after reading the rule book about modification of the rear fenders...it appears you can roll the rear fenders only (no pulling), but cannot cut the rear fenders and put flares on it because it is part of the unibody? I assume that is why all the SM DSM cars tires stick way out of the fenders? Please clarify... thanks.

"...front fenders, rear fenders not part of chassis structure (unibody), front & rear fascias, and side skirts may be modified or replaced..."

This is my understanding......

Under the 2015 SCCA Solo Rulebook:
Under Street Prepared:

• A. Fenders and bumpers may be modified for tire clearance. This includes the portion of a hood which serves as a fender/wheel well, where applicable. This does not permit modifications to the chassis or bodywork inboard of the vertical plane of the hub/wheel mounting face (at rest, with front wheels straight ahead). Flares may be added although tires may extend beyond the bodywork. Replacement of complete hood, flared fenders, or quarter panels is prohibited. Plastic and rubber wheel well splash shields may be modified for tire clearance and for installation of fender flares as allowed herein. Hardware may be added to the steering system outside the passenger compartment to limit steering travel, provided it doesn not alter steering or suspension geometry within the limited range of motion and serves no other purpose.

Under Street Modified:

• A. All Street, Street Touring®, and Street Prepared category modifications are authorized. Except as noted by these rules and the referenced rules, vehicles must be as originally delivered including all road-going components such as lights, wipers, interior, heater, etc.

2gmitsueclipse said:

This is my understanding......

Under the 2015 SCCA Solo Rulebook:
Under Street Prepared:

• A. Fenders and bumpers may be modified for tire clearance. This includes the portion of a hood which serves as a fender/wheel well, where applicable. This does not permit modifications to the chassis or bodywork inboard of the vertical plane of the hub/wheel mounting face (at rest, with front wheels straight ahead). Flares may be added although tires may extend beyond the bodywork. Replacement of complete hood, flared fenders, or quarter panels is prohibited. Plastic and rubber wheel well splash shields may be modified for tire clearance and for installation of fender flares as allowed herein. Hardware may be added to the steering system outside the passenger compartment to limit steering travel, provided it doesn not alter steering or suspension geometry within the limited range of motion and serves no other purpose.

Under Street Modified:

• A. All Street, Street Touring®, and Street Prepared category modifications are authorized. Except as noted by these rules and the referenced rules, vehicles must be as originally delivered including all road-going components such as lights, wipers, interior, heater, etc.

Click to expand...

so it appears flares can be added, but the original fender cannot be flared? ...but can be cut if it does not pass the vertical plane of the hub into the chassis? If I reading this correct you can cut that 1" or so hanging part of the fender (but not into the unibody) and add flares? So why are people in street prepared claiming they can't add flares? Thanks for your help.

Some of these rules do seem vague. I currently run STX in SCCA Solo events and am limited to a 245 tire. You may want to contact one of the chairs of the events listed in your region. How the rules are interpreted differently depending on the region. You could also contact a chairman of a national event.

Here is a quick image I looked up for street prepared cars:
DSP


Here is a thread on an SCCA forum you could read through (it is from 2010):
http://www.sccaforums.com/forums/aft/42738/afpg/2

You can modify the wheel arch profile, you can pull it out, roll it up, or cut off a couple of inches all round and then weld it back up. You cannot replace the entire quarter panel with an aftermarket flared quarter panel - If the 924 and 944 were on different lines, you wouldn't be able to swap 924 quarter panels for 944 quarter panels, OEM or aftermarket.

The Panda has complete plastic flared quarter panels riveted over the stock quarter panels, and the wheel arch on the original quarter panel is heavily cut away. That's normal for Street Mod but rare in SP.

I cut and rolled the front fenders on my SP car, but didn't need to change the rear arches up until the last (reliable) season, when the tyres started touching. Since the trans ate the Cusco, we haven't been able to get back to that level of grip, so it's no longer an issue.

These guys have it spot on.

I run SM in 2 SCCA regions.