Sprocket Talk

[bigdano711]

It has recently come to my attention that a 14/33 (.424) combo might work better than the often recommended 17/45 (.378). The figures in decimal are direct representations of the ratio...it helps my brain to see it that way. To me, it just looks taller, like going with 17/40 (.425)


What I'm trying to understand is what the YouTuber is trying to explain, but either I'm missing it or what he's saying simply does not compute. I was hoping to get you guys' expert opinion on the matter. He does explain that a similar Honda from the factory comes with the 14/33 combo, which I find intriguing.


https://www.youtube.com/watch?v=gjHFYOJVSdk&lc=UgxT9LJOtpMPMLHcXx54AaABAg.A9BDgV6-fHjA9BM2CSRoPR

[TominMO]

When he is saying a 233 gear ration for the 14/33 sprockets, he means 1:2.33. (Actually it is 2.35 though.) Rather than dividing 14 x 33 as you are doing, he is dividing 33 x 14. Same difference, just a different way of doing it.

You are correct, it is taller, but that seems to work for him and how he rides on the highway.

[Sport Rider]

I'm curious to understand if there is value to one or the other approach. seems like from an overall gear ratio perspective they would both achieve similar speed/RPM numbers. But I wonder if the larger sprocket in the back on a 17/40 would provide better torque to the rear wheel under load. I have absolutely no clue. hmmmmm....

[ProDigit]

A taller front will reduce the torque on the chain, and therefore allow the chain to last longer.

It'll also reduce engine vibrations through the frame, acts a bit like a flywheel, not the sprocket itself, but the sprocket driving that chain.

Generally speaking, there are only 2 forces exerted on the chain, 1 from the engine to the wheels in terms of thrust and acceleration,
And 2, from the wheel to the engine in terms of engine braking.
The former being much larger than the latter.

In terms of rotating mass, usually the mass of sprockets don't significantly contribute or detract from acceleration; if you were for instance to compare a steel 34t to an aluminum 34t.
But if you're counting in the realm of milliseconds, you might as well get the smallest sprocket setup you can get, and using an aluminum rear sprocket, to reduce weight.

In terms of reliability, using taller sprockets will usually result in longer lasting drive train.

Ideally, for longevity and mpg reasons, you'll keep the stock rear sprocket, and go up on the front one to a 17, 18, or 19tooth, or more if you can.
Ideally you'd be increasing the front sprocket in the same amount as you decrease the rear sprocket, to the point where both sprockets are nearing equal size (if gear ratio wasn't an issue).
For instance a 15/45 will have a lot more sprocket and chain wear than a 20/40 or 20/35 setup.

In terms of what gear ratio is ideal for touring or even top speed, you'll want to have at least 4th or 5th (or with a 6spd 5th or 6th) gear as a top speed gear, and if you can, use the final gear as a true overdrive gear where you can't reach top speed, but usually can still be able to reach a respectable speed for downtown, resulting in extended mpg.

The ideal engine rpm to ride in at any time, is the rpm where the torque of the engine is highest, if you need it. Otherwise it's the lowest rpm your engine can push, without lugging.

On small bikes, they usually tune it to ride at the hp peak, which quite often is near the redline. But this is quite inefficient.
A 50cc doing 45mph at 8k rpm may use just about the same fuel as a 250 doing the same at ~3-3.5k rpm.

The absolute worst you can do, is put a small front and a large rear sprocket on. It'll be bad in terms of mpg, sprocket and chain reliability, engine reliability, cush drive and bearings,and the reliability of the wheels and tires (especially if you are running spokes).

[Megadan]

Nobody mentioned what chain size between the two. Still 428? I run a 520 chain and 13 front and 33 rear, which is equivalent to a 17 front 43 rear on a 428 chain setup.

I only say this because a 13T front 520 chain sprocket and a 17T 428 sprocket are almost exactly the same size. A 14T front 520 sprocket barely fits on some bikes, and I can't run the sprocket cover on mine. It's huge.

[bigdano711]

The YouTuber is on 428, but I think I see what you're getting at. I was trying to justify buying this setup, but it seems to be the same as going with a 17/40 setup, which I may try. Like, less rolling mass, fewer teeth=less resistance or the motor doesn't have to work so hard...some kinda weird science that will let me eek out another .5 horsepower.


