Just for the sake of discussion lets say I could change the final drive gear ratio on the gl1800 to drop interstate type driving by 500 rpm's. I'm using 500 as thats pretty much how much the rpm's change from 4th to 5th and I like some others I know would really like a 6th gear type rpm at interstate speeds. What do you think the average rider would be willing to part with to have that kind of mod done? It would involve removing your final drive (not difficult at all) sending it in having a new gear set installed and of course properly set up and you re-installing it. I don't want to get into whats it made out of or is it reliable or any other type of tangent issues. Lets just keep it simple. I ask this question to find out if it would be worth going thru all the monkey motion a set of properly designed gears would cost to do this...I am considering it obviously or would not throw it out there. My question is aimed at those that feel as I do that the rpm's could come down for interstate type speeds so mpg doesnt take as much of a hit. Thanks fellow riders
tp
I have tried for many years to get someone with a machine shop to do just this.
It would increase fuel mileage by a condiderable amout, ,make the engine last even more then it does now.
looking at honda cars and toyota cars, I'd say drop the rpm by 1000, make it about 2400 rpm (not 3400) at 70 mph.
I really do think this is the best idea in quite sometime. The transmission is so hard to get to the rear screw would be the easy fix.
your in top gear at the bottom of the ramps, and this should just not be, there is not really a true overdrive as there should be.
I've wriiten many many letters to Honda about this.
please keep my e-mail address I'm very interested
Robert Taylor
vawing@gmail.com
It would increase fuel mileage by a condiderable amout, ,make the engine last even more then it does now.
looking at honda cars and toyota cars, I'd say drop the rpm by 1000, make it about 2400 rpm (not 3400) at 70 mph.
I really do think this is the best idea in quite sometime. The transmission is so hard to get to the rear screw would be the easy fix.
your in top gear at the bottom of the ramps, and this should just not be, there is not really a true overdrive as there should be.
I've wriiten many many letters to Honda about this.
please keep my e-mail address I'm very interested
Robert Taylor
vawing@gmail.com
Although that could improve mpg and lower the cruising rpm's it would negatively affect your performance.
G
I agree that I'd like a bit less rpm on the interstate.
Four ways to achive that:
1) another gear in the tranny. That's up to Honda; cost prohibitive and design intensive to the nth degree for us mere mortals.
2) taller 5th gear in the tranny. See above answer.
3) taller rear drive ratio. A bit more "doable" from the design and machining perspective. It's done in the aftermarket all the time for performance cars and 4x4 trucks. Perhaps enough positive pressure for the 'Wing crowd would persuade them for a design quest. For those who don't think this all the way through, it would be quite intensive as there is a pinion AND ring to address. The upside is of course, better economy. The downside is a bit slower acceleration relative to any given gear selected in the tranny.
4) taller tire. Been done several times before. Drop a few rpm, and gain some ground clearance at the same time. Some like this approach; some don't. Another upside to this approach is that it's easy and inexpensive (realtive to the other options) to do, and it's easy to reverse if you don't like it.
As for the "amount" of rpm drop desired, that's a debate within a debate. My observation, from both GL1500's and my current GL1800, is that 350 rpm or so would be good. I say this because there seems to be a universal aspect of fuel consumption with the GL series of engines. It is true of all internal cumbustion engines as well, generally. Spin it higher, consume more fuel, right? I don't know why, but the GL's seem to hold fuel consumption fairly steady until around 3000 rpm, then they start on some parabolic P+I BSFC consumption gas guzzle fest that just goes up at an insane rate past 3000 rppm. If you go from 3000 rpm to 3300 rpm (10% gain), you might use 20% more fuel. And it gest worse from there.
Now part of this is because 3000 rpm is APPROXIMATELY 70mph, depending on the speedo accuracy. Most people don't realize that wind resistance is not linear; as your speed doubles, the wind resistance is SQUARED! In other words, to go from 35 mph to 70mph makes the wind resistance FOUR TIMES the amount at 35 mph! This is why the harder you push past a higher speed, the fuel consumption rate goes way up.
The upside is the the GL1500 and GL 1800 engines have enough torque that it's quite possible that they could offset the energy requirement to break past each successive mph increment. At some point, the engines would get into a "zero sum gain"; if you dropped the rpm by 25%, the engine may not have enough torque to overcome the load based upon speed and wind. That's why I think an approximate 10%, no more than 15%, drop would be enough to gain fuel economy, but not enough as to overburden the engine.
Let me put some rough numbers to it. Assume 70mph is 3000 rpm in a traditional GL1800. If you went up 10% in speed, you'd be around 77mph and 3300 rpm. If you could drop the rpm by 10%, you'd be back at 3000 rpm; at that point, I feel the GL1800 has enough torque to overcome the load, and the drop in rpm would be more than the "throttle" needed to sustain the rpm. You will NOT get a direct 10% gain in fuel economy, as it does take some more fuel to sustain that torque load. But you might gain 5% more economy?
