Interpreting the SCCA stability rule and pickup trucks

The SCCA has a rule for the stability of vehicles not otherwise classified in Appendix A of the rule book. Basically, the height of the car must not be greater than the track width (measured at the midpoint of one side's tire to the midpoint of the other side's tire). This is pretty clear. What is not entirely clear to me is how a pickup that gets listed in Appendix A would go when it doesn't meet the class rules.

Section 3.1 says "The chart below is for all vehicles not specifically listed in Appendix A", so I'm assuming if a vehicle is called out in the Appendix, it's good to go. I'm building a 2WD Chevy S10 (with a V8 swap). 4 and 6 cylinder S10s are called out in STX and CP, and H-Street Has RWD pickups as a "Catch-All". None of those classes allow engine swaps, though, and the while the truck could meet CAM-T or CAM-S rules, those are in Appendix B, not A.

So, my question is, does my car need to meet the 1:1 rule, or are the callouts in Appendix A enough to have to exempted? I've lowered it already, but at this point, I will still need to do more lowering or widening the track width to meet the 1:1 rule. I don't want to go to the Challenge and not be allowed to run in the autocross, but I'd also rather not have to lower it to the point it's useless to haul anything, or widen the track width with spacers to the point it looks ridiculous.

I'm guessing it'll need to fit the 1:1 rule, but really hoping I don't. It's not like there's a ton of weight high up on a 2WD standard cab pickup that's been lowered 2" in the front and 3" in the back. Not to mention, in H-street, it looks like a stock 2WD S10 could run.

The stability rule tends to mainly affect Street classes, where you can't lower the vehicle. The Safety stewart of your group will make the final decision on if you can run. Since S10s are classed and have been autoxed quite a bit, you should be okay, especially since you lowered yours. The V8 swap pushed you into classes like CAM, SM, maybe XP and EM. I would run CAM, probably the best fit.

What tires are you going to run at the Challenge? Would that get you the extra you need?

In reply to Stampie:

I'm still pretty open on that. I have 14" and 15" wheels in my budget, and access to cheap 16" wheel. If I have to meet the stability rule, I'll probably try to scare up some 185 or 195 width 14" R-comps, just to reduce the diameter, and thus the height. If it's not a problem, I'm probably going with whatever 15" TW 200 tires I can fit on 15x7 wheels.

ALWAYS talk to your local tech guy first. It's much easier to get things sorted when he's calm and can think through the issue. Being right doesn't always mean you get to run.

In reply to eastsidemav:

I forgot to ask what tires you are measuring with now. Even better question is how far away are you? Would SM7s lower you enough? They're pretty cheap used. Since it's a Challenge build an email to them or asking in the Supreme Court thread might be best. I remember you have plans for after the Challenge but if it were me I'd try lowering through tires so that at the Challenge there isn't any question.

It's got 215/65R15 tires right now. At this point, it is 6" too tall, I think 60" tall, and 54" track width. I have a 4WD rear axle that'll bring the rear track width up by 4", and will probably add 2" spacers up front to match it. That brings it to being 2" too tall. Going with some old "Honda-sized" 14" r-comp tires should bring it down to less than an inch too tall, but at that point, I'll need a different set of tires for the drags, as I'll run out of gear at the end of the track.

There's definitely room for safety steward interpretation. If they feel it's safe to run, they can let it run. The 1:1 guideline is a rule of thumb for them to go by, but not a hard rule.

Wow I just did some double checking and you're right as hell. I'm kinda amazed just looking at one that it doesn't meet the 1:1 ratio. That got me thinking. Did you know that a stock BMW 2002 doesn't either?

Since it is a listed vehicle you aren't going to need to worry about the 1:1 rule. You will get lumped in somewhere up the food chain because of the swap but I don't recall where. There was a guy in NWOR who had a v8 swap s10 he ran. As said above get the steward involved early to class it so that your worries are minor.

They let that ford truck thing autocross last year at the challenge so if it is safe they'll let you run

They let me autocross my old 2006 Scion xB, mostly because I lowered it, strut brace and rear sway bar. If they let that box out on course, I wouldn't think you'd have a problem. Well at least in Ohio.

In reply to chandlerGTi:

I only want to speak for myself but I think there's a real fear that the safety issues from last year are going affect the builds in future years. Yes that's positive if it means safer builds. Problem is how creative is a team going to be? For us, we decided to not only limiting our changes for this year but we pushed back a future build and it might not even happen. You'll notice that the OP asked about the Challenge yet everyone seems to be taking about their local club. I think the question here is if the Challenge is going to be sticker than the local clubs.

Stampie wrote: In reply to chandlerGTi: I only want to speak for myself but I think there's a real fear that the safety issues from last year are going affect the builds in future years. Yes that's positive if it means safer builds. Problem is how creative is a team going to be? For us, we decided to not only limiting our changes for this year but we pushed back a future build and it might not even happen. You'll notice that the OP asked about the Challenge yet everyone seems to be taking about their local club. I think the question here is if the Challenge is going to be sticker than the local clubs.

Exactly. I'm not too worried about local regions, I think I'll get away with it here, especially after I widen the track width by 4". The challenge would be my main concern, and after reading about some of the entrants, I don't blame them for taking a more hard line on safety rules. I just want to make sure my truck ends up on the "allowed" side of that line.

widen the track width with spacers to the point it looks ridiculous.

That's what i did on my Caravan for $2016. Certainly no regrets over here! Caravan Autocross

The Fiat 500 is one of these cars. Can't compete in Street due to stability, but lower it for Street Touring and it's fine. We just went through a similar discussion in my home Club regarding a Mini Countryman and a Mini Paceman. One barely fits under the line while the other sits just above it.

For the Challenge, it needs to pass the 1:1 rule. That's the benchmark we used for Minivans, and it seemed to work.

Slightly off-topic:

Does the roll bar count when measuring the height of the car (open car,) or does it stop at the body metal?

Tom Suddard wrote: For the Challenge, it needs to pass the 1:1 rule. That's the benchmark we used for Minivans, and it seemed to work.

Looks like it's time for me to find someone in my region sitting on some obsoleted 14" R compound tires.

eastsidemav wrote:

Tom Suddard wrote: For the Challenge, it needs to pass the 1:1 rule. That's the benchmark we used for Minivans, and it seemed to work.

Looks like it's time for me to find someone in my region sitting on some obsoleted 14" R compound tires.

They're pretty old, but I have some freebie Hoosiers if you want them.

I'm so glad I went full size. It met the 1:1 stock height. Added spacers and lowered and it's uber good.

Aim to beat the 1:1 rule - go down and out.

Tom Suddard wrote: For the Challenge, it needs to pass the 1:1 rule. That's the benchmark we used for Minivans, and it seemed to work.

Question. I have differing track widths front and back, which applies?

Ranger50 wrote:

Tom Suddard wrote: For the Challenge, it needs to pass the 1:1 rule. That's the benchmark we used for Minivans, and it seemed to work.

Question. I have differing track widths front and back, which applies?

IIRC, it's the average of front and rear track.

rslifkin wrote:

Ranger50 wrote:

Tom Suddard wrote: For the Challenge, it needs to pass the 1:1 rule. That's the benchmark we used for Minivans, and it seemed to work.

Question. I have differing track widths front and back, which applies?

IIRC, it's the average of front and rear track.

I believe you are correct.