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Tandem Cycling A bicycle built for two. Want to find out more about this wonderful world of tandems? Check out this forum to talk with other tandem enthusiasts. Captains and stokers welcome!

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Old 06-17-14, 02:33 PM   #26
Ritterview
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....just climbed our first proper mountain pass on it last weekend

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Old 06-18-14, 09:42 AM   #27
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Originally Posted by Neru View Post
I realize that this discussion has gone to sleep a while ago, but I came across it as I was looking for info on the DT 535 tire pressure (I just had a Cannondale road tandem delivered, and was pretty surprised by the low maximum pressure).

A few years ago, I shifted from ordinary wide mtb tires to narrower Continental SportContact 26x1.6. These basically resemble wide racing bike tires for mtb's. My Mavic X317 rims stated a maximum pressure of 7.7 bars for 1" tires and 3.3 bars for 2.3" tires. Inflating the 26x1.6 tires to 5-6 bars was apparently well beyond this limit, as it eventually led the rim walls to bend outwards (yes, it was a bad idea to check only the recommended tire pressure and ignore the rims).

It may therefore generally be a bad idea to exceed recommended rim pressure, but the limit should be seen in relation to the tire attached. A 35 mm tire will generate more rim wall stress at 5 bar than a 25 mm tire, but it will also give better suspension at a given pressure. I find it hard to believe that the apparently solid DT 535 rims will have trouble handling 25 mm tires inflated closer to 7 bars, and as the technical document you supplied indicate that they are intended for 1"-2.35" tires, I assume it will be safe to inflate mine at least to 7 bars. Thanks for sharing!
Some additional info for those interesting in attempting to compare stress on rims of various wide tire/rim combinations. Not written by me but I have found it helpful.
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Old 06-19-14, 02:25 PM   #28
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Thanks a lot, Waynesulak, that did the trick. I also found the mentioned excel chart (http://dl.dropbox.com/u/7489636/Felgenbelastung.xls) in this thread: New rim needed,yet again
The calculations based on that formula suggest that the DT 535 rims should handle up to around 10 bars with 25 mm tires. I suppose some extra margins should be added due to the extra rider weight on a tandem, however.
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Old 06-21-14, 07:05 PM   #29
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can you put a cyclocross tire on it? What is the widest tire you can put on the front/rear.
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Old 06-22-14, 06:23 AM   #30
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Originally Posted by Neru View Post
Thanks a lot, Waynesulak, that did the trick. I also found the mentioned excel chart (http://dl.dropbox.com/u/7489636/Felgenbelastung.xls) in this thread: New rim needed,yet again
The calculations based on that formula suggest that the DT 535 rims should handle up to around 10 bars with 25 mm tires. I suppose some extra margins should be added due to the extra rider weight on a tandem, however.

I found that that the easiest way to find a rim that resists outward force at the bead is to go with a "tubeless ready" rim. This type of rim have a very low distance from bead down to rim bed. The rim wall is therefore very well supported even on a light weight rim.
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Old 07-01-14, 11:22 PM   #31
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hello.

We just looked at the new 2014 Cannondale Tandems. Our LBS carries all 3 models: Road 1, Road 2, and 29'er in med and small sizes. One thing I found rather very strange is Cannondale has braze-on lugs for shift cables but strangely omitted braze-on for the rear brake cable. My initial assessment with the braking (in the shop, anyways) feels very spongy as I can tell the extra long brake housing compresses under hard squeeze, and it is especially pronounced with the rear brake since the cable jacket is probably a good 3 meter length!

Why would Cannondale omit braze-on for brake cables? I am sure this is not an oversight. One possible guess would be because they want to leave the option for hydraulic brake, but thus far I don't know of a road-tandem-specific hydraulic disc setup in the market...

Have that been a problem for any of you C-dale tandem owners on long, steep descent? Love to hear your comments. We live in hilly area, some rides nearby at 1000 meters elevation with grade ranging from 6 to 11%, so I take braking seriously.

