Charles Ramsey

Sram makes an 11 36 ten cog cogset called XX it costs about $320. Outside of the price I don't like the ratios of the sram set it is hardly worth the trouble to shift from a 32 to a 36. Shimano makes a 12 36 nine cog cogset but I can't find one for sale. Santana sells an 11 34 ten cog cogset for their perfect 10 shifting system it also has a better selection of ratios https://santanatandem.com/Bikes/Perf10Shift07.html I would like to buy an 11 36 ten cog cogset suitable for tandem stresses.

jnbrown

There is one here but it's 9 speed:

https://sheldonbrown.com/harris/k7.html#9

zonatandem

We run a SRAM 11/34.
Instead of blowing $320 on a cogset get a smaller inner or middle chainring.

mrfish

1) It's not worth it. When you're in a gear lower than 30x32 you're probably better off walking. To go faster more training not lower gears are required. Also the gaps between 11-36 are a bit crazy. Assuming you're wanting this for the road, the gaps between gears become irritatingly large.

2) All 9 or 10 speed cassettes of reasonable quality are suitable for tandem use. I suggest not bothering with the top of the range Ti cassettes or lightweight Aluminium ones (these fail under spirited single bike riding), but anything from Shimano 105 upwards or Campag Chorus upwards will give good durability.

TandemGeek

Tell me about it: granny on our off-road tandem is 24x34 and you either spin like a hampster or fall-over when you use it... which is rare. Again, at some point it's just more efficient (and faster) to get off and hike.

can56105

We use the 24x34 a lot on miserably steep fire roads. In these situations the hills are too steep to spin like a hamster, and we often wish for an even lower gear as the cadence slows. It doesn't seem like balancing is a problem and we try to get our weight back for traction. Probably not much faster than walking but we take pride in climbing difficult hills without stopping. I like Shimano's 11x36 but it weighs a ton compared to an 11x34 XT or XTR.

WebsterBikeMan

Maybe we have a more stable bike. We go all the way to our 24x34 when loaded (for unloaded I've switched the cassette so it's 24x28). I've been able to keep it upright just fine. And walking is so demoralizing.

merlinextraligh

30x36 is 5.4 mph at 80 rpm. definitely faster than you can walk up a steep hill.

I could see that being a reasonable choice if you like to spin, and are doing some really steep stuff, or loaded touring.

However, going the other direction, and using a smaller inner chainring , such as a 26, in my experience gives better shifting and is a bit lighter setup

jeff^d

You could buy a single 36-tooth Action Tec cog, remove one of the smaller cogs from an XT or SRAM cassette, and put the 36-tooth in the back with a spacer. This is probably the easiest way to get a lower gear out back.

The Shimano 12-36 cassette is Deore level and I believe there are plans to make higher level (LX, XT) next year if it's popular this year.

SRAM XX is 10-speed and even if you blew the money on the cassette, it wouldn't work without a new derailleur, chain, cranks, shifters, etc. Total proprietary system which is silly.

rmac

I think the OP was talking about a 10sp. On Shimano 10sp cassettes the last cog is special so it can't be replaced easily.

I think the SRAM XX cassettes use the same spacing as Shimano so nothing would have to be changed except for the cassette (and maybe a longer cage rear derailleur if the current one can't handle the new cassette).

There are always the IRD cassettes. However, except for the 11-30 or 12-30 the last jump is pretty large.

mrfish

True, but jeff^d is suggesting just adding one cog behind the biggest cog, not drilling out the rivets holding the largest three cogs to their carrier and somehow replacing them.

Downside to jeff^d's suggestion is that when you use bottom gear, the full force of two tandemists is transmitted through the single cog spline, assisted by the leverage from a 24x34 gear. The cog will likely rip through the splines of the cassette and deposit you on the ground, face first. This is why high end cassettes use cog carriers for large gogs. Another idea is to use a, pinned shimano cassette if you want to modify the cluster as you can unscrew the pins then reinstall them on the modified cogset. This ensures torque is transmitted by all the cogs in the cluster onto the cassette body.

jeff^d

Ah, yeah I didn't catch that they're on a 10-speed system. I agree though, XX cassettes will work with Shimano shifters. For the 11-36 you'd definitely want an XT or XTR rear derailleur. I've read the XX cassettes are a lot smoother (and lighter) than the IRD cassettes, and IRD only offers an 11-34 cassette (albeit at 1/2 the cost of XX).

I feel this general resistance to move to a 10-speed system, but most of my riding is on the dirt so I don't have any 10-speed setups. 9-speed works fine for me, but I guess people said the same thing when 8-speed went out the door.

rmac

Take a look at the last cog of a Shimano 10sp cassette. It's not flat like normal cogs. You can't just take the last cog from say a 9sp cassette and stick it on the back with a spacer. The cassette won't fit properly on the wheel.

I thought higher end cassettes use an aluminum carrier for two or three cogs to save weight. The Campy Centaur cassettes have now switched to all single cogs. Wouldn't there be more torque on the smaller single cogs?

VaultGuru

Take a look at Sheldon Brown's Gear Inches. Zona called it. Enter your current gear selection and compare to what you want in gear inches. I'll bet you can change your front chainring(s) to get the results you want
https://www.sheldonbrown.com/gears/

Chris_W

It is certainly possible to put one larger cog behind a regular cassette, and remove an intermediate cog to get a wider-range cassette. It takes some playing around with different spacers between the loose big cog and the three on the carrier, but it certainly can be done. However, as mentioned above, I would not recommend doing so on a tandem because of the extra power that needs to be transmitted and the danger of damaging the freehub body.

I've done this on a single bike, where I made a custom 12-28 10-speed cassette. I took a 12-25 cassette, removed the 16 tooth, and used a loose 28 tooth on the back (which came from a partly-used 11-32 MTB 9-speed cassette), and used trial and error to find a couple of spacers that positioned the 28-tooth cog correctly in the end. This then gives me well-spaced low gears: 19-21-23-25-28. Interestingly, it appears that the 17 tooth cog was made to have a 16 tooth inside it, because shifting between the 15 and 17 is not quite as smooth as it should be, it sometimes require a little extra nudge which is not needed for any other shifts, but this is not a big deal. The 25-28 shift works fine. It would be great if someone were to start making a stock cassette like this. Campagnolo recently released a 12-29 11-speed, which is a step in the right direction, but doesn't help the majority of people with their Shimano/SRAM set-ups.

[EDIT: I took a look at my freehub and the loose 28 tooth is already starting to eat into it a little, even on this single bike. Fortunately, I just discovered that BBB make a stock 12-28 10-speed cassette with the exact cog sizes that I want, so I now have one on order for a very reasonable cost of 40 UK pounds.]

I certainly recommend going with smaller inner chainrings before wider-range cassettes - the cost is cheaper and the spacing between the rear gears remains decent. Only once you've reached the limits of gear range on the front (yes, you can normally quite easily exceed Shimano's recommendations for derailleur capacity front and rear) should you start to look for a wider range in the back.

rmac

That's true. If you're not concerned about the spacing between the cogs, with the right size spacer you could put anything on.