How many links are in a mongoose model 270 bmx bikes chain?

Answer 1

Good bikes are made in different frame sizes. And dedicated riders often chainge the gearing ratio by replacing either the sprocket or the driver with one with another tooth count than it came with.

These things influence chain length, so you see that no one can tell how many links your chain should be.

Chains are just about Always bought a Little long, then cut to length on the bike. Faster than counting links. Chain breakers aren't expensive. Either have a shop fit the chain when you buy it, or get a chain breaker (and a quicklink) and fit it yourself.

Do note that chain, driver and sprocket wear together, but usually the chain wears the fastest.

So sticking a new chain on old sprockets can often lead to the chain skipping and slipping.

If you don't know how to measure a chain for wear, better replace aat least chain and driver at the same time.