[jaydrake]

I'm sure this guys software app must have been posted here, but in case it hasn't.... http://www.pollensoftware.com/shadow/gearcalculator.html

Kind of hidden in the app itself, he makes this pitch:

"This application can be used by those who want to experiment with different rear sprocket sizes, but as the originator of the software I feel I should make my stance on this clear.

My stance is that A) Honda did not get it wrong, they designed the bike for the stock sprocket, B) you loose two-fold when you change out the sprocket, and C) most people change out the spocket for aesthetic reasons only. Add to this that there is a lot of misinformation about what changing out the spocket can do for you.

If you are changing out the sprocket for aesthetics alone, then that's fine, I guess... it's your bike. What I would say is that while the Shadow ACE 750 is the best looking cruiser to ever go down the road, the bike is NOT a HD. Many (especially those in countries that have a lot of HDs and HD culture ;-) ) expect the bike to run at the RPMs HDs do, either because they think that's the speed engines should run at, or because they think it sounds better. While it may sound better to them, the ACE's motor is designed to run at MUCH higher RPMs than a HD.

By changing out the rear sprocket, and forcing the motor to run at lower RPMs, you loose power AND top speed. You actually loose power in two ways, 1) you are loosing torque by changing the ratio of engine speed to road speed, and 2) you are loosing power because the engine is now running slower for any given speed. You also loose top speed, as the bike's top speed determined by terminal velocity, or in other words, a factor of the engine power. So now your bike is working harder, you're getting less power off the line, less ability to accelerate up, and a lower top speed!

My suggestion is that you should get to know your ride, and then ride it to the best of your abilities."

Any thoughts?

 

[vbm]

Rear sprocket

Although I ride a 1998 1100 Aero with a shaft drive I simply must comment. I've owned many chain driven bikes over the years and while lowering the number of teeth on the rear sprocket will indeed reduce torque and therefore acceleration it does not reduce top speed. If anything it will increase top speed. You see changing the rear sprocket for one with a lower number of teeth decreases the rpm's of the engine at any given speed. It does not reduce the rpm's that the engine is capable of turning. Therefore if you continue to accelerate until you hit the rev. limiter or to the rpm range that the engine turned prior to changing the sprocket you will find that your ground speed has increased.

[/img]

 

[Olivereaman]

I'm sure this guys software app must have been posted here, but in case it hasn't.... http://www.pollensoftware.com/shadow/gearcalculator.html

Kind of hidden in the app itself, he makes this pitch:

"This application can be used by those who want to experiment with different rear sprocket sizes, but as the originator of the software I feel I should make my stance on this clear.

My stance is that A) Honda did not get it wrong, they designed the bike for the stock sprocket, B) you loose two-fold when you change out the sprocket, and C) most people change out the spocket for aesthetic reasons only. Add to this that there is a lot of misinformation about what changing out the spocket can do for you.

If you are changing out the sprocket for aesthetics alone, then that's fine, I guess... it's your bike. What I would say is that while the Shadow ACE 750 is the best looking cruiser to ever go down the road, the bike is NOT a HD. Many (especially those in countries that have a lot of HDs and HD culture ;-) ) expect the bike to run at the RPMs HDs do, either because they think that's the speed engines should run at, or because they think it sounds better. While it may sound better to them, the ACE's motor is designed to run at MUCH higher RPMs than a HD.

By changing out the rear sprocket, and forcing the motor to run at lower RPMs, you loose power AND top speed. You actually loose power in two ways, 1) you are loosing torque by changing the ratio of engine speed to road speed, and 2) you are loosing power because the engine is now running slower for any given speed. You also loose top speed, as the bike's top speed determined by terminal velocity, or in other words, a factor of the engine power. So now your bike is working harder, you're getting less power off the line, less ability to accelerate up, and a lower top speed!

My suggestion is that you should get to know your ride, and then ride it to the best of your abilities."

