Tandem Cycling - Changing cassettes according to planned ride?

How many of you will change the cassette according to the ride terrain (and distance)? Our tandem has an 11-32 9-spd cassette with a 24-36-48-60 set of chainrings. This is great when we're climbing, but if I know in advance that the terrain is moderate, let's say not much over 6% I'm thinking of swapping out for something like a 13-25. Is this a common practice? Would make it a bit easier to keep up with fast singles. I'm comfortable anywhere between 80 and 100 rpm, but I don't want to go over 85 or so until my wife gets more comfortable at these higher cadences. The wider spacing on our current cassette makes it a bit difficult to find a mutually agreeable sweet spot.

I think having the desire to try a new combo is reason enough to make the change. Any excuse that keeps your motivation to ride is good in my book.
I know many single bike riders who tailor their cassettes/ cranks to the terrain for every ride.
I personally ride the same gearing for every ride, but I am just to lazy to change parts. Actually, i think it's cause i am an old guy set in my ways. I spent at least 2/3 of my life riding 6 speed freewheels, so the current 9/10 speed set ups, to me, seem like i have infinite gear choices.
I would definitely go with whatever your instinct is leading you to do.

I'm a bit obsessive about gearing combinations. We mostly keep the cassette on that will work best for all-round riding, which is an 11-26 (10-speed) with a 24-32-42-53 quad crankset. In a couple of weeks, we're doing a 110-mile mostly flat ride with 2,000 other people, so I'll be switching to an 11-23 (i.e., trading the 26 tooth for a 16 tooth) for that and will block off the 24-tooth chainring using the limit screw on the FD to keep the chain from falling onto it by accident. When we go to hit some serious, long Alpine climbs, or we're touring with luggage, then I put the 12-28 on (i.e., trading the 11-tooth for a 28-tooth, which I actually achieve by using a 12-25 cassette with the 16 tooth removed and replaced with a 28 tooth from a MTB cassette, plus a special combination of spacers).

12x27t is our default using 53-43-32t chainrings. However, when we know there will be some steep climbs or when we're feeling puny I run an 11x32t.

As noted, the mid-range gearing steps on the wider range cassettes can be annoying.

Last year we used a 12-27 for our flat local rides and 11-4 for hilly rides. Using the 12-27 most of the time made the jumps on the wider range cassette more difficult than ever. I wish that Shamino still made the 12-34 XT cassette, that helped some.

I think I'll play around with my gearing calculator a bit. I notice that both 13-25 and 14-25 are available. A 60-14 combination would give us 29 mph at 85 rpm. I can see spinning out with a big tailwind, but at our age we're not about to pedal downhill above 30 mph? Sounds intriguing!

We have two. 12-25 and 11-28 10 speed. The first for flatter routes [<6%] and the other for everthing else. Front is a 55-42-28. I really appreciate small drops between shifts.

We live in a quite hilly area so normally I leave our base setup (11-32) on the bike all the time. But we spent this past Feb in Florida for the full month so I switched out to 12-27 for that and really enjoyed the close splits.

Bill J.

We always keep a 12-27 10sp cassette on. However, next month we are doing a fairly hilly tour so I just bought a 12-30 10sp cassette. We'll try it over the next few weeks before we decide to switch for the ride.

How many of you will change the cassette according to the ride terrain (and distance)? Our tandem has an 11-32 9-spd cassette with a 24-36-48-60 set of chainrings. This is great when we're climbing, but if I know in advance that the terrain is moderate, let's say not much over 6% I'm thinking of swapping out for something like a 13-25. Is this a common practice? Would make it a bit easier to keep up with fast singles. I'm comfortable anywhere between 80 and 100 rpm, but I don't want to go over 85 or so until my wife gets more comfortable at these higher cadences. The wider spacing on our current cassette makes it a bit difficult to find a mutually agreeable sweet spot.

as it you've got it covered from 147 to 20 gear inches. That is a huge range.

A 12/25 cassette would still give 135 to 25, with closer spacing. I would think that for most teams that range would handle just about all the terrain you're likely to run across.

We set up our tandem for Everest Challenge with 53/39/26 and a 12/27 (29,000 verrtical feet in 2 days, with sections of 17% grade)

In Florida, we typically use an 11/23. The 11/23 with the 2 outer chainrings gives nice tight spacing.
And if we venture into hilly terrain the 26/23 combination is still pretty low. The 12/27's would only go back on for an extreme ride.

Is this a common practice?

