# New Project Time...Gates Carbon Drive



## Ailuropoda (Dec 15, 2010)

I'm going to send my El Mariachi Ti to a frame builder to have a seat stay splitter installed (and additional braze-ons on the top tube and down tube). 

The outer diameter of the 39-tooth CDX:EXP sprocket is 5.3 inches (compared to the 6 inch OD of my Surly 32-tooth cog) so it should fit in the frame and clear the chain stay without having to shim anything. 

Gates insists that a "snubber" is necessary for a Rohloff hub. I really don't want to put one on. Assuming the chainline is straight, is it really necessary and why just on a Rohloff?


Do I need the Belt Drive? No...but I think it will be cool.


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## Velobike (Jun 23, 2007)

On conversions I've done, a snubber makes a huge difference when the chainstays have too much lateral flex*. 

You set the snubber at the 7 o'clock position about 1mm above the belt. It only comes into contact with the belt when the belt starts to ride up on the teeth. Surprisingly effective.

However I have come to the conclusion that the belt is best for non mtb use. I would use it on a road or gravel bike, but not an mtb. 

Also after a few conversions I have gained a greater appreciation for chains - they are amazing pieces of engineering in the dirtiest and worst place on the bike and rarely maintained properly. These days I would be more likely to put my efforts into full enclosure of the chain than a belt. (I have 80+ year old bikes on their original drivetrains because they are in an oilbath chaincase)






*The best frames for conversion are frames designed for singlespeed use because they tend to have chainstays that are more laterally rigid.


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## Ailuropoda (Dec 15, 2010)

In now way am I busting on chains. They work and roller chains are probably the most ubiquitous form of power transmission in the world...for a good reason.

I’m just doing it because I think it will be cool. The El Mariachi is used for a lot of single speeds. I think it will be alright.


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## Velobike (Jun 23, 2007)

Ailuropoda said:


> In now way am I busting on chains. They work and roller chains are probably the most ubiquitous form of power transmission in the world...for a good reason.
> 
> I'm just doing it because I think it will be cool. The El Mariachi is used for a lot of single speeds. I think it will be alright.


What I like most about belts is the silence, the cleanliness, and the lightness. The cleanliness is great when you have to remove the wheel, lift into a car or take on public transport for example.


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## fokof (Apr 24, 2006)

I have two bikes with Belt/Rohloff setup : my MTB and my Fatbike.

I don't have a Snubber on either and never had a problem.
Getting the right tension is key.


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## shwinboy (Jan 13, 2004)

It’s probably a bit late but I’m getting a Rohloff gates drive frame made and made the mistake of getting a 39t front sprocket. Since the smallest rear sprocket is 19 t the ratio is well under Rohloff’s recomended lowest gear ratio. You could damage your hub. I found the lowest safe ratio I could go with gates sprocket combos is 46t x 19 t. 
On the snubber. I haven’t found anywhere any reason why it is deemed essential for the Rohloff but no other rear hub apart from some hand waving warranty reason. I get what it does but why would you need it if the gates system is set up properly?


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## fokof (Apr 24, 2006)

Smallest permitted ratio by Rohloff is 1,9 
2,5 for tandem (+100kg)
https://www.rohloff.de/en/experience/technology-in-detail/specifications/

I run 39/20 on both my MTB and Fatbike , low enough to climb walls.


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## shwinboy (Jan 13, 2004)

Aw man I was reading the tandem gear table. Might have to order a different belt now.


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## fokof (Apr 24, 2006)

Maybe you saw right ; they lowered the ratio a couple of years ago to accommodate the 700 wheeled crowd.


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