Any thoughts?

jaydrake,
I have zero inside inside info about Honda, I must make that clear up front. That being said....what I do know about Honda:

They are a world class automotive designer and manufacturer. Their entry level dive train engineers probably have more access to high tech automotive functions during their first 6 months at Honda than many have in a career. They are definitely not dumb. Some things that they may do in search of profits might be... but I am absolutely sure that they're not operating from mechanical ignorance. I don't think something as trivial as a 41 tooth or a 39 tooth sprocket will not deter Honda from doing the correct thing. I can't imagine the difference in price at their level amounts to enough to justify over-riding an engineer.

I can tell you this, there's a whole lot more going on inside an engine than many people realize. Honda is in the business of making engines, they have equipment available to them that would have almost any engineer getting wood just thinking of the possibilities! They understand forces on a engine as well as anyone. If they concluded it needed a 41 tooth sprocket, I would really need to have someone's explanation as to why they think it doesn't and from a purely mechanical standpoint, just saying it sounds better doesn't do it for me.

As far as power goes, my experience has given me some small idea about optimum and maximum power and it's effect on wearing engine parts. RPM isn't anywhere near the engine killer, as long as we stay in the design limits and those limits also include low speed thresholds, that people believe it is. In fact, the opposite is the truth. A low RPM, high load, high throttle setting is probably one of the worst combinations you can come up with.

My conclusion....Honda has tried many combinations and scientificly evaluated the results, then settled on one that they can produce from standard parts. If there is more than a little difference, they are able to produce the needed parts. I don't think they are afraid to spend profits to make a better product that will bring more profits. If they built it, that's probably the best way. That buzz that might be produced may very well be the best trade off obtainable for a durable engine/drivetrain that's priced competitively. They also have the unfortunate task of satisfying Government regulations, which most aftermarket suppliers rarely, if ever, deal with.

One thing to realize.... Honda doesn't warranty their bikes by miles, they warranty them by time. Look around at the competition and see how their warranties stack up. And also compare the costs. It tells me that Honda is fairly confident in their designs.

John

PS. Some people love to tinker, and I'm not against that. But they must remember if it all goes wrong, don't blame the engineers at Honda. I've ruined a lot of good machinery of many descriptions over the years by trying to 'improve' it, I've also made a lot of improvements that benefited me for the purpose I wanted. The one I'm really determined to hurdle is the low beam lighting issue on my Shadow Spirit, that's the one area where I'm convinced Honda can do better!

 

[Olivereaman]

Re: Rear sprocket

Although I ride a 1998 1100 Aero with a shaft drive I simply must comment. I've owned many chain driven bikes over the years and while lowering the number of teeth on the rear sprocket will indeed reduce torque and therefore acceleration it does not reduce top speed. If anything it will increase top speed. You see changing the rear sprocket for one with a lower number of teeth decreases the rpm's of the engine at any given speed. It does not reduce the rpm's that the engine is capable of turning. Therefore if you continue to accelerate until you hit the rev. limiter or to the rpm range that the engine turned prior to changing the sprocket you will find that your ground speed has increased.

[/img]

vbm,

I'm not sure..but I think we're running out power before we run out of speed. I used to have charts and co-effient factors for determining that sort of thing, but from memory, a 40-50 HP machine isn't really capable of topping out in a high ratio gear like My Shadow has. I've never tried it, so it's only speculation.

 

[Guest]

Who changes their rear sprocket for aesthetics ??? That's insane. A smaller sprocket doesn't look much different from a 41 or 42 tooth. Most of the aftermarket sprockets available are not anodized in pretty colors.

Changing to a smaller sprocket will lessen engine wear at any given throttle position. Cruising at 65...if you lower the rpms by 300 or 500 rpms, that's less revolutions and less wear.

If the engine is still operating in its powercurve, gas mileage will likely increase.

It is by far one of the best mods for comfort on the highway that you can do. If you go too small, yes it will be counterproductive. That's why I don't recommend going smaller than 38 tooth with a stock bike.

Design always has tradeoffs. Honda wanted good performance around town as well as on the highway. They also design for 0-60 times and quarter mile performance which is often publicized in publications.

The stock Honda gear ratio isn't optimum if you spend much time on the interstate. The RPMs generated create a buzzy feeling which isn't best for comfortable cruising.

