Yakob/Merged article on tyre size

[GUMP_]

Thinking of getting some big tires on my road trip.

Thinking some big 2.25 aitken streets

[cmc4130]

1.75? Nah, too thin. 1.95 as a minimum. But 2.1 front and back is a good standard I think.

I dont think the inflation diameter has that big of an impact of me riding. But I wonder, is there like a standard or norm to what tyre size to use when measuring frame geometry, like BB height?

From what I've seen they assume the tire size is 20''. So for BB height it's 10'' plus the rise above axle line. It would, in my opinion, be better/more correct/make more sense to measure BB height from the axle line and not from the "ground".

Yep, it's pretty common to hear about "bb drop" and "bb rise" in mtb and road.   

[Eggit2]

The rise/drop is certainly more true than the way BMX measures it, but even that has issues because fork length is going to change it slightly.
Its really hard to come up with a 100% true way of measuring a frame thats consistent across all manufacturers, you can also see this in the several different ways Top Tube length gets measured.

[JFax]

The BMX industry often leave a lot to wish for when it comes to specifications. I find it beyond annoying to go on shops' and producers' homepages only to find they only list one or two specifications, like TT and CS.

Probably since a lot of the buyers have no idea what they are buying anyway.