Jump to content




Photo

Question(s) about gear pitch


  • Please log in to reply
9 replies to this topic

#1 Dan Searcy

Dan Searcy

    Backmarker

  • Full Member
  • PipPip
  • 56 posts
  • Joined: 15-July 11
  • Gender:Male
  • Location:SoCal

Posted 09 August 2017 - 05:39 PM

I downloaded and read the SCRRA rules for Retro Can-Am and Retro Coupe. I noticed that there was no mention of gear pitch in the rules. I'm assuming this was intentional. Is that correct?

 

There doesn't seem to be a lot of 64 pitch crown gears out there for sale. I see mainly 48 pitch for inline cars. Is there any particular reason why? It would seem that 64 pitch would be much smoother than 48. Am I missing something?

 

Finally, from what I can tell, anything goes with gear pitch for anglewinders. It appears that many racers are using 64 or 72 pitch for those. Is that correct? I'd appreciate any input. 

 

I may show up at BPR one of these Saturdays and I don't want to bring a knife to a gunfight, if I can help it.

 

Thanks,

 

Dan


Steadfastly refusing to grow up...
Dan Searcy




#2 gotboostedvr6

gotboostedvr6

    Checkered Flag in Hand

  • Full Member
  • PipPipPipPipPipPip
  • 1,418 posts
  • Joined: 19-July 11
  • Gender:Male
  • Location:Mt. Laurel

Posted 09 August 2017 - 06:02 PM

The late Jay K. once told me he put forth some effort testing 64 pitch inlines and had too many failures.


  • Cheater likes this
Freedom is never more than one generation away from extinction. We didn't pass it to our children in the bloodstream. It must be fought for, protected, and handed on for them to do the same, or one day we will spend our sunset years telling our children and our children's children what it was once like in the United States where men were free. - Ronald Regan #40 (1911 - 2004)

David Parrotta

#3 MSwiss

MSwiss

    Grand Champion Poster

  • Advertiser
  • PipPipPipPipPipPipPipPip
  • 19,691 posts
  • Joined: 16-April 06
  • Gender:Male

Posted 09 August 2017 - 06:07 PM

The teeth on 48P are much bigger, thus that much stronger.

As the previous post mentions, 64P, both Sonic aluminum drag, and JK plastic, was tried by a few guys, and they just don't hold up in Retro cars.

Mike Swiss
 
IRRA® Components Committee Chairman
Five-time USRA National Champion (two G7, one G27, two G7 Senior)
Two-time G7 World Champion (1988, 1990)
Eight-time G7 King track single lap world record holder
17B West Ogden AveWestmont, IL 60559, ( 708) 203-8003
mikeswiss86@hotmail.com (also my PayPal address) 
Note: Send all USPS packages and mail to: 5858 Chase Ave., Downers Grove, IL 60516
Make checks out to Chicagoland Woodworking, Inc.


#4 Phil Hackett

Phil Hackett

    Posting Leader

  • Full Member
  • PipPipPipPipPipPipPip
  • 4,626 posts
  • Joined: 29-January 07
  • Gender:Male
  • Location:A Big Red Star on a Kremlin Map

Posted 09 August 2017 - 07:38 PM

To use 64 pitch crowns would need some serious reworking of the motor mounting and rear end chassis stiffening. Stiffening the chassis would most likely radically change the handling properties in uncompetitive ways. It would also, most likely, require changes in tire requirements and body set-ups. Not a lot of retro racers want to relearn tuning an unknown design.

 

Besides, the 48-pitch crowns seem not to be a problem so why change?


  • Half Fast and NSwanberg like this
Click HERE to contact Sonic Products. The messenger feature on my Slotblog account has been disabled.

Posted Image

#5 Bryan Warmack

Bryan Warmack

    Posting Leader

  • Subscriber
  • PipPipPipPipPipPipPip
  • 3,565 posts
  • Joined: 17-July 07
  • Gender:Male

Posted 10 August 2017 - 11:51 AM

Dan,

 

You are correct. There are no SCRRA rules governing any gear pitch restrictions in any of the SCRRA classes.

