Thanks for the quick reply.
I thought of santoprene first also and have just received samples and the material is not strong enough. I will try Hytrel also.
The parts are triggers for rock climbing cams. I molded them out of nylon and I think that is as bad as it could be. I am now thinking that a glassfilled ABS might be good. I just want to find a material with more friction than nylon. As much friction as possible while being rigid.
Mark