Eulers

Hi. Am in the initial stages of my planning effort to modernize the drivetrain of my 1996 Cannondale Los Dos Tandem. I'd appreciate input from similar experiences modernizing to a 11-speed mechanical for a C'dale.

Current spec:

• OEM stock frame and drivetrain (triple chain rings)
• 140mm distance between rear drop outs
• 10 mm rear dropouts slot width
• 26" rims
• 32 mm tires (will carry over)
• External cables
• 295# team weight

Constraints:

• No electronic shifting (e.g. Di2, eTap, etc.)

Assume modernization to:

1. 11-speed mechanical rear & shifters (Prefer Shimano Ultegra b/c of familiarity from single bikes, but not committed to it)
2. Double front chainrings (brand & model TBD)
3. New 26" rims (exact model TBD)
4. 140mm hub (Most likely a 40-hole White Ind hub from Tandems East but not committed to it)

The 140mm rear hub compatible for 11-speed seems to be a driving factor, so my embryonic plan is to build out from that potentially with an Ultegra GS Cage, 11t to 34t cassette.

My main concerns are:

• Although I've rebuilt cars, and replaced like parts for like parts on bikes, this tandem project puts me in uncharted waters. To wit, I don't know what the foundational parameters are that should be dealt with first.
• For example:
• Will a 140mm hub and 40-spokes (20/20) properly support use of 11-speed with a 295# husband/wife team?
• If I go with Da Vinci cranks, then what do I need to measure on my existing frame so as to spec the front and rear Da Vinci cranksets and bottom bracket?
• 
  
• Will the new Ultegra R8000 mechanical group still shift well when used with the extra long derailleur cable needed for a tandem frame?
• What concerns are there for chainline dimensions during this build?
• 
  
• From a standpoint of future-proofing one's investment - What is the potential for the manufacturers to release a roadie 12-speed, for double chainrings, in the next 6-months?
  

Thanks in advance.

fietsbob

I think Shimano freehubs for tandems are 145, so it may fit, or thin the left spacer stack 5mm..

I don't own the tandem you have or a Shimano freehub, like that, but you can search the PDF online of them.


how about a Rohloff? 14 speed 36 hole (no dish), 135mm, * can be used with 2 regular cranks, same side drive, rather than the crossover type.



* maybe bond 2 2.5mm stainless steel washers inside the frame dropouts, notched like the dropouts ..

retrofit kit includes chain tensioner and torque reaction strut..
now several 3rd party offerings to shift it with out the grip shifter. on the bars..






...

geoffs

I'm just about to go through the process of measuring our tandem for double chainrings too. I presume you're keeping thlhs for the timing chain. Don't be tempted to use the Davinci titanium BB with the Davinci cranks as they use a non-standard bearing which isn't easy to source.
Unless you live somewhere very flat I would be looking at a larger cassette. We're going to use an 11- 42 with a Wolftooth roadlink on a eTap WiFli rear derailleur. I'd look at using Velocity Cliffhanger or Blunt 35 if you have enough room. We run Schwalbe Supreme 2.0" tyres for touring on Blunt 35's 26" and they roll really well.

Artmo 

I have a stripped down Los Dos frame hanging on my garage wall. It was supposed to be my winter project last year to rebuild the tandem, but it’s still hanging there. I’ll be very interested to see how your project progresses.

Mr IGH

Without any problems. You could easily use a 32H wheelset with some modern rims. For the money and effort, you might be better served going 3x10 and using Tiagra 4600/4700 series levers. That would allow you to keep your wheelset and crankset. You could also upgrade the OEM crankset by adding modern chainrings with shift ramps. You're going to pay a fortune to make an old tandem 2x11....

Do you have a rear drum brake? If not there are some low cost rear hub options for 32H/36H.

mtseymour

Your 11sp upgrade is feasible, but is it worthwhile to spend around $1,400 to get a modest improvement in shifting on a 20 year-old frame?

