I am considering swapping the 165 2.75 on my Khaos 9R to the Composit M770 3". Do I need to gear down for that? It looks like the gearing is the same for the Series 8 and the Series 9, is that right?
If you already have a QD2, the only real option to gear down is an aftermarket belt drive like TKI. The 9R works really well with the QD2 and the 3.25”, so you should be good.
Either of the tracks you mentioned will be a huge upgrade over the 2.75” Polaris track.
Regards to the M700 (3"), Last fall I installed one on a friends spare 850 174", and I rode this sled in Revy for 3 days in a row as my 163" sled was down. It is a beefy track for sure and lugs are fairly soft, and I found it climbed and hooked up quite well (as any 174 should lol), but have never been a fan of the side lugs that are shouldered at 90 deg. As wicking around trees it hooks the sled straighter to the line you are looking for. Something to get use to, but I would go with M770 in my opinion.
Personally I’d go 300lx, it’s a very good track and 8-10lbs lighter than the Composit tracks. Close to the same price on Tracks USA. Not saying the Composit tracks are bad, they are a multiply design and weigh more (most other tracks are single ply). The multiply probably gives a little better durability because of the extra material in the design.
I put the M770 on my 22 850 155 last season to replace the S8 275. Much better track for climbing in moderate to deep snow. Durability is also much better than the 275. It is a heavier track but didn’t notice it out riding. I would definitely purchase again.
I put a m770 on my 2023 165" 9r last year. I ride in the maritime snow zone and there was a significant increase in arm pump compared to the series 8 2.75" or whatever came on the sled.
Maybe it was the quarter inch extra length? I personally think it's the lug stiffness. I could bend my series 8 lugs all the way back and touch the track with the tips of the lugs. This makes me think that in Sierra cement the series 8 is comparative to giving a san fran cute boi a hand shake.
The m770 lugs you can barely bend by hand. Ya it's heavier but I think it performs amazing on the West Coast. I actually like the extra weight for attitude adjustment in the air. That rotational mass makes a big difference when you're weightless.
From what I've read, I think you cant go wrong on the West Coast with a 300L, m770 or doo track. All are going to be a direct performance increase for your sled.