Hi Mac!
I remember....
http://thorncyclesforum.co.uk/index.php?topic=8955.0
I'm slowly developing another thesis...
When coasting -- no matter how short a distance -- do you habitually stop pedaling with the same foot at the bottom of the stroke?
If so, it might not cause a shift in weight (same weight each side no matter the leg position in the pedal stroke), but it could shift your balance more to one side and I'm wondering if this could be enough to cause more wear on one side...maybe enough to offset road crown.
Another factor might be positioning on the saddle. If one leg is a bit shorter or if one's pelvis is a little less than symmetrical, it could result in sitting more heavily on one side of the saddle.
If touring, are your pannier loads distributed evenly side to side?
Do you make a lot of right turns? In the UK (or elsewhere when riding on the left), right turns are longer than left turns and so can cause more wear over time.
Also, I recall your bike was a Rohloff-equipped Bike Friday? If this is the same bike, it is possible the rear triangle is not exactly in plane with the rest of the bike. I have an unserialed prototype Bike Friday New World Tourist (the factory is in my town) hanging in my garage rafters. The pivot for its rear swingarm (used not for suspension but for folding) is misaligned vertically to one side so the wheels are slightly out of plane with each other, a bit like "X" when viewed from the rear, but so subtly off as to be unnoticeable when just eyeballing. A number of BF models have the downtube deliberately offset to one side to also facilitate folding. There's a lot going on near the bottom bracket connections and everything is a little "different" than on a conventional bike, so it takes careful measurement on an alignment table or surfaced reference to spot any problems. In my own experience, I've found smaller diameter wheels tolerate greater dropout misalignment than larger ones without causing obvious handling problem because the tangent from axle to rim is smaller.
Best,
Dan.
Hi Dan!
That's a really good memory! Mystery never solved but your last possibility is really good!!! The tire in question was replaced after it developed sidewall cracks. Current tire shows nothing out of the ordinary and it must be reaching at least 10,000 kms by now. The front tire that I mentioned has worn beautifully with over 20,000 kms on it.
So, first, the coasting...no, I don't believe I have a bias as to which leg is "down" and which is "up" when I coast.
The shorter leg thesis...very possible because I have noticed at times that I feel a bit "off" when pedaling as in I feel I have to "reach" with one leg over the other.
No touring due to wife's directive.
I make a lot of left turns from what I can recall.
And that last thesis is pure genius! Yes, the bike's rear triangle is a bit offset which is confirmed by the folding lever. I had a creaking noise coming from the bike and I had to work it over quite a bit so I saw more of the bike from below than I would necessarily like.
I think, in the end, at this moment I would put it down to a bad tire. The current tire seems to be wearing evenly so far...knock on wood...do I dare even look???
Best,
IM
