Originally Posted by
Jimmy Legs
....wouldn't going to a skinny tire from my 2.1" tires significantly drop the bottom bracket enough to cause problems? Wouldn't I need to keep the overall outer diameter of the tire the same?
No. Imagine your bike with no tires on the wheels at all. Besides no traction and a bad ride, where do you see any problem for the BB? While in a turn, your pedal might be a tad closer to the ground. I doubt you will be banked over that much. And if you do pedal through turns and have a strike, you'll learn quickly not to be pedaling through those turns at that bank and speed.
If you know the ISO or ETRTO size of your tire and just compare the difference in ISO width of the two, then that will also roughly be the change in height of your bike from the ground. So if you are looking at a 32 mm wide tire then your bike height only changes about 3/4" to maybe not quite an inch.