%postname% – max. length? Permalink question

Hi there,

I have built a small portal where users can submit posts. The content comes from the post titles (250 signs limit). I have set the permalinkstructure to “%postname%” – but this setting gives too long urls back. I sthere a way to automatically shorten the “%postname%” urls to a maximium of e.g. 40 signs in URLs?

thanks!

AD