At 80 mph, you increased RPM 267. Probably just enough to bring the V-twin out of it's shudders. That is according to gearing commander. As far as the mass of a couple of sprockets and the chain, sure there's some rotational reduction there, but at the expense (like you said) of increasing wear. RK and DID make high tensile 520 chains for racing, but as racing is concerned, stuff is consumable.

I totally agree I be dropping to 16 once the chain sprocket worn 11k mikes on clock should be to long now . Shame have to lower 123rd too . I think ktm addressed the 5&6th to high

Life saver, thank you!

Great video, just subscribed. Nice bike 👍. I have a 2015 I bought new tricked out. The 1290 is the best engine ever. I may drop that front sprocket size as well.

I've done this to many bikes and will likely invest in it for my 1290R as well next summer. I can feel the difference in any bike I've done it to. The only caveat is that I usually use a hardened aluminum rear sprocket and those DO wear quicker (but go a lot further than you might think on the street) just to lower overall rotating mass. On all my track bikes this is a no-brainer. Strength-wise I've used the EK endurance chain with no-stretch feature and that usually outlasts two aluminum rear sprockets or around 16K miles on the street... last bike I converted was my 201hp RSV4 RF and it was a great upgrade IMHO.

I’ve got mine with 16 already, it’s great but I also got myself a 15 teeth one to try. Staying with 525 for a while, if I will start taking it often to a racetrack will switch to 520. I always raced my litre race bikes on 520 and changing chain and sprockets once n two years is least of the expense as you go through the set of 700 usd tires at least once per race weekend, if your pace is more formidable then once a day or once a race. Just swapped my Ktm 690 sm from 16 40 to 15 42 with a new 520 chain. No extreme whatsoever if you know how to se the clutch, monster power wheelies in first and nice power wheelies in second but very timid clutch wheelies in third. Much nicer to drive between 40 and 120 kph what this bike is aimed for.

Awesome video; where did you buy the sprocket and chain

Just watched your video again, and what you say makes sense, so I am going to order the same kit you installed on the bike as a final thought. After having it installed now and riding the bike for over a month, does it make a big difference in the lower gears? Is it better than standard, and, in your opinion, the riding experience overall is far better.