loopless

Hi,

I'm on the brink of placing an order for a set of these however, aside from the known wins such as lesser maintenance etc, do we still need to bother about tensioningthe belt often? For those of you who have made the swop, what benefits have you realised so far from the upgrade?

on my RT2, as we do lots of climbing I find that the TC tension needs to be adjusted every 200-300km or so therefore I'm keen if this kit really presents less of periodical tensioning required.

ps: Does anyone have this on a RT2 ? if yes, which set did you get? there are a couple of combinations and since I have to order internationally (i'm based in Singapore), I really do not want to get the order wrong.

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739mm 66T CDX system = Tension Point is 739mm. Install point is 729-732mm. These frames measure close to 736mm or 29".
Typically these would be Precision Triplets and some Cannondales.

726mm 69T CDX system = Tension Point is 726mm. Install point is 719-722mm. These frames measure close to 724mm or 28.5".
Typically these would be Co-Motions, Calfees, and Paketas.

706mm 74T CDX system = Tension Point is 706mm. Install point is 699-702mm. These frames measure close to 704mm or 27.7".
Typically these would be Santanas since about 1999, some Burleys, and maybe older pre 2000 C

Paul J

One of the members on the Tandem Facebook page just did the conversion on their Cannondale. They had Tandem Cycle Works in Colorado do the work. We have the belt on our Co-Motion which has about 1,500 miles on it with no need for re-tensioning. I do think you may need to look at your eccentric and see if it is slipping under load and it is doubtful that you would be stretching the chain in that about of time. I think you would have the same problem with the belt if it is the eccentric BB is slipping.

mtseymour

I also think that you should look at your eccentric because a chain or belt should not require re-tightening so frequently. The Cannondale seems to use a split-wedge eccentric which is an older and more finicky design. We prefer the Bushnell Featherweight EBB because it's is easy to adjust and doesn't slip. We also like our CDX belt because it needs minimal maintenance plus all the other benefits (clean, lightweight, etc).

Paul J

That's a great point mtseymour, a new eccentric might solve the problem at a lower cost then the belt conversion, the Bushnell is readily available. Thought with that said, we too love our belt. We have the Bushnell eccentric on our Bushnell tandem which used a chain and the stock Co-Motion eccentric with the Speedster which has the Gates set-up. I think the Co-Motion eccentric works somewhat similarly to the Bushnell though I've never looked. Tandems East did our Gates belt conversion this past spring on the bike which was about a year old at the time. I hadn't done anything to that bike to that point and haven't touched anything since they did the conversion.

Artmo 

We have the early gates on our Comotion and have probably done at leas 5000 miles on it without it requiring any adjustment.

prathmann

Agreed. We never readjusted the eccentric after the initial setup - just replaced the chain every 10,000 miles or so.

Eddie50

I have a set of 69T CDX rings for sale if interested, never used, it was the wrong size for my older Trek.

You can PM me if interested.

Carbonfiberboy 

We ran the early Gates version until the timing rings wore and the belt wouldn't stay on anymore. We've have over 5000 miles on our CDX setup, haven't touched it, works great.

One of the benefits of a belt that we've noticed is the no-slop communication between captain's and stoker's pedals. We have a much better feel for each other. When we had a sync chain, I probably re-tensioned it about every 1000 miles, replaced it when it was worn just as I would a drive chain, to protect the rings from excessive wear.

Scraper

You are not stretching the chain, the eccentric is slipping. I have a RT2 also. After adjusting the eccentric, and torqueing it properly, check torque again after a short ride. Then check again after a longer ride a few times. It will need retightening/retorquing I bet.

loopless

I now have the gates installed and am having a very hard time getting the tension right. Some parts are loose, some are right. I've tried usimg the gates mobile app to gauge tension but I can never get a consistent tension within 60-65hz. At some point when checking the belt, the tension will be a good 10hz difference.

Too low a tension has its risks... But when i torque it up i can real bad vibrations at a specific segment. At the lower tension settings the vibrations are less pronounced but im sketchy if this is safe?

Aside, my cdale has 6nm written on the ebb... Does that refer torque of the bolt or ? Ive tried Google but articles only state 13nm (which i think is madness) or 6.5, which is closee to the imprint currently.

ahultin

Sounds like you need to center the chain rings better. Once done you should be able to get tension pretty even throughout the pedal range.
We run our the belt on out rt2 at the low end of the tension range and have had no issues with it.

alias5000

This is how I interpreted it so far. My experience is that below 6Nm (5Nm-ish), the eccentric does not sit firm and has moved before. 6Nm seems to be the sweet-spot.

Scraper

Mine torques to 13nm (115inlb). It's the three piece eccentric. And I've had it slip if I don't retighten after short use as noted above. And yes that seem like a lot of torque!

loopless

May I ask what tension setting are u using on yours ? I will try centering the captain ring today as I doubt that was done - only the back was. Does your rt2 front ring have somewhat a silver surface on the spiders? Also, how many T r ur rings? I was sent a 69t one which tandemseast reckons was correct.

loopless

As a quick update I dropped the tension down to 55-60... there was a segment where it was 47 but the overall tension still seems pretty taught. Spinned the cranks and can notice a much lesser vibration, next to none.

I don’t have a crank bolt tool and am having challenges finding a tool that provides sufficient yield so giving a miss at centering the bolts today. Will be ordering one.

ahultin

I cant remember the tension but i used the gates app and tensioned it to the low end, i believe it was about 50. I am running the 69t rings and Ill have to look at the spiders when i go out this morning

loopless

Thanks. Also could you let me know if you used spacers on the chain ring bolts ?

merlinextraligh

In our experience, there really is not much risk of running too low of tension with the center track belt.

If its grossly too low, it can skip under very heavy load.

But it is much harder to skip a center track belt than it was the original belts.


We run our belt well below what Gates specs and have had no problems, and we're a relatively large team that produces a decent amount of power.

If the belt feels reasonably snug, and the cranks spin freely, I don't think you need to be more precise than that.

EthanBixby

We caught a stick in the belt and it jammed up. I was able to get the stick out, and roll the belt back on, but on the next hill when standing we realized the pedals were out of sync. Once home, I reset everything, but had a vibration. Turns out I had moved the eccentric a little out of line, and it had a vibration in one spot on the rotation. Loosened it up, moved it over a little, and all quiet again. So check the alignment, as it doesn't take much to be off and cause a noise or vibration.

Carbonfiberboy 

Also our experience.