B500 Logo
Slot Car Bracket Drag Racing

Library Old Articles
Projects on Bracket500
Chat Room Mondays
Instructional Links
World Tribute Car
Spec Cars
All Car Galleries
Slip Joint 101
Front Page
Links
Tracks
Contact Bracket500
Bracket500
Message Board

You are not logged in. Would you like to login or register?



9/19/2012 2:01 pm  #1


gearing question

I am currently finishing an Edge chassis that I have swapped over to 3/32 rear axle and 64 pitch gears.  Using Protrack 1 1/16 x .300 rears and 3/4 fronts(not that fronts matter).  Will be using Proslot balanced Super 16D Speed FX PS-2001 and wondering what would be a good starting point for gearing for 1/8 mile.  Was told 14/56 but that sounds kinda high to me as final ratio would be around 3.7 after factoring in tire size.  Would this be right for an 1/8 mile?  Thanks for any help.  Weight will be around 115-120 grams.

Last edited by Tree'd (9/19/2012 2:02 pm)

 

9/19/2012 4:56 pm  #2


Re: gearing question

I would try 13/54,56


"It ain't about Class, It's about FASSST!!!
 

9/20/2012 5:09 am  #3


Re: gearing question

Thank you Timmy!

     Thread Starter
 

10/02/2012 4:43 pm  #4


Re: gearing question

This car made its debut tonight and after fighting some initial crown gear slippage problems was pretty consistent.  1/8 mile with what glue was on the track, car ran .694-.712 all night with 60 foot times in the 150's.  Very happy with my first car and I think I am now hooked.

     Thread Starter
 

10/03/2012 9:12 am  #5


Re: gearing question

If my math is right, that means motor was at about 50,800 rpm's when it went through the trap at 40mph.  Please let me know if that calculation is incorrect anyone.

     Thread Starter
 

10/03/2012 11:58 am  #6


Re: gearing question

14/54 64 pitch.  Corrected ratio with tires calculated in is 3.78.

     Thread Starter
 

10/03/2012 2:19 pm  #7


Re: gearing question

Thank you sir.  I was just going off of a chart I had printed out.  Is that where I want to be (rpm wise) at the stripe?

     Thread Starter
 

10/06/2012 3:53 pm  #8


Re: gearing question

Tree.d one thing I have found out runnind d can motors is they don't like being geared real short. I have seen time after time in econo cars if your too low 60 foot suffers and it kills mph. Yhe motor just wont rev up quick enough to use reall low gearing.

Think of a d can motor as a 460 ford and a c can like a 454 chevy. Basic design of the motors allows the chevy to rev up quicker due to smaller main and rod journal size.

Marty no tire growth figgured in? LOL your slipping.

 

10/08/2012 5:35 am  #9


Re: gearing question

I actually typed in wrong crown gear when suppling Timmy with my gearing.  It is actually 14/56 and my 60ft time is now in the low .140's.  Motor must be waking up.

     Thread Starter
 

10/08/2012 3:39 pm  #10


Re: gearing question

I will play around with that suggestion.  Much appreciated.

     Thread Starter
 

10/08/2012 4:12 pm  #11


Re: gearing question

Like Marty said, drop a tooth or two on the pinion....  .140's are getting it, probably not much more in the 60' foot, but the shorter gear will help it rev up a little quicker.  You only have to run 33 feet, so I would get after it....  MPH has never won a race for me, but e.t. has....   

 

12/09/2012 8:42 am  #12


Re: gearing question

Still on 14/56 gearing and car went its fastest pass of .6662 at 43mph with a .1402 60 ft.  Slowest pass was a .6728.  Very happy with the performance of this Edge chassis with Speed FX motor.

     Thread Starter
 

1/15/2013 8:17 pm  #13


Re: gearing question

I have a speed FX in a WRP chassis(brand new build) with a hardbody weighing about 114 grams. I have it geared 13/54 with 1 1/16X .435 tires. It only runs .830's in the scaled 1/8 @35mph with a .160 60ft. I have ran several cars with these motors running much faster, anyone think this motor is a dud or do I need to change brushes to golddust? I was hoping more for .700 @40mph or so, any thoughts?

 

2/10/2014 3:05 pm  #14


Re: gearing question

Marty wrote:

With 1-1/16" tires (1.0625) and 14/54 gears your corrected ratio 3.63:1.

54/14 = 3.86 the 3.86 / 1.062 = 3.63

40 MPH then = 48,810 RPM.

(((40 mph*5280)/60)/.2782)*3.86 = 48,810

The .2782 is the tire circumference in feet. (1.0625 * 3.14159) / 12 = .2782

I am new to the board and found this very interesting. Would the same calculation work for 1/4 mile?
I am trying to get my PS-101 in a higher RPM range and thoguht I could play with the numbers and figure out a good RPM to run on my car that weighs 113 grams... Having a hard time getting it to keep from spinning tires. Have used glue and seems to help some.  I want to make a spreadsheet and flip some numbers by putting in my desired time and mph and see if I can calculate my pinion and crown need. I am going to try a 20T Pinion with a 48 Crown and see what happens thursday (13 Feb) Have gone to a wider tire, .700 also to see if that helps. The wheelbase is only 4" I believe on a 32 Model Ford Truck. Any input would be great.


It is not always possible to be the best, but it is always possible to improve your own performance.
 

6/21/2014 10:23 am  #15


Re: gearing question

mlsntx wrote:

Marty wrote:

With 1-1/16" tires (1.0625) and 14/54 gears your corrected ratio 3.63:1.

54/14 = 3.86 the 3.86 / 1.062 = 3.63

40 MPH then = 48,810 RPM.

(((40 mph*5280)/60)/.2782)*3.86 = 48,810

The .2782 is the tire circumference in feet. (1.0625 * 3.14159) / 12 = .2782

I am new to the board and found this very interesting. Would the same calculation work for 1/4 mile?
I am trying to get my PS-101 in a higher RPM range and thoguht I could play with the numbers and figure out a good RPM to run on my car that weighs 113 grams... Having a hard time getting it to keep from spinning tires. Have used glue and seems to help some.  I want to make a spreadsheet and flip some numbers by putting in my desired time and mph and see if I can calculate my pinion and crown need. I am going to try a 20T Pinion with a 48 Crown and see what happens thursday (13 Feb) Have gone to a wider tire, .700 also to see if that helps. The wheelbase is only 4" I believe on a 32 Model Ford Truck. Any input would be great.

Your gearing will give you a soft launch & rpm on the top, but what are you running, a mile long track??? Try to keep it around 4:1 for starters...


Formerly of SARN
 

Board footera

 

Powered by Boardhost. Create a Free Forum






B500 Logo
Return to Main

WRP Products

Return to Main
Click on banners to see catalogs
 
Copyrights reserved ©2014