Time to buy the Stage 2 kit from MotoCult!

[XLsior]

You might end up increasing friction on the swing arm and wearing out spockets, chain and output shaft faster with smaller sprockets.


So give and take.

[Megadan]

The YouTuber is on 428, but I think I see what you're getting at. I was trying to justify buying this setup, but it seems to be the same as going with a 17/40 setup, which I may try. Like, less rolling mass, fewer teeth=less resistance or the motor doesn't have to work so hard...some kinda weird science that will let me eek out another .5 horsepower.


Time to buy the Stage 2 kit from MotoCult!

There is no science to "eek out .5hp"

Science says hp = torque/5252. Engine ratings are done via brake dynos, and brake dynos function by applying a maximum load to an engine. The number you get = all the horsepower it has.

What you are doing is shifting where the engine sits in the rpm range at a given speed. This is why a complete stock Hawk can barely do 59mph indicated (more like 56-57 actual) with the 15/50, and then 64-65mph with the 17/45.

Just for fun, some comparison data that should help prove that point. A carbureted Hawk 250 is rated at 14.1hp@7000rpm and 12.1ft-lbs @5500rpm. Stock top speed being 56-57ish actual MPH, and generally can cruise at 45mph comfortably all day long. Would you like to guess what RPMs those speeds happen at? 56mph is at 7500rpm, right at the point the HP peak rolls over and falls off hard. 45mph happens just past torque peak at 6000rpm, still in the "meat" of the torque peak.

17/45? I think we can reasonably agree that an otherwise completely bone stock - no exhausts or air filter shenanigans - with a 17/45 is pretty much maxed at 63-65mph depending on the rider, and can comfortably cruise along all day at 50-55mph. I bet you can't guess the top speed RPM... 65mph is more or less exactly at 7000rpm 55mph? That's right at about 5800rpm.

With a full exhaust and the carb jetted for it, the power peaks both leveled out a bit and carried the power up a few hundred RPM - call it about 300. and my top speed walked up a couple mph on the 17/45 and I found myself able to stretch out to 67mph

17/43? I ran this on the same bike as the other 2 combinations and on the same exhaust only upgrade as the 45 rear. I actually did so as a test to see where the reasonable limits were as far as gearing was concerned. My repeatable top speed was 68-69mph and it absolutely cruised along at 60mph without screaming it's head off. Bet you can't guess what RPM 69mph lands on, yep 7000 exactly. 60mph? just a tad past 6000rpm. I did gain some speed, but I started to drop off on the tail end past the peak, despite the exhaust giving me a bit of extra room. That more or less says "We have reached maximum velocity for power output."


Have you noticed a pattern? Power at top speed and the best cruising speeds all happen at the same RPM point - the peaks.

I even tried a 40 tooth just out of curiosity and I actually started to lose a little on the top speed. In terms of power, a Hawk with an exhaust and a 6ft4in tall 260lb man sitting on top of it has exactly enough power to just barely hit 70mph (actual mph)

I have tried a few other combinations over the years, and I keep going back to running an equivalent of a 17/45. It's hands down the best comination for a mostly road going Hawk. The 43 is definitely what I consider "street only" use, and it starts to lose a little climbing ability when up against a proper incline. JerryHawk ran a 17/40 and was able to hit in the low-mid 70mph range, but he's also not Megadan sized, not even close.

Going beyond a 17/43 starts going into heavier and heavier diminishing returns.

On the plus side, a lot of these sprocket combinations can run the same number of links, so you can experiment for relatively cheap and see what works best for you and where/how you ride.

[david3921]

Just a note, sprocket changes may affect how your speedometer reads. There is no problem if your speedometer reads by cable from the front wheel. There is, however if it's electronic. There are speedo "healers" you can buy.

[Thumper]

Just a note, sprocket changes may affect how your speedometer reads. There is no problem if your speedometer reads by cable from the front wheel. There is, however if it's electronic. There are speedo "healers" you can buy.