 

Everyone uses 48 pitch for the inline classes and for the anglewinder classes I'd say about 50/50 with 64 pitch and 72 pitch.

 

I'm not really sure if the higher pitch gears actually makes the cars noticeably smoother but as others have pointed out here, I am certain that the lower pitch gears with their bigger teeth are more forgiving and cause less problems!

 

Hope you can make it to BPR sometime and join in the fun! The SCRRA Retro races are twice a month. On the second Saturday of every month we run F1 and Can-Am on the Flat track and on the fourth Saturday the F1 and Can-Am races are on the King track. The major SCRRA events disrupts this a bit but generally on the second and fourth Saturdays some Retro race will be going on at BPR.

 

Hope to see you soon! :)



#6 Ecurie Martini

Ecurie Martini

    Ecurie Martini

  • Full Member
  • PipPipPipPipPip
  • 759 posts
  • Joined: 19-February 06
  • Gender:Male
  • Location:Baltimore MD

Posted 10 August 2017 - 03:46 PM

Some time back Sonic made 32 tooth 64 pitch bronze crown gears. Combined with a 72 pitch (yes, 72) steel pinion they would handle about anything you cared to throw at them. Alas, they are no longer made but there may be some examples hiding on a parts board somewhere.

 

EM


  • TallyBernie likes this
Alan Schwartz

#7 MSwiss

MSwiss

    Grand Champion Poster

  • Advertiser
  • PipPipPipPipPipPipPipPip
  • 19,691 posts
  • Joined: 16-April 06
  • Gender:Male

Posted 10 August 2017 - 04:00 PM

I still have four 31t Sonic bronze crowns on my wall.

We tried them with the Red Fox vintage F1 cars, back in 2005. IIRC, they were hard on pinions.

Regardless, anyone that tried them switched to Parma 48P crowns with ARP pinions.


  • tonyp likes this

Mike Swiss
 
IRRA® Components Committee Chairman
Five-time USRA National Champion (two G7, one G27, two G7 Senior)
Two-time G7 World Champion (1988, 1990)
Eight-time G7 King track single lap world record holder
17B West Ogden AveWestmont, IL 60559, ( 708) 203-8003
mikeswiss86@hotmail.com (also my PayPal address) 
Note: Send all USPS packages and mail to: 5858 Chase Ave., Downers Grove, IL 60516
Make checks out to Chicagoland Woodworking, Inc.


#8 Phil Hackett

Phil Hackett

    Posting Leader

  • Full Member
  • PipPipPipPipPipPipPip
  • 4,626 posts
  • Joined: 29-January 07
  • Gender:Male
  • Location:A Big Red Star on a Kremlin Map

Posted 11 August 2017 - 11:26 AM

It's been forever since those small crowns were made but if I remember correctly, those solid bronze gears were made with an offset of .020". Meaning the pinion shaft is supposed to be located .020" below the axle centerline.


Click HERE to contact Sonic Products. The messenger feature on my Slotblog account has been disabled.

Posted Image

#9 Dan Searcy

Dan Searcy

    Backmarker

  • Full Member
  • PipPip
  • 56 posts
  • Joined: 15-July 11
  • Gender:Male
  • Location:SoCal

Posted 13 August 2017 - 12:40 PM

Thanks for the input everybody. I appreciate it. I had a good time at BPR this Saturday. I'm sure I'll be back when I can get down there.

Dan
Steadfastly refusing to grow up...
Dan Searcy

#10 Tom Eatherly

Tom Eatherly

    Checkered Flag in Hand

  • Full Member
  • PipPipPipPipPipPip
  • 1,809 posts
  • Joined: 28-October 11
  • Gender:Male
  • Location:SoCal

Posted 13 August 2017 - 10:17 PM

Good seeing you there Dan. Hope you make some more races.


Tom Eatherly





Electric Dreams Online Shop