1 mil out with no cold setting – I’ll take it.

I checked the alignment on Michael’s Max frame today and found the seat tube was out 1 mil and the head tube had .5 mils of twist over 250mm.  I’m leaving it as is because there’s no sense in bending a frame to make it “perfectly” aligned when its this close.

The problems with cold setting are not clearly nailed down.  One theory is that bending the steel past its yield point results in a shorter fatigue life.  That being said, who knows if that shortens the fatigue life from 40,000 stress cycles to 35,000, or whatever that number might be.  Another theory is that cold setting takes the spring out of a frame.  For example, if you take an actual spring and stretch it out it’s not so springy anymore.  The same applies to a bicycle frame.  Again, I’m not sure how much I subscribe to those theories, but that’s what’s being said about it.  

There are lots of great bicycle frames out there that are and were cold set.  I’m not trying to discredit builders that use this method.  I think about it very simply: not bending a frame is probably better than bending it, so I try not to.  

If you’re a competent builder, make good miters, and have a good process that may or may not involve a fixture ( I think it certainly makes it easier to use a fixture), your frames should fall within a reasonable allowance of alignment – let’s say within 2mils.  You probably wouldn’t be able to notice even 4 or 5 when riding, but that baby should be pretty straight if you’re going to charge money for it.  If it doesn’t, and you have to torque on it to get it there, then there’s probably something wrong with your process.  

There is a lot of debate out there about frame alignment and what is acceptable.  ”Industry standard” is 2 to 3mils out (I’ve heard both), but I’ve seen plenty of Treks, Cervelos, and Pinarellos that are 4, even 5mils out. In my opinion it’s important that a frame is within 1.5 millimeters so that I can confidently send customers screaming down long descents, but that’s without cold setting and on a brazed frame.  Heat distortion is trickier when brazing as apposed to TIG welding.  Anyone who claims their brazed frames are within .5mil are bending that bastard.

Frame alignment in general is blown way out of proportion.  Somebody comes into a shop and says, “I think my frame is out of alignment.”  What the shop should say is, “probably not, let’s check your fork, wheels, and stem.”  Unfortunately what often happens is that the shop guy says,”Let’s check it with this string doodad I made.  Yep, its out and that’s probably the problem.  You call they guy who built your frame and tell him he sucks while I stick it in my vice and bend the crap out of it.” 

Anyway, my two cents on the subject.