Yes, speedo depends on the front wheel. Most these days have magnet(s) on the brake rotor and a sender on the fork wired to the instrument cluster.

[ProDigit]

The YouTuber is on 428, but I think I see what you're getting at. I was trying to justify buying this setup, but it seems to be the same as going with a 17/40 setup, which I may try. Like, less rolling mass, fewer teeth=less resistance or the motor doesn't have to work so hard...some kinda weird science that will let me eek out another .5 horsepower.


Time to buy the Stage 2 kit from MotoCult!

What happens most of the time, is that the engine makes peak HP at say 7k RPM. But you're running the bike top speed at 8k RPM.
And the HP curve shows 0.5HP loss from 7 to 8k RPM (insert RPM and HP figures of your bike there, is just an example).

So running heavier or taller gears, can get you running your engine closer to that sweet spot.

Another thing that Megadan doesn't seem to get, and keeps denying is that an engine under load, runs hotter, and more efficient.
As a result it's HP figures do increase.
He keeps denying the science behind it. but it is true to some extend;
Hotter running engines, are running more efficiently, and thus can put out more HP or TQ if you just load heavier.

Anything from the valves being open a bit longer under load, to more air fuel entering the engine during heavier load, to hotter running engine (better for air/fuel expansion), to lower friction losses, contribute to a higher performing engine, over it's stock ratings.

So yes, you're right. In most cases you will gain engine HP and torque when changing the gears to taller gears; albeit less than single digit HPs, especially on small engines.
Torque to the wheels will lower due to the gearing differences though.

[Thumper]

What happens most of the time, is that the engine makes peak HP at say 7k RPM. But you're running the bike top speed at 8k RPM.
And the HP curve shows 0.5HP loss from 7 to 8k RPM (insert RPM and HP figures of your bike there, is just an example).

So running heavier or taller gears, can get you running your engine closer to that sweet spot.

Another thing that Megadan doesn't seem to get, and keeps denying is that an engine under load, runs hotter, and more efficient.
As a result it's HP figures do increase.
He keeps denying the science behind it. but it is true to some extend;
Hotter running engines, are running more efficiently, and thus can put out more HP or TQ if you just load heavier.

Anything from the valves being open a bit longer under load, to more air fuel entering the engine during heavier load, to hotter running engine (better for air/fuel expansion), to lower friction losses, contribute to a higher performing engine, over it's stock ratings.

So yes, you're right. In most cases you will gain engine HP and torque when changing the gears to taller gears; albeit less than single digit HPs, especially on small engines.
Torque to the wheels will lower due to the gearing differences though.

Gee. This again?

[ProDigit]

Gee. This again?

Truth is truth, bro

[XLsior]

Truth is truth, and bullshit stinks...


Pro Digit...more like Single Digit.


Huffing on you on hot air to increase performance while everyone else understands optimal operating temperature.


You are like Jim Cramer of motorcycle advice.

[Megadan]

Another thing that Megadan doesn't seem to get, and keeps denying is that an engine under load, runs hotter, and more efficient.
As a result it's HP figures do increase.


I keep repeating facts. You keep repeating unfounded bullshit based on literally nothing, and you can't provide proof for it.

I've grown tired of your dumbass and your incorrect information. What you just said there, is bullshit. Always has been, always will be. You act like they don't do the dyno for the engine under the appropriate conditions. You live in a fantasy world where maximum engine output isn't given down to the tenth of a horsepower, because why would a manufacturer sell an engine that makes less power when they could rate it as high as possible. Must be too high IQ for you to comprehend...

Want me stop saying you are wrong, WHICH YOU ARE, then prove it. Post something. ANYHTING, from a couple of credible sources that proves it and I will admit it in a new post. Hell, I will take a picture of myself in a pretty pink princess dress. Remember, credible sources, and more than just a couple.

Challenge is on. Put up, or shut up.:tdown:

(Edit: Don't call me out by name next time and insult me - you instigated this, not me.)

[Megadan]

Truth is truth, bro

Correct. Truth: You're unintelligent, uneducated, and too arrogant for your lack of actual knowledge. :tup:

[Megadan]

Anyway, back to an intelligent conversation with people that aren't completely brain dead.

