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11t lx <--> 12t ultegra casette ring swap?(9 posts)

11t lx <--> 12t ultegra casette ring swap?dpb
Jun 5, 2003 10:14 AM
Hey Folks,

I seem to remember someone saying you can swap casette rings from mountain to road casettes. I'm running an 11-30 lx casette on my mountain wheelset, and a 12-24(?) on my road wheels.

I recently switched my crankset from a 42-52 to a 38-48 and miss some of the top-speed I had on road (spinning out with a tailwind). Can I swap the 11t and 12t rings without trouble?

Cheers all,
re: 11t lx &lt;--&gt; 12t ultegra casette ring swap?atpjunkie
Jun 5, 2003 5:42 PM
you may have to switch more than the 11. most small gears on cogs have a 1 tooth increase. So your 12-24 (are you running 8 or 9 speed? I ask because 11-30 sounds like the old 8 sp. If not let me know where you found an 11-30 9 sp) so a 12-24 9sp would run 12-13-14-15-16-18-20-22-24. If you just switch the smallest gear you will have a 11-13 gap, might not work so well but I'm no expert. normally 11 cogsets runs to 21 or 23
11-12-13-14-15-16-17-19-21 or 11-12-13-14-15-17-19-21-23.
you may be able to franken rig (11-12-13-14-16-18-20-22-24) but this may take additional cogs
8sp all the waydpb
Jun 6, 2003 5:20 AM
Yah I use 8sp gear. When I was building my rig, thg guys at bikeman were pushing it for its durability. No regrets here.

That frankencasette idea sounds interesting. I wonder if I swap like three or four of the smalles cogs like you suggest...anyone ever try this?

one thing...rockbender
Jun 6, 2003 8:50 AM
Be sure to use the appropriate lockring with the 11t or 12t cog. They are not the same and don't work if you switch them... this is at least true for 9 spd, and i am assuming the same holds true for 8 spd.

FWIW, I have switched just the small cog from a 12 to an 11 on a 12-23 cassette (9 spd) without any problems.
good info all the way aroundatpjunkie
Jun 6, 2003 11:02 AM
yes eight is great. one thing, I was riding a moderate downhill this AM with a 48/12 ratio and I didn't start to spin out until 37-38 mph and I'm a masher.
some more interesting notes...dpb
Jun 7, 2003 10:19 AM
I agree, the 48/12 is okay in 98% of the riding conditions, but then you get long enough or steep enough decent with some 20c slicks and a tail wind, I'll take the extra speed anyday!

I just looked at my casette more closely, it's an 11-28 8sp not 11-30. But more importantly, the second smallest ring is a 13t, so obviously the jump shouldn't be a problem.

Incidentaly, I was doing the calculations that may interest people. I think I'm doing the math correctly, if not someone feel free to correct:

52 / 12 = 4.33 (old setup)
48 / 12 = 4.00 (new setup)
48 / 11 = 4.36 (proposed setup)

Am I right in thinking the 48-11 is actually a slightly higher gear ratio (faster) than a 52/12? And if so, why bother with more teeth up front on road rigs? I was always perplexed at why the road clusters started at 12...why make everything bigger / heavier?

Thanks for the heads up on the lockring rockbender, you may have saved my life :)

the 11T debateatpjunkie
Jun 9, 2003 10:36 AM
because of the minute size of an 11T cog you actually get far more friction from chain wrap. It wears chains faster and most of that .o3 advantage is negated by this friction. there was just an article in Bicycling about a month ago about this, so in reality running bigger rings is a more efficient transfer of power to the ground.
blast...foiled again by physicsdpb
Jun 10, 2003 7:10 AM
But having said that, I assume the differences here aren't enough to cause actual problems in running a setup such as this? I mean I can deal with a little chain wear, and if I'm at 98% efficiency instead of 99%, I won't cry myself to sleep. And I'll still be going faster then my 12t setup.

I guess that's my argument...not 52/12 vs 48/11, but 48/12 vs 48/11.

blast...foiled again by physicsatpjunkie
Jun 10, 2003 11:26 AM
have fun. I've been experimenting. On a slight downhill with about a 5 mph tailwind I was able to (TT Style) sustain 29 mph for well over 2 miles on my cx 48x12 with 38 semi slicks