7 replies to this topic

[Mudhen]

I have been running the flat track at  Fast Track hobbies and I am a bit stumped. My best handling car is an LMP body with a JK 21 chassis, running a vintage BOW Contender motor with shunts and BB'S on both sides and 44degree timing. It is a beautifully made motor, uses 72 pitch gears, 43 spur and 9 tooth pinion. It's plenty quick enough to whack the wall in a corner if I'm not paying attention, and quick off the corners. I am running the car with my brake almost off as I find that this allows me to get into a corner safely. Here is my dilemma. I have several other chassis motor setups with a Hawk with 40 / 10, 64p gearing, 2 Big dogs, each with 72p 42/ 10, and  phoenix with 64p 33/12, which must be for a big, swoopy track. The other cars have been gone over and are pretty darn straight, but they don't handle worth a rat on the flat track. Would a change of gearing more closely aligned with the Contender be in order or do I need to look at something else. Tire height? I have been swapping off the LMP body with these to eliminate that possible issue. If this was your situation, where would you look first?   

 

Thanks, 

 

Richard M.

[Pablo]

Without knowing your wheel OD(s) there is no way to speculate.

In general, flat tracks like conservative gears and small OD wheels.

[LtDan]

Running a Hawk 7,JK21 chassis. For race day we are allowed 1/32 clearance on the back at Fasttrack. I run .720 JK's I'm geared 12/37 64 pitch. I haven't raced this setup yet on the flat track but that is what I plan on running. If that doesn't work I will go 11/37. On the red and purple tracks we are required to have 1/16" clearance which means about .750 to clear. Two weeks ago I did my first race since 1966, it was on the purple angel geared 12/37 my top speed was equal to everybody else.

[Mudhen]

Running a Hawk 7,JK21 chassis. For race day we are allowed 1/32 clearance on the back at Fasttrack. I run .720 JK's I'm geared 12/37 64 pitch. I haven't raced this setup yet on the flat track but that is what I plan on running. If that doesn't work I will go 11/37. On the red and purple tracks we are required to have 1/16" clearance which means about .750 to clear. Two weeks ago I did my first race since 1966, it was on the purple angel geared 12/37 my top speed was equal to everybody else.

Thanks Dan, I have been wondering what you guys race with. It's now obvious to me that my Contender runs well due to the tires being more or less .720's.

 

Without knowing your wheel OD(s) there is no way to speculate.

In general, flat tracks like conservative gears and small OD wheels.

Can you amplify what conservative gearing is? Thanks.

[Pablo]

Dan, I will say, .063 is huge for a modern flexi race car. Most raceways use .047.

Flat tracks (ISRA for example) use .032 in some cases.

I know you probably can't control that.

 

I'll hazard a guess for your H7/C21 with .750's. I think you'll be happier with 11/37.

With .720s I'd go 11/36

 

Frank, aggressive gearing is a big pinion and small spur. Result:

Very little brakes, blazing straightaway speed for a quick burst, but it would be too punchy and a nightmare to drive smoothly.

Motor temp would be hot and possibly cook the motor.

 

Conservative is smaller pinion, bigger crown. Result:

Easier to drive especially on technical tracks. More brakes. Cooler temps. Faster in the curves.

 

On a flat track you're best to lean towards conservative.

On a swoopy banked King you go more aggressive.

 

Danny Zona once said "Lap times are the only truth in slot cars. Everything else is just theory".

Just remember to monitor the motor temps. Some of them tolerate heat better than others   

[NSwanberg]

9-37, it ought to be fast off the corners.

I agree with just about everything in the above.

"It is nice to be fast in the back half on king but fast on the straightaway is the gift that keeps on giving."

[Bill Seitz]

I'll add a couple ideas. Not everyone's reaction times are equal, and mine are quite slow to many better racers. My best times on the Yellow Dragon and other similar flat tracks have been with a car geared in the vicinity of 4:1 where I ran the entire lap in the top half of throttle and never used the brakes. It's the only way I can get any decent times. Another advantage to running in the top end of throttle is that this is much easier on the controller. Controllers are generally designed for spending a lot of time at high throttle and will overheat when used extensively at low to mid throttle.

[LtDan]

At Fasttrack are racing series components are JK21, Hawk 7, front wheels but not touching,.010 body, interior with driver, 1/16 clearance at the rear for Purple Angel and Red Engleman, the yellow flat track we're allowed 1/32 clearance.