I don't fully agree with this guy,as the stock shift points are 5600 rpm,not the 6,000 he's using,but still a decent article on gearing

[HEMIMANN]

Now You're talking my language! Add more power it solves any gearing issues

Torque - not power! Otherwise we'd all be driving Chrysler gas turbine powered vehicles. There's a place for 30,000 rpm engines, and it ain't ground transportation.

 

[Wild one]

Torque - not power! Otherwise we'd all be driving Chrysler gas turbine powered vehicles. There's a place for 30,000 rpm engines, and it ain't ground transportation.

If you watch the video,the pistons are amazing for their size,torque was not a feature of these race bikes,lol



Honda built a "250cc" 6-cylinder motorcycle road racing machine, the legendary RC166, which was a dominant force in Grand Prix racing, particularly in the 1960s.

Here's a more detailed look:

• The RC166:
  This motorcycle, powered by a DOHC 250cc six-cylinder engine, was a marvel of engineering and a key factor in Honda's early success in Grand Prix racing.
  
  
• Mike Hailwood:
  The RC166, ridden by world champion Mike Hailwood, won eight straight 250cc Grand Prix races in 1966.
  
  
• Sound and Performance:
  The engine's sound through six open pipes was legendary, and the bike was known for its high-revving capabilities.
  
  
• Engineering Excellence:
  The RC166 was a testament to Honda's engineering prowess in the 1960s.
  
  
• Piston Innovations:
  Piston axial length in Honda's early 1960s 250cc fours was 1.24 times bore diameter, giving them a “1940 Chevy” look.
  
  
• Crankshaft Analysis:
  The unique crankshaft design and its impact on the engine's performance and reliability have been subjects of analysis and interest.

This video showcases the Honda RC166, a legendary 250cc six-cylinder road racing motorcycle:

The Tiniest Bike 6-Cylinder

Join the membership to fuel this channel on its way:https://www.youtube.com/channel/UCXtx43lso-J9taKABVa-Rtw/join- Patreon -https://www.patreon.com/visiorace...

www.youtube.com

 

[Wild one]

They also built the RC149 which was a 5 cylinder 125cc road racing bike,that would spin to rpm numbers that are still out standing to this day

, Honda built a 125cc five-cylinder road racing motorcycle, the Honda RC149, which was a 1966 DOHC four-stroke inline-five race bike.

Here's a more detailed look at the RC149:

• Engine: DOHC four-stroke inline-five, four valves per cylinder.
• Displacement: 124.42cc.
• Output: 34 hp.
• Bore and Stroke: 35.5 x 25.14mm.
• Redline: 21,500 RPM.
• Compression Ratio: 12.0:1.
• Gearbox: Eight-speed.
• Dry Weight: 187.4 pounds.
• Top Speed: Over 130 mph
• Purpose: Designed for racing, not road-legal.

The 1966 Honda RC149

In 1965, Honda unveiled the incredible RC149, demonstrating just how far the engineers could reach beyond convention to produce a winning design.

www.cyclenews.com

 

[Wild one]

Honda built a 50cc, 2-cylinder road racing motorcycle, the Honda RC116, designed for the 50cc class of Grand Prix motorcycle racing in the 1966 season.

Here's a more detailed look:

• Model: Honda RC116
• Engine: 49.77 cc, 4-stroke, DOHC parallel-twin, air-cooled
• Purpose: Designed for the 50cc class of Grand Prix motorcycle racing
• Year: 1966
• Performance: The RC116 won three races from six during the 1966 season
• Development: It was a development of the previous RC115 version
• Notable features: The RC116 had cylinders the size of egg-cups, eight tiny valves, and revved to a giddy 22,500 rpm

This video shows the Honda RC116, a 50cc racebike from the 1960s:

The 50cc Motorcycle with a top speed of 118 mph in the 1960s

Today we're looking at the incredible Honda RC116, a 50cc racebike from the 1960s capable of well over 100mph, producing up to 16 horsepower at 22k rpm. This...

www.youtube.com

 

[Wild one]

Honda did build a 50cc twin-cylinder road racing motorcycle, the RC115, which was a key part of their success in the smaller displacement racing categories in the early 1960s.

Here's a more detailed look:

• The RC115:
  This motorcycle was a 50cc racing machine designed specifically for the 50cc class, featuring a lightweight, compact frame and a high-revving, 2-stroke engine.
  
  
• Early 1960s:
  The RC115 was introduced in the early 1960s and played a significant role in Honda's success in smaller displacement racing categories.
  
  
• Twin Cylinder:
  The RC115 was a 50cc twin-cylinder motorcycle
  
  
• High Performance:
  The RC115 was known for its impressive performance for its size, winning multiple championships.
  