I've said this in other threads. When looking at the responses, try to figure out what kind of rider the poster is and whether it fit your riding style and experience. I venture to say that most replies are from enthusiasts with 1000s of miles under their belt. Do you fit that pattern? I seem to remember that you've had your tandem for a few weeks. This is important, because reading this thread gives the impression that changing cassettes standard practice for everyone, and you are likely to get sucked up in this whirlwind of possibilities (better tires! lighter wheels! different cassette! better brakes!). I know I do get caught up in that whirlwind at times. I have in the past bought bike components that once I installed them turned out to be no improvement at all over the given situation.

My own guideline is to make mimimal changes to the bike, get some serious miles on the bike and then evaluate options for improvement.

Of course, if money is not issue, by all means, buy a second cassette and give it a try.

Now for my response to OP's original question: I've never switched a cassette on any bike other than to replace a worn out one. We are a beginning tandem team (less than 1000 miles total under our belt) and our riding has been flat sofar (Midwest). I do ride 4-5k miles annually, about 2/3 on road commuting, 1/3 longer rides

Just my 2 cents
Duppie

as it you've got it covered from 147 to 20 gear inches. That is a huge range.

A 12/25 cassette would still give 135 to 25, with closer spacing. I would think that for most teams that range would handle just about all the terrain you're likely to run across.

+1.

If I were on a DaVinci (which you are), I would definitely think about a narrow(er) cassette all the time, not for changing according to circumstances.

We run a 28-42-54 upfront with an 11-32 in the rear. I used to run an 11-27 in the back and then swap to the 32 but gave up doing it because we simply ride too many rides where we need something more than the 27. Eventually I might look into a 26-38 or 39-53 with an 11-29 10spd campy rear but I'll wait till I need new chainrings to consider that.

Living in the AZ there is hardly ever any flat terrain. We run a 9 speed 11-34 cassette and just leave it on.
Better to have it and not need it, than to need it and not have it.

Definitely some choices. Right now we don't have enough of an overlap in our "power bands" so the wider range cassette has some drawbacks. I'm going to think on this some more before I make a decision. Very good input all.

We run the original SRAM PG-970 11-34 and up front 52/39/30. We live in a hilly area and they seem to work well. We ride wherever and the set up seems good.

When do you know and how do you know when a different cassette is going to provide a better ride?

Are there better cassettes than others?

How difficult is it ot upgrade from 9 to 10? Can it be done easily?

I upgraded from 105 9-spd to Ultegra 10 over the winter, and it was the best change I have made. The brifters are the most expensive part, and I got them cheap, so it really was a piece of cake. The shifting is much better. I was never satisfied with the 105's. We run 11-23 and only use the granny (30t) for emergencies, so it is a close to my racing bike as possible.

The bike came set up with the Ultegra 9 front to back on the drive train. I was wondering how best to decide when is a good time or reason to switch out a cassette. The one currently on the bike has a wide spread which would seem to be intended to cover a wider variance of riding terrain. To date it covers us well as when we ride we try to find 4-6 hills to climb to help in building our legs for distances to come.

I was wondering it we ride along the coast would it be good to go with a 11-25 or 11-27 just to have closer shifting since their would be less hills? Or stick with what we have because torrow we will be back riding around home where we easily find many hills to climb?

I think you have to decide how much you use the small chainring. We decided that we would never want to climb something needing a 30x27, since we don't want to descend such a thing, and besides we don't see much of that. At ETR 2008 (in NH), we did use the granny and lowest gear on one of the rides; but that was still 30x23.

Tandemnh wrote:Are there better cassettes than others?

How difficult is it ot upgrade from 9 to 10? Can it be done easily?


For a wide range cassette use the Santana and not the IRD. The Santana cassette works but the IRD seems to be a problem. It is surprising how the 10th cog takes the jumps out on the Santana 11-34 but the 10 speed is more finicky. The 10 speed chains are reported to wear out faster, up to 50% faster and the Santana cog sets are $170.

I think you have to decide how much you use the small chainring. We decided that we would never want to climb something needing a 30x27, since we don't want to descend such a thing, and besides we don't see much of that. At ETR 2008 (in NH), we did use the granny and lowest gear on one of the rides; but that was still 30x23.

I'm familar with the area around Durham [ETR 2008 (in NH)] and it is similar to the middle of the state where we live though we can find more hills to climb. The nice thing is that they can be tough but no to long. For this reason I like having the spacing of gears on the back end. We rarely us the 30 up front unless we are on a long ride and we're hitting hill 6+, then the 30 comes into use.

By the way will you be attending the ETR 2009 in PA?

Tandemnh wrote:Are there better cassettes than others?

How difficult is it ot upgrade from 9 to 10? Can it be done easily?


