Wheelbase or Length /STR

[dbradley]

We're looking at building a Street Roadster class LSR vehicle.  Is there a maximum or minimum wheelbase for the class?  I find overall lengths and wheelbase minimums in other classes but not in Street Roadster.

[maguromic]

Rules are pretty clear for STR.  Try to get a rulebook; it describes it pretty well in there. If you want a longer wheelbase move the wheels out in front like the BMR car, and have the arms come through the radiator. It doesn’t say that the radiator has to hold water. PM me and I will give you some ideas.

[Stan Back]

Engine set-back requirements, along with hood length restrictions have (so far!) made wheelbase minimums and maximums superfluous.

[Stan Back]

The BMR car is an (altered) Roadster.  A Street Roadster must have a complete radiator within the grille shell -- with no parts missing for suspension members protruding through.  Don't have to hold water, tho!

[dbradley]

I have a rule book.  It doesn't specify any length or wheelbase requirements for a street roadster as far as I can tell.  You can extend the 'hood' three inches, move the 'cross member' three inches BUT these changes do not set the wheelbase or overall length of the car.

[Stan Back]

To be more specific -- the 15% engine set-back and the 3" hood extension limit -- in combination -- limit the wheelbase.  You can't move the front axle far out front without violating one of these.  And you can't move the engine back (for the same reasons) without encroaching on the driver's compartment (which you can't extend).  And, of course, you can't modify the bodywork from the cowl back at all, so you can't extend the wheels out the back.

All in all, these restrictions have kept most of the Street Roadsters looking like street roadsters.

Some have removed door hinges (which I would define as streamlining) and punched holes in the radiator shell for intakes (which I believe to be at the very least re-contouring {not allowed}, and decreasing the overall surface of the grille shell below the minimum, also not allowed). 

Stan Back

[dbradley]

Thanks Stan.  I just didn't want to miss something.  When you start with a pile of tubing, setbacks and (original) wheel base, etc. will be different for every model of car.  I may have  access to a factory frame to measure but who knows.  May just have reference books.  Haven't actually decided on body make at this point.  And, who just wants to build another '32?  No offense to '32 owners.  I have looked at several radiator shells and see what you mean about how they relate to the book.

[jimmy six]

Many questions: Be careful with "tubing on the floor"... no multitube frames. As said radiator must be complete and fill the shell, Most street roadsters are not 32's...They are too big; most are 27's tight fit for a blown big block. The 15 % set back was to clear blower drives. The 3" hood length was for this too. Axles in front of a grill shell makes it tough for the 15% that's why it's there to keep these vehicles looking like street cars and not gas/fuel roadsters. Good Luck and choose wisely....

[interested bystander]

Stan Back and Jimmy Six- they be knowin'

Read the rule book VERY carefully for this class.

Street Roadster is kind of the seminal class that started this all, and you could probably trace it right up to Top Fuel Dragster today (I like that word seminal-it has  a kinda sxxxual connotation) and should be kept as PURE as possible IMHOP!

You ain't gonna pull a lot of borderline stuff on racers with thirty/forty years experience. Guaranteed you can't BS them.

Tony Thacker's great wind tunnel article in  Hot  Rod in 2006 gave a lot of pointers as to what CAN be done and still be legal re aero stuff. Besides those hints, one needs to work on horsepower and (gently) getting it to the Salt/Dirt.

[dbradley]

Thanks for all the input.  Not trying to put anything "over" on anyone.  Just don't want to waste an effort only because we overlooked some vague rule.  I'm just more used to hard rules as far as construction goes.  (NHRA starting in the early 60s) Just wanted to be sure we weren't overlooking something.  The rule book has you going here and there so much, I've actually pulled the rules out and reorganized into a Word document that is more logical as far as requirements needed in an order for building a car for class.  Been an observer several years, time to play.  Thanks again.

[interested bystander]

No scolding intended, and I'll bet that if you pose a  question to Stan Back about the class he'll answer HONESTLY and promptly- I met him forty years or so back and had a favorable impression of him at that time and time hasn't changed it!

Good luck!

[JackD]

The Street Roadster definition and first rules were included in the SCTA program when the LA Roadster Club wanted to come out and play on an equal footing without the evolution of modifications that had been developed for the more traditional SCTA racing roadster.
The rules have not changed much except to further define what they are and safety developments.

[interested bystander]

O.K, So we're in agreement, right, JackD?

Everybody ought to read Dean Batchelor's Dry Lakes and Drag Strips. (Available at Motorbooks in Burbank, Ca. where you'll probably see Jay Leno most Saturdays.

The book's about our tradition.

[JackD]

SCTA is tradition, unhampered by the sideshow progress that some wish for it, but hopfully will not prevale.

[836dstr]

"dbradley",

Stan Back and JD are right on with their comments, having both campaigned in the STR class (sucessfully I might add).

We run a '27 body that has a stock hood length of 27 inches that's stretched to a total of 30 inches. After some carefull figuring the longest wheelbase we could achieve was 107 inches using 15% setback using a SBC. The relationship of the spindle center line and the #1 spark plug.

Using a 28 or 29" rear tire means that the rearend must be centered under the fender. With a smaller tire you could possibly move the rearend back a bit adding to the length of the wheelbase and thus the setback but would it be worth that hassle, probably not. I haven't looked at the rulebook lately regarding rearaxle position so this might be a moot point.

Read the rulebook and ask questions. Always think creatively !

All of the above is bases on a '27 body. The hoodlength on a '28/'29, '31/'32 '33/'34 will be longer with more room to play, but with wider bodies. Again all of the above relates to Ford bodies. Maybe there are other roadster bodies to consider. Starting from scratch is a great thing!

Tom

Tom