Hi, I’m Beanz and this is my M100RS Sirion build thread. I’ve owned this car for a few months now and while its been a lot of fun and surprisingly speedy on the local backroads, I have noticed several aspects that would benefit from modification. The most apparent of these is a lack of grip. Right now I have the car on the stock 14x5" alloys with a set of end-of-life Bridgestone Ecopia’s. While they ride nice, the rears squeal terribly anytime I apply throttle in a bend and the loss of grip on entering corners at higher speeds is pretty restrictive.
I picked up a set of crusty SSR Integral A2’s (ET40 15x6.5) off Facebook marketplace and spent a few weekends sanding, bogging and painting them. I then got them wrapped in a set of 195/50/15 Bridgestone Potenza RE003’s.
When I went to fit my newly refurbished rims on the car I found that the rear wheels interfered with some extrusions of the rear torsion beam . When I picked up the wheels I only though to test the front fitment, thinking that if the front fit, then surely the back would too . I did some digging here on L2D and found several posts confirming that I would need to either run spacers or take a Dremel to my suspension in order to make my rims fit…
I had previously read through Oropi_dai’s M100 Sirion build and remembered that he’d run 15x6.5 rims with a +34 offset and hadn’t encountered any clearance issues with his torsion beam, however he did say that he planned on shaving it a bit just to gain an extra mm or two of addition clearance. I had also seen that TPG was also running +34 15x6.5 rims on his beastly track M100.
Armed with this knowledge and some simple math, I figured that a set of 8mm spacers would alleviate my clearance issues completely without pushing out the rear track too much and introducing too many handling quirks.
I test-fitted my rims with these spacers when they arrived and confirmed that I now had excellent fitment both front and rear. All that is left to do to get the rims on the car is install some extended stud bolts and get some new lug nuts.
Big shoutout to everyone I’ve linked here, super helpful having this forum to troubleshoot the issues I ran into. I’ve got the bolts and nuts ordered, so everything should be together within the next couple weeks.
Looking forward to giving more updates,