Short wheelbases effect the ride in several ways
- Think of the bike as a double-ended lever with the fulcrum being the hubs. A bump or pothole's effect is more pronounced on a short wheelbase vs long since the lever arm is shorter. This means more shock is transmitted to the wheel and frame for shorter wheelbase bikes. This could mean more flats and frame and fork problems. In the extreme imagine a 10 cm bump on a 100 cm wheelbase vs a 10 cm bump on a 50 cm wheelbase. The short wheelbase lever goes up and down twice as fast and twice as hard. Longer wheelbases smooth out the road. Try a tandem on long wheelbase recumbent for a good comparison! Smaller diameter wheels just makes all this worse.
- Longer wheelbases mean more frame length to flex and dampen shocks. Not as big issue if you have suspension.
- Shorter wheelbase means less room for you. This leads to an upright, cramped riding position unless you get longer stems and drop the seat angle to move the seat back. This can lead to the problems below...
- Shorter wheelbase usually means your butt is much closer to being over the top of the rear axle and your head is closer to being over the front axle. On hills this means wheelies and loss of control. With sharp braking it means you are more likely to have the bike do a front flip or at least have the rear wheel come off the ground as you stop. Steep descents and fast stops are even worse on short wheelbase bikes. The last time I did a front flip on a bike was about 50 years ago, but it made quite an impression on me and I have no desire to ever do that again
- Shorter wheelbase most likely means shorter chainstays and a that means shorter chain lines and poorer shifting if you have a derailleur bike. Not an issue on internal hub gears or single-speeds.
- On bikes with 26" or 700c wheels your toe may hit the front wheel as you turn on a short wheelbase bike, not a issue with smaller wheels. Short and long are relative terms. For 700c road bikes wheelbases used to range from about 38.5" to 42". Mountain bikes lengthened that another couple of inches. With folders and small wheels the range is more like 35" to 45" which is a large range.
- The big plus for small wheelbases is folding size. The Brompton-type fold is a nice fix for keeping the wheelbase long while the fold stays small.