Sorry to have Hijacked your thread fellow large Dan.

[bigdano711]

It's all good, guys. I had a feeling that 14/33 was not gonna do anything for me, so thanks for confirming.


In other news, I have pulled that Nibbi PE28FL and put the stock carb back on. The Nibbi has been leaking fuel right down the intake. Pretty sure since I installed it, although there is a possibility the JJH needle isn't seating properly. I had a tank leak and thought that was it. Turns out it was the Nibbi all along, considering the amount of fuel in the oil.

[Thumper]

Dropping revs with taller gearing is great for road conditions. The limitation, as you are fully aware is wind resistance.

It's nice to have lower revs on the highway, and you can get to pretty amazing speeds with a tail wind!

[bigdano711]

I'm pretty happy where it's at. Megadan was dead nuts in his post where he talks about sprocket ratio/peak torque/speed/rpm. I am very close to his numbers but less because of sprocket choice and my bike is not as hopped up as his. With my 17/47 I can get 53mph in 4th gear fully wound out (7500-8000rpm), even up a pretty decent hill. 5th gear is more like a highway gear that struggles on the highway. On the downhill WITH a tail wind, I can hit 65-70, fully wound out. She cruises pretty good at 60, and that's plenty.

[ProDigit]

Seems like some people can't understand the facts.
Told you they won't admit they're wrong.
I KNOW I'm right. They're just reading textbook BS, without actually understanding the mechanics behind it all...

You keep repeating things without actually proving what I said was wrong.


@Megadan
and of course, the forum troll XLsior, who contributes nothing to the conversation.

[Bill Hilly]

Seems like some people can't understand the facts.
Told you they won't admit they're wrong.
I KNOW I'm right. They're just reading textbook BS, without actually understanding the mechanics behind it all...

You keep repeating things without actually proving what I said was wrong.


@Megadan
and of course, the forum troll XLsior, who contributes nothing to the conversation.

Thanks for the expert advice. I just added a set of 38/17 sprockets, and shroud around the cylinder and head of my Hawk. I also filled the saddle bags with sand , which along with my 260 lb weight should increase load, as well as temperature. I need to add a Hot air intake, but can't find one, but Honestly it runs like a striped ape, Truthfully??, Well it runs 85 in 4th. To tell the truth, any more than 1/4 throttle,pulls the front wheel in 3rd. When I get that hot air intake on it, it will probably pull it in 5th. And that's the truth.

[Megadan]

Seems like some people can't understand the facts.
Told you they won't admit they're wrong.
I KNOW I'm right. They're just reading textbook BS, without actually understanding the mechanics behind it all...

You keep repeating things without actually proving what I said was wrong.


@Megadan
and of course, the forum troll XLsior, who contributes nothing to the conversation.

:lmao::lmao::lmao::lmao:
"I KNOW I'm right" is not proof, nor is it a credible source.

You know what is a credible source? Published Textbooks with factually verified referenced information from leading experts in their fields.

Leading Field experts and countless years of tested knowledge and experience vs. what you "know"

Should have stayed in school.:tdown:

Oh, and XLsior has contributed way WAY more to this forum than you have. Actual good information, both through his own build thread and ideas to just good generally accepted mechanical advice. I would rather have 100 of him to this one version of you.

[ProDigit]

Yet you can't prove I'm wrong, with your text books.
You quote some formulas that make sense on a fixed dyno, but never acknowledged that there are parts that don't apply on what I'm talking about.

According to your formulas nox will not increase HP. Because of your textbook formulas.
You fail to understand what I'm talking about about is outside of your understanding. But oh well...
Keep believing what you want. You're not hurting anyone with it. Except for people who are actually trying to tell you you're actually wrong.

[bigdano711]

ProDigit, you remind me of me 20 years ago. What you post KINDA makes sense and I want to back you or believe you, but I just can't get there. You seem so sure of what you're talking about, but grifters also speak (or type) confidently. Also, you are very antagonistic, which makes you come off as arrogant. Maybe dial that down a little?

Typically, science is repeatable. Have you done any simple testing/experiments to prove your theories? Where did you get your theories?

