4 Speed Transmission Ratios

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48moon
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Location: Central PA

4 Speed Transmission Ratios

#1

Post by 48moon » Sun Feb 27, 2005 2:36 am

I'm having my transmission rebuilt and it needs all new gears.
He recommended changing 1st gear from the stock ratio of 3.1 to 2.4 or 2.6. Also changing 3rd gear from 1.35 to 1.23. These are "Andrews" gear sets.
Anyone have any experience with these gears and/or ratios? Is it a wise thing or are stock ratios best?
I don't have a sidecar but carry the occasional passenger on my buddy seat. Also, its a 61 ci bike not sure if that effects it more than if it was a 74"?

Thanks,

48moon



48moon
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Location: Central PA

#2

Post by 48moon » Wed Mar 02, 2005 1:12 pm

Found several good postings on the old board regaurding gear ratios.
Thanks anyhow...

Pantony
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ratios

#3

Post by Pantony » Fri Mar 11, 2005 7:37 am

I had a 71 superglide that I put andrews gears in, the 2:44's were what I put in. The ratios work better than stock because it closes up the gap between 2nd & 3rd. The 2:44's are for FX's ; really! nothing else. for my 48 FL i would put stock ratios exept for 3rd if i could. but thats because i have a foot clutch

panheadron
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Re: 4 Speed Transmission Ratios

#4

Post by panheadron » Mon Mar 18, 2013 9:55 pm

2:66 ratio first gear period. Stock is too low. Not to mention the clunk & drop in revs. The street light turns green; Stock gears; here you go! Do you really like shifting in the middle of the intersection? NO!
IMO the 2:44 is too high. I run the 2:66 with close ratio 3rd. Perfect. A Panhead with Sportster gears. Smooth.
Remember one thing. Harley engineered the transmission around 1936. Why change it. They made their money back. Are you pulling a sidecar? NO! Don't need a 3.00 ratio. You really don't even need that heavy leftside Flywheel. 2 rights work better.

58flh
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Re: 4 Speed Transmission Ratios

#5

Post by 58flh » Tue Mar 19, 2013 12:52 pm

Hello gents!---In my exp. with this I know the mixers are BULLET-PROOF stock!!!--The Pan dont whine--its TOURQUE.,Save yer MONY & accomplish with motor & tranny sprocket!---Combination is endless 8) 8) --do what is right for you & save the $$$ for the Hybrid blowermotor to have fun with!--In the K-base is a CALCULATER/MULTYPLIER---that A VERY GOOD GUY put -up to use--use it its free.I am strictly saying for a stock or mildy-stroke moter,& HD MATIERIAL!---USE AFTERMARKET stuff for having fun!--The bikes cant die stock!---KEEP her in your MAX.RPM comfortably crusing speeds-2up!---you will not be having fun ,& much $$$ untill you find the combo that sticks. We are at the point where shredding tires is GREAT!,but I want my HYBRID AFTERMARKET PARTS for that 8) ,Save the IRON thats HD ITS GOLD!----Respectfully---RICHIE,--George your read & hybrid word,(I love it!) 8)

kitabel
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Re: 4 Speed Transmission Ratios

#6

Post by kitabel » Tue Mar 19, 2013 10:04 pm

The original transmission ratios were designed for a 61" motor to allow it to run fairly low (numerical) gearing and still accelerate well in slow traffic.
They still do that very well.
We don't know any more about transmission ratios today than we did in 1900, there is no new science or technology.
The original ratios:
3.004:1
1.820:1
1.228:1
1.000:1

There is no 2.66 1st gear.
Andrews 1st gears move 1st closer to 2nd by reducing the torque multiplication in 1st.
AP (and late FX) close-ratio 1st gear:
2.447:1 = 18% less torque, makes your 61" motor feel like 50"
AP semi-close 1st gear:
2.600:1 = 13% less torque, makes your 61" motor feel like 53"
This effect is continuous throughout 1st gear, like up to 40 MPH.

The factory stock 3rd gear has the closest 3-4 shift of any gear set, in fact slightly closer than the factory 5-speed 4-5 shift. Why? because this shift takes place at a speed where wind resistance is very high.
Andrews close-ratio 3rd:
1.357:1
This closes up the gasp between 2nd and 3rd - by pushing 3rd away from 4th. The gap between 2nd and 4th is still there, it just got bumped over.
Sounds like a good idea to have the 2-3 shift close? It means you can't catch 3rd at high speed any more, and with a small motor it may actually reduce your top speed.

Did you ride the bike with the stock ratios?
Until then you won't know what you want. Making the wrong choice here is very expensive to reverse.

james
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1952 FL
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Re: 4 Speed Transmission Ratios

#7

Post by james » Wed Mar 20, 2013 1:35 am

Someone please enlighten me. Over the last six or so months I see old posts opened up, some are over 5,6,7 years old. Don't you think the ones who started these posts have moved on? Is it me or am I being obtuse?

