waynesulak

How did it test ride?
Is that bike using road shifters or mountain?
If the low is lower than you need would a road Shimano 11 speed cassette be low enough?

twocicle

+1. did the same setup on ours. no quick disconnect hydraulic couplers req'd.

fietsbob

2 themes the Di2 wiring and hydraulic brake lines are un affected by the separation of the controller and the controlled ..

In RimBrakes, I like my Magura HS33. there now is a possibility to run them via Magura's own Cable brake to Hydraulic converter
For the Closed Hydraulic system of those Brakes , so as to use The Road Di2 Brifter..

and perhaps even use a cable doubler , to run both rim brakes off 1 lever (long done in tandem setups)
and a drag, disc Hydraulic rear Brake off the Other brake lever.

there are other cable to hydro master converters, featuring double expansion bladder cylinders fitting right under the stem.
Hope , UK; Trickstuff, DE; TRP, TW.

TooMany

Will do. I need to get some (non-bad) pictures first.

zonatandem

We are a bit older (82 and 80) than Mel and Barb K from TandemsEast. And, yes, have ridden with Mel and Barb in Arizona.
Been tandeming since 1975 and have tried/tested majority of all the innovations for tandems since then, including Di-2 and discs.
We prefer our setup. Rim brakes front and rear and 9-speed bar end shifters. Simple, fixable, long lasting.
Pedal on TWOgether!
Rudy and Kay/zonatandem

tandemraw

More info for those interested on the trial setup of XTR Di2 front and back derailleurs with the FSA 52-39-30 crankset and XTR 11-40 cassette:

1. Shifted fine in the big and middle rings. The big ring had good access to most of the cogs.
2. Rear shifts are noisier than we were used to -- apparently the spider of the cassette being carbon fiber allows a bit of reverberation.
3. Showstopper: while shifting into the small ring worked fine in the stand, it did not work under load.

The mechanic who set this up is trying to tweak the setup to fix #3 .

tandemraw

waynesulak, please see my other post for the test ride evaluation. The bike had road shifters. A standard Shimano 11-32 cassette would not meet our needs, as we are trying to maintain the 28 front - 32 back low gear ratio we have now.

All advice is welcome. Thanks.

oldacura

I looked more closely at our bike this weekend. The gearing is 54/44/32 with an 11-32 8 speed cassette. So our high gear is nearly 5:1 with our low gear exactly 1:1. We have ridden short rides one day on the last 2 weekends. We did not do any mountain roads. Our 32/32 gear is our "bailout" gear (when we need it). We didn't use it on either recent ride. However we did have occasion to use the 54/11 gear yesterday. We were riding a popular route approaching a hill crest. A go-fast Triathelete was closing in on us. He closed the gap near the hilltop. As we started down we stepped it up and chased him down. As we pulled around him I dropped into the 11t gear and pushed hard. "Tandem Time"! We dropped him for a while. As we rolled over hilly terrain we swapped leads several times. He was a strong rider. Eventually he dropped us & we never saw him again.

My point in this is that sometimes we "need" the 32/32 bailout gear. Maybe lower as we age. Sometimes we "want" the 54/11 top end because under the right circumstances, we can for a while drop much stronger riders that I could never accomplish on my single bike. So, am I willing to trade the extreme range for snappier gear-change? I'm leaning toward not.

Also, as I shifted our bike this weekend, I realize how much I enjoy the tactile feedback of the Ultegra rear derailler shifted with bar-end Durace shifters. However, the front derailler requires much more planning, finesse and luck.

oldacura

Another thought I had in a discussion with my stoker this weekend: While the captain experiences the quick shifts of the Di2 directly, for the stoker it is more of a vicarious experience. True?

twocicle

48-36-24 in front is imaginative, but impossible on his standard road triple (130bcd middle is min 38t). chainring availability for those teeth and in a different bcd would be what?

waynesulak

I think the best chance of the front shifting to work is to go with something like Carbonfiberboy's suggestion.

Quote:

Well heck, if that even sorta works, how about going 48-36-24 in front and 11-28 in back? That gearing looks better than what you have now except for giving up a tiny bit in top end:

This uses front rings closer to the mountain rings the FD was designed for and maintains your low gear ratio. I might suggest a 50-36-26 or 28 in front if 48-11 to get a little more top end. That 50-11 is not very much lower than your current 54-11.

tandemraw

Thanks for the suggestion of trying a 50-36-26 in front. With that, an 11-32 cassette would give us plenty of low range.

Who makes a 50-36-26 crankset (or chainrings) compatible with 11 speed chains? And with a 130 BCD so that we can use a gates belt for timing?

waynesulak

Ahh there is the rub. 130BCD cranks limit you to a 39 or maybe a 38 middle ring. To use the 36 ring which nicely bridges smaller granny rings and a 50 or 48 big ring you cannot use a 130BCD. You have to use the time tested 110 BCD. I use a davinci square taper cranks which have interchangble spiders and would allow for a 110BCD on the right and 130 BCD on the sync side. The high cost high tech alternative would be very light weight Lightening cranks also with replaceable spiders,

Both are available in a wider range of crank lengths than name brand cranks if that makes a difference. We use a mechanically shifted 50-36-24 with an 12-28 on the back with da vinci cranks.

twocicle

110BCD + granny triple?

waynesulak

Yep. Its rare but sometimes we use the 24 ring to get gears smaller than 1-1. It rare enough that an aluminum 24 ring has lasted 10,000+ miles and is just starting to show wear. Most of the time we use the big (50) and middle (36) ring for what has been termed "compact" gearing.