 

[wpur]

I gotta chime in here as one who has changed the rear sprocket on a 98 ACE 750. I went to a 37 tooth. The reason was not aesthetics, nor was it performance or longevity of the engine. The intent was rider comfort for extended periods at highway speed and the improvement was remarkable.
It has been my experience that many engineering choices are compromises. Performance vs. comfort vs. mileage vs. aesthetics and on and on. The bikes are being sold to humans and therefore marketing as well as engineering will always be in the design decision making process. And where one customer places their priorities won't be the same as the next. Viva la differance (or something like that ).

 

[IndyAce]

I've had the 38t sprocket on mine for three years. Love it. Don't need much more analysis than the seat of the pants test for me. Don't over analyze things. The sprocket swap on this bike just plain WORKS.

Mark

 

[Tropic traveler]

Changing sprockets for aesthetics?? :lol: :lol:
That sounds like what a HD guy would do! :twisted:
Jay, your point is well taken, however.......... IMHO and experience over the years has taught me one thing for sure, almost ALL production vehicles of any sort are real big on compromise. They strive to "hit the middle" on most important engineering challenges while having an eye on keeping costs down too. That is not a small point either! The specific issue of rear sprocket changing shows some flexibility on Hondas part too as the nearly identical Shadow 750 line up has both a 42T and 41T offered on the Spirit and Ace/Aero from the factory.
I do agree that straying wildly from Hondas engineering could VERY easily bring you a bike that loses proper functionality. I have noticed {& spent my $$ accordingly} that Honda engineers are some of the best in the world! I love tinkering and swapping and many times have messed up a bit. It seems that the best mods are subtle and I try to "reuse" OEM components as much as possible. Sometimes it ISN'T better to reinvent the wheel, but gains can be made by making little changes that suit your own specific ridings style and needs! 8)

 

[chornbe]

I agree with the guy. Even if he can't spell "lose" (the education system is going to ****).

 

[Guest]

I agree with the guy. Even if he can't spell "lose" (the education system is going to ****).

Your argument is vacant and nice catch on the spelling error :roll:

 

[metlcutr55]

most people make the change because they want to pull less revs at highway speeds in high gear. or they want their gearbox to feel "longer", dont know if im sayin this right, but they want a longer span between shifts. ive ridden a stock spirit and a spirit with a 36t rear, both were fine for me @ 230 lbs. different, i liked the 36t better. i can see where going 2 up with the 36t might be a stretch off the stopsigns. if you have on a smaller sprocket and need revs or power, dont forget there is a gearbox that can be shifted if you like. wont pull 5th gear on the hill anymore? try 4th. my ace1100 and my valk pull more revs on the hiway than i like, if i could gear em down i would.

 

[morepower]

Honda, just like any other manufacturer, has to build a bike that suits the needs of the widest variety of buyers under the widest variety of conditions. That's why the aftermarket is in business so that the rider that spends a lot of time on the freeway can tailor the gear ratio to fit the situation. I wonder if anyone has gone the other direction and put a bigger sprocket on to blast between stop lights?

 

[metlcutr55]

morepower, i used to make a few sprockets for the ss750, can tell you the smallest i ever made was a 35, the biggest a 44. the guy who bought the 44 wanted it for exactly the reason you said. the guy with the 35 really liked that long gear feel.

 

[coppertop]

stock 41tooth works for me but part of riding a bike is personality no one I know ever leaves their bike stock there is always something to add or take away that is why there is an after market. Personaly the first thing I did was take all the stickers off of my bike. I hate stickers just my 2 cents

 

[harryco]

In my opinion, the design of bikes, and cars, is dictated by the Government regulations, and not the design engineers choice. Period.
An example is how the car engines in the UK were engineered by the bore and stroke formula, which was a Govt idea, which forced the engineers to design the engines to meet that formula.

If the EPA emission regs, or MPG figures, or 0 to 60 times are met by using a smaller rear sprocket, that's what we get. It can be, and is changed later by many, including myself. I run with a 39T instead of a 41T, and it suits my 2 up riding just fine.