[ProDigit]

ProDigit, you remind me of me 20 years ago. What you post KINDA makes sense and I want to back you or believe you, but I just can't get there. You seem so sure of what you're talking about, but grifters also speak (or type) confidently. Also, you are very antagonistic, which makes you come off as arrogant. Maybe dial that down a little?

Typically, science is repeatable. Have you done any simple testing/experiments to prove your theories? Where did you get your theories?

My response is merely one due to a- trolls, and b- misinformation. Doesn't mean that I'm wrong though.

Do a dyno pull in 1st gear and in 6th gear.
You'll see torque is way up in 1st and HP is lower. Meanwhile in 6th HP is up, but torque is lower.
Should be self explanatory.
For anyone not understanding that is the exact same result you're getting as doing the pull with stock gears and with a taller gear setup.

I'm not sure if the process continues indefinitely. Meaning, can't put a 38t on the front and a 15t on the rear and expect better results. But yeah, plug in ideal gearing over stock, and the dyno results will show.

Second, when they use a static dyno, the results are clearly better than on a regular dyno. A regular dyno keeps load constant, while a static dyno keeps rpm (nearly) constant. And you can't load an engine heavier than by keeping rpm constant. A constant load emulates a taller gearing where the engine has a hard time accelerating. The results from such a dyno will show higher HP, than on a regular dyno run, unless the regular dyno run results have been modified to show that discrepancy. In which case they're not going to show the exact HP figures for all bikes (like, they might overread smaller bikes, and underread bigger bikes).

[bigdano711]

My response is merely one due to a- trolls, and b- misinformation. Doesn't mean that I'm wrong though.

Do a dyno pull in 1st gear and in 6th gear.
You'll see torque is way up in 1st and HP is lower. Meanwhile in 6th HP is up, but torque is lower.
Should be self explanatory.
For anyone not understanding that is the exact same result you're getting as doing the pull with stock gears and with a taller gear setup.

I'm not sure if the process continues indefinitely. Meaning, can't put a 38t on the front and a 15t on the rear and expect better results. But yeah, plug in ideal gearing over stock, and the dyno results will show.

Second, when they use a static dyno, the results are clearly better than on a regular dyno. A regular dyno keeps load constant, while a static dyno keeps rpm (nearly) constant. And you can't load an engine heavier than by keeping rpm constant. A constant load emulates a taller gearing where the engine has a hard time accelerating. The results from such a dyno will show higher HP, than on a regular dyno run, unless the regular dyno run results have been modified to show that discrepancy. In which case they're not going to show the exact HP figures for all bikes (like, they might overread smaller bikes, and underread bigger bikes).
Right off the bat, I know nothing of dyno's or what data is recorded and looked at to figure out HP and torque numbers. I can only deduce that you have poured over dyno data and have come up with a theory (or theories) that is proven by the data?


My original question, which has been satisfactorily answered, was: What is the YouTuber trying to say when he recommends the 14/33 combo? He recommends it over the 17/45. He seems to imply there is more torque or hp where you need it. To me, it just looks like taller gearing, similar to 17/40. Mostly, that's really all it is. However you come in out of left field to try and explain something that I already have a slim comprehension of and completely bamboozle my head. Thanks?

[Megadan]

Right off the bat, I know nothing of dyno's or what data is recorded and looked at to figure out HP and torque numbers. I can only deduce that you have poured over dyno data and have come up with a theory (or theories) that is proven by the data?


My original question, which has been satisfactorily answered, was: What is the YouTuber trying to say when he recommends the 14/33 combo? He recommends it over the 17/45. He seems to imply there is more torque or hp where you need it. To me, it just looks like taller gearing, similar to 17/40. Mostly, that's really all it is. However you come in out of left field to try and explain something that I already have a slim comprehension of and completely bamboozle my head. Thanks?

You won't convince the lonely narcissist that he is wrong. He can't support his made up BS because it is enirely made up. There is no science, math, or anything of any credible value that supports what he "just knows." Pretty much everything that says he is wrong and full of shit is all of the factual and credible information in the motor vehicle industry.

