[Supersonic]

I recently fashioned my own Shimano 9-speed 11-25 cassette out of some cogs I had laying around.

What I am trying to decide is whether or not the cog ring I left out (the 14 tooth) was the right one.

I now have my 11-25 set up like this: 11, 12, 13, 15, 17, 19, 21, 23, 25

I need the 11 for a TT I'm doing that has both steep climbs that may necessitate a 25 and steep descents that I may spin out in a 12.

So, does that set up sound about right, or should I put the 14 back in there and get rid of another cog?

i couldnt' locate any info online about 11-25 setups you can actually buy anymore

(p.s. i didn't search this one so forgive me if it's been answered before...)

 

[brblue]

Seems right, but i'd still keep the 12-25 and get a larger big chainring. the 13-15 is quite a jump. It all comes in the end to which gears you are using most.... You might even end up with a non linear setup that suits you - i.e. leave 12 or 13 out and put 14 back in

Good luck,
br.

 

[BugMan]

I need the 11 for a TT I'm doing that has both steep climbs that may necessitate a 25 and steep descents that I may spin out in a 12.

I'd stick with the 12-25. If the descent is steep enough to spin out a 12-t, that's a good opportunity to rest your legs for the climbs. You'll expend far too much energy hammering the descents for the minimal gain in speed you'll see and, more importantly, compromise your ability to give a hard effort on the climbs. Best tactic for a hilly TT is hard efforts on the climbs and recover on the descents - the potential time gains on the climbs are far greater than on the descents

I'd hate to be stuck with 2-tooth differences that far down on the cog. In a TT you're on the rivet the whole time - ability to shift up or down a tooth at a time can make the difference between constantly surfing the edge and bogging down.

 

[Al1943]

I'd stick with the 12-25. If the descent is steep enough to spin out a 12-t, that's a good opportunity to rest your legs for the climbs. You'll expend far too much energy hammering the descents for the minimal gain in speed you'll see and, more importantly, compromise your ability to give a hard effort on the climbs. Best tactic for a hilly TT is hard efforts on the climbs and recover on the descents - the potential time gains on the climbs are far greater than on the descents

I'd hate to be stuck with 2-tooth differences that far down on the cog. In a TT you're on the rivet the whole time - ability to shift up or down a tooth at a time can make the difference between constantly surfing the edge and bogging down.

+1 Bugman is right.

 

[MR_GRUMPY]

If you are so competative that you need the extra 2 mph that an 11 will give you, you might want to go with a 56X12. For myself, I'd use a 12-25 and rest my legs when I got over 40 mph on the downhills. Hell, for a TT, I'd probably use a 13-25 and have the 16. With a 13, you should be able to spin it to 38 mph......Fast enough for me.

 

[Spunout]

The big 56 plate up front allows you to use a very straight chainline into the 14/15/16 when you're cruising at 50km/h in your ITT.

Good luck, post your results!

 

[Supersonic]

uphill & downhill; no rollers

I'd stick with the 12-25. If the descent is steep enough to spin out a 12-t, that's a good opportunity to rest your legs for the climbs. You'll expend far too much energy hammering the descents for the minimal gain in speed you'll see and, more importantly, compromise your ability to give a hard effort on the climbs. Best tactic for a hilly TT is hard efforts on the climbs and recover on the descents - the potential time gains on the climbs are far greater than on the descents

I'd hate to be stuck with 2-tooth differences that far down on the cog. In a TT you're on the rivet the whole time - ability to shift up or down a tooth at a time can make the difference between constantly surfing the edge and bogging down.

The TT course is goes 1/2 uphill, turns around, and then goes back down the same hill. Therefore, there are no rollers or places where a recovery in the 12T as per your suggestion will be possible.

i am therefore thinking that the 11-25 i put together might be ok, but i'm going to pre-ride the course this afternoon so i suppose i'll find out if the gearing is right...

FWIW, I'm talking about the Rocky Mtn Omnium TT course in Evergreen, Colorado - in case anyone is familiar with that or has ridden it before.

if so, what gearing did you choose?

 

[Supersonic]

yeah, but...

The big 56 plate up front allows you to use a very straight chainline into the 14/15/16 when you're cruising at 50km/h in your ITT.

Good luck, post your results!

yup. next year I hope to get a TT specific bike set up. and that would def. have a 56 plate up front if i can afford it.

in the meantime i'll have to stick with the 53.

 

[BugMan]

The TT course is goes 1/2 uphill, turns around, and then goes back down the same hill. Therefore, there are no rollers or places where a recovery in the 12T as per your suggestion will be possible.

I'd still put all my effort into getting up the climb as soon as possible and coast super-aero on the descent. You'll reach the turnaround much faster but descend only a little slower (if at all) than if you let up a little on the climb and then pedal like mad on the descent.

And please, do not show up at your local TT events next year with a 56-t plate until you're at least competitive in the overalls - that is, unless behind-the-back snickering doesn't bother you much.

 

[RivMac]

A 56 is a Superhuman ring. remember if you run the 56 you should have a 46 little ring to make it shift smooth. I think the best TT set up is the 55/42. I'm set up that way and have yet to run out of gears in a TT (best 10mi is 21.58).

We used to have a guy who would show up at crits with a 56t chainring. He would jump off the front and hammer then blow up. We nicknamed him KABOOM. Once I was in a group with him and he was in his 56-19. What a bad chainline. Dont be that guy. Run a 55t for TT only.


My 2c.

Garrett