There is a Speedway thread concerning this subject and occasional failure of said part. Do a search ( speedway perch failure) and it will come up.
Stainless is softer than carbon steel because of the nickel content, go with the chromed steel for strength
...... at normal temps most generally used alloys of stainless are also weaker than mild steel. And, "regular' mild steel has better fatigue resistance than most stainless alloys.