38 replies to this topic

[Pablo]

Questions:

-what's it geared?

-what width are the pans?

-what track width are the rears?

 

You could buy yourself some room to use wider rear rubber at the set screw area on the gear side by trimming the pinion.

I can't tell from the photos if there is enough room to widen the right hand side in the same manner.

Slightly wider rubber tread patch may be all you need.

 

Remember, that type chassis design was used with lots of glue. Without it, they drift. Nature of the beast.

[tonyp]

You can also try a spring on the drop arm and light springs on the pans. Harder old school fronts and using stiffer lead wires that center guide would probably tighten it up.


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[grooverunner]

Paul Thanks!

 

The car is geared  12 tooth pinion 36 tooth spur   3:43  gear ratio . It doesn't show any signs of hopping when you hit the throttle coming out of a corner.

 

Width of the side pans are .75

 

3'' rear track width

 

I have the room to do your suggestion on the pinion side, but there is no room on the right hand to go wider.  I 'm building a second chassis and I brought the dog leg in more on the right side  so to get more width on the tires.

 

 

Ken

[grooverunner]

Tony,

 

I got the Idea about the springs and the stiffer wire, I will try them or at least note them if not used here for future tuning.

 

But I have a question about the hard fronts. How would the Hard old school fronts tighten up the chassis ?

 

Thanks

Ken

[tonyp]

Less grip in the front as they slide rather than get traction.


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[Pablo]

1. 12/36 using .875 wheels is an awful lot of gear to pull, even for a 16D.

Here is my reasoning: A stock 16D normally is geared about 3.5/1 using .750 wheels.

11/38 is about 3.5/1 and with .750 OD gives a final drive ratio of 4.6

 

https://www.proslot....?tiresize1=.750

 

Change it to .875 wheels and look for about 4.6, looks like 9/36 or 10/40 would be close

 

https://www.proslot....?tiresize1=.875

 

This would probably change the whole acceleration personality of the car. Only one way to find out.

 

2. By pan widths I meant overall width. That body looks like it may support 3 1/18 widths and that may be just what you need to use wider rubber.

[grooverunner]

Thank you very much Paul,

 

WOW! Your explanation just made the light bulb come on about tire size association to gear ratio how the two work together for roll out. Yes it would change acceleration a lot going from a 3.42 to a 4.6. I'll up the gearing.

 

I can go to a 3 1/8'' width on the rear width.

 

Ken

[Pablo]

Cool. Along with Tony's suggestions, may I suggest making only one change at a time.

 

I'd also like to suggest, scratchbuilding vintage cars like this isn't about lap times and searching for every last bit of speed.

It's about creating a car that is spooky fast, yet is a joy to drive. If you can overdrive the car into a tight corner and she plants and swings the rear out a little too much but stays in the slot, consider your job done. Sounds like you are almost there and maybe the car can use the power of the H motor.

 

I hear you saying the stock 16D isn't hopping, good. But when you put the H power in there, she may start hopping. Easy fix, just add a brace to prevent the motor from wiggling up and down as the pinion tries to climb up the spur.

[dc-65x]

Hi Ken,

 

You have a beautiful car there. Do you want it to drive and handle like a 1968 vintage car or a modern car?

[grooverunner]

Hi Rick,

 

I want it to drive like a vintage 1968 car.

The car handles incredibly well for my first time ever building a brass and piano wire chassis ( I have built brass pan chassis my of times).

So well it flat out amazed me, It really is a joy to drive.

The reason I ask these questions is so that I understand how these chassis handled and how they were tuned to handle, and what to expect from the chassis.

Paul and Tony I think has done that.  So I'm pretty much there already with maybe some finer tuning.

 

Ken

[grooverunner]

Paul,

 

My home tack has tight corners being 2 lanes especially the 2 out side corners . Put it this way, after I built this track and drove it for awhile and then when I went out to Modelville  and I got on the black and purple lanes, I could almost drive them with ease.

 

This could be the reason it hangs its rear out a bit, on a bigger track this might not be there as much or at all.

 

Thank you again

Ken

[dc-65x]

Sounds like a plan to me Ken.   Keep the car within the '68 rules (3" track, 5/8" tire width, etc.) you built for and tune it with the tips from the best like Tony and Pablo.

[MSwiss]

Are you using that Marcos Mantis?

 

It certainly isn't the choice of current Retro racers.

 

Maybe go with a popular Can-Am body of the era, and the appropriate air control.

[Horsepower]

Here's a tip I discovered last year by accident.

Although it works better to restore old rubber tires, it works just as well on silicone tires. And the secret to restore old tires is to soak them overnight in Orange Goop hand cleaner... it softens and cleans the rubber.

BUT... be advised, soaking "rubber" tires for too long will start to dissolve them, and also soaking in regular Goop hand cleaner is more harsh, and although it speeds up the process, it can also destroy "rubber" tires faster! As for using on Silicone tires, I haven't seen any start to dissolve even after a week or more submerged in Orange Goop.

So give it a try, it's really safe on silicone tires, but only use the Orange Goop, and for limited time on "rubber" tires.

PS: If you just keep a small jar of Orange Goop in your pit case, along with some cotton swabs, you can clean your tires before and after a race, and it leaves no residue behind if you wipe it off, although it does tend to soak into rubber and then evaporate.

Thousand thanks for giving me the answer to the question I have had through 2 centuries!