  
• Technology:
  Honda design engineer Shoichiro Irimajiri's masterpiece, the 50cc twin-cylinder, 21,500-rpm RC-115 put Honda in the vanguard of ICE technology.
• 
  
• 
  
• 
  
• Honda RC115 was a 50cc racing motorcycle introduced in the early 1960s. Designed specifically for the 50cc class, it featured a lightweight, compact frame and a high-revving, 2-stroke engine that delivered impressive performance for its size. The RC115 played a significant role in Honda's success in the smaller displacement racing categories, winning multiple championships. It showcased Honda's engineering prowess and commitment to dominating motorcycle racing, especially in the 50cc Grand Prix class. The bike's success helped establish Honda as a major player in global motorsport.
  #HondaRC115 #50ccRacing #MotorcycleRacing #HondaRacing #VintageMotorcycle #2StrokeEngine #HondaGP #MotorcycleHistory
  
  
  
  
  
  
  

 

[Brandon-w]

If you watch the video,the pistons are amazing for their size,torque was not a feature of these race bikes,lol



Honda built a "250cc" 6-cylinder motorcycle road racing machine, the legendary RC166, which was a dominant force in Grand Prix racing, particularly in the 1960s.

Here's a more detailed look:

• The RC166:
  This motorcycle, powered by a DOHC 250cc six-cylinder engine, was a marvel of engineering and a key factor in Honda's early success in Grand Prix racing.
  
  
• Mike Hailwood:
  The RC166, ridden by world champion Mike Hailwood, won eight straight 250cc Grand Prix races in 1966.
  
  
• Sound and Performance:
  The engine's sound through six open pipes was legendary, and the bike was known for its high-revving capabilities.
  
  
• Engineering Excellence:
  The RC166 was a testament to Honda's engineering prowess in the 1960s.
  
  
• Piston Innovations:
  Piston axial length in Honda's early 1960s 250cc fours was 1.24 times bore diameter, giving them a “1940 Chevy” look.
  
  
• Crankshaft Analysis:
  The unique crankshaft design and its impact on the engine's performance and reliability have been subjects of analysis and interest.

This video showcases the Honda RC166, a legendary 250cc six-cylinder road racing motorcycle:

The Tiniest Bike 6-Cylinder

Join the membership to fuel this channel on its way:https://www.youtube.com/channel/UCXtx43lso-J9taKABVa-Rtw/join- Patreon -https://www.patreon.com/visiorace...

www.youtube.com

Check out the Honda nr750 oval piston bike. Epic failure but cool concept.

 

[HEMIMANN]

I remember the oval pistons.

In fact, when I decided to start riding again, I found Honda VTX 1800 was discontinued. So went with Harley. Fit and finish is impeccable, and USA-assembled, at least. I'm ok with air-cooled, I don't race.

I put a Stage III performance upgrade on it, now it's fun to ride. Not interested in floating boat touring models.

I miss the 2 cycle dirt bikes, tho. Talk about instant torque!

My dream bike in college was Honda CB360T. 50-60 mpg. But I couldn't afford that and tuition.

 

[Bmags]

3.92 and I drive 80+ often... I'm plenty happy.

 

[HEMIMANN]

3.92 and I drive 80+ often... I'm plenty happy.

What do you get for mileage dead-heading?

 

[Bmags]

I'd also wager that the "extra" fuel economy of the extra over drive gear is a myth... since the engine will lug with any kind of resistance on the roadway. Better off running the truck in the RPM range that produces useable power.

 

[Bmags]

What do you get for mileage dead-heading?

I don't keep track of daily mileage changes. I can say that my average dropped "slightly" after making my change in gearing from 3.21 to 3.92... (less than 1MPG). And I run my truck plenty hard

 

[HEMIMANN]

average summer time mileage?

I'm around 15 mpg with a 6.4L Hemi, 6 sp trans, 3.73 axle, premium fuel, but 10% ethanol is forced on us by state scam law. They all get around 10 mpg loaded / towing - even Ford's vaunted ecoboost w h i z motors. Because - work is work.

The only difference in mileage between bigger motors and boosted small motors is dead head mileage. But that is where the majority of truck owners drive.

 

[Wild one]

3.92 and I drive 80+ often... I'm plenty happy.

Do you make 200 miles at 85 to 90 mph,if so what's your oil temps after 200 miles at those speeds.
The cruise stops at just a little over 95 mph,and i've ran 150+ miles with it set at it's maximium,and have never had a 3.92 geared truck keep up,as their oil temps are starting to go through the roof

 

[ramffml]

I'd also wager that the "extra" fuel economy of the extra over drive gear is a myth... since the engine will lug with any kind of resistance on the roadway. Better off running the truck in the RPM range that produces useable power.

