Editors Note: From time to time we get a question that we choose to post here. The answers given hopefully will help others and at the least, be somewhat entertaining.

Question: Can I put a 26 inch rear wheel in my 29″er? How will that affect the bike? Is it a good thing to try?

Answer: Well, three answers really. Yes. Negatively. Not really. Now, let me flesh this out for you.

The answer to your first question is “yes” only if you are dealing with a frame and wheel that is disc brake compatible. Rim brakes won’t work with such a change in diameter. Pretty simple there.

The second answer, “negatively”, is a bit more complicated. Let’s take a look at what really is going on when we pop a 26″er wheel in a 29″er frame. Think of the front axle as a pivoting point. Now imagine lowering the rear end of your bike without a rear wheel in it by pivoting the bike downwards around that front axle. Watch how the angles all become slacker and the bottom bracket gets a little closer to the ground. Yep! That’s what is going to happen to your 29 inch wheeled bike when you put a smaller rear wheel back there.

This causes several things, all of which I would deem negative, and I think most of the time, in most cases it is true. First the head angle gets shallower, causing slower steering and strange cornering behaviour. The seat angle changes, putting you further behind the bottom bracket and adversely affecting your seated pedaling posistion. It also will make seated to standing pedaling posistion maneuvers more difficult to pull off. Finally, your bottom bracket will be closer to the ground, increasing the chances for pedal strikes.

Now for the third answer, “not really”. It isn’t going to be a good representation of what a properly designed mixed wheel bike will do. At best, you will have a functional bicycle, at worst, it may be deemed unridable off road. Best to save up for a properly designed mixed wheel bike and leave the 29″er alone.