Tandem Cycling - Revivng some gearing questions

A short while back there were two topics started about gearing. One dealt with rear cassette range and the other topic was related to what size front inner chainring.

I'm digging up these previous topics to see where you folks settled, especially in regards to the front inner chainring.

http://www.bikeforums.net/showthread.php?t=438583&highlight=chainring

http://www.bikeforums.net/showthread.php?t=480833&highlight=chainring

Also, does anyone know if stainless 74mm 32t 9speed rings can be bought?

Thanks
PK

Unlike others we get on fine with 11-34 rear 10 speed cassettes and 53/39/30 front FSA MegaExo. Have regularly used top, bottom & all between on tours in the Alps, volcanos of Canary Islands, Slovenia, Tuscany, Corsica, Sardinia, etc. We do find that our IRD 11-34 cassette works less well than the Santana supplied original.

Also, does anyone know if stainless 74mm 32t 9speed rings can be bought?

Stronglight certainly make a steel 32T 74mm ring (see here (http://www.stronglight.com/stronglight/page.php?nom=produit&keyProd=74mm)), but a quick Google search was only showing me European dealers to buy one from - you may have more luck using Google from a US IP address to find a more local source.

We do a lot of climbing, and we're now using a 26T inner ring with 38 and 53 in the middle and outside spots. I've been playing around with cog combinations on the back, and have already tried 11-28, 12-28, and 12-32 to try to find the sweet spot with spacing and range. I think we'll go with the 12-28 (12, 13, 14, 15, 17, 19, 21, 23, 25, 28) except when touring with extra weight, when I'll switch the 14 for a 32. Having a variety of chainrings, cassettes, and spacers around has made it easy to put together custom combinations to try out. Shifting is done by an Ultegra FD and XT RD.

Stronglight certainly make a steel 32T 74mm ring (see here (http://www.stronglight.com/stronglight/page.php?nom=produit&keyProd=74mm)), but a quick Google search was only showing me European dealers to buy one from - you may have more luck using Google from a US IP address to find a more local source.

We do a lot of climbing, and we're now using a 26T inner ring with 38 and 53 in the middle and outside spots. I've been playing around with cog combinations on the back, and have already tried 11-28, 12-28, and 12-32 to try to find the sweet spot with spacing and range. I think we'll go with the 12-28 (12, 13, 14, 15, 17, 19, 21, 23, 25, 28) except when touring with extra weight, when I'll switch the 14 for a 32. Having a variety of chainrings, cassettes, and spacers around has made it easy to put together custom combinations to try out. Shifting is done by an Ultegra FD and XT RD.

While I just updated my rear cluster, shifter and chain to SRAM and a Davinci SRAM X9 to mate my SRAM derailleur to my Campy Ergo 10 shifters (works beautifully) I keep wanting to get 10 gears in the back. However - I don't want to loose my 28-32 low. I run 28-42-54 with the 11-32. We do alot of climbing as well and like having the flexibility of a nice low gear when we need it. Since Campy only makes a 29 tooth - I was thinking the 26-29 combo might be close. Then dropping the 54 to a 53 and then the middle in the 38-40 range. I need to work these out on a gearing calc - but sounds like you've run this or close combo.

53/39/26 w/ 12-23 10sp. Sonoma County with lots of steep mountains, fit riders/4 rides or more weekly. We stand alot. We like the closr ratio rear cluster. When we go real steep/long such as tour of the Unknown coast we will use a 24t inner w/ a 12-25

Unlike others we get on fine with 11-34 rear 10 speed cassettes and 53/39/30 front FSA MegaExo. Have regularly used top, bottom & all between on tours in the Alps, volcanos of Canary Islands, Slovenia, Tuscany, Corsica, Sardinia, etc. We do find that our IRD 11-34 cassette works less well than the Santana supplied original.

Glad to hear I'm not alone in this. I'm sure the IRD could be better, but I've found that tweaking the drive train and keeping it tuned works pretty well. My problem is that I've always run campy on my singles, so I don't really know what the Shimano 10 is supposed to feel like.

We have 53/39/26 up front, and 12-27 in the rear.

We put the 26 on the front to do Everest Challenge. By going to the small front chainring, we get low gearing, and can still run a Dura Ace RD, and get crisp, relatively closely spaced gearing.

Most of our riding is flat to rolling, and this setup also allows switching out the rear cassette to an 11-23. Which gives close spaced gearing, that shifts like a racing double setup (staying out of the 26) and you still have the 26, if you need a low gear.

IMHO, I would go to a smaller inner chainring, before I went to an 11-32 or 11-34 in the back.

