# ECDM right side drive / lock out suspension Build



## rhxpro (Oct 9, 2006)

Newly built ECDM!!! well a newly rebuilt anyways. After much forum searching and hearing deferent ideas and opinions I've finally pulled the trigger and revamped this old 96' ECDM. The results are awesome and I hope I can help lay some of the questions to rest.

Quick summary of project upgrades:

IS compatible swing arm
Carbon Powder coat main frame and rear triangle
Ventana refurb rear suspension and powder coat
Front/Rear Marzocchi suspension with lockouts
Hope External Bottom Brackets
Right Side Drive
XT 2x10 38/24 front / 11/36 rear
Tubeless rims

Essentially I've rebuilt the whole bike. Many have asked why not just buy a new tandem? Ventana has a great trade in program! I said if Ventana didn't make their products so well I could do that... But as it were the tandem was fine and with the new lockout front and rear suspension it is better than ever!!! Plus I like the old suspension design.

This bike has been upgraded many times over and the first set-up I had was XT v-brakes and a Judy DH single crown fork. I raced the bike in Big Bear back in the day and hammered it down the Fall Line. Since then it has seen DH double crowns and a few other singles. In addition it has run many different brake set ups. The build now is set up for XC/Aggressive trail riding 2’ drops at speed etc. We ride so Cal trails including Mammoth and Colorado. The way it is set up now is a perfect balance for ME! So this is only my 2 cents.

Marzocchi Roco lite rear / 55r front with blk 35mm stanchions and both have lockouts. The 55R is a custom build by marzocchi and you will have to call Bobby there for the specs. Bottom line is set it at 25-35% sag based on your ride and lock it out when you want to climb hard or hammer on the flats. It works awesome. The Fork is 6”, 20mm thru axle, lock out and has very little flex including under braking.

Drivetrain:
And much debate I finally went with External BB and XT Right side drive. I love it and it looks awesome and it saved a bit of weight overall.The cranks are XT triple in rear and double in front. I also got 2 Hope single rings 32 tooth as the timing chain. I kept the 24 in the rear and removed the 32/42 ramped rings and will try and sell. I then took the rings off the double front and will use the 26 as a spare for another FS bike and moved the ramped 38 to the rear middle position. I then put a 32 single out board on the rear triple and a 32 in the front where the 38 was. There is just enough space to clear the chains without spacers and if you want more you can space it. The only issue is that you have to set your Front derailer so that it will not go off the big 38 ring. I converted to 2x10 because the 3x was a waste in my opinion for the level of fitness we have. Even with my wife who does’nt ride much we have no problem makin it up the verdugo’s and the Santa monica’s. With my Race stoker we’re not usually in the 2nd-4th gears and leave the 24/36 for tight technical uphills that are stop and go.

We’ve put about 100 miles in a week in the Santa Monica’s and hammered the Backbone Singletrack and we’ve really put that thing to the test… We will be racing the So Cal races for 13’ and hope to see some of you out there. 

Also I’m looking to put together a So Cal tandem Stage Rally similar to some of the one’s you’ve seen on Youtube. I’ll have some dates soon and I’ll be posting some Tandem friendly rides.


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## rhxpro (Oct 9, 2006)

I put the build pictures on a video and here are links to the ride and the video

Mountain Bike Ride Profile | Santa Monicas on A Tandem!!! no dab! ok 2 spots! near Los Angeles | Times and Records | Strava

tandem - YouTube


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## PMK (Oct 12, 2004)

Looks great.

PK


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## mhopton (Nov 27, 2005)

Nice job on the rebuild!


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## ds2199 (Sep 16, 2008)

rhxpro - Nice work on the rebuild! I really like that color (maybe b/c its the same color as our bike)!

Let us know how the 2x10 on the right side works out. We have used it with about 99.xx % reliability. Or at least I should say that it is just slightly lest reliable than the 3x10 with the left side drive.

I keep meaning to get some video of us negotiating switchbacks. I will say that the one in your video is nice b/c there is a guardrail. We have some near us that have a REALLY big dropoff so I have been reluctant to do the dowhill switchbacks, but we have figured out some of the uphill ones and get major props from the "non-tandem" riders when we "clean" the switchbacks.


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## Hurricane Jeff (Jan 1, 2006)

Been thinking about a right side timing chain also, never considered a drive on the outside of the chainrings. It looks like you could use a triple with that setup, if you liked, usinging chainring spacers on the timing wheel.
I heard from the people at Santana once, that said that having the timing chain as inboard as possible is the best way, stating the reason for this was to combat flex, with the boom tube and the super stiff frames that Ventana is known for, dont know if that applies. It is something I'm going to look into on my El Testigo.


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## jajst35 (Jan 14, 2011)

Hey Hurricane Jeff,
Any chance you might think about selling your El Testigo?


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## Hurricane Jeff (Jan 1, 2006)

I sold the El Testigo about a year and a half ago....Im now tandemless.


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