Deda Dog Fang

Kev C · Post by **Kev C** » 12 Apr 2013 19:43

Has anyone used a Deda Dog Fang on their bikes? It's a small plastic accessory which attaches to your bicycle to prevent your chain falling off the inside of your smallest chainring. My bike seems to be set up and properly adjusted but occasionally the chain slips off so just wondered if they"re worth buying and fitting.

Carl_Williams · Post by **Carl_Williams** » 12 Apr 2013 22:22

I use them as a precaution on a couple of old bikes and would recommend one. They only work on round seat tubes though so you'll need a chain catcher on a 'modern' carbon frame.

Kev C · Post by **Kev C** » 13 Apr 2013 03:08

Thanks for that. I think I'm going to get one and fit it as a precautionary measure as they are fairly cheap and look like they could save any potential chain slip.

AlanW · Post by **AlanW** » 17 Apr 2013 15:09

If its not to late, but IMHO the N Gear Jump Stop is a far better and more reliable piece of kit. Even with a Dog Fang fitted your chain can still wrap around the bottom bracket, trust me.

As far as I am concerned if you have a Shimano triple then it is a must have, not matter how good you think you have it set. When it "fires" the chain onto the granny ring, it will derail at some point. Available from HERE

Kev C · Post by **Kev C** » 17 Apr 2013 18:07

Thanks for that Alan. What with one thing and another i haven't yet made the purchase of the dog fang so will certainly give this a look. Appreciate your advice.

George · Post by **George** » 01 May 2013 10:01

Good tip, Alan.

One question. You say it is a must-have with a Shimano triple. Why do you mention Shimano specifically? Because you don't have personal experience of using it with other brands, or because it isn't suitable for (some) other brands?

AlanW · Post by **AlanW** » 01 May 2013 12:31

George wrote: One question. You say it is a must-have with a Shimano triple. Why do you mention Shimano specifically? Because you don't have personal experience of using it with other brands, or because it isn't suitable for (some) other brands?

Basically George because I dont have the experience for any other makes.

But certainly with Shimano its a bit of a double edged sword really. The "problem" is the sheer force of the return spring that is used to fire the front mech back to the inner most ring otherwise known as the granny ring. It really is a very aggressive return action and even with all the limit screws set as they should be, when the conditions are right (or wrong in this case) it will literally fire the chain of and potentially wrap around the bottom bracket shell. Excessive chain alignment, uneven road surface and dropping to many gears as once IMHO can all contribute to the possibility of the chain being dislodged.

Now here comes the but......I am guessing that you really need a strong return spring because the chance are that when the need arises to opt for the granny ring, you will already be climbing and probably applying a great deal of load to the chain and chain rings. And yes we all know that you are supposed to ease the load on the chain when changing down gears. (or even upwards for that matter) But its sometimes easier said than done, and do we ease is it off enough to allow the chain to be collected and consequently dropped onto the granny ring?

In truth, probably not, hence I am guessing the reason why the return spring has to be so strong to cater for this.

George · Post by **George** » 01 May 2013 15:16

Thanks, Alan. I have Campag triples on all my bikes (except TT bike), and have rarely had a problem dropping the chain. The problem that I have sometimes had is the other side of the coin that you refer to, namely the shift is sometimes not positive enough and the chain consequently won't drop ... especially if it's old & slack or derailleur alignment isn't perfect.

However, I was prompted to look up this thread because my daughter has a problem on her commuter bike, which does have Shimano: it drops the chain about 25-50% of the time when she shifts to the granny ring, even though I've fiddled and fiddled with the adjustment. The gadget you recommend looks like an ideal solution ... except that her bike has a rather odd front mech, where the mounting band is well below the dérailleur plates, as opposed to above, as I'm used to. This makes me worry that the mech's mounting band may be exactly where I would want to mount the gadget.