Chain & Sprocket Sizes

[Jakobi]

The extra 2 teeth on the rear take the bike which I think is geared too tall stock to just right. It means you only really need to go back to 1st gear for the nasty stuff and most tight single can then be navigated in second gear without too much clutch work. As you get into 3rd/4th/5th the 50 tooth just seems to keep the engine in the meat of the power a bit better too. IE you don't have to continually rev really high before changing for fear of dropping off the pipe. You can just keep clicking around 3/4 throttle and the bike stays on song. IMO this is easier than changing early, having power sign off, clutch it up or hold on past the transition etc. For a 250 I would probably go to a 51/52 tooth even depending on where you ride.

[prunty]

Thanks for your comments, very informative. Mines the EC300 so I'll try the 50T on the rear...

[mtnmanseth]

So, if I'm reading this right, when I install my new 50T rear with a barely worn stock (OEM) chain from the stock gearing (13/48) I WILL NEED TO BUY a new longer o or x-ring chain, then? Is buying a 120-link then cutting 6 links off my best bet? Thanks!

[djroggen]

Nah you should have plenty adjustment left to keep the same chain. The tire you run makes a difference as far as how tall it sits from the rim, then maybe if you have no clearance you may need a longer chain. I have ran a 52 with studded trelleborgs down to a 48 with stock chain and no destruction of mudguard.

[mtnmanseth]

Whew, that's great news... And $100+ savings for more add-ons, which never end - thanks to this forum! I'm currently running a Bridgestone M404 110/100 (love it) and felt like there was ample space to mud guard, but definitely don't want to figure out that I need a new chain/tools the night before another awesome SoCal singletrack ride! I do, however, have an MT43 up next in the tire queue, so I'll reassess after trying it with the M404. Thanks djroggen.

[mtnmanseth]

Wow, I was wrong... The counter sprocket is an "Ironman Sprockets" 12-tooth! I just assumed it was stock (13T) because the previous owner never rode it, never mentioned it, and didn't seem like he made a single change to the bike. Could my bike have come stock with 12/48 gearing? Well, I guess I'll try 12/50... 12/48 was a lil too tall for me...

[pigpen966]

12/48 is almost the same as a 13/50, isn't it?

[adv rider]

Originally Posted by pigpen966

12/48 is almost the same as a 13/50, isn't it?

12/48 is a little lower than 13/50. It is more like 13/51+. If I am remembering correctly 1 tooth on front is something like 3.6 on the rear. I'm sure someone knows exactly though.

[bkwdc]

51/13=3.92
52/13=4.0
48/12=4.0
50/13=3.84

[Jakobi]

Originally Posted by bkwdc

51/13=3.92
52/13=4.0
48/12=4.0
50/13=3.84

Spot on!

You'd be mad to call 12/48 or 13/52 tall. Thats about as short as anyone ever goes.