thanks to jfheath's colour-coded article on the bleed process
The long and short of it was that my fancy* Shimano derailleur wore out much too quickly; I moved on to better† things, and I think I threw that rubber boot in the bucket.
Having recently splurged on a new SMC that has, thankfully, solved¥ the brake problems that sidelined my bike for so long, and having seen the utter mank in the old SMC when I took it to bits, I got to wondering how I might prevent it rusting all over again. The late, great bicycle designer, Mike Burrows, described how bearings in hubs and pedals and cranks tended to wear out owing to an "excess of environment" – which is exactly what the Grunge Guard sought to ameliorate. So I look at my shiny new SMC and I think, "y'know, that little rubber boot is the only protection the plunger and piston have against everything they'll encounter", and "why didn't Honda include a bleed nipple at the piston end?" and "why isn't all this made of out of stainless steel?" and "why is no-one making a pattern part?". I look at the old SMC, with its rubber boot now more than a little loose at the seams, and I think "well, quite".
It occurred to me that perhaps what the SMC needs is its own little mudguard, not so much a larger all-enclosing Grunge Guard but kind of two-thirds of one. Something flexible and specifically shaped but free draining. Did anyone ever try making one? I never saw it mentioned anywhere, so I went prototyping yesterday with chopped up inner tube. I freely admit I'm either reinventing the wheel or, as a complete newbie who thinks she knows better, inventing a solution to which there is no particular problem – except to say that it's blindingly obvious that a) the SMC is a bit of a long term liability, and b) after 45,000 miles (and more importantly perhaps, many years) of unknown quality, my bike's SMC piston was so very nearly completely seized I'm amazed the bike got through its MOT test last year (a month or so before I bought it). I'll post the evidence on my other thead in due course, just for the heck of it.
Perhaps I am inventing a solution no-one needs, and that the best option is to inject silicone grease into the boot using a blunt needle. Seems a fine and dandy idea as long as it doesn't ultimately cause moisture to gather where it can't drain out.
* insofar as my PSO status allowed
† much
¥ grateful thanks to jfheath's colour-coded article on the bleed process
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