I have another tandem using Avid 203mm disc set up: Fandango hard-tail mountain bike. I used avid Full Metal Jacket in addition to brazed on cable routes. The brake is extremely responsive and not spongy at all, resulting in excellent modulation and no loss of braking power.



All other setup seems alright, I prefer SRAM 1:1 shifting for tandem (it is very forgiving, a welcoming advantage for tandem bike), may swap out if I decide to get this bike.

Last edited by shredlock; 07-01-14 at 11:34 PM. Reason: details
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Old 07-02-14, 12:46 AM   #32
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To avoid using full-length housing then hopefully one of the tubes is the right diameter to take a pair of the Backstop housing stops from Problem Solvers:

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Old 07-02-14, 03:38 AM   #33
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Are you sure they are not there and the bike shop has just assembled the bikes incorrectly? Previous models have run the rear brake under the bottom brackets with the gear cables.
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Old 07-02-14, 08:27 AM   #34
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Are you sure they are not there and the bike shop has just assembled the bikes incorrectly? Previous models have run the rear brake under the bottom brackets with the gear cables.
I think so. the rear brake cable/jacket was mounted right next to the gear cable, running through both bottom brackets before splitting out to the disc brake. brake cable braze on was missing, only shift braze-on available.
as for the problem solver , its an interesting solution but probably won't fit modern bike frame. For this tandem, i can't even tell if there is a single tube in the entire frame that would look round enough to fit a conventional diameter clamp (except perhaps the seat tubes)
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Old 07-02-14, 03:36 PM   #35
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We just looked at the new 2014 Cannondale Tandems. Our LBS carries all 3 models: Road 1, Road 2, and 29'er in med and small sizes. One thing I found rather very strange is Cannondale has braze-on lugs for shift cables but strangely omitted braze-on for the rear brake cable.
It would be nice to have a detail photo of the present and absent braze-on lugs for the shift and brake cables, respectively.
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Old 07-03-14, 05:05 AM   #36
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To avoid using full-length housing then hopefully one of the tubes is the right diameter to take a pair of the Backstop housing stops from Problem Solvers:

Why would you not want full length housing? I prefer full length housing because of less maintenance.
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Old 07-03-14, 09:04 AM   #37
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swiss-toni picture slide have nice picture of the brake braze-on: it appears to be only there to hold the cable housing. See his link here. ( make sure to flip through the slides)

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Originally Posted by Ritterview View Post
It would be nice to have a detail photo of the present and absent braze-on lugs for the shift and brake cables, respectively.
OTOH: that lug looks like it could be re-purposed with some sort of lug adapter~???
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Old 07-03-14, 03:09 PM   #38
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OTOH: that lug looks like it could be re-purposed with some sort of lug adapter~???
I agree. Plus, I just did a quick Google image search for "brake hose cable stop" and immediately found a couple of solutions.
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Old 07-03-14, 03:35 PM   #39
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Why would you not want full length housing? I prefer full length housing because of less maintenance.
cable housing compresses. the longer the housing, the more it compresses. For tandem, depending on housing quality, that compression could eat up all of your cable pull length needed for a good brake, increases friction, and reduces modulation. A few companies are addressing it with "compressionless housing" made of solid aluminum sections, but at a stiff price, and none are available that i can find a for full length tandem.
As for maintenance, I could argue that small section of housing is easier for brake line maintenance (lube, clean and such) than full length housing, unless you ride on unpaved dirt trails in the rain, in that case i'm better off with hydraulic brake.

