waynesulak

Thanks for repeating that information. Switching from 10 speed KMC to KMC 9 speed made less difference in weight than I expected. I came up with 50 grams of additional sync chain weight comparing the dirty 10 speed to new out of the box 9 speed. Some dirt probably added weight to the 10 speed chain so that understates the savings by some amount.

A couple years ago I weighed some chains and found that all 10 speed Shimano chains 105, Ultegra and DA seem to weigh about the same when new. Newer DA chains may be different.

DubT

My current Wipperman 8 speed front chain weighs right at 460 grams, so my estimate of a potential weight savings of about 1/2 pound should be very close.

I am going to upgrade for 2 reasons, a little weight reduction, but primarily for the cleanliness factor. We haul the tandem inside of our Honda Odyssey and we have to stay away from or cover the chain to keep from getting things dirty inside the car.

Wayne

zonatandem

We haul our tandem (with real chains) inside our '97 Honda Acord station wagon.
We put a rug/carpet remnant on the wagon floor to keep things clean.
Works fine for us!

Monoborracho

We are planning the center track system for our new Seven Ti S&S coupled tandem, currently in design phase. And if Shimano made a Di3 system I'd buy it also.

One of my goals in life is to have a bicycle that's worth more than my daily vehicle. I may reach that goal by late June.

rhino919

Never thought of that goal, but we will achieve it in early August

waynesulak

Cleanliness seems like the big benefit of the belt system but it appears to only solve half the problem. I am interested to see if what looks like higher tension than a chain effects BB bearing life over the long haul.

Wayne

DubT

If I remember correctly the CDX system does not have to be as tight as the original belt.

DubT

Rudy,

In the Odyssey, we can haul the tandem in a vertical position and still access the center and rear seats. I remove one center seat and fold 1/3 of the rear one down. This past weekend we hauled the tandem and 2 grandkids along with one of their friends. I had to tell them to be careful of the chain. Later this month we are going to Florida for a wedding and one of our daughters will be joining us, she is renting a bike so we will be hauling the tandem, her rental bike and three people. So for us the belt will offer some benefits that you do not require.

Wayne

Ritterview

The cleanliness of the belt system is sufficient onto itself. If the belt otherwise has no glaring drawbacks, it is worth it right there; it needn't solve any other problems.

Maybe not if the tandem is moored in the garage, and you ride straight out the garage door and put it back in, it doesn't matter so much. But if you are transporting, especially in a car, or going to hotels, or bringing it the house, then it is soooo nice not to have that long sync chain hanging out there, a threat to indelibly stain any fabric it touches.

A tandem with a belt is more like a house pet, it is okay inside, or in your car, etc. A sync chain tandem is an outside dog.

twocicle

I packed up the older system's 69T rings and 2000mm belt and returned the items to the stores from whence they came - as "incompatible with our tandem". We never did get our hands on the 71T rings which are apparently the size we need for our 2007 Calfee frame.

At this point we can wait and see what transpires with the CDX component availability. Hopefully someone produces a compatible CDX size to the older system's 71T rings and the 2000mm belt.

Meanwhile, you could say we are "beltless", or "have a well hung chain".

Carbonello

I called Gates yesterday to order a belt and rings. Steve priced the belt at $79 and 69 tooth rings at $66. each. But then he said the CDX system was not available till after Interbike. He said it would be maybe 10% more. I'll wait.

CaptainHaddock

What is the current understanding regarding compatibility of the extant gates systems and Cannondale road tandems?

Carbonello

The Co-Motion web site has a nice summary of the requirements, it applies to all bikes.
https://www.co-motion.com/index.php/i...ng_belt_system
Here is the meat:
[h=2]Gates Carbon Drive Checklist[/h]If your tandem meets these criteria, the Gates Carbon Drive may work for you
28.5”/724mm boom tube length (measure from rear bottom bracket to front bottom bracket)
Tandem crankset with 130mm BCD timing crankarms
Same length bottom bracket spindles front and rear
A way to adjust chainline or “beltline” on front and rear cranksets

Dean V

I couldn't get it to fit on my 2009 RT2. The rear pulley wouldn't clear the chain stay (Gossamer cranks).

Chris_W

How big was the interference? If it is only 2 or 3 mm then I would certainly try just putting some spacers between the ring and the spider - I had to do this for one of the crank setups that we've tried with our belt drive to get the beltline straight, and it didn't cause any problems.

twocicle

In order to achieve sufficient clearance on the rear stay with our 2007 Calfee frame, I had to install the rings flipped inside-out (with the shield ring to toward the bottom bracket). This yielded a good .5cm clearance. Adding a couple washer spacers with a normal ring orientation still did not give enough clearance. As long as the rings are in-line with each other, it does not matter which way they are installed. If concerned about catching pants, etc in the ring then consider that the new CDX system does not have a ring shield at all - so they must believe it is not necessary for that purpose.

Regardless, at this point I'm waiting for the CDX system.

Dean V

I can't remember the details as it was several months ago that I tried it. I do remember that I tried it in every combination, inside, outside of spider, flipped around, etc and none of them worked. It either hit the chainstay or crank arm and I think any spacer to correct it would need to be more than 2 or 3mm.

DubT

I just pre-ordered the CDX system, Gates hopes to have them available around the end of September. I did not get the exact price. When the parts are ready to ship I will receive a call to get the payment information. If the price is out of site I will cancel the order.

Wayne

DubT

The CDX drive should ship yet today or tomorrow. The price is $75 each for the 69 tooth sprockets and $95 for the belt.

i placed the order directly with Gates.

Wayne

waynesulak

It is interesting to compare measurements taken by Ritterview to the CoMotion site at :

https://www.co-motion.com/index.php/i...ng_belt_system

Also note the estimated life of the system stated by CoMotion in the quote below.

DubT

I will weigh our current chain (8 speed) and the two Ultegra chain rings and then weigh the new CDX components and will post the results here in a few days.

Wayne

twocicle

FWIW, I just called Gates to inquire about their CDX CenterTrack timing ring sizes and confirmed they do not have a 71T, only 69T and 74T (Santana). Unfortunately, my 2007 Calfee (and earlier "gates compatbile" Co-Motions) requires the 71T. Current frame builder specs use the 69T and 74T (Santana).

DubT

just for the sake of curiosity what is the center to center distance between your bottom brackets? Mine is 28.5 inches.

wayne

twocicle

Something like 72cm (28 5/16"). Falls between the 69 and 74 tooth rings (ie: 71T). When I tried the previous Gates system the belt was quite loose in spite of the eccentric being in the most forward position. I then confirmed with Calfee that the 71T rings were needed for the <=2007 frame years.

Chris_W

If your bike is a Co-Motion then the 69 tooth rings should work better than the 71 tooth. We bought a Co-Motion just when the Gates belt was first available, and so got the 71 tooth rings. To get the belt on, we have to have the eccentric in the most rearward position possible, getting it on is awkward (we have to ignore the warnings against rolling the belt on under tension) and then it already has enough tension on it, there is no need to use the eccentric. They soon realized that the 71 tooth rings were a little large, so within a year had started to make the 69 tooth rings instead (and Co-Motion never changed their frame geometry).

I wish that we did have the 69 tooth rings, it would make mounting the belt so much easier, and we could then choose a more forward and lower position for the eccentric, which would help us to achieve a better fit for our bodies on the bike. If the CDX drive is now readily available, I may consider getting one of those in the 69 tooth version.