Dear Welder Series…
How narrow would the frame rails have to be for a 49 inch track width? thanks
coop

Dear Coop…
As the crossmember gets narrower, the upper towers must also be brought closer together.  These two things happen in a 1:1 ratio.  If the crossmember is narrowed by 7″, the upper towers have to be brought in by 3-1/2″ each side.  The simple answer to your question is 19″ – 23″ outside.

Here are some other considerations:
The frame width range for a 56″ kit is from 26″ – 30″ outside.  This is affected by the height of the frame relative to spindle height.  If the frame is wider than 30″, the spring can hit the top outer corner of the frame rail.  This can be overcome by notching the corner.  If the frame is narrower than 26″, the upper towers don’t have a surface to weld to.  The frame can be built our at this point.

This was a good question.  I hope the answer helps with your planning.

Paul Horton