Hi All!
A very happy update and concludion to this thread: My problematic Sherpa is a problem no more, thanks to Thorn's superb warranty response. I am convinced no company on earth could have done a better job in addressing the problem I experienced with shimmy -- a problem I have never heard affect any other Thorn product besides this one example.
I have detailed Thorn's wonderful response elsewhere as a preface to the description of the problem in the thread appearing here:
http://www.thorncycles.co.uk/forums/index.php?topic=4320.0I will repeat the summary of their response here so all readers and owners can be reassured this is a company that stands behind their products to an extraordinary degree, with care and attention far beyond what one might expect from any other bicycle manufacturer:
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My Sherpa developed a severe shimmy problem under heavy load. Despite applying my best efforts and calling on the collective wisdom of the Forum, the problem persisted. as soon as they became awareI had a problem, Robin Thorn, his designer and "test pilot" Andy Blance, shipping supervisor Cath Colenso, and the entire Thorn staff became involved in addressing the problem and made every possible effort to help and assist me. They communicated with me nearly every business day by email, and at their expense shipped a Thorn EXP rack and a replacement front fork in a different offset in an attempt to resolve the problem with this one single rogue Sherpa.
When it became evident the problem could not be addressed, they offered to replace my bike with a Nomad Mk2, since the Sherpa Mk2 was no longer available and the Sherpa Mk3 has a lower load rating insufficient for my expeditionary needs. My experiences with the extraordinary Nomad Mk2 are detailed here:
http://www.thorncycles.co.uk/forums/index.php?topic=4523.0My acceptance of their offer did not mean the end of their help and assistance. They
volunteered to test the new bike to be absolutely certain it would meet my requirements. Andy loaded the bike with my maximum expected load and set off to do just that, as Robin followed in the company van and Cath caught it all on video, available for viewing here:
http://www.facebook.com/TouringbikesI have now shipped the Sherpa back to Thorn for a complete analysis of the problem. They have provided simply outstanding customer service, and we can all rest easier knowing that Thorn stand behind their warranty and have gone far beyond the efforts of any other bike-maker I can imagine. My sincere thanks and gratitude to Thorn the company, to Robin Thorn himself, to Andy, to Cath, and to the entire staff for an outstanding job. I can't begin to describe the incredible care and detail with which the new bike was assembled, packed, and shipped; it is simply perfect, and performs as one would expect -- like a Thorn.
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When and if the cause of my Sherpa's shimmy can be found, I will append it to the end of this thread. It is entirely possible the exact cause may be unkown if it is due to an internal flaw in the tubing or a hidden issue, such as a problem in heat-treatment.
Because I no longer own Sherpa, I will probably not be adding much new material to this thread. I will, however, be happy to answer any questions about my Sherpa Mk2 when it was mine. It really was a fine and outstanding bicycle in its own right, and I loved it dearly. Sadly, my single example developed problems that made it unusable and Thorn did wonderfully by me as I am sure they would by any owner. I can heartily recommend you purchase their products in full confidence they will and do stand behind their warranty.
I hope you'll join me in my new adventures with the Nomad. I can already tell you it is much like Sherpa in all the positive ways; the bikes definitely share the same DNA, and the Nomad is like the Sherpa but "more" -- a good all-rounder, but also more robust and heavy-duty as befits a true Expedition Tourer with enormous cargo capacity. At the same time, it maintains lively and accurate low-speed steering with or without a load, and is entirely pleasant to ride in either state, though biased toward loaded touring. The Nomad's frame is a bit heavier, of course (a difference of no importance when carrying a full touring load) but the light steering belies the weight and once up to speed, it is easy to maintain progress at the same rate as on Sherpa. I believe the Nomad Mk2 relies more on tires to provide comfort and suspension, and it does well on both counts, providing a smooth and confident ride regardless of terrain. I am running the same tires and rims (albeit in 32-hole rather than 36 as on Sherpa) and have the identical position/fit on the new bike, so some direct comparisons and contrasts can be made between the bikes and the gearing (derailleur vs. Rohloff). Those will come to light in the "Danneaux's Nomad" thread, available here:
http://www.thorncycles.co.uk/forums/index.php?topic=4523.0All the best,
Dan.