In reallity, a change to the smalle rear sprocket does change the performance of the bike for the better, where acceleration is not the issue.

Enjoy the ride.

Harry.

 

[psychoboy]

I've got the solution...

i'm gonna build a 2 sprocket setup with a derailer. (think of the back of your ten speed bicycle)

a 45 tooth for when i plan to race around in-town, and a 35 tooth for interstate cruising.


no, really, I've been considering a sprocket swap, cuz i've noticed the bike is kinda buzzy around 90 mph or so.

but in my experience with honda cars over the years i have found that swapping a (numerically smaller) taller differential should increase top speed (or decrease revs), but the motor no longer has the oomph to get it thru the wind to the old top speed.

(ever notice that superfast performance 6-speed cars get thier top speed runs in 5th? why? cuz 6th gear is too long for the motor to push thru the aero drag at the same speed.)

for instance. my first honda CRX was the HF model. the gears in the tranny allowed for about 2000 rpm at 80 mph in fifth. theoretically, the car would run 160 mph at the 6000 rpm redline in fifth, but in reality, the motor's power couldn't get it over the century mark, and even that took the better part of five miles to achieve....and you better pray against gust of headwind or a small hill.

my second CRX was the Si model. more power, shorter gears. tho theroretically limited to about 150 at it's higher redline (the same 6000 would be about 140), it actually stood a half-assed chance of getting there. it was still pulling reasonably well at 100.

since then, i've built HF motors on Si trannys, and Si motors on HF trannys. the low power motor on the short gears, felt peppy off the line....but quickly ran out of steam. the stronger motor on the long gears pulled to a solid 100-110, but i had to spend what felt like a week in fourth (all the way to the red line) in order to allow the motor a fighting chance of pulling in fifth. if i shifted too soon, i'd lose speed in fifth, cuz the torque was not high enough yet to fight the aero drag.

there is nothing weirder that driving against the aero limit of the motor, especially when that motor is turing something like 1750-2000 rpm...


what did i learn from the above novel?

honda is pretty good at doing what it does.

honda has decided that the ACE buyer wants hi-speed travel, the spirit buyer wants quick acceleration. look at the differences...the spirit LOOKS faster than the ACE....the little fenders, the little bars, it doesn't typically appeal to the "gonna step up to a goldwing" crowd.

assuming the transmissions have the same gears in them (i think they do), and assumig the weights and aeros are the same, the spirit will beat an ACE off the line, but the ACE will get better gas mileage, and probably top out at a higher speed.

the ACE will seem more comfortable at hiway speeds, while the spirit feels more squirty in town.

but then.....that's just one man's opinion.

 

[Olivereaman]

I've got the solution...

i'm gonna build a 2 sprocket setup with a derailer. (think of the back of your ten speed bicycle)

a 45 tooth for when i plan to race around in-town, and a 35 tooth for interstate cruising.


no, really, I've been considering a sprocket swap, cuz i've noticed the bike is kinda buzzy around 90 mph or so.

but in my experience with honda cars over the years i have found that swapping a (numerically smaller) taller differential should increase top speed (or decrease revs), but the motor no longer has the oomph to get it thru the wind to the old top speed.

(ever notice that superfast performance 6-speed cars get thier top speed runs in 5th? why? cuz 6th gear is too long for the motor to push thru the aero drag at the same speed.)

for instance. my first honda CRX was the HF model. the gears in the tranny allowed for about 2000 rpm at 80 mph in fifth. theoretically, the car would run 160 mph at the 6000 rpm redline in fifth, but in reality, the motor's power couldn't get it over the century mark, and even that took the better part of five miles to achieve....and you better pray against gust of headwind or a small hill.

my second CRX was the Si model. more power, shorter gears. tho theroretically limited to about 150 at it's higher redline (the same 6000 would be about 140), it actually stood a half-assed chance of getting there. it was still pulling reasonably well at 100.

since then, i've built HF motors on Si trannys, and Si motors on HF trannys. the low power motor on the short gears, felt peppy off the line....but quickly ran out of steam. the stronger motor on the long gears pulled to a solid 100-110, but i had to spend what felt like a week in fourth (all the way to the red line) in order to allow the motor a fighting chance of pulling in fifth. if i shifted too soon, i'd lose speed in fifth, cuz the torque was not high enough yet to fight the aero drag.