Engines are most efficient at peak torque. I'm not sure where peak torque is on a GL1800, but it seems to be around 3000 rpm or so, by my general observations. The goal would be to get the most vehicle speed out of the engine, realative to the rpm and BSFC. If I can get the GL1800 to turn 3000 rpm at 77 mph, rather than 70 mph, I gain fuel efficiency, as long as the wind resistance load does not overcome the BSFC relationship.
Food for thought. The next time I'm going to change tires, I'm going to try a taller tire. The rpm drop ratio is about what I'd be looking for. I didn't buy the GL1800 as a drag bike; it's a LD touring and commuter ride for me. If I gain 10% economy at 75mph, but only loose .3 seconds in a 0-60mph run, I'll take the fuel economy edge any day, especially with gas nearing $3.50 a gallon!
Four ways to achive that:
1) another gear in the tranny. That's up to Honda; cost prohibitive and design intensive to the nth degree for us mere mortals.
2) taller 5th gear in the tranny. See above answer.
3) taller rear drive ratio. A bit more "doable" from the design and machining perspective. It's done in the aftermarket all the time for performance cars and 4x4 trucks. Perhaps enough positive pressure for the 'Wing crowd would persuade them for a design quest. For those who don't think this all the way through, it would be quite intensive as there is a pinion AND ring to address. The upside is of course, better economy. The downside is a bit slower acceleration relative to any given gear selected in the tranny.
4) taller tire. Been done several times before. Drop a few rpm, and gain some ground clearance at the same time. Some like this approach; some don't. Another upside to this approach is that it's easy and inexpensive (realtive to the other options) to do, and it's easy to reverse if you don't like it.
As for the "amount" of rpm drop desired, that's a debate within a debate. My observation, from both GL1500's and my current GL1800, is that 350 rpm or so would be good. I say this because there seems to be a universal aspect of fuel consumption with the GL series of engines. It is true of all internal cumbustion engines as well, generally. Spin it higher, consume more fuel, right? I don't know why, but the GL's seem to hold fuel consumption fairly steady until around 3000 rpm, then they start on some parabolic P+I BSFC consumption gas guzzle fest that just goes up at an insane rate past 3000 rppm. If you go from 3000 rpm to 3300 rpm (10% gain), you might use 20% more fuel. And it gest worse from there.
Now part of this is because 3000 rpm is APPROXIMATELY 70mph, depending on the speedo accuracy. Most people don't realize that wind resistance is not linear; as your speed doubles, the wind resistance is SQUARED! In other words, to go from 35 mph to 70mph makes the wind resistance FOUR TIMES the amount at 35 mph! This is why the harder you push past a higher speed, the fuel consumption rate goes way up.
The upside is the the GL1500 and GL 1800 engines have enough torque that it's quite possible that they could offset the energy requirement to break past each successive mph increment. At some point, the engines would get into a "zero sum gain"; if you dropped the rpm by 25%, the engine may not have enough torque to overcome the load based upon speed and wind. That's why I think an approximate 10%, no more than 15%, drop would be enough to gain fuel economy, but not enough as to overburden the engine.
Let me put some rough numbers to it. Assume 70mph is 3000 rpm in a traditional GL1800. If you went up 10% in speed, you'd be around 77mph and 3300 rpm. If you could drop the rpm by 10%, you'd be back at 3000 rpm; at that point, I feel the GL1800 has enough torque to overcome the load, and the drop in rpm would be more than the "throttle" needed to sustain the rpm. You will NOT get a direct 10% gain in fuel economy, as it does take some more fuel to sustain that torque load. But you might gain 5% more economy?
Engines are most efficient at peak torque. I'm not sure where peak torque is on a GL1800, but it seems to be around 3000 rpm or so, by my general observations. The goal would be to get the most vehicle speed out of the engine, realative to the rpm and BSFC. If I can get the GL1800 to turn 3000 rpm at 77 mph, rather than 70 mph, I gain fuel efficiency, as long as the wind resistance load does not overcome the BSFC relationship.
Food for thought. The next time I'm going to change tires, I'm going to try a taller tire. The rpm drop ratio is about what I'd be looking for. I didn't buy the GL1800 as a drag bike; it's a LD touring and commuter ride for me. If I gain 10% economy at 75mph, but only loose .3 seconds in a 0-60mph run, I'll take the fuel economy edge any day, especially with gas nearing $3.50 a gallon!
If I were to tackle a job like this I would get a new or used 5'th gear set. Then have a gear expert (I know one) measure the tooth geometry then have a engineer/designer/drafter (I am one) draw up a new gear drawing with a different number of teeth. Now I would have to find a gear job-shop to manufacture and grind it (I know several) and then finally heat treat it.
I have done something similar to this for a ship motion simulator we use for antenna testing. We have also reverse engineered gears several times in my professional duties. It's very expensive.
Now comes the fun part in removing the engine and split the case to install the new gear set. Of course your warranty just poured away with the engine oil.
I suppose it's also possible to do the same procedure with the gears in the final drive. This would affect all gear ratios. Some might consider this a positive but others not......