Jim

panheadron
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Re: 4 Speed Transmission Ratios

#8

Post by panheadron » Wed Mar 20, 2013 2:16 pm

To James. I happen to be in-process of rebuilding "another" 4 speed. You can take all the others advice if you wish. Personally, I cruise my Panhead on the side roads vs. hwy. Lets look at my automobile for instance. It is a 4speed automatic. 4th being O.D. Now hed out to the hwy. It is only a small 4 cylinder w/4:11 rear gears.. It up-shifts quickly. When you get to O.D. shifting speed, the RPMs drop considerably.
Lets look at my early Sportster. It has factory close ratio gears right! When you shift into 4th, the rpm drop, again, is alot.
IMO, this is what you want from your Panhead. That is why I like the close ratio 3rd.
Wind resistance? Come on! If your final gear ratio is too low, say 3.40-3.30...., you will feel wind resistance on the hwy in 4th. You're definetly not going to drop it down to 3rd!!.
My Panhead is running the cose ratio 1st 2:60 & close 3rd. Primary drive is BDL belt set-up. Doing the math, the comparetable chain set-up would be running a 23tooth engine sprocket. 23 is considered the hot rod sprocket vs. 24 hwy. I ran a 24 with a 23 tranny. Nice! Now, with the belt(being back to a 23 set-up), I need to up the tranny to 24T.
Keep in mind the question of the 2:44 1st gear. IMO, way too tall of a gear. If you up your sprockets to gain hwy, it will be too slow starting in 1st. Solution: 2:60 ratio!
Remember one thing. Changing to a close ratio 1st is relatively cheap compared to changing 3rd. You can live with that. Living with a 3:00 1st gear is rediculous! Spend the money while it's apart.

RUBONE
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Re: 4 Speed Transmission Ratios

#9

Post by RUBONE » Wed Mar 20, 2013 8:17 pm

I have run a factory FX low gear set and an Andrews third gear set in my '47 Knuckle since I assembled it 20 years ago. I love them, and the shifting is butter smooth, much nicer than stock. I also run a primary belt. And zero issues with climbing and altitude. Here is my bike loaded up returning from an AMCA National Road Run on top of Slumgullion Pass Colorado, 11530 ft. I had to pass some twinkies as they were traveling much too slow...
Robbie
Image

panheadron
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Re: 4 Speed Transmission Ratios

#10

Post by panheadron » Wed Mar 20, 2013 10:44 pm

RUBONE wrote:I have run a factory FX low gear set and an Andrews third gear set in my '47 Knuckle since I assembled it 20 years ago. I love them, and the shifting is butter smooth, much nicer than stock. I also run a primary belt. And zero issues with climbing and altitude. Here is my bike loaded up returning from an AMCA National Road Run on top of Slumgullion Pass Colorado, 11530 ft. I had to pass some twinkies as they were traveling much too slow...
Robbie
Image
Hi Robbie
Nice machine. Pretty colors. I am aware of the primary belt set-up. I'm running the inclosed BDL. It has a 62tooth clutch pulley & 39tooth engine pulley. Do the math & you get 1.58974... On a chain drive primary, with a 23tooth engine sprocket, you get 1.60869.. A 24tooth engine sprocket you get 1.54166. So basically, the belt set-up is say, engine sprocket 23.2 tooth.
I don't get much hwy with a 23 engine & 23 tranny sprocket. Final ratio is 3.5664.
My chain set-up was engine sprocket 24 tooth,trans 23 . Final ratio is 3.4177 I liked that.
With the belt, primary ratio has changed back to 23.2T Final ratio is 3.5243 Need to lower it
The next set-up ratio will be belt(23.2),trans sprocket 24T Final ratio is 3.3781 That's the closest I can get to 3.4177
Raising the trans to 25teeth, I believe would be too much. Bogging down in 4th gear on the hwy.
What are you running for a transmission sprocket?

james
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Re: 4 Speed Transmission Ratios

#11

Post by james » Thu Mar 21, 2013 1:39 am

Panheadron, I'm all open to any advise or suggestions and I appreciate them all.
I was just wondering why 7 year old posts were being brought back from the dead, that's all. Has nothing to do with what your running. Also with respect.

Jim

panheadron
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Re: 4 Speed Transmission Ratios

#12

Post by panheadron » Thu Mar 21, 2013 3:23 am

james wrote:Panheadron, I'm all open to any advise or suggestions and I appreciate them all.
I was just wondering why 7 year old posts were being brought back from the dead, that's all. Has nothing to do with what your running. Also with respect.

Jim
Hi James. I'm with you on the 7 year old posts. I don't even know really how I got back to it.
My 1st Panhead was when I was only 19. I already was a wiz at mechanics back then. That was 41 years ago!

RUBONE
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Re: 4 Speed Transmission Ratios

#13

Post by RUBONE » Thu Mar 21, 2013 4:06 am

Simple. Someone did a search for a certain topic and it popped up. In most cases the info is still relevant despite the time gone by...

58flh
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Re: 4 Speed Transmission Ratios

#14

Post by 58flh » Thu Mar 21, 2013 1:26 pm

James & Panheadron----That always happened to myself also,---When I found this site,I thought I was doing something wrong!,,But In the 3yrs. i have learned if you put in a topic ,It --(computer)--recognizes it?-& points you in a direction that you can get info from.--Is this correct?,,anybody?---I since have learned to just read it & go to K-base & just choose what you want.Or ask a question & everybody is helpful in directing me around the site!--(thank-you all).It took me AWHILE to get used to that samething your exp.ing---the keyboard is what my problem is --I push 1-letter & 2,or something of no relevance pops-up!--There 2-small for me.But the payoff is reading REAL reviews by guys as yourself,myself,all.----Richie 8)

panhead
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Re: 4 Speed Transmission Ratios

#15

Post by panhead » Thu Mar 21, 2013 6:12 pm

In most cases the info is still relevant
That's why they are in the KB.

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