We have 53/39/26 up front, and 12-27 in the rear.


We basically have the same setup but with lower top end -- 48/38/26 chainrings. I was thinking of going to the IRD 12-30 cassette. Has anyone tried it?

What type of shifters are used to shift to a small chain ring of less than 30? Does 48, 38, 26 shift well with STI? We tried a 52, 42, 28 with STI of few years ago to ride Bike Virginia. It shifted so poorly that we put the 30 back on when we got home. It was put on by our LBS mechanic who is a tandem specialist.
Thanks,
Sheldon

What type of shifters are used to shift to a small chain ring of less than 30? Does 48, 38, 26 shift well with STI? We tried a 52, 42, 28 with STI of few years ago to ride Bike Virginia. It shifted so poorly that we put the 30 back on when we got home. It was put on by our LBS mechanic who is a tandem specialist.
Thanks,
Sheldon

We have the same setup on a Campy and a Shimano tandem and they both shift fine. Originally, I had a 28 since I wanted to keep a 10 tooth difference. That shifted fine so I dropped to a 26 and found that it shifted fine too. Just try to keep the tooth difference less than 12. We use a Jump-Stop on both bikes.

We originally had FSA rings on one of the tandems and when using the 26 it rubbed on a 39 in all but the largest 4 cogs on the back. Switching to TA rings and a 38 instead of the 39 solved that problem. I think the FSA rings have wider ramps.

Caveat ... compared to most people here, I have close to zero tandem experience. However, I have putzed around testing drivetrains because of riding bikes with small wheels and having a penchant for lower gear ranges than who Shimano/Campagnolo targets.


We basically have the same setup but with lower top end -- 48/38/26 chainrings. I was thinking of going to the IRD 12-30 cassette. Has anyone tried it?

I have the 12-32 with a triple Ultegra derailer on my road bike. Doesn't shift as well as a Shimano HG. But it shifts fine in my opinion as long as you use a little "english" when you shift; i.e., when I shift up I push the lever a little past the click. I can still shift multiple cogs and so on.

I think that this link is still active. Sorry, can't check from work.

http://www.facebook.com/video/video.php?v=1091389917217


What type of shifters are used to shift to a small chain ring of less than 30? Does 48, 38, 26 shift well with STI? We tried a 52, 42, 28 with STI of few years ago to ride Bike Virginia. It shifted so poorly that we put the 30 back on when we got home. It was put on by our LBS mechanic who is a tandem specialist.
Thanks,
Sheldon

With the "correct" front derailer, the 48-38-26 will shift well. Long story short, the cage is shaped to fit smaller chainrings than the typical road derailer. The IRD compact triple below shifts a 48-36-24 on my commuter well. With a Shimano Tiagra derailer, I would have to shift the front derailer to the "4th" position between the bottom and middle chainrings before "firmly" shifting to the middle to achieve a decent shift from granny to middle.

http://harriscyclery.net/itemdetails.cfm?ID=2435

On my Bike Friday I once put a 26 on a road triple/105 front derailer and could shift from the 26 to 39 using the same technique described for Tiagra front derailer above. However, this still isn't the 14-tooth jump you describe above.

We're running with an XT fd driving a 48-36-24 or 26 (not sure which one, I'd have to go look - there was some debate at the time we were configuring it). For shifters, it's Campy Ergos, which handle it fine.

Actually our low gear is quite excessive for around-town stuff, but we do have loaded touring in the plan, at which point we'll get a whole lot more experience getting in and out of the granny...

Another data point: We have ultegra 10 spd, originally with 54-42-30 and IRD 11-34. This winter added chainstop and 28 tooth small in front and changed to 12-27 ultegra in back. Better shifting in back. Good down shifting in front, but a little challenging going up from 28 to 42 tooth chainring. Have to really backoff the pedal pressure. Had to make some adjustment on the der stops and cable tension. Now its liveable. In flat or rolling hills I really like the tighter spacing and crisp shifting of the 12-27 for fast riding, but in hilly areas it makes for more chainring shifts which aren't so smooth and I wish for the wider range gearing. We will give it till then end of season to decide if we stay with it.

Caveat: Per suggestion in another thread I also placed some Teflon® TFE sheet under the cable in the der. guides so this may be helping make the 12-27 shift crisper. Our co-mo speedster has plastic guides that already appear to be pretty low c.o.f, but this may be another variable.

Just a couple of points on the rear cassette. I Borrowed an IRD 10 spd cassette for my solo and the shifting was not good. The ratio for the two highest gears was ridiculous. The change from 28 to 34 was stupid. Slog away in the 28 and the 34 meant I lost speed and was spinning far too high.

