124Spider

Hi,

We have a beautiful new Rodriguez tandem that we're loving (our first tandem; we have put about 300 miles on it). But we're quite sure that the lowest gear isn't adequate for when we take it on the road and encounter a long, long 6% uphill.

We have a 3x9, with 53/42/30 chain rings and 11-32 rear cassette.

I am pretty sure that a 26 nanny ring would work fine for us.

On semi-level ground (+/- 3% grade), we stay in the middle ring, and use pretty much all the gears in the cassette. So I'm not inclined to change the middle ring to something lower.

If I put in a 26 ring to replace the 30 ring, (i) will the derailleur have any trouble with such a wide range, shifting up from the 26 to the 42? and (ii) is it likely that a couple of fit folks would be fine with a 26 nanny gear driving an 11-32 cassette? Or is it likely we'd wish we had gone with a 28 instead of a 26?

For context, on my road bike, I have 54/37 rings, and an 11-28 cassette, and I've not yet hit a hill I can't get up. My wife has 50/34 rings, and an 11-36 cassette on her road bike, and hasn't yet (after switching to a lower cassette) found a hill she can't get up.

Thanks.

Mark

Leisesturm

If you are like most teams your tandem climbing style does not involve much out of the saddle honking in the cruising ring, and much more of a 'sit and spin" (if it can be called spinning) in the granny ring. On your road bike you attack the climb with plenty of momentum to start and stand up as it bleeds off. If the hill is short enough you may never have to shift down. That is why a 34Tx28T low gear combination can serve well on a roadbike. We have had a number of tandems and all of them, including the double recumbent tandem we just started riding, all of them, first thing we do is change the granny to 24T (they are usually 30T as sold). You will regret not going all the way down to 24T more than you might have regretted going to 28T instead of 26T.. 24T is the lowest possible granny with a 74mm bolt circle spider which yours almost certainly is. If you are going through the hassle of pulling the crank and swapping out the rings you may as well go all the way down. We have both a 52/42/24 and a 52/39/24 on different tandems. The shifting from the granny to the middle ring is equally easy for both, but we prefer the feel of the shift to the 39T cruising ring and I am looking around for another so both tandems will have 39T cruising rings. FWIW.

124Spider

Really a thoughtful excellent post; thanks so much!

Mark

Ludkeh

We live in a very hilly part of the country, so the factory chain ring combination did not work for us at all!. On our Co-Motion tandem I tried various combinations of chain ring. Shimano Ultregra 52,42,28 combination shifted well but did not give us low enough gearing. Than I tried 52,42,26. Still not enough low range and the shifting became sketchy. The drop from 42 to 26 required a chain catcher and the pickup from 26 to 42 was hit or miss and very frustrating.

Finally I went to a 52,39,24 tooth chain ring setup. I went to Spécialités TA and purchased a 39 tooth middle chain ring with pickups and a 24 tooth small chain ring. Shifting between the middle and small chain ring are smooth and chain pickup happens effortlessly. Chain catcher is still a good idea. The only negative with this setup is that you can use only the 4 largest sprockets on your rear cassette. Anything else will cause severe chain cross. For us the trade off was well worth it. We have a few very low stump puller gear for those very steep hills. Once the hill is climbed and we've made a few shifts it's time to grab the middle chain ring anyway.

reburns

rm -rf

Here's your 9 speed 11-32 with a 39 chainring (red) vs a 42 chainring (black)
The 39 is just about a half shift lower. Both have good coverage from 10 to 25 mph. So I'd switch to the 39 if it helps the front shifting.

These settings in Mike Sherman's Gear Calculator. The charts update on the fly as you change gearing, tire size, or cadence. The settings are in the URL, so you can bookmark that display. Change the 39 & 42 to 30,42,53, etc.

124Spider

Great information, folks!

SparkyBeacon 

We are not fast and do not race. I could care less about maybe spinning out the high gear under favorable circumstances some day. I want to be able to keep going if possible when challenged by hills.

I shrunk each chain ring by 4 teeth. Out tandem came with 54-44-28 chain rings and now has 50-40-24.

jnbrown

We have 50/39/28 on front and 12-32 on back (10 speed). It has been working well for us and we are in our 60's. Max gradients we ride are maybe 15%.
I am tempted to go to 11 speed 11-32 because we often spin out the 12-32 on downhills.

124Spider

Thanks so much for all your excellent comments and suggestions.

I expected that I would do the work (I'm comfortable changing chain rings), but I decided that this is a fairly major surgery, with a significant chance of needing some additional work to ensure smooth shifting.

I decided to change the rings from 53/42/30 to 53/39/24. I'll bring it to Rodriguez next Saturday for them to do the work, and make sure it's done right.

Thanks again; I'll report back after we've had it for a while, and tested the new gearing on some serious local hills we've avoided when riding the tandem.

Mark

fietsbob

As I recall TA Zephyr triple cranks offered 2 bolt circles for the granny gear 74 & 56mm
with a 110 large chainring bolt circle.
56 allows a 20t, 74, a 24t..

124Spider

I brought the tandem back to Rodriguez, who swapped in the desired 53/39/24 rings, but determined that it didn't want to shift well that way, so they instead used a 26 nanny ring, and replaced the 11-32 cassette with an 11-34 cassette. And they didn't charge us, since it's a new bike. Yay for good customer service!

Today, we took it out and tried out the tough hills in our area. And it worked just fine! It's a much slower slog up than on my half bike, but we're convinced that we can get up anything we're likely to encounter.

2frmMI

Its not a nanny you ninny its a granny!

oldacura

We got our new Calfee with 52x34 tooth chainrings and an 11 - 36 (11 speed) cassette. I changed the cassette out for an 11 - 40 and like it better.

124Spider

Update:

We brought the bike back to Rodriguez, with the plan to swap out the 53/42/30 for a 53/39/24. But they found that that didn't shift well, so they put in a 26 instead of a 24, and swapped out the 11-32 cassette for an 11-34. And didn't charge me anything (yay for good customer service).

We took it on a long ride with significant hills yesterday, and we like the gearing. Unlike with my half-bike, on which I can blast up even long hills, it seems that going up long hills in a tandem is just a matter of slogging to the top; but at least we now are confident that we can slog our way to the top of just about any hill we're likely to come across.

Thanks for all your advice; much of it was very helpful!

Mark

etasch

Remember if it’s not momentum, it’s mo legs!

Leisesturm

I see what you did there. The o.p. might not though, just saying ...

124Spider

OP doesn't care "what he did there." Either it was a very poor joke (in which case he/she should at least have used some sort of emoticon to indicate it was a joke), or it was a nasty swipe. Either way, that's why the administrators gave us the "ignore" option, so that we could keep tabs on people whose "contributions" are suspect. As I have now done with 2frmMI.

oldacura

I think most of us knew that the OP meant Granny.

I don't think 2frmMI meant any disrespect.

2frmMI

2frmMI indeed thought he had found a funny way to make a rhyming little comment. He enjoys his own jokes and didn't intend any harm. He thought putting ninny between nanny and granny was clever. He will rethink that. Furthermore, used his nanny gear this weekend doing the 'wall' on the Michigan Mountain Mayhem ride, without success - ended up walking the steepest pitch (18%).

124Spider

Thank you for this; rethinking is good.

Mark

WPH

I am gonna call it the nanny gear from now on!