eischman

I am building a new tandem 2 X 11 and am thinking about a single side drive. If I purchased a triple and a single it should work right? What are the pros and cons and what cranks would you use and timing rings? For road and some gravel. I want to use my rolf wheels and swap with mountain bike wheels. What do you think? Pros and cons?

Kuresumi

Rumor has it that single side is better for BB wear. What bottom bracket standard is the tandem frame? What chainring sizes are you hoping to run for 2x11 and what cassette/rd do you want to go with?

We have a Burley Duet which I installed Minimotos on, link housing here n there and not much else. It still has the timing stuff still on the non drive side. I think it’d be nice to have single sided as well, but am more interested in keeping the low gears for when we attach a trailer onto the bike. (Triple)

rocknrollin

You could run 30/ 46t chainrings in the front, and 11- 42 shimano xt cassette in the rear. If you want to use road derailleurs, you would need a wolf tooth tanpan converter. That would give you a 610% gear range.
If you want low gears, you will have to use the inner and middle position since the smallest Chainring for 130 BCD is 38t. For the timing chainring the size in the outer position should not matter . >46t might be useful so that the chain does not drop into smaller chianring in case it goes over the second ring.

As a triple crank option, the FSA Gossamer megaexo comes to my mind (there is also a tandem version of the same model). Q-factor looks reasonable for a 3x setup. But that also depends on your BB.

rocknrollin

Sorry, the range would be 585% with that combo. Its 610% with a 11-44 cassette, but that would officially not work with a double setup.

Brian25

You are going to have to consider a potential chain angle.issue. The doube crank will be narrower than the triple. In the 26 to 30 inch typical boom tube length this might be an issue.

bwebel

I ran some single side drive in the past without a perfect chainline and didn't have particular issues. You can always space one of the rings out to some degree as well. Compared to the angle encountered on a drive chain, it is still going to be pretty straight.

Chris_W

We use a single-side drive setup on our tandem by using triple road cranks on the front and rear, but only two driving chainrings plus a timing ring. The rear triple crank has a 30-tooth inner ring and a 46-tooth ring in the middle position (made by Specialites TA). The outer ring is then for the timing chain. Using the same model triple crank in the front means that it's easy to get the chainline the same by again using the outer ring position.

Part of the reason that we went for this setup is because we both use 165mm cranks and tandem cranks are hard to find in that length at a decent price and decent weight, whereas Shimano road 3x10 cranks satisfy all of those criteria easily.

The rear cassette is a Shimano 11-40 11-speed, so the bottom gear (30-40) is very low and the top gear (46-11) is sufficient for us - we can still easily pedal up to about 50 km/h (30 mph), more with an elevated cadence, so that's all we need. The short cranks predispose us towards using a higher cadence anyway. Shifting is with XT Di2 derailleurs and Ultegra levers, although with the new GRX group it could be achieved with those parts - the XT front derailleur only JUST moves far enough in to make the shift down from the 46 to 30 tooth.

eischman

Can I use non di2 shifters? I bought some ultegra sti with hydrolic brakes. What rear derailerr? And front?

Chris_W

If you have an 11-speed Ultegra shifter, you can use any Shimano road 11-speed rear derailleur and also the GRX rear deraileurs, which allow the use of the larger cassettes. Same for the front derailleur, any 2x11 Shimano road or gravel model should work.

eischman

Chris, Which triple cranks do you use? where did you get the 46T? Id love a 32Tx 48T combo

merlinextraligh

When we spec’d our Calfee, I wanted a single side drive train. Even though we went with a 2x11 setup , the folks at Calfee strongly recommended the traditional two sided drivetrain. As I recall their point is that it’s an easier setup with more clearance and less finicky.

And we still ended up with a 24 pound bike.

Bad1

A properly built right side drive:

marciero

^^ That thing is pretty rad.

One other issue, of greater or lesser importance depending on one's preference or sensitivity, is the possibility to get lower Q factor with a double and cross drive.

tkramer

Or you could go full on custom and have a 10-arm spider machined to accommodate a Praxis 48/32 chainset with a 44T timing ring.

Markeologist

conspiratemus1

Clever—let’s see: the timing ring is on the normal outer position on the NR crank, the large final-drive ring is on the usual inner position, spaced inward far enough not to foul the timing chain, and the small chainring, not visible, is spaced against the large chainring, all held together with extra-long fixing bolts? Right? Or wait, is there only the one large chainring and the FD is only to keep the chain on?

Markeologist

You can see the teeth of the inner ring in photo... teeth low down and the apex of the cuts between the teeth through the cut-outs towards top.

conspiratemus1

Now I see it. Thanks for the help.👌

fietsbob

Tandems with Rohloff hubs can & did that a lot..

Chris_W

Sorry, I only just noticed this question. We're using Shimano 5603 cranks, which probably aren't available anymore because they're part of the Shimano 105 3x10 group that was current from about 2006-2011. They have 130/74mm 5-arm spiders.

As I mentioned in my comment, our 46 tooth "middle" ring is made by TA Specialites (a French brand with worldwide distribution). A few years ago, TA were still making a 46 tooth, 130mm BCD ring for the outer position of a double or triple OR a different 46 tooth for the middle position of a triple, which has the bolt recesses on the inner side rather than the outer side, which is essential. They didn't offer anything bigger than 46 teeth for the middle position. I don't know if that's still the case.

conspiratemus1

Researching (OK, surfing) this recently, I found some eBay sellers with 51-tooth middle TA rings. And you can get outers as small as 40.
But my big difficulty has been protecting that whirling timing chain from getting fouled and hopelessly jammed in the final​​​​​​-drive chain if the front derailer overshifts it off the big ring. I’m fussy about adjustment and maintenance but mishaps do happen. It’s a mess when those two chains embrace. Any thoughts?

fietsbob

People have use Gates belts between front & rear cranks , then a chain final drive..