The DaVinci cranks use square taper BB to fit 68mm shells, and the arms come in a wide range of lengths. Retail is around $600.

The Ultegra R8000 11sp mechanical will be fine with the long cable run. The front shifting will be better than a triple, esp if you use high quality rings with ramps and pins. However, Di2 or eTap will be substantially better than any mechanical drivetrain. Chainline should not be an issue. The cost for R8000 shifters, derailleurs chain, and 11sp cassette is around $500.

Shimano is much more likely to introduce a 12sp group for mtn bikes rather than for road bikes. This would be to match the SRAM Eagle 1x12 drivetrain. Some gravel bikes use 1x12 but it's a niche market. Regardless, 11 and 10sp road groups will be around for a long time.

It will be hard to find a 11sp rear hub with the old 140mm spacing. Even if you find one, the rear hub (without rim or spokes) will probably cost $300+.

Dean V

Isn't the LosDos a flat bar mountain bike?
Has yours got drop bars on it?
Is it 3x8 gearing at the moment?

Eulers

Thanks, mtseymour, for the info on Da Vinci as I've not been able to raise a response from them. It could be that they're shutdown for the holiday. The 68mm shell info is good to know.

Eulers

Yes.

Eulers

Thanks MrIGH, Tiagra is a good backup plan. I'll keep it in mind.

Eulers

** Sorry, IDK what THLHS is. I'll be keeping the OEM Cannondale cam chain tension adjustment.
** Good tip about Da Vinci! Thanks!
** Locally it is a lot of rolling hills. Vacations are rail trails. Am not averse to switching cassettes for vacation. We always appreciate more range! Mo' is betta!

Dean V

Personally if in the end you want a road tandem I would not start with what you have.
I would sell it and get a newer road tandem that already has what you want.

Eulers

Seems like the foundational items are (1) the rear hub and (2) the compatibility to the crankset (chainline, etc.) and (3) new Bottom Bracket compatibility with existing frame's shell.

So far I'm trying to get these questions answered but there has been no response the past week or so from DaVinci. It's likely b/c of the holiday for sure with the hub supplier as they told me so. I'll retry mid-Jan when they return.

HUB:
I have these Questions:

MATERIALS:

1. What material is the axle (aluminum, stainless, or steel)?
2. Does the freehub have steel splines, or does it have any type of "anti-bite" freehub?

AXLE:

1. I'm concerned that the 15mm axle you spec'd won't fit in my dropouts (which are made for 10mm). Any suggestions?

HOLES & SPOKES:

1. I saw you replied 40-hole. Is there a 36-hole or 32-hole option?
2. Is the hub flange made for standard J-bend spokes?

MISCELLANEOUS:

1. Any idea what the hub's Right Flange Offset is in millimeters (drive side)?
   • (I'm hoping this will help me verify chainline dimensions).
2. On which White Ind model is this hub based (e.g. Racer X, etc.)?

Eulers

In the meantime, until I hear back from Da Vinci and TandemsEast, I'll double check the benefit vs cost story using the suggestions from MrIGH (Tiagra 10v) and DeanV (newer tandem).

Dean V

Do you know what gearing range you need to suit your riding?
It needs to be considered as well before deciding on components.

nfmisso

Why? What benefits do expect?

On our T50, we went from the original 3 x 7 to a 3 x 9 because:
* the rims split along the brake track.
* neither I nor the LBS could get the Sun Tour cassette of the Sansin hub. The LBS broke two chain whips trying. I don't think that the original owner ever took it apart and that it was not adequately greased originally.

Benefits: wider range across each chain ring; and slight closer ratio spacing.

I used a Wheelmaster 135mm tandem hub with a 2mm precision shim (washer style) on each side. The Wheelmaste hub has a 15mm axle, with 10mm nubs on each side that slide into standard drop outs. It's construction is very similar to Phil Wood's. It is available in 36H, 40H and 48H. Might be in 32H too - I have looked. It has an 8/9/10 speed steel freehub - which I believe works with 11 speed road cassettes - but not positive.