there is nothing weirder that driving against the aero limit of the motor, especially when that motor is turing something like 1750-2000 rpm...


what did i learn from the above novel?

honda is pretty good at doing what it does.

honda has decided that the ACE buyer wants hi-speed travel, the spirit buyer wants quick acceleration. look at the differences...the spirit LOOKS faster than the ACE....the little fenders, the little bars, it doesn't typically appeal to the "gonna step up to a goldwing" crowd.

assuming the transmissions have the same gears in them (i think they do), (and the weights and aeros are the same) the spirit will beat an ACE off the line, but the ACE will get better gas mileage, and probably top out at a higher speed.

the ACE will seem more comfortable at hiway speeds, while the spirit feels more squirty in town.

but then.....that's just one man's opinion.

psychoboy,

You've been to end, and seen what happens. I have too.

One of, in MHO, best stories of all time was when I was a kid and had a 58 Chev with a six cylinder with a three speed manual.

I won a lot by betting people the car would actually go faster in 2nd than in third. They would look at me like I had two heads and take the bet!! I take out and let them watch me do it. Right to floor on the level.....89 in high.....92 in second!! They just couldn't believe that proper geaaring makes a difference. The old girl couldn't make enough of the second part of the torgue/RPM equation to overcome wind resistance!!

John

 

[Guest]

but in my experience with honda cars over the years i have found that swapping a (numerically smaller) taller differential should increase top speed (or decrease revs), but the motor no longer has the oomph to get it thru the wind to the old top speed.

You're discussing the performance of vehicles at speeds over 100 mph. That's really not relevant here. These Shadow 750s will never see those speeds.

The general consensus is that these 750s are geared too high from the factory for comfortable cruising and I've never heard any complaints from riders who've switched to a smaller sprocket.

If you go too small on the rear sprocket, yes you will reduce top end because the bikes don't have the horsepower to pull at those speeds with such a low final gear ratio.

 

[psychoboy]

but in my experience with honda cars over the years i have found that swapping a (numerically smaller) taller differential should increase top speed (or decrease revs), but the motor no longer has the oomph to get it thru the wind to the old top speed.

You're discussing the performance of vehicles at speeds over 100 mph. That's really not relevant here. These Shadow 750s will never see those speeds.

i disagree....

aero drag is noticable and has an effect as low as 50 mph.

add that to the fact that my HF motor made 62HP and my Si made 100, whereas my shadow motor makes what, 36?

i'll bet the aero drag on me (in normal riding posture) and my ACE is not as good as my CRX's were, either.

sure, my ACE and I are 1/3 the weight of me and my HF, and the ACE only has half the HP (so the bike is a higher hp/lb ratio), but i'll bet that 36 HP is working it's ass off to push me thru the wind at normal highway speeds (especially in a state that a constant 30 mile an hour headwind wind is not uncommon).

due to the wind here over the weekend, i tried pulling my feet up on the passenger pegs, and leaning over the forks.

i can't see my mirrors, i can't easily see the speedo, my hands are about even with my ears, and obviously I can't operate the foot controls......

but i could hold hiway speed with 1/2 the throttle....and i didn't vary my speed nearly as much. that tells me I moved the operable threshold of motor vs wind further up the scale. since my motor didn't have to work as hard to keep my speed, i could run it out faster.

oh yeah..one more thing.....in my state, on some roads, 100 mph IS fast lane hiway speed, people get pulled over on some of our freeways for going too slow (usually 5 under the limit) where the traffic flow is about 15-20 over the limit.

 

[chornbe]

but in my experience with honda cars over the years i have found that swapping a (numerically smaller) taller differential should increase top speed (or decrease revs), but the motor no longer has the oomph to get it thru the wind to the old top speed.

You're discussing the performance of vehicles at speeds over 100 mph. That's really not relevant here. These Shadow 750s will never see those speeds.

i disagree....

This will be fun to watch (and you're right, by the way).