Last edited by shredlock; 07-03-14 at 03:46 PM.
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Old 07-03-14, 03:45 PM   #40
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This gives me some hope, but i have to take a close look and make sure this isn't just "glued on" or if it's just a tack-weld for guiding the housing only: re-purposing it for braking function could rip that glue or tack-weld right off the bike frame!!!!
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Old 07-03-14, 03:49 PM   #41
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We have these same braze-ons on our 2011 RT2. They use a different center insert to go with non full length housing.
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Old 07-04-14, 05:03 AM   #42
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I used a Jagwire Pro XL cable kit when building up my '10 Cannondale. It comes with compressionless brake housing which is made with longitudinal wires like shift housing but with a kevlar weave over that to prevent bulging. It has worked very well so far with my Hy/Rd brakes. For the cable stops I used Jagwire CHA056 end caps.
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Old 07-11-14, 09:00 AM   #43
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I've got a couple of hundred miles on a 2014 RT2 now and I have to say it's an incredibly fun machine. We're an unusually heavy male team (450lbs) with a 6ft4 stoker and 6ft 3in captain but the Cannondale stays stiff and true under some pretty harsh pedalling. We've swapped out the rear gears for Shimano XT 11/32 and I think we're about to change the front 52 for a 54 or maybe even a 56 because we're spinning out on the flat if the road is long and smooth enough.
The worst flex I've noticed so far is about an inch of sway side to side at the stoker's BB when going downhill and pedalling hard. Honestly, we were pedalling too fast to be smooth and should have been free-wheeling by that point. The captain didn't notice anything. On the other hand, when I stood up and honked up a short hill in our top gear I couldn't feel a hint of flex and it just shot up and over like a rocket.
Exhilarating!
Let's hope it all stays stuck together.....
Morat - stoker for "Team Fat Bastard"
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Old 07-30-14, 01:45 PM   #44
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Happy to report that the long brake cable housing ended up not being much of a problem after a bit of retrofit. We took the plunge and got a T1 model but retrofitted for our liking with flat bars and shimano brake/shifter for flat bar, increase grainy range with 11-36 XT cassette & XTR derailleur. Our LBS (Bicycle Outfitter of Los Altos) carefully tuned the brake line, making sure caliper mounting is aligned and centered. In combination with longer pull from the flat-bar brake level, we got marverlously responsive braking on a 12% grade and the 11-36 allows us to crawl up the 1 hr, 5 mile long climb - although I could definitely appreciate even more grainy gear!
The bike is very nice. for such a large set of tubes, it still feel relatively smooth, not jarring at all while 28+mph downhill. M/S frame fits us very well (stoker only 5' and she's comfortable with a thudbuster short post), the only thing is the stoker stem is too short for the stoker, solved by taking the unused drop bar in the front and reverse-mounted for the rear (I would not have been able to fit my short stoker with a stock Co-motion Speedster or Primera).
Kevlar belt settled in quickly, very smooth, and the grease-free left side means less black-grease tattoo on my shin and much easier to transport.

When I have a chance I will estimate the bike weight with my bathroom scale( UPDATE: the cannondale Tandem1, as retrofitted, is 37.6 lb)

Last edited by shredlock; 08-10-14 at 10:18 PM.
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Old 05-21-15, 06:44 AM   #45
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No - we went up the other way :-)
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Old 05-21-15, 07:15 AM   #46
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Update - 1 year on

Just thought I would do a quick update on the bike. It is still running strong with no problems so far.

After our first puncture a few weeks ago I noticed that the original tyres were worn and needed replacing so we are now running 700x28C Continental Grand Prix 4000xII tyres. So far they seem good.

We also just added a specialized CG-R seat post for the stoker to make longer rides more comfortable.

Last year I also updated the front derailleur as per the recommendation of Chris_W in his post. This definitely improved the front shifting.

The rear chain needs replacing due to stretch which I will be doing in the next few weeks. The timing chain is still fine.

We have probably done about 2000km on the bike including olympic and half ironman distance triathlons. We will be using it for our first ironman triathlon in a few months time. I am toying with getting some aerobars but it is not a top priority. We have also used the bike for some weekend pannier tours (using a thule pack n pedal rack) and it performed fine there as well. We are still very happy with the bike and are looking forward to many more km of riding.


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Old 05-22-15, 09:50 PM   #47
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Shredlock. I noticed you said the shop centered your caliper. If this an Avid BB7 you must not center the caliper. You must offset it as far as possible to expose as much fixed inner pad as possible. I have seen folks center the caliper and not have enough fixed pad out so when it wore down the rotor ate away the caliper body causing brake overheating and failure.
Good luck.
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