Just when you thought you had solved the hemline hassle -- that unless you have the chutzpah to hang them where you want, most hemlines are going to end up at the bottom of the knee -- designers have raised the pants length question.

One thing for sure is pants aren't where they were. The traditional cut is the classic man's style with the straight leg often pleated at the top and often ending in a cuff.

That's the easy part, hardly a challenge to designers, and consequently you aren't much aware of the classic pants except at places like Oscar de la Renta (who also is doing some pretty funny knee-length shapes as well). Designers here have managed to cutt off pants everywhere on the leg and thigh, challenging everyone's fashion vocabulary about what to call them.

The shortest are obvious -- looking most at home around the track, although some will no doubt show up for disco. Then there are Jamaica shorts, a couple of inches shorter than Bermuda shorts, which stop just above the knee. Below the knee are knee pants and knickers, then pedal-pushers, then clam diggers, then ankle-length pants. It's all very familiar.

Of course, pedal-pushers on one model are knee pants on another, just to add to the confusion.

Where will it all end up? Well, there are already fashion types in New York wearing pants that look by traditional standards too short for them. They cut off at the ankle, or an inch or two above, and that becomes a fine way to show off neutral of funny colored hose, and bright-colored, low cone-shaped heel shoes.

Actually you don't make these pants by shortening what you already own . . . at least that's not what they are doing in New York. Because the current crop of pants are looser and rounder than classic trousers and often start their fullness from a yoke over the tummy.

They come from recent past collections of Harriet Winter, Sonia Rykiel and a few others who also have them in their current collections.

The more you see them, the less they look like floodwater or highwater pants (the general joke about men who wear their pants too short and show off their socks . . . sometimes white socks. No one we know, of course). s

But if there was a happy medium on pants lengths as there is for skirts, it is likely to be Bermuda shorts. As in Europe, particularly in the recent collections in Milan, where they were often shown as suits meant to be worn to the office, designers like Cathy Hardwick, Richard Assatly, Charles Suppon and others have shown them very seriously done up with stockings and lowheels, meant to go directly to the State Department, the Department of Commerce or whatever.

Designers have tried City Shorts (as they call them) before, ever as recently as last spring. They were not much of a success then, but designers are willing to try again. $"I think they make women look young," said designer Assatly. "And cut off the same length as a skirt, they are even more comfortable."

Only the customer can say if he is right.