plasmapuff wrote:This could be because the gearing is big chainring/big cluster cog, which is not the gear of choice. I usually use gearing such that the big half of the cluster is on the smaller chainring, and the smaller half of the cluster is on the big chainring ie 17-23/39 and 11-15/53 to avoid stretching the chain and derailleur.
Whoops I didn't know this... I was using big chain ring with large cluster pretty consistently on the flats on the 100 km ride on Sunday.
So in that case whats a good combo to use on the flats? Say if you wanted to maintain 30km at high cadence? (I was using the big-big previously)
Big-to-big and little-to-little is called 'cross-chaining'. It's best to avoid these two extreme gears. I'd mainly avoid them because they're often a bit noisy (the chain might rub on the front derailleur cage). Putting the chain on both the largest sprocket and chainring bike forces the chain to engage or leave each at the most extreme angle possible, which (in theory) stresses the links. I wouldn't say you have to avoid it completely, but I'd avoid cross-chaining for prolonged periods. There's just no need.
On modern road bikes you've got so many gears to choose from that there's no need to cross-chain. If you find yourself needing to be in the big-big combination, shift your front chainring down and go up a couple of gears at the back. You'll find a similar gear easily enough.
FWIW, I think your chain length looks fine. You've got enough length there that the big-big combination isn't locking up your rear derailleur. Most of us don't often see a photo of a bike in the big-big combo, which is perhaps why it's raised a few eyebrows.