bad mechanic said:
It seems like a solution in search of a problem. There are already several excellent tensioners in the $45 range, like the DMR STS or the Rennen Rollenlager (plus they're made from aluminum, not plastic). Also, rigid tensioners (not sprung) have already proven themselves and shown a spring is simply not needed. I just don't get it.
typically i would agree to disagree but i think yours seems like an opinion in search of an argument.
'excellent' tensioners? good at best.
1) the fixed arm requires regular adjustment to compensate for chain 'stretch'.
2) the fixed arm does not allow for tolerances in chainring or cog diameters. riders must find and tolerate a compromise between these tight and loose spots.
3) the fixed length and fixed angles of the arm restrict the type and application of the conversion. for example, frames with chainstays that are (low) in relation to the hanger (center) cannot be converted or it must be done in the push-down configuration.
aluminum over 'plastic'?
i suppose that depends on the science or engineering you are considering, either way, selling one arbitrarily over the other is no less shortsighted then providing the nod based on colour.
i sell approximately 400 spring-type tensioners (
like so) and 100 fixed-type tensioners (
like this) per year. the price differential is a mere 7$ (25 vs 32).
over the course of 5 years i have only taken back 2 spring loaded tensioners and i have only exchanged 2 fixed tensioners (for spring style). what i mean is, i think most people know what it is they are buying and they understand the limitations of any tensioner.
i have experience converting a range of frames for a range of purposes through a range of budgets, maybe that matters, maybe not.
we set out to design a tensioner, based on experience and feedback. we set out to offer a substantial improvement on what was available...at a reasonable price...made domestically if possible.
by point of comparison, tensioners i consider 'excellent' (YESS for one) cost upwards of 80$.
we attacked what we considered the two achilles heel(s) of current tensioners, FIXED ARMS and SPRINGS.
in order to eliminate the necessity for moving parts (like springs and pulleys) we needed a material with no memory and a crazy fatigue life. aluminum (
i do love it) is not appropriate for this application.
maybe the DMR style is all you need. i'm not naive, i expect it will be ALL a few other people need too.
but i fail to see how a product that eliminates specific failures in design, limits compromises and costs no-more is a bad thing.
those interested can read more on the design concepts
HERE and
HERE.