Originally Posted by
twocicle
I understand your trepidation in venturing < 145mm. However, it depends on your intended use and team specs. There are plenty of teams now using 130mm and 135mm (disc) rear wheels without issue. I believe modern components have better design and capability that those of years past, which is allowing for a move to less extreme spacing, etc. Your mileage may vary of course.
Rear spacing choice is not always just a SWAG either - it is sometimes necessitated by the cranks/chainline.
In the past I have found that the wheel user's determination of what constitutes "without issue" or having "no problems" varies with the users maintenance expectations as well as the actual stress put on the system.
I am considering a 135mm rear drop out tandem but really wonder if the extra choice in hubs is worth unavoidable weaker wheel geometry. A 135mm hub (which has flange spacing about the same as a 130mm hub) may be strong enough for us. We are about 290lbs and high volume tires that protect the wheels from a lot of hits. On the other hand If I have to I can get a Chris King or Hadley 145mm hub made that is pretty light and high quality. Might pay a premium for those vs an off the shelf 135mm hub, but if you narrow the 130mm and 135mm hub choice to only those with lots of points of engagement then off the shelf list gets much shorter, heavier and more expensive.
For me chain line is a secondary consideration. Currently my wife is increasing her flexibility and starting to narrow her original really really wide Q-factor which was 205-210mm. Using a various bottom bracket widths, pedals, pedal spacers, and washers we are able to do this in small increments. Currently we are running a 106mm square taper BB on a 160mm drop out Santana. We loose use of a two or three of the small cogs in the middle ring but other then that it is actually shifting well. We stay in the big ring a lot and the chain line in the big-big combination is very useable. This is an extreme, and temporary set up but it goes to show that chain line is not as critical and some think.