Cannondale Bad Boy SS conversion

Question

I'm interested in converting my Cannondale Bad Boy 2011 into a single speed bike. I found somebody who's done it on a Bad Boy 2008 (there), and somebody else who's done it one a more recent model (there).

But a bike expert told me that not every bike can be converted into SS bikes, and that most Cannondale bikes couldn't, because of the shape of the frame making it impossible to put a single speed cog (or something along these lines).

So, I'm looking for advice as to whether I can convert my BB 2011 into a single speed bike, and if so, whether there is anything different I need to do to do so.

Thank you.

Answer 1

I'm guessing that they were talking about replacing the rear cassette with a freewheel. However, you can convert pretty much any bike with a rear cassette to a single speed with single speed conversion kit like this one:

http://www.universalcycles.com/shopping/product_details.php?id=1764&category=2621

And a chain tensioner like this one:

http://www.universalcycles.com/shopping/product_details.php?id=47140

NB: I don't necessarily recommend either one of those products or the store that I found them on. They're just examples. You can actually even "hack" your own single speed conversion by dismantling a couple of old cassettes and using the spacers in the same way that you use the larger spacers on the ready-made conversion kit.

Answer 2

Doing a little research the bad boy line includes both an internal hub model:

and a standard hanging derailleur model:

If you have the former then your bike includes an eccentric bottom bracket, which will provide chain tension; the biggest of the hurdles when converting to single speed. If so you will most definitely be able to make the conversion without much issue. Your LBS will be able to find you an appropriate wheel and sprocket to get you rolling.

On the other hand if you have the hanging derailleur model then you do not have the eccentric bottom bracket. You will have a vertical dropout and no simple way to provide chain tension. There are 3 basic methods to deal with chain tension.

1. Eccentric Bottom Bracket - The bottom bracket moves inside a casing in an ovular fashion in order to move further away or closer to the hub creating chain tension. Since different models of your frame use this it may be an attractive option. It does require specialized tools and disassembling nearly all of your drive train to replace.

2. Eccentric hub - The hub moves inside a casing in an ovular fashion on order to move further away or closer to the bottom bracket creating chain tension. The main disadvantage with this method is the added cost in getting a custom built wheel.

3. Using a tension arm. In fact some even use their derailleurs although it's a less elegant solution than this: