1/26/14 8:29 PM

I mentioned when Dan got his Richard Sachs that I also had a bike on order. It's not as sought-after as a Sachs and I didn't have to wait anywhere as long.

Well, on Friday my bike finally arrived via Fedex Ground shipping. I promised Pete Hauser I'd post here. Anyhow, here's the story. It's a bit long...

http://sandiway.blogspot.com/2014/01/the-da-vinci-jointventure-tandem.html

Sandiway

1/26/14 8:59 PM

Interesting. And wishing you many happy miles!

Question - Is that frame stiff enough? The lack of any additional crossbraces would make me think that it may a bit of a noodle.

1/26/14 9:04 PM

Thanks Parkin!

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Question - Is that frame stiff enough? The lack of any additional crossbraces would make me think that it may a bit of a noodle.

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1/26/14 9:26 PM

Enjoy Sandi & stoker. ;)

How about a little dialog on your choice of wheels/tires sizes et al.

I guess I expected 650B or 650s. What is going on
for the smaller wheel choices on tandems these days?

If you and stoker come this way, be sure you bring that steed. Our Ibis needs some company. ;)

Some details on the driving gears set up? Driving gears 12-18-24-30, intrigued ? Your take on the gear changing performance etc.

Thudbuster ?

1/26/14 10:29 PM

Yes, that's a Cane Creek Thudbuster ST (Short Travel) for the stoker. It weighs a ton...

Since I'm shorter (5'8") than most of you, I ride 650c on my Litespeed Ghisallo bike. (I've never really been a fan of the 700c wheelsize.)

26" or 700c are the options at da Vinci, so it was a no-brainer to go for the 26" size. I've got 26 x 1.25 Panaracers at 90psi on it at present. Since I'm new to the 26" size, I'm not sure what the best tires possible are.

The gearing is wide enough to tackle major hills. 11-12-14-16-18-21-24-28-32 9speed SRAM cassette in the back. The front cluster is equivalent to 24T, 36T, 48T, and 60T chainrings. So that gives a range from a 133" high gear to a 18" low according to Sheldon Brown's calculator, which I guess is sufficient for everything I'm likely to encounter.

Will be glad to ride with you Sparky if we get the chance!

Sandiway

1/26/14 10:39 PM

Some serious gears and range there. Allows for closer ratios to be maintained as well ?

What does it weigh, curious? EDIT, saw blog 35 lb.
Tandems don't get to much lighter than that I guess.

Are the Rims MTB and wider profile like 23+mm wide?

1/26/14 10:57 PM

I'm still learning the gearing. I'm not used to 4 chainrings.

The V-23 rims are supposed to be tandem duty rims.
See http://www.davincitandems.com/comp.html#rim . It says 22.9mm wide.

35lbs is what I got on my bathroom scales. I guess I could cut more than 2 lbs easily by spending a lot more money.

However, 2 lbs is almost nothing when compared to the total weight of the bike + 2 riders (300 lbs).

Sandiway

1/27/14 5:01 AM

nm

1/27/14 5:05 AM

Sandi, that's awesome. I don't think I could process the gear selections, but I'm sure you're up to the task. Have a ball!

1/27/14 6:06 AM

...rather than 10 or 11? Either would give you tighter spacing between gears and I can't think of any downside. Just curious.

1/27/14 7:56 AM

I asked about that too. Todd said 9-speed was proven and durable chain-wise for a tandem. It uses the KMC 9-speed chain (three of them!) with that easy-to-pull-apart connector.

From their website:

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We do not want to give up the reliability, rebuildabilty, comfort and front derailleur trim that only Campy Ergo shifters offer, but ten speed chains are proving to be too finicky and not very durable. Keeping to our Credo of "Drawing outside the chalkboard" we modified SRAM X9 Long cage and Medium cage derailleurs to work with Campy shifters. Now you can use any Campagnolo ten speed Ergo shifter and SRAM or Shimano compatible 9 speed cassette together.

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1/27/14 8:09 AM

I think on that bike I would like to minimize the number of times I needed to change the chain(s)...

1/27/14 1:00 PM

They make some neat bikes. The caebon ones used to be made by Calfee to their specs. Do you know if that is still the case? The Calfee version was somewhat cheaper, but I don't know if they do the ICS on the Calfee bedged frames.

