Custom cassette; 12t lockring on a 13t second position cog?
 

I am trying to fine tune the gearing on my 10 speed setups. After mixing and matching from various old cassettes laying around, I've found a setup with the ideal gear range. Since I rarely ever find myself in the 11t/12t cogs, I would like to go with a 13t on the high end (of course I will add the proper number of cogs back into the cassette to fill gaps). The problem is I do not have a first position 13t cog (the terminal cog that mates with the lockring). These first position 13t cogs are getting harder and harder to find (and more expensive), as are the corresponding lockrings. So, I am considering using a 12t lockring on a 2nd position 13t cog (which I have several of). I did a quick check and it does hold, but it's obviously not ideal; the 2nd position cog lacks the lockring mating surface, but it does still overlap with some of the cog. I will also need to stack an extra 1-2mm spacer on the bottom end of the cassette to take up the extra slack (or put it between the lockring and the 13t cog - the lockring sinks a bit deeper into the 2nd position cog because it's smaller and the cog itself lacks the mating surface and is thinner near the splines compared to a first position cog).


Has anyone else done something similar? I already understand this is not ideal, but is this a truly terrible idea?

So long as it is torqued up against the sprocket and not the freehub you will be fine.
I have been doing just this for years.

You have come up against the problem many of us have, a current 9, 10 or 11-speed cassette with a 13T or even a 12T first position cog is difficult to impossible to find. My favorite cassettes in the past were Campy's 13x29 and Shimano's 12x27 10-speed but these aren't listed any more and it seems nearly everything starts with a (to me) useless 11T cog.

Actually, AFAIK, the lockrings that came with the 13T first position cassettes and 12T cassettes are the same and only 11T cogs required a different (smaller OD) lockring.

Another experienced vote for yes, it's fine. Been using the same setup for about 15k miles and no issues.

I have a Campy 12-30 10 speed that I bought new 2 years ago. They're around.

50x12 gets you 27 mph @ 80 rpm.

10 and 11 teeth are for a smaller chainring. It gets used a lot more in a 1x set up where you might have 40 or 42 for the only chainring.

I tend to agree though, on a double, whether compact 50-34 or standard, 53-39, 12 is plenty. My old Dura Ace bike is 13-24 uniglide. It's fine (pointing down anyway).

FWIW, Assuming a 2x crank (?) an 11-XX cassette makes the 12 and 13 tooth cogs that more likely to be usable if cross-chaining is an issue with your setup when in the small crankring. A cassette that starts with a 13-tooth, means that your highest gear when in the small front ring probably starts with the 15-tooth cog.

I have done similar as this without issue. I have used .5mm thick stainless spacers between 1st cog and the lockring. This resulted in a smooth surface for the lockring. Never had an issue.

As others have noted. It is all about the torque. Which means a torque wrench would be beneficial, and not just a guess.

John

Thanks for all the perspectives. Glad to know it's been done 👍
For context, I'm thinking about doing this on multiple setups, 1x and 2x. I've obsessed over gear ratio calculators and based on my riding experience, am willing to make the trade-off (at least for now) between having lower top gear vs filling in gaps in my wide range cassettes.

It is funny that you mention obsession with gear ratios. I have an excel spreadsheet that lists both my bikes and my wife's bikes. I set it up with an arbitrary cadence of 75 as a reference point even though I am usually spinning out a lot more than that. It calculates the speed I am going with different ratios by cog and chainring. I can throw 90rpm in there if I want to see those results. Since I know how I ride different routes, speed is the quantifying factor to make a change... higher or lower.

I have listed the bikes and the changes made since the late 80's, (I couldn't recall the exact gearing before that time), to present for both road and mountain. It is interesting to compare the changes over the past 30+ years and the wider ranges as father time has reeled in my breakaway.

Last month I set up a 14-34 on my road bike, (installed a slightly larger large chainring), and this past weekend I installed a 40t cog on one of my mountain bikes... LOL! I also run potential changes and compare if this cassette change or that chainring change is worth it. It is a really good way to help decide what to buy.

John

Yep, they are around but not common. I have two Shimano 12x30 10-speed cassettes I purchased a few months ago and they will go on my bikes for their next overhaul. It took some searching to find them as nearly everything else starts with a 11T

My favorite used to be a 12x27 10-speed but it's out of print now. The best thing about it is it's a straight block from 12 through 17 and combined with a 50/39/26 triple crank gives me a range from 26 to 112 gear-inches. That will do for everything except loaded touring.

Agreed, though I've always wondered why they never just offered 12-28 with those gear jumps. It was always 11-28 (missing the 16t) or 12-28 (missing 16t but going 21-23-25-28). Instead of looking for a coveted 12-27, I always just customized using 12-25's high end with 11-28's low end until recently. Now I'm doing more gravel and want wider range cassettes with ultra low climbing gears.

