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K&K
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Discussion Starter · #22 ·
Well I'm running out of threads, so if it's spoke tension my spoke length is wrong. Certainly could be, I didn't do the calculations myself, and the Mavic inserts might throw the calculator off... When I re-dished, I only added tension so overall tension is higher than it was.

Not at all a stupid question Paul. I used to do a lot of rock-crawling and my truck buddies and I would routinely find enormous differences from one gauge to the next. My digital reads about 2 psi higher than the floor pump that I usually use to measure pressure.

Heading out for a ride now...
 

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Rim width comparo?
According to my quick search on the Goog, you went from a rim width of 32mm to a rim width of 24mm. That, when combined with a large-volume tire, will give you a lot more squirm on its own, but especially in changing from the wider rim itself. Can you verify your actual rim widths to compare?
 

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K&K
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937 Posts
Discussion Starter · #25 ·
Okayfine, You're right, the old rims are wider. Measured on the outside I get 29 mm vs bit less than 32 mm; not as big a difference as the specs suggest but maybe I'm measuring wrong. This was the only tandem suitable UST rim I could find, so width wasn't a consideration when I chose these.

There is certainly less squirm with the higher pressure, but during the 2 short rides I took with higher pressure, washouts seem to happen faster, more frequently, and with no sense that there might be a chance to ride out of it. I dropped the pressure back down to 32 today and had a much better ride (along with re-dishing). Twice I washed out "big" and recovered, something that has become routine on our rides in this loose gravely terrain. 2013-09-07 08.34.38.jpg

It's clear I'm in the minority here, but I am much more secure with softer tires. I'll trade a bit of squirm for the added traction. I would probably feel differently on more stable surfaces.
 

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Glad you found a fix! And terrain definitely has an impact on suitable air pressures.

Any data on how much your dish was out? Just for future reference.
 

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K&K
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Discussion Starter · #27 ·
The medium feeler gauge I made is 2 mm and the thick is 4 mm I would put the difference somewhere between there. That amount was similar on front and back, both on the same side (flat side).
 
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