He has no proof. I already have asked for it multiple times. He just ignores it or tries to use ad hominem, strawman arguments, gaslighting, and red herrings to steer the conversation away from actually having to back up anything he says. He is trying now to convince you of this and is manipulating you through your attempts to be friendly and kind. Trust your gut with him, because it's right. He's a bully with too much ego and no brains.

I trust the rest of the world's 150 years of internal combustion science, engineering, and experience over some wannabe google fueled internet "expert" that can't even get basic mechanical theory correct.

[Thumper]

While it is true that you can optimize the power your engine makes by adjusting the final drive ratio with sprockets for practical purposes, depending on how you use the vehicle. But I don't think it is good to wring out every bit of the 19hp my engine makes. Once in a while, I need it for a short hill climb or something. But only rarely, and only for a few seconds.

Generally, I am using 5 to 15 hp while I ride. Maybe more when I am on the highway. Running an engine at peak power output constantly is a great way to decrease engine life, and it just feels bad! If I need more power, I will buy a bike that makes more horsepower, and run it at ~70-80% of what it can make. Less if it is a larger bike, like my 1200S Bandit or Katana 1100 did. The power was there, but all it did was wear out the rear tire if I kept using it, and launch me to traffic citation velocity real quick!

Sadly, no gearing will change the amount of power an engine makes. You don't see Hayabusas making more than peak horsepower with a sprocket change. It simply does not happen. You would hear all about changing sprockets if it were true. It just isn't. I have no idea how anyone thinks the can increase the horsepower of an engine with the transmission or final drive ratio. It is really ludicrous (meaning so foolish, so unreasonable, or out of place as to be amusing, synonym: ridiculous)

[GypsyR]

Shoot, everybody knows that if you want more free power from a vehicle you just have to put lots of "R-Type" and "Monster Energy" type stickers all over it. SO much horsepowers!

[ProDigit]

You won't convince the lonely narcissist that he is wrong. He can't support his made up BS because it is enirely made up. There is no science, math, or anything of any credible value that supports what he "just knows." Pretty much everything that says he is wrong and full of shit is all of the factual and credible information in the motor vehicle industry.

He has no proof. I already have asked for it multiple times. He just ignores it or tries to use ad hominem, strawman arguments, gaslighting, and red herrings to steer the conversation away from actually having to back up anything he says. He is trying now to convince you of this and is manipulating you through your attempts to be friendly and kind. Trust your gut with him, because it's right. He's a bully with too much ego and no brains.

I trust the rest of the world's 150 years of internal combustion science, engineering, and experience over some wannabe google fueled internet "expert" that can't even get basic mechanical theory correct.

On social media I would laugh such a ridiculous answer off, due to mister narcissist thinks he knows everything, but his answer shows he doesn't know what he's talking about, and can't admit he's wrong.

There's not an ounce of false information I've shared. Please, go to a dyno tuner and get corrected. Then come and apologize here for your stupendous answers.


Bigdano,
As far as the 14/30 vs 17/45 that was answered in a previous answer on this thread. Just scroll back to see your question answered there.
This is just merely a follow up on a comment someone else made.

Stick to the thread before you start ridiculing.

As far as thumper the forum troll,I'm glad he's on my ignore list, not even worth my time with his troll answers.

[XLsior]

Ahh the old projection angle Mr Digit...


If I'm such a Troll why did you take my advice and put a 250cc engine in you're 150 Vadar?


You're happy enough to copycat when it elevates an insecure ego...


But as soon as the lies get exposed everyone is wrong and we're all bogeymen and trolls...


Why did you get NK450 and not the Yamaha M07 you recommended to me?


I suggest you change you're own sprockets find that horse power gain look for that missing reverse gear and back up out of here while what ever left of your perceived intelligence remains intact...

[sburk]

How about people post sources for their argument/ point of view and then we can all see what's fact .I'm on here to learn things and would like awnsers to claims

[Thumper]

I searched for key terms like best sprocket ratio for dyno horsepower, various high performance bikes and quickly found some dyno focused forums and sections within forums about dynos. Rather than give you quotes, I will just let you do the searches. I would not feel right using those other forum members posts anyway. Also, I don't want to spoil the fun, and I swear if we had a beat a dead horse icon on this website I think we would have broken it by now! ;)