Redbullet

Is there any possibility to remove 11T cog and add 18T cog between 17T and 19T on 1170 (11-28) cassette?
I noticed that, mysteriously, it looks that SRAM does not even produce 18T.

Andrew R Stewart 

The era of sprocket boards ended years ago. These days since many riders don't know the nuances of smooth shifting the manufacturers find it easiest to sell systems that work well even with poor technique. This requires the cog shifting locations to be synced WRT the adjacent cog's shift points. (as though shifting more then one cog at a time is the common method). Thus we have "A" and "B" cogs (and rings) of otherwise the same tooth counts. "A"s will ONLY work with other "A"s. (According to manufacturer's guidelines).

Of course those of us who grew up with no indexing or gated shifting know this to be a false premise. But it pervades the industry so much that single cogs are, pretty much, no longer made available by the main stream brands. Andy.

dsaul

If you have a look at the 11t cog and then the one behind it, you'll see why this is not possible. The 11t has serrations around the outer edge and the lockring tightens against them. The next cog in line has a recess for the integrated spacer on the back of the 11t cog to fit into. The last cog in the stack is specially designed for that purpose and cannot be discarded and replaced with another cog from the stack.

fietsbob

No.

KD5NRH

Don't listen to the negative nancies on here. With an arc welder and a lot of skill, all combinations are possible.

While you're building up that welding skill, get really good with a plasma cutter too.

ThermionicScott 

It would be a pretty sweet progression if you could swap the 11T for an 18T in the middle. Alas, SRAM seems pretty committed to 11T cogs and other things that annoy me, though.

What crankset are you running, @Redbullet? If I found myself in the position where I couldn't make the top cog any bigger, I'd look at making the big ring a little smaller so that I'd get better use of the whole cassette.

oldbobcat

Shimano makes a Dura-Ace 12-28t 11-speed cassette. Alas, the website doesn't indicate if there's a 19t sprocket.

ThermionicScott 

Found it on the Colorado Cyclist website: "12-28: 12-13-14-15-16-17-19-21-23-25-28"

Redbullet

SRAM Force 52/36. Switching to 50/34 would not be enough and it would be expensive.

Homebrew01

Stupid that most Shimano/SRAM cassettes start with an 11.
I just bought Campy 13-26 for non-racing with my 53/39.
No need for 11 or 12, and would rather have middle cogs that get used all day.

Redbullet

There is a 12-25 Shimano Ultrgra cassette. I wonder whether it is compaatible with Sram Force chain and shifter...

dsaul

Sram and Shimano cassettes are cross compatible, as long as the number of cogs is the same.(ie. 10 spd, 11spd, etc.)

oldbobcat

Right. I wouldn't have brought it up had that not been the case.

Delmarva

+1
However Shimano and Sram choose gearing ranges that appeal to the vast majority of riders who rarely if ever shift the front derailleur. The Shimano 13-26 is also a very useful design.

ThermionicScott 

Replacing just the outer ring with a 48T would give you pretty much the equivalent of a 52/12 top gear for about $28. Something to consider.

P.S. A 46T big ring might be even easier/cheaper to come by, and would put the 15-16-17 where your 17-19 is now. Just speaking for myself, that 111" would be plenty big for a top gear.

Redbullet

That's interesting. I should check whether such alternatives are compatible or not with my spider.

fietsbob

ACTUALLY THERE ARE cassettes made for Junior racing that start out larger , its just that the places stocking them are few.

Here with just a little search is one : https://www.excelsports.com/main.asp?...jor=1&minor=10

Starting out with a smaller wheel like a Bike Friday then the 11t makes some sense.

Set the High-limit screw in a ways so It wont shift onto the 11 solves the problem cheaply, It does not cost a thing.

ThermionicScott 

Good call, @fietsbob.