1/27/14 1:32 PM

8/9/10 speed tandem.

9 speed chain is probably pushing it already. A lot of torque pulling on a narrow chain. The guy I got the IBIS from wanted it to be 10 speed, they told him they won't do it where he had it built. Make sense too. Thus the Ibis is 9 speed.

1/27/14 1:42 PM

I'm not sure if they farm them out but I saw carbon tubes at their facility; one of my pictures has some carbon tubes showing.

Another picture has one of the carbon ICS bikes (700c); I believe it the one sporting Reynolds wheels. To be frank, I was trying to avoid picking up or asking about the carbon frame option. I really wanted to keep the price reasonable. I only partially succeeded.

When I was there, they were welding stuff for a race car. There was a car with a roll cage etc. being worked on. An a stack of race car tires. Todd mentioned he was an autocrosser.

They have their own paint facility. It seem bigger than needed for bicycle frames.

1/28/14 6:31 AM

You shouldn't need any modifications.

As for the shifters, you would need a new shift ring, assuming that they're actually 9 speed shifters, which aren't being made anymore. I wonder if they're actually using current model 10 or 11 speed shifters with the rear derailleur modification that they speak of. The pics look like Chorus 10 speed.

1/28/14 8:13 AM

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.....assuming that they're actually 9 speed shifters, which aren't being made anymore. I wonder if they're actually using current model 10 or 11 speed shifters with the rear derailleur modification that they speak of. The pics look like Chorus 10 speed.

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1/28/14 10:04 AM

Seems like that's exactly what they're doing. Chorus 10-speed brifter with SRAM X.9 rear derailleur to a SRAM 9-speed (PG-980) cassette:

1/29/14 10:12 AM

Terrific pics; both of the bike and of the stoker. Perhaps an introduction is in order…

;>))))

1/29/14 10:21 AM

Thanks Sandi for the write-up and for this thread!

I learnt a good bit here.

Your choice of smaller wheel size is totally consistent with the structural and weight concerns (not to mention packing dimensions) of a tandem, and the wider rubber will keep the front tire from tracking along any pavement seams, important since you can't unload and/or toss around the front end while riding a stretch limo as you might on a regular bike.
Any concerns about "whippiness" are somewhat further addressed with these smaller wheels as well.

It took me a few (minutes and/or drinks, er, coffee) to understand how the captain drives the outer shell of the freewheel, and the stoker drives the ratcheted inner shell. Clever engineering. How's the shifting in the front???
I guess then that a slightly higher bb (and perhaps shorter crankarms) might be best on the stoker's end?

That's a really good weight you arrived at, abetted again by your wheel-size choice, and still weighing several pounds less than my 1976 Schwinn Varsity!

I would think that any chain that can handle a strong MTB rider on a full-suspension rig with a 22t chainring would probably be much stronger than you'll need.
I suppose that if you were doing off-road climbing it might over-tax the chain though.

1/29/14 11:30 AM

Nice bike! I hope you enjoy it as much as watching this brilliant & hysterically funny table tennis match: http://www.youtube.com/watch?v=ITR88wT8ekM

1/29/14 1:47 PM

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Perhaps an introduction is in order…

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1/29/14 1:58 PM

CONGRATS. I believe we met in Tucson last time I was there.

1/29/14 2:03 PM

quote:

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I guess then that a slightly higher bb (and perhaps shorter crankarms) might be best on the stoker's end?

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quote:

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That's a really good weight you arrived at, abetted again by your wheel-size

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I would think that any chain that can handle a strong MTB rider on a full-suspension rig with a 22t chainring would probably be much stronger than you'll need.
I suppose that if you were doing off-road climbing it might over-tax the chain though.

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1/29/14 2:50 PM

I had a KMC chain and link on my MTB for years of heavy use, and I used the link over too. I'd wager I might have same or more push than you both mashing low RPMs like I used to on the MTB too. I almost never used the granny when I could just mash up stuff. ;) you got some seriously low choices for gears on that. Is your better 1/2 a spinner ?

I still have a KMC link in the saddle bags of a few bikes for insurance... Maybe a Sachs in one too. ;)