That was road solo but just a point some you may find aswell.

On the Tandem- we run 48/36/24 and an 11/32 cassette in 9 spd. It is an offroad Tandem and that gearing gets us up the steepest (When we are both on song) Slicks fitted for the road and 48/11 with a cadence of 100 and we are doing 30mph. Faster than that and we are coasting downhill.

Occasionally we felt that we could do with a lower gear for when it gets steep. I tried an11/34 and we bent it. Replaced by the shop as it is obviously faulty and we bent it again. High torque on those exposed rings and it will not take the strain for us. This was a Shimano XT cassette and I think we learnt a lesson in that you can go "Too" high a quality on components- if that higher quality also leads to a reduction in strength. Since then we have stayed with the OLD faithfull of LX cassettes and just keep wearing them out.

Were not to concerned at how fast or how much U back off to change rings up front. When your'e there U stay 4 a while so who cares how fast it changes. Full dura Ace w/ 53/39/26. It shifts great BTW.

Showing support for the topic I started...

We ended up with a 12/26 SRAM PC970 9 speed cassette, Front chainrings of 54/44/32/24, SRAM XO rear derailleur and shifter set, Shimano Ultegra front derailleur.

So yes I guess we have a 36 speed.

The short throw front derailleur with the mountain shifter let me add the "greatgranny".

There are a few unusable gears, either because of chain slack, and a couple from front cage rub, but nothing to bad.

Will possibly end up similar to others but for now this works for us. Time will tell.

PK

That quad setup sounds very interesting. Over the weekend, I was thinking about our 26-38-53 setup, and thinking that it wasn't ideal. The 38 to 26 drop is a bit of a large cadence change, and the 38 tooth is not really big enough as a general-use ring. Having a 42 tooth would be much better for general use, and having a 24 and 32 on the bottom end would make the shifts more gentle.

I would think that the easiest way to achieve this would be to use extra long chainring bolts to hold the two inner rings on, with spacers in between them. Is this how you did it? I already have a down-tube shifter for the front derailleur (mounted to the bars using a Kelly's Take Off), so hopefully that will be able to handle the range of motion needed for the quad. I'll then just have to see whether I need to put another spacer between the BB shell and BB cup to get the crankset out far enough to mount the fourth ring.

This is certainly my next project to play with :)

EDIT: I just made some measurements on my Co-motion Speedster with FSA Gossamer cranks and it appears that there will be enough clearance for the extra chainring and for the extra swing of the Ultegra front derailleur without changing anything. I can get the two new rings and long bolts for about US$35 total, so I'm gonna give it a try.

Not sure how PMK did it, but Mountain Tamer Quad is one answer.

http://www.abundantadventures.com/quads.html

Not sure how PMK did it, but Mountain Tamer Quad is one answer.

http://www.abundantadventures.com/quads.html

I know about that product, but I would imagine that you don't need it if the smallest ring is no less than 24 teeth.

After I clean the bike up from this weekends wet rides, I'll post a couple of photos.

Basically as Chris mentioned, I utilized the 74mm bolt circle diameter of the existing inner 32t chaninring, added a set of spacers, longer bolts, and a great granny for the quad front setup. (243 Loctited the bolts also)

A friction type shifter would be ideal. I have XO mountain shifters with index. One thing I did learn in regards to front derailiuers is that the pull rates are different for road compared to mountain. This is what let the mountain triple shifter paired with a road front der, pull four front chainrings. Using a mountain triple front shifter is pretty good, but the more I ride this, I'm wondering if using a nine speed rear shifter would have better fine tuning on this quad front.

While it may be overkill for us locally, it is a blessing for my stoker.

I need to make a couple of simple adjustments...The 32t needs a couple of teeth pulled to make it drop easier, and I'd like to get a drop stop to prevent the chain from dropping to far inboard. We dropped the chain once in testing, likely my fault from shifting too quickly, as for it not wanting to drop to the greatgranny, not a big deal if you plan the shift, I'd just like it a bit better.

Weight gain was minor being only longer bolts, aluminum spacers and the chainring.

PK

Not sure how PMK did it, but Mountain Tamer Quad is one answer.

http://www.abundantadventures.com/quads.html

I wasn't sure if those guys still were making parts. Very old school mtb, back from the days of 28/38/48 with a big rear of 28.

When I take the photos, I'll see if I can get details on how I did the front der cable, I opted out on the plastic block as the cable bend radius was pretty tight and wear would be inevitable. Went with a short outer section of cable. Front shifts are smoother and seem more consistent.

I'm thinking the Robusta is the same as the Roadster if you care to look.

PK