We did not change the 28-44-54 chain rings. The rear went from 12-28 to 11-34. 12-36 might have been a better choice. Since then I got a 26T granny.

sch

On a recent thread ( https://www.bikeforums.net/bicycle-m...ad-triple.html )
under reply #8 there was mention that Shimano's latest 11 spd cassette, the 8000 series Ultegra 11-34 is back compatible with 10 spd hubs
sort of like the 11 spd MTB cassettes being compatible with 10 spd hubs. Researching this gave some incomplete data but may
be worth exploring, as a way to keep your present wheelset (ie some Shimano sites show no 11-34 11spd, others do but no other info).
The 8000 series Ultegra 11 spd RD can go to 11-36 as is and likely to 11-42 with a Wolf extender. There have been a number of posts
about the electric SRAM and Shimano RD being pushed 4 teeth larger on the cassette than their nominal max. No reason this would not
apply to the mechanical RD as well and the 8000 series Ultegra is clearly designed for larger cassettes than the 6800 series.

mtseymour

An 11-sp cassette (eg. CS-R8000) can't be used on a 10sp hub because the freehub body is not wide enough. On the other hand, a 11sp freehub can accept a 10sp cassette by adding a spacer. I don't know why anyone would want this option but it's possible. If you go to the Shimano website, you'll that the Ultegra freehub is listed as 10/11sp, but the cassette is only listed as 11sp. Here's the link:

FH-6800

Mr IGH

I'm upgrading a 1998 Santana Arriva from 8 speed to 10 speed (and customizing bars/stem/saddles/pedals). Here's the path I took to keep my costs low. I'm not a fan of 2x11, I prefer triples for my own reasons (and choose not to discuss my reasons here on BF ).

- I kept the original cranks and mounted modern Shimano 10 speed chainrings from 105 crankset (53/39/24). Cost was ~$50 total (ebay). Setting up a tandem with Ultegra crankset isn't going to be easy or cheap. For that matter, anything except your stock cranks is going to be expensive.

- I bought Tiagra 4603 shifters off ebay that are brand new in OEM bags for $110. I like them because they have the window for chain position (nice to have on a tandem) and external shift cables to help with the extra long rear derailleur cable friction. Also, Tiagra 4603 shifter should work with low-cost 7-8-9 speed MTB derailleurs (of which I have several in my spare parts bin). The Tiagra 4703 have hidden shift cables, lack the chain position window and need a special version rear derailleur. Anything 2x11 requires an 11 speed rear derailleur.

- I stayed with 10 speed so I could use low cost rear hubs. I bought a set of 40H Shimano HF-08 for $180. If I wasn't stuck with 160mm spacing and a rear drum brake I'd just buy 32H Shimano XT 756 rear hub and install a steel axle and 5mm of spacers. I'm building new wheels so I can run 35mm tyres on wider rims. I'm selling the old skinny tyre wheelset because it's cheaper in the end.

Dean V

Some good ideas here.
But if you were desperate for 11sp double without spending too much I would,
- get 11sp cassette and turn 0.070" out of the back. It will then fit your existing wheel.
- New chainrings on your existing cranks. Leave off granny ring. Just not sure if the spacing between chainrings would be too much.
- New, shorter BB at the back to correct chainline. Maybe not essential. Need to make sure new front mech has enough reach too.

Kiss4aFrog

What did you end up doing with your project ?
Yes I know it's been years since the last post.

Ludkeh

I can't get into the technical aspects of your build, but I can't imagine going from a triple to a double. In my neck of the woods a triple with a wide range cassette is essential when going up our very steep hills. Also how strong is your Stoker? I think it would take a strong team for a double chain ring. PS, we have a da Vinci, set up with the widest gear range that was available at the time.