For a wide range cassette use the Santana and not the IRD. The Santana cassette works but the IRD seems to be a problem. It is surprising how the 10th cog takes the jumps out on the Santana 11-34 but the 10 speed is more finicky. The 10 speed chains are reported to wear out faster, up to 50% faster and the Santana cog sets are $170.

Am I safe in assuming I would need to change out my shifters up front to accomodate the 10th gear?

By the way will you be attending the ETR 2009 in PA?
No. Am sorry to miss it, but the schedule didn't work out this year. 2008 was much later in the summer, I think, and that plus proximity made it easy.

Will the chain need to be shortened if you change from a 34 tooth cog to a 27 tooth cog?

Will the chain need to be shortened if you change from a 34 tooth cog to a 27 tooth cog?

It depends on how big a range you have in front. On my tandem it did - so I kept two different chains and swapped em with the cluster.

tandemnh wrote:Am I safe in assuming I would need to change out my shifters up front to accomodate the 10th gear?

Probably. Ten speed requires 10 speed shifters. Jtek's chart http://jtekengineering.com/shiftmate.htm
shows a 9 to 10 speed conversion but I don't know how well it works.

I've decided to go with a 12-27 cassette as our everyday configuration. That still gives us a 24-27 low gear which should be fine unless there is going to be extended climbing over 10%. Tried doing a bit of climbing yesterday using the 36-32 combination (avoiding the small chainring) and that felt pretty good for short stretches over 6%. The 24-27 is exactly the same low gear on my wife's single so no compromise there. Heck, maybe we'll not need the 11-32 cassette. We certainly wouldn't need the 11 very often with a 60t chainring!

I've decided to go with a 12-27 cassette as our everyday configuration.

If you have the choice, get a SRAM 12-26 instead of the 12-27. I find that the 21-24 jump in the 12-27 is too large, and this is avoided in the 12-26 (it is a 21-23 jump instead). For me, this slightly closer spacing is more important than the one extra tooth, but your priorities may be different.

It depends on how big a range you have in front. On my tandem it did - so I kept two different chains and swapped em with the cluster.

Huh? If your rear der wraps enough chain to use your smallest combo without sagging with a 34 tooth cassette, there will be zero difference with a 27 tooth.

Huh? If your rear der wraps enough chain to use your smallest combo without sagging with a 34 tooth cassette, there will be zero difference with a 27 tooth.

I'm going to assume you know how to determine proper chain length for you bike. That being said - a proper chain would be shorter on a 27 tooth cluster than a 34 and not run into any problem wrapping in ANY gear.

I'm going to assume you know how to determine proper chain length for you bike. That being said - a proper chain would be shorter on a 27 tooth cluster than a 34 and not run into any problem wrapping in ANY gear.

Not necessarily. It depends completely on whose instructions you follow.

Shimano says to make the RD cage perpendicular to the ground on the big chain ring and smallest cassette. This gives correct function to the max capacity of the RD and requires no chain resizing for a bigger cassette as long as it is within the RD specs.

If you use the big ring + big cassette + 2 links rule, then what you say would be true, but I would prefer the Shimano method where I might be changing cassettes frequently.

Will the chain need to be shortened if you change from a 34 tooth cog to a 27 tooth cog?

The question is, should you shorten your chain when you change the size of your largest rear sprocket.

Technically, the answer is YES when you're making changes

This is the simple mathematic formula that a lot of folks use to calculate chain length.
Length = 2 (C) + F/4 + R/4 + 1

(C) = chainstay length
F = front chain ring tooth count
R = largest rear sprocket tooth count

So, for a tandem with 16.5" rear stays and a 12x34t cassette and 53/42/32 chain rings you get
Length of 55.75 = (16.5 * 2 = 33) + (53 / 4 = 13.25) + (34 / 4 = 8.5) + 1
Therefore, you need a 111 - 112 link chain for this combination.

Now, if you switch to a 12 x 27t cassette you get...
Length of 54 = (16.5 * 2 = 33) + (53 / 4 = 13.25) + (34 / 4 = 6.75) + 1
You now need a chain that is basically 2" shorter, i.e., a 108 link chain.

That's the technical side of the story. Now, in reality on most tandems with triple chain rings you can't use the small-small combinations because the chain line is so screwed up by the 145mm - 160mm rear spacing that the rear chain will usually begin to rattle and chatter against the middle chain ring or rear derailleur's cage when you are in the third or fourth smallest sprocket, perhaps even the middle sprocket on some tandems. Therefore, unless you make a shifting error and drop into granny while your chain is sitting in the lower 1/2 of your cassette that extra 2" of slack chain that is created when you switch from a 34t to a 27t cassette won't come into play or become a problem in and of itself.

