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another simple thing to check is the spacing of the fork ends

the front hub should be 100mm "over locknut dimension" or OLD for short

so the opening in the fork ends should be the same

for your string test with the ~five mm difference you could try moving both blades ~three mm to the left (non-drive side)

best to remove the fork from the frame for this step; alternately you could clamp crown in a bench vise

the steel tubing has a measure of springyness so when cold setting it will have a slight tendency to move back in the direction it came from; this means you need to move it slightly past where you want it to end up

then you could check if that stops the pulling to one side

the ride test will be some trouble for you since you already have the bicycle fairly far apart in order to make the measurements...

of course if the adjustment solves the pulling problem you won't need to disassemble the bicycle again...


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