I've never understood the matching notches on the smallest cog/lockring. They just increase the force required to get the same amount of tightness on the lockring. And I don't think there's any risk of the lockring loosening on its own.

I've also used "middle" cogs at the end and never had an issue.

Wanting to use the 12 or 13 in the small ring is an unnecessary stipulation. You should be in the big ring by that point anyway.

How people use the range of their cassettes, IMO is personally-driven decisions -- based on fitness, cadence and what the current terrain looks like. There's no universal 'should be'.

The point is that whatever position cog in the cassette, where you personally feel you should be moving to the big ring, changes when you change the starting point of the cassette. If you think it should be the 4th cog (14-tooth with an 11-xx cassette), then with a 13-xx cassette, then it becomes the 16-tooth). A wider ranged cassette offers a wider range for EACH of the crankrings. Same goes on the low-end: eg. a XX-28 vs XX-34. You pick up some addt'l low gears available using the xx-34 while remaining in the large chainring, potentially avoiding more frequent need to downshift to the small chainring (depending on your terrain, etc)..

Let's say a person has a 50/34 crankset and an 11-28 cassette. Even though they *could* use the 34/13 combination, there is no advantage over the 50/19. The 50/19 runs smoother, wears the chain at a slower rate, and still has plenty of runway in both directions. So personal fitness and terrain don't enter into it.

It's not like I'm going to make "citizen's arrests" when I see people tooling around in their small-small, but there are no mechanical or physical reasons to do so, only personal quirks.

I agree that the 50/19 would be better if that suits a consistent cruise speed for wherever you are. In a perfect world we can always be riding in the middle of the cassette, and generally that's what we aim for for either of the front chainrings.

But if the 34/13 is where you end up, perhaps during some flat sections on some rolling climbs, it can have utility if it gets you back to your climbing gears without necessitating front der changes. In other words, the 13 is part of the runway you refer to, but for the small chainring.

So, I gave this example because 50/19 and 34/13 are the same gear ratio. You would be "cruising" at the same RPM for a given speed either way.

Gear shifting is pretty quick and easy these days, so I just don't see the point of hanging out in a rough and inefficient gear combination if you don't have to.


Perhaps we should define "cruising" better. I see people refer to it sometimes, but it's a nebulous term.

I guess I'm living in the perfect world after all! With a 46/28 front. The 46T chainline lands in the middle of the cassette, and the resulting gearing means that I'm usually using the middle cogs. And I can use all 8 cogs without feeling like I'm cross-chaining. The 28T is hardly used but nice to have for very steep hills.

50/34 with a standard double-chainline was possibly my least favorite setup. Way too much front shifting, poor chainline in the big-big combinations, and the huge gap between the 34T and 50T meant that a front shift usually required a few rear shifts too. 42/52 is so much easier to use, even it it means the lowest gear is not nearly as low.

It's a bad idea.

First position cogs have a builtin spacer so they have good spline engagement overhanging the end of the freehub, and serrations to prevent lock ring rotation. While you can probably get away with no serrations, poor engagement with the freehub splines is a bad idea especially if they're aluminum like Campagnolo spline freehub bodies and many aftermarket Shimano/SRAM pattern parts.

Just buy a cassette with a 13T first position cog. The lock rings are the same for all 12T+ first position cogs.

13-14-15-16-17-18-19-21-23-26 is my favorite for the 10 speed era.

Having issues acquiring 13-21 8 cog cassettes after Campagnolo moved on to 9, I probably have enough 10 cog 13-26 spares for 75,000 miles in my parts bin,

Small ring x small cog is usually usable without rub when you properly adjust front derailleur trim.

When you have a narrower than normal crank you can add 0.5mm shims made by Wheels Manufacturing, LeTour, and Origin 8.

You pay about a 1% efficiency penalty for doing that instead of moving to the big ring and might find the noise annoying but aren't going to hurt anything.

https://www.ceramicspeed.com/media/3...ize-report.pdf

Big x big can lead to uncommanded shifts to the small ring as the teeth wear down which can cause crashes when you're standing at the time.

The point about spline engagement is a good one. I've noticed this firsthand when putting the cassettes together. On one setup I did not need any spacers and the lockring torqued down nicely with the spline engaged. On another set it was a little tricky and I needed a very thin spacer between the lockring and high cog. Will give these setups a try, but certainly something to keep an eye on.

Yeah, everybody's setup varies about how much cross-chaining can be done, and to what detriment. As I've mentioned though, I'm not advocating the practice as a default, but pointing out that it can and does occur when riding in transitional terrain.

https://cimg2.ibsrv.net/gimg/bikefor...7333b3023.jpeg
Singlespeed conversion kits like this exist. So it is a safe mod.