All that said, geeks like me and others will still prefer to have a chain that's sized to match the big/big chain ring and sprocket count because it gives you the shortest chain possible that is sized correctly for optimal drive train performance. It's not essential, but it's technically correct.

Now, hopefully the followers of this thread will have picked up on the most important aspect of chain sizing... and that is making sure that your chain is always long enough to wrap around the largest chain ring and largest rear sprocket. If you short-change your chain length and happen to end up cross-chained in that large-large combination you could find that your drive chain, rings and sprockets will become completely bound-up to the point where they won't turn. If it's bad enough, the only ways to undo it so that you can resume riding is to break the chain (assuming you have a chain tool) or to pull off the stokers right side / drive crank (assuming they have self-extracting crank bolts) and even that's not all that easy once the drive train is bound-up by a chain that's too short. Note: The last time this happen to someone on a group ride they were lucky because (a) they had self-extracting crank bolts and (b) I happened to double back to check on them and had both the knowledge and tools needed to undue the mess caused by the LBS that built the tandem using a chain that was too short.

So, while it's not essential to shorten your chain when you go to a somewhat smaller cassette, it IS essential that you either confirm your chain is long enough to support or lengthened to support a change to larger size cassette.

- a proper chain would be shorter on a 27 tooth cluster than a 34 and not run into any problem wrapping in ANY gear.

Oh, I agree with that, but what's it got to do with the question? The thread is about changing cassettes for different rides, the specific question was "Will the chain NEED to be shortened...", and the correct answer is NO.

The question is, should you shorten your chain when you change the size of your largest rear sprocket.

That's what the question perhaps SHOULD have been. And in the case of "should you", the answer is "not a bad idea", and Joe's method of swapping out correct length chains with cassettes is a fast way to accomplish that.


Therefore, unless you make a shifting error and drop into granny while your chain is sitting in the lower 1/2 of your cassette that extra 2" of slack chain that is created when you switch from a 34t to a 27t cassette won't come into play or become a problem in and of itself.

Perhaps just a poor choice of a word here, but "slack" gives the reader the image of a chain that would be sagging just by going to the smaller cassette, which is not the case. Perhaps "extra" would be a better word.

With a chain length that will fit a 12-34, there is no difference between "dropping into granny while your chain is sitting in the lower 1/2 of your cassette" on a 12-34 OR a 12-27. If your derailleur was originally capable of wrapping that much chain and keeping it reasonably tensioned, it still will! Nothing's changed. You're just carrying around 2" of extra chain you won't need until you put the 34 back on.

Not necessarily. It depends completely on whose instructions you follow.

Shimano says to make the RD cage perpendicular to the ground on the big chain ring and smallest cassette. This gives correct function to the max capacity of the RD and requires no chain resizing for a bigger cassette as long as it is within the RD specs.

If you use the big ring + big cassette + 2 links rule, then what you say would be true, but I would prefer the Shimano method where I might be changing cassettes frequently.

Using that method and wide range gearing - you won't be able to use all the cluster in the small chain ring. It just won't happen. Will the bike be ridable? Sure. Will you be able to use all the gears or almost all the gears - no.

Oh, I agree with that, but what's it got to do with the question? The thread is about changing cassettes for different rides, the specific question was "Will the chain NEED to be shortened...", and the correct answer is NO.

Sorry - I don't do things half assed - maybe if I did - I might of answered the question correctly :rolleyes:

Sorry - I don't do things half assed - maybe if I did - I might of answered the question correctly :rolleyes:

Answering the question that was asked is not "doing things half assed".

Answering the question that was asked is not "doing things half assed".

I answered the question - it was your logic that was half assed.........

If you want to keep harping on the word need - IMO you need to shorten your chain. Can you run a longer chain - sure. You can also ride a tandem which has misadjusted derailleurs, frayed cables, and worn out brake pads . According to your logic - there's no need to fix any of those problems as the tandem will still be ridable.

I answered the question - it was your logic that was half assed.........


If you cannot debate a point without resorting to personal attacks perhaps this is not the forum for you. I've passed the insult on to a moderator, and I'm done.

If you cannot debate a point without resorting to personal attacks perhaps this is not the forum for you. I've passed the insult on to a moderator, and I'm done.

:lol:

If you cannot debate a point without resorting to personal attacks perhaps this is not the forum for you.

It's interesting that each subforum has its own vibe.

Sometimes I have to remind myself that sarcastic remarks I would post in the racing subforum and would be viewed as par for the course there don't fit in in the tandem forum.