Originally Posted by
SoSmellyAir
The RD cage is so close to the ground; does the 4T max cog difference between an 11-46 vs. an 11-50 cassette really change things that much?
It's easy enough to do the arithmetic calculation yourself to see the difference in gearing range between one and the other. One is 418% while the other is 455%.
Is it possible to install both a smaller chain ring and a smaller cassette to maintain approximately the same low end of the gearing?
Yes, it is possible. At the expense of top-end gearing. It's a game of trade-offs. Gearing range vs. Ground clearance. There's no free lunch.
See embedded answers above.
Earlier this year, I toured South Korea for the third time on a folding bike. This time as in the previous occasion I rode a 16" (305) wheel folder with RD ground clearance shown in the following image:
Provided you have achieved sufficient ground clearance, as in the setup in the image, you'll find that the biggest threat to the drivetrain is not RD strikes against surface features, but rather increased dirt deposition on the chain. I am not concerned -- neither should you -- about RD ground clearance on the build-in-progress, the subject of this thread. Ironically, most votes in the poll so far are "Too short". Were I to use a longer chain, RD ground clearance would
decrease. If RD ground clearance is a factor, a consideration, "Too long" and "Just right" are, in practice, preferable choices.