I've been getting by for a few years on different bikes with different set ups for different times of year and conditions. I'd like to make something definitive now that I have a good idea about what would work best for me. I live in Chicago, and my rides are almost all less than 5 miles, flat, and entirely on paved roads which are at least fairly maintained in the winter. I don't ride in deep, fresh snow, but I do in all other conditions. Main purposes are for commuting and errands including groceries. I do have access to a car, so I don't need it for heavy duty hauling. Here are my non-negotiables:
1) Mounts for rack/fenders
2) Spacing wide enough to accept at least 35mm studded winter tires
3) Usable with Shimano Nexus inter-3 rear wheel with coaster brake, for wet/slushy weather (I've considered instead a new fork with disc mounts but ruled it out for various reasons)
4) Ideally a somewhat upright posture, but not dutch-bike-esque
Although buying a new frame and building up from there would be the "best" option, I can't find a way to get this project done for less than $1200 that way--my budget is more like $6-700. What I've done before is bought old, steel bikes and rebuilt them with modern components. I'm thinking that would be my next best option again, but I don't know whether to use a mountain or road frame.
Problems with mountain frame are:
-Typically spacing of rear dropouts is 135mm, which I would need to "cold set" to 126 or so to accept the IG hub I have in mind (it comes spaced to 120mm, can be respaced up to 126).
-Frames are often heavier and often cheap, Taiwan-made and TIG welded.
Problems with road frames are:
-Cannot accept any more than about 35mm max, and I couldn't run wider if I wanted.
-The geometry is less flexible to allow for more upright riding.
-Likely the stock wheels are 27", which means I also need a new front wheel (for 700c tires), whereas I may not need one with a 26" mountain bike frame assuming it's in good condition still.
SO, I'd like your thoughts on whether you think picking up a road or mountain frame would be preferred. Thanks all.
With the choices you gave us, it seems like an aluminum (not steel) mountain bike frame is best for you. I would stay away from any suspension components as buying them second hand is a gamble. The mountain bike frame will have enough clearance for most of what you want but you are going to have to make compromises here and there to get what you want.
I do the same thing you do, I get old bike frames from second hand stores and either completely restore the parts on them or replace them with newer more modern parts. The second bike I built was by far my best. I had a summer and fall version of it for the different weather. It was based on a road bike frame but seemed like it was a hybrid between that and a cruiser bike. I had the slick tires with a tight set of brakes during the summer. In the fall I had bigger tires for more traction with wider brakes to fit. I loved that bike!