It's not. Good grief. The engine is not lugging at 1500+ rpms. And at lower rpms it's well under 60 mph so power isn't an issue.

 

[Wild one]

It's not. Good grief. The engine is not lugging at 1500+ rpms. And at lower rpms it's well under 60 mph so power isn't an issue.

Remember he's the guy who locked out 8th gear with HP on his truck,so it acted like a 3.92 geared truck,with a 7 speed Then came unglued when i answered a couple questions,and accused me of trying to side track his thread
In reality he's got a 3.21 geared truck with a 7 speed,and is trying to pass it off as a 3.92 truck

Exhaust Drone Fixed! Spoiler Alert another 3.21 vs 3.92 discussion

Just figured I’d throw this out there to the group. BACKGROUND: There are many reasons why folks love the 3.92 gears… (way lower 1st gear, lower reverse gear, better acceleration, etc) but for me I mainly was searching for ways to remove my highway drone from my Carven Competitor (which I...

www.ramforum.com

 

[Jas34]

• 
  #1

I hope this post will help to end the debate with facts and not opinions, and become THE post people refer to those who are having a hard time deciding.

You already know that 3.92 is better for towing, and 3.21 gets better fuel economy, so I will talk about what you might not know

Bottom line up front:

In layman's terms, to conceptualize the difference, imagine

1) 5 out the of 8 gears have the same final drive ratio between 3.21 and 3.92.

2) 3.21 has "an extra" overdrive gear.

3) 3.21 has 2 unique lower gears for towing.

4) 3.92 has 3 unique lower gears for towing.

5) Speed range that 3.21 is better at towing: 31-38 MPH, 48-57 MPH.

6) Speed range that 3.92 is better at towing: 0-30 MPH, 39-47MPH, 58-70 MPH.


Explanation


1) 5 out the of 8 gears have the same final drive ratio between 3.21 and 3.92:

Here's the gear ratio for the 8 speed transmission:
1) 4.71:1 2) 3.14:1 3) 2.10:1 4) 1.67:1 5) 1.29:1 6) 1.00:1 7) 0.84:1 8) 0.67:1 Reverse) 3.30:1

Final drive ratios with 3.21

1st. 15.12, 2nd. 10.10, 3rd. 6.74, 4th. 5.36, 5th. 4.14, 6th. 3.21, 7th. 2.70, 8th. 2.15, R 10.6

Final drive ratios with 3.92

1st. 18.46, 2nd. 12.31, 3rd. 8.23, 4th. 6.55, 5th. 5.06, 6th. 3.92, 7th. 3.29, 8th. 2.62, R 12.94

From the list below, we can see that gears 3-7 in 3.21 matches gears 4-8 in 3.92:

-- NO MATCH -- = 18.46 - 1st - 3.92
3.21 - 1st - 15.12 = -- NO MATCH --
-- NO MATCH -- = 12.31 - 2nd - 3.92
3.21 - 2nd - 10.1 = -- NO MATCH --
-- NO MATCH -- = 8.23 - 3rd - 3.92
3.21 - 3rd - 6.74 = 6.55 - 4th - 3.92
3.21 - 4th - 5.36 = 5.06 - 5th - 3.92
3.21 - 5th - 4.14 = 3.92 - 6th - 3.92
3.21 - 6th - 3.21 = 3.29 - 7th - 3.92
3.21 - 7th - 2.70 = 2.62 - 8th - 3.92
3.21 - 8th - 2.15 = -- NO MATCH --

2) 3.21 has "an extra" overdrive gear:

The 8th gear in 3.92 is the 7th gear in 3.21, thus effectively mean the 8th gear in the 3.21 is an extra gear to the 3.92.

Meaning, when you go test drive the 3.21 you will have to downshift to 7th to get the same acceleration at 3.92's 8th on freeways. That is why some people complain about how "sloppy" the 3.21 is, because the 3.21 has an extra overdrive gear for fuel economy. If you shift 3.21 in 7th gear, you will get the same acceleration as the 3.92 in 8th on the freeway. No, 3.21 isn't sloppy, you're just in a gear that 3.92 does not have.

3) 3.21 has 2 unique lower gears for towing:

As we know from 1), 5 gears have the same final drive ratio.
You "gain" an overdrive gear, but you "lose" one towing gear.
Here's the final drive ratio for the 2 towing gears.
1st. 15.12, 2nd. 10.10,

4) 3.92 has 3 unique lower gears for towing:

Same logic as the last
Final drive for 3 towing gears.
1st. 18.46, 2nd. 12.31, 3rd. 8.23.

