by Calnago on Sun May 05, 2019 5:27 am
You both (Tobin and PdlPsher1) don't get it and one's arguing for fine thread pitch, which has already been decided upon for good reason, which we have always had, we're just simply changing to an essentially equivalent metric pitch and nomenclature. And now Tobin, who's arguing for coarser, which we have never had, but he seems to think it's better for some reason. You only want to remove as little material as possible from the PF30 bore of 46mm. Coarser threads mean greater depth as well, and hence, more material gets removed. But still... please explain why you think coarser threads are better. Up to this point, you've been like a child, claiming "Threads should be coarser" and when asked why, at least so far, your answer seems to be "just cuz". That may work when you’re 4 years old, but a bit more of an explanation might be nice. The fine pitch has seemed to work for many many years in both English and Italian bb shells... why would a coarser pitch be better.
While you ponder your answer, I will tell you why a fine pitch is good for this application... one, already discussed, the threads don't have to be too deep so the walls of the shell can be thinner, but really I think the more valid reason is this... At some point the cups will thread down to the shell face and the finer the pitch the more gradual and uniform that interface between the cups and the faced shell face will be, and that's a good thing. And yes, the shells will need to be properly faced. With the fine pitch, they will settle in on that perfectly faced shell nice and solid and straight and aligned. End of story and all is well.
And when we're all talking metric these days... don't you think it makes sense to have the complete measurement in one measurement system... metric. Hence, 47mm x 1mm. Taps are available, I've already checked. It's easy to understand, well, for most. For some reason Pdlpsher1 seemed to think there was quite a difference betweeen a pitch of 1.0 and 1.058 (24tpi converted to metric). There really isn't. But it's clearly confusing to some. That's all. I'm all for calling it 47mm x 1mm over 47mm x 25.4tpi any day. When you refer to your height, I'm going to assume you're short... do you call yoursefl 5'ft 15cm... or do you say 5'6", or 168cm? Because the 5ft 15cm thing is analagous to the 47mm x 24tpi thing.
I'm out, you can figure it out yourselves. For now I'm going to just wait to see what Trek actually does before thinking about it too much more.
Night you two, have fun.
Last edited by
Calnago on Sun May 05, 2019 5:27 am, edited 1 time in total.