merlinextraligh

I'm not seeing where anyone is selling the 250 tooth center track belt online.

I see an number of sites where it's out of stock or unavailable.

Anybody bought one recently, and from where?

wn rider

I bought our CDX centertrack belt/rings from Precision Tandems but it was a couple of months back. Looks like they still have it listed on their website, https://precisiontandems.com/catframepart.htm, but don't know if it is actually available.

LouM

Not sure if this will help as it's not the same Gates partnumber (8M-250T-12CTS Blue vs 8MGT-2000-12). Both are Gates products. It does meet the 8mm pitch, 250 teeth, 12mm wide, 2000mm length requirement though. Wonder if the performance specs are the same? The 8M is oil and heat resistant. Industrial application I guess.

https://www.biedlers-belts.com/synchronous-belts/poly-chain-gt-carbon-belt/8mm-pitch-12mm-wide/gates-8mgt-2000-12-belt.html

LouM...

Bezalel

That part doesn't look like a centertrack.

LouM

$95.00 vs $45.00 might make you reconsider if it meets the same performance criteria.
The 8MGT has the blue nylon tooth facing if the look is important. The 8MGT picture doesn't show that. There seems to be a black stripe inside the 8M-250T belt that you can't see on the 8MGT.
I believe that I see a performance rating of approx 3.2 HP (approx 2,300 Watts) with a 75T sprocket. Kind of a guess here as I haven't spent a whole lot of time doing the exact calcs. HP would be de-rated with a smaller sprocket set. But still well within tandem power output. 1 HP = 746 Watts.

Gates Belt Design manual:
https://www.gates.com/catalogs/file_d...gates\catalogs

Just a thought here. But if I wanted to put a belt drive onto a system, I would see what types of belts are already out there that will met my HP needs then design/mfg the sprockets for my application.

LouM...

twocicle

the "8M-250T-12CTS", CTS = CenterTrack System. https://www.carbondrivesystems.com/products/tandem

the "8MGT-2000-12" does appear to be virtually the same belt, but without the CenterTrack groove. unless you cut your own groove it won't work on the CDX rings.

https://www.gates.com/brochure.cfm?br...ocation_id=742
https://www.gates.com/catalogs/file_d...tes%5Ccatalogs

LouM

Ahh. That's what that line is. I'll check it out this weekend. One of our club members has a CDale tandem with Gates Synch belt.
Also noticed that the CDC ring does not have the groove? Although it's 10mm width vice 8mm.

LouM...

twocicle

Correct, the older model CDC Mudport belt is 10mm wide with 8mm pitch (tooth spacing) and squared off teeth. The tracking of this belt relies on the CDC Mudport ring slots and side flanges to keep the belt teeth from wandering off the ring. It's a setup that does not always track perfectly (ie: derail potential is greater than with the CDX system). The tension spec (quite high) for the CDC belt tension results in a fair amount of constant load on the BBs, something that can cause more wear on those components.

The CDX (CenterTrack) belt is the same 8mm pitch but is 12mm wide and rounded teeth. The center groove + raised center flange on the CDX ring does a better job of keeping the belt on the rings. Another benefit is that it can be run with less tension than the CDC setup, and so it is easier on the BB bearings.

Neither of these belts is cross compatible with the other system.

Bezalel

But Gates' perspective is that there are no preexisting belts so they designed a belt for the application. I'm interested in seeing third party sprockets.

LouM

Some more info from Gates.
Their carbon drive tech manual. Looks like they offer a few sprockets at 130 BCD. Also a clear picture of the CDX belt with cutout.
https://www.carbondrivesystems.com/~/...g_Apr2013.ashx

LouM...

DubT

Something in the pictures looks a little bit wrong! The picture on page 1 is a picture of the original design which was called CDC as far as I know. It has been redesigned and now looks like the picture on 2, revision 4. This is what we have been calling CDX or as Gates calls it "Center Track". Page 3 shows something that looks just like the cover picture and they call it CDX??? That is the original system. Some people experienced issues with the original version, belts coming off, premature wear of the sprockets. The new design has taken care of most of those issues and is also supposed to be able to absorb a bit more misalignment. A call to Gates might help explain the differences. I ordered our system directly from Gates and it is the new design. The guy that I talked to is Steve Pardoe, he is very knowledgeable of the system and the design changes.