Shimano 12-28 cassette has nice small jumps between cogs all the way through. 12-13-14-15-17-19-21-23-25-28

joe@vwvortex 

We use a 26-39-53 with a Campy 12-30 10 speed rear with a 130 BCD. Give a great flat land set of ratio's and we have a decent low to get over most anything we ride. Sure wish Campy made an 11-30 in 11 speed - although the 29 is close - that one tooth does make a difference - we had an 11-29 10 speed on it before and like the new ratios better. I miss the 11 sometimes, but not all that much.

Chris_W

To make a front derailleur perform middle to small ring shifts well, the most important thing is the front derailleur height relative to the middle ring, which is determined by the difference between the large and middle rings. You should therefore try to match this difference to the difference that the FD was designed for. The XTR 9000 triple crank has 40-30-22 rings, so even when using this derailleur with a road crank, I would keep the 10-tooth difference between middle and large rings. So, I'm not surprised that the test setup with 52-39-30 didn't work that well - the wrong part of the cage is lined up with the chain when trying to shift down to the small ring. Tell the mechanic to try it with a 50- or 48-tooth large ring, with the FD lowered accordingly.

tandemraw

Chris_W, thanks for the advice. If the critical issue is the tooth gap between big and middle rings, might it work as well to use a 52-42-30? Or would you expect other problems with that?

waynesulak

Someone can check me on this but I calculated the speed difference on a 700c bike between a 52/11 gear and 50/11 gear at a cadence of 90 is about 2 kph or 1.25 mph.

jnbrown

52 x 11 90RPM = 33.7 MPH

50 x 11 90RPM = 32.4 MPH

50 x 12 100RPM = 33 MPH (This what I use on tandem and single)

tandemraw

You're right ... not a big difference. The mechanic will be changing out the 52 for a 50 and trying again to see if shifting from the middle to the small ring under load is resolved.

tandemraw

For anyone interested in the gearing setup on the bike with XTR Di2 shifting I was test-riding, changing out the 52 tooth ring for a 50 tooth ring didn't solve the problems. Shifting under load from the middle to the small ring was now possible, but very rough and slow, and a new problem was introduced ... shifting from the middle to the big ring was occasionally rough. I'm beginning to think that trying to use the XTR Di2 gearing for this tandem road purpose just may be too far from the intended purpose to work well.

Any other suggestions for wide ranging gearing? Ideally I'd be looking for modern gearing that would be similar to the range I have on our current bike (54-44-28 chainrings with 11-32 9 speed cassette). We can give up some gear range on the high end, but need the low end for climbing the hills around here. Having an old flight deck now, I would prefer if possible to retain the convenience of a gear indicator.

All ideas are welcome and appreciated.

Thanks.

waynesulak

Not sure what you define as modern however shimano Tiagra is still triple crank 10 speed and should shift well. I use a Tiagra 10 speed cassette and it works as well as the ultegra and dura ace ace cassettes I also use. There is a weight penalty however. There are still new 10 speed triple 105 components in the market which you may also be able to blend in.


if you want to take a risk with the DI2 FD, I suggest the option of shaping the cage arc to fit the rings by removing a littl material. This would allow for a tight fit around the edge of the rings and should force the chain to shift. This may or may not work and you may ruin the FD.

Chris_W

With the 11-40 11-speed cassette, you could get a similar gear range to what you have now with a 50-34 double crank. The double crank should have far fewer shifting issues than with a triple. If you're already used to the spacing on the 11-32 9-speed cassette, then the spacing on the 11-40 11-speed will be pretty much the same. One problem would be if you want to keep your current crank that has a 130-74mm BCD spider. If so, you could just use the inner and middle ring positions, but would then be limited to a 'large' ring of 46 (TA make a triple-specific middle ring with shifting ramps in this size), and then the inner ring could be either 32 or 30.

BTW, this is the setup that we're currently using on our tandem - 11-40 11-speed cassette plus 30-46 chainrings. It's working very well with a crazy mixture of mechanical shifters and derailleurs (SRAM Rival RH 11-speed shifter controlling a SRAM X-9 '10-speed' rear derailleur, plus a bar-end LH shifter controlling a 6600 Ultegra double FD). I was hoping that Shimano would release an XT Di2 group later this year, and we'd then upgrade to that. The Ultegra Di2 groups both came out one year after the Dura Ace, but unfortunately there has been no mention of when we'll see XT Di2, so we're sticking with what we have for now.

oldacura

Tandemraw - It sounds like you have a setup similar to ours. Ours is a late 90s Co-Pilot with 54/44/32 up front & 32-11 8 speed in the rear. Ultegra derailers. We have Sram V-brakes actuated by 287V brake pulls and bar-end shifters. The rear shifts great. The front can be a bit balky but because I can trim it, I can almost always get it to shift & then run quietly. Sounds like trouble trying to get Di2 to work with a triple.