5) Speed range where 3.21 is better at towing: 31-38 MPH, 48-57 MPH,
AND
6) Speed range where 3.92 is better at towing: 0-30 MPH, 39-47MPH, 58-70 MPH:

Calculated towing shift point to be 6000 rpm, if I'm off the logic is the same but the speed will vary.

For towing,
From the speed 0-30 MPH, 3.92 has higher final drive ratio over 3.21 (18.46 vs 15.12) until it has to shift to 2nd gear at 30MPH.

From the speed 31-38 MPH, 3.21 has higher final drive ratio over 3.92 (15.12 vs 12.31) until it has to shift to 2nd gear at 38MPH.

From the speed 39-47 MPH, 3.92 has higher final drive ratio over 3.21 (12.31 vs 10.10) until it has to shift to 3rd gear at 47 MPH.

From the speed 48-57 MPH, 3.21 has higher final drive ratio over 3.92 (10.10 vs 8.23) until it has to shift to 3rd gear at 57 MPH.

From the speed 58-70 MPH, 3.92 has higher final drive ratio over 3.21 (8.23 vs 6.74) until it has to shift to 4th gear at 70 MPH.

The key takeaway here is that towing heavier trailers uphill with 3.21 might never reach the desired speed within the 58-70 MPH range (typical highway towing speed) because 3.21 jumps from 10.10 to 6.74 without the 8.23 final drive ratio found in 3.92 that really help maintaining highway towing speed at max load.

Do you value the "extra" overdrive gear for fuel economy? or do you value the extra towing capability that you tell yourself you might one day need? That's up to you.

Great explanation. I would love to see someone actually do real world testing side by side with 2 of these trucks with the same trailer over a long haul with hills involved. Not sure if any of the TFL truck videos ever did this.

I get the math behind the theoretical advantage of one rear end over the other at certain speeds, but there's more than just speed involved with shift points. Maybe I'm wrong here, but I always just assumed since the 2 rear ends have overlapping shift points at most of the gears that you'd be using on the highway, so for towing, the transmission would essentially take care of the different gear ratios. Maybe one would hunt more at certain speeds to find the right gear than the other? I do know that doesn't apply from startup from a stop, and I believe that's the real reason the .392 is rated higher for towing than the .321. They both have the same payload which is often the limiting factor.

I only have my own experience to go by, but when towing about a 6k travel trailer, I set the cruise to 65 and let the truck do its thing. With the .321, I've never had it loose speed even in the hills in the east (Tn and Ky), and no times I've ever noticed any hunting back and forth in certain gears. Since I'm usually on cruise I wouldn't notice if it seemed to have a lack of power accelerating at different cruising speeds, though.

 

[Bmags]

Do you make 200 miles at 85 to 90 mph,if so what's your oil temps after 200 miles at those speeds.
The cruise stops at just a little over 95 mph,and i've ran 150+ miles with it set at it's maximium,and have never had a 3.92 geared truck keep up,as their oil temps are starting to go through the roof

Never care to look to be honest. Not worried about it. If something grenades I'll grab a junkyard 6.4L and run that instead haha.

 

[Bmags]

Remember he's the guy who locked out 8th gear with HP on his truck,so it acted like a 3.92 geared truck,with a 7 speed Then came unglued when i answered a couple questions,and accused me of trying to side track his thread
In reality he's got a 3.21 geared truck with a 7 speed,and is trying to pass it off as a 3.92 truck

Exhaust Drone Fixed! Spoiler Alert another 3.21 vs 3.92 discussion

Just figured I’d throw this out there to the group. BACKGROUND: There are many reasons why folks love the 3.92 gears… (way lower 1st gear, lower reverse gear, better acceleration, etc) but for me I mainly was searching for ways to remove my highway drone from my Carven Competitor (which I...

www.ramforum.com

Haha... yes, and since as you so accurately pointed out the 7th gear option is equivalent to the 3.92 gearing... I am offering my experiences to help benefit the masses. To be fair your whole post is just a copy from someone else anyways (I know this because I found that thread before doing my lockout)... but I digress.

 

[Wild one]

Haha... yes, and since as you so accurately pointed out the 7th gear option is equivalent to the 3.92 gearing... I am offering my experiences to help benefit the masses. To be fair your whole post is just a copy from someone else anyways (I know this because I found that thread before doing my lockout)... but I digress.

I never claimed it to be my post,lol. I shared it to help out alot of guys who have never had much experience with how final drive ratio's affect a vehicles performance,it was intended to be used as an educational post,nothing more / nothing less.
Question though,if you found it a year ago,why didn't you have the common courtesy to share it at the time????

 

[Bmags]

No need to share it, the information was already available...