This is one of the most common questions we hear. The question should be how wide SHOULD you go.
Keep in mind this is only my opinion, and many fat tire guys will swear by their last breath that running a 250 or 300 monster is the way to go. I just don't happen to agree with them.
In my opinion, the ideal tire width is the 200
for the average rider. It looks nasty (especially with a shortened fender), it has a lot of rubber on the road, and it still handles good. If you have a pile of money and time on your hands to build a 300 monster, by all means, don't let me talk you out of it. But here are some things to consider:
1) Extra Cost
200 tire frames and spacer kits are expensive enough as it is, and if you go any wider than this, the costs skyrocket.
2) Balance/Drive IssuesIn order to make a really wide tire work, you have to offset the driveline so the belt/chain will clear the tire. This is fine on a 200, as the amount is very small, but when you get up to a 250, the offset is an inch or more, which makes your bike heavy to the left.
The way around this is to go with a Right Side Drive (RSD) setup, where the transmission drive components come out on the right side of the transmission. The problem with this is that you need special, and usually very expensive, components. These include transmission, frames, and spaced-out exhaust. For the average rider it is not worth it.
3) HandlingPut a 250 or 300 in a Softail frame, and it handles lousy. Put it in a rigid, and you will feel like you are herding cattle. The biggest issues comes when cornering, where bigger tires tend to push you out of curves.
4) Little BenefitYou read that right, a 250 will give you little or no traction gain over a 200. Motorcycle tires are not like car tire; only a small patch of rubber is touching the ground at any time because of the curvature of the tires. The difference in the area touching on a 200 and 250 is negligible.
So basically, you will be paying twice as much for a bike that handles poorly, and has no additional traction. Then again, wide tires look
real cool, so it's just a matter of where your priorities lie.