the spring has nothing to do with the pipe touching the wheel. Actually the long wire xray is offering has to do with mounting the exhaust a little further outside, this is good for new pipes with a small fat stinger. I know that because i use it on my 720.
Serpent 720 09 mega zx 12 dsII+, Serpent 733 nova 353 tuned/sirio XXXV
Futaba, Graupner, Hudy, RB fuel