The downside is the reverse engineering costs and manufacture of onsey/twosey gears wold be very high.
I have done something similar to this for a ship motion simulator we use for antenna testing. We have also reverse engineered gears several times in my professional duties. It's very expensive.
Now comes the fun part in removing the engine and split the case to install the new gear set. Of course your warranty just poured away with the engine oil.
I suppose it's also possible to do the same procedure with the gears in the final drive. This would affect all gear ratios. Some might consider this a positive but others not......
The downside is the reverse engineering costs and manufacture of onsey/twosey gears wold be very high.
G
It would be nice if such a mod was as simple to perform as on the Suzuki C50. With that bike,
you swap in a C90 rearend - and shorten the driveshaft slightly to keep the C90s driveshaft from binding.
It's currently the most popular mod by far (judging by posts) on the Volusia Riders board I frequent:
Different rear drive ratio/highway cruising
you swap in a C90 rearend - and shorten the driveshaft slightly to keep the C90s driveshaft from binding.
It's currently the most popular mod by far (judging by posts) on the Volusia Riders board I frequent:
Different rear drive ratio/highway cruising
TP -
I would say that the average rider would be willing to pay $700 - $1000 for a final drive reduction. BUT I would ask that if you do this you do it as an add on Over Drive Unit, like used to be on cars and lite trucks. A unit placed between the drive shat and rear end where you flick a switch in 4th or 5th gear and get a true over drive. I would gladly pay $1K - 1.2K for that! A true 6th gear! And I don't think it would take much change, heck they used to just add them on to the differential in the old days.
I would say that the average rider would be willing to pay $700 - $1000 for a final drive reduction. BUT I would ask that if you do this you do it as an add on Over Drive Unit, like used to be on cars and lite trucks. A unit placed between the drive shat and rear end where you flick a switch in 4th or 5th gear and get a true over drive. I would gladly pay $1K - 1.2K for that! A true 6th gear! And I don't think it would take much change, heck they used to just add them on to the differential in the old days.
An indicated 70MPH has the tach at right around 3k with a 70-series E3 on the rear. My cycle used to show ~77MPH at the same RPM before the tire change.dnewton3 said:
I think some basic research and development are going to be needed. At least a prototype should be developed and test run to show evidence to either veriry or refute the assumptions that there would be better fuel economy and less engine stress/wear. If observations based upon use of 70 aspect ratio rear tires are credible evidence (and such observations should be, but may not be, simlar to results from a final drive ratio change); then the developer of the new final drive component system is likely in for a disappointment. If it is the case tha the final drive ratio increase is similar to the drive ratio increase of the 70 rear, then true fuel economy will NOT be significantly improved and drive power efficiency will be decreased (maximum high end speed will decrease because horse power at the rear wheel will be less to overcome wind resistance). That second unfortunate possibility would likely translate into MORE engine wear since a less efficient drive power would have the engine operating outside of its power band more ofter (more engine lugging, more deposit build-up, and perhpas more wear on stress parts). But; I think the R.&D. should be done if so many folks are williing to invest in the effort. I hope it delivers your every desire. Even if it is less efficient of fuel and power, some or many riders may embrace it because a positive subjective seat of the pants evaluation.
prs
prs
G.E.M. made R&P Gear Sets for the early Wings to correct some of their limitations in various conditions and they did what was needed then with the high Red Line engines and unuseable for some gearing. That was a major issue back then but Honda evolved the overall package to better fit it's actual use and the need for the mod's dropped to -0-
In the past several versions of the Wing, 1200-1800, some folks just can't be satisified with the quantum leaps in available power, increased torque band and all around performance.
For those few I would think that G.E.M., if they are still around, or others would have stepped up already. Perhaps those in the know about actual marketing and cost of development realize that the 1800 is just fine as is and developing a very limited High $ product would be a waste of time as well as net loss. :?
Don't forget to factor in the $Cost$ of the change and questionable improvement in MPG vs actual Fuel Cost over the live of the bike. :idea:
If memory serves the G.E.M. Gear Set's ran $300 before install in 1975-79 money which was about 10% of the cost of the bikes. Who would be willing to put another 10% into the cost of todays Wings for a net loss over time for most :?:
Not me :!:
For those that realy demand higher MPG why not get a HD or Oil-Head Beemer that are proven. Or why not simply get a smaller bike with less cross-section, ie wind resistance, or Mega-Scooter?
In the past several versions of the Wing, 1200-1800, some folks just can't be satisified with the quantum leaps in available power, increased torque band and all around performance.
For those few I would think that G.E.M., if they are still around, or others would have stepped up already. Perhaps those in the know about actual marketing and cost of development realize that the 1800 is just fine as is and developing a very limited High $ product would be a waste of time as well as net loss. :?
Don't forget to factor in the $Cost$ of the change and questionable improvement in MPG vs actual Fuel Cost over the live of the bike. :idea:
If memory serves the G.E.M. Gear Set's ran $300 before install in 1975-79 money which was about 10% of the cost of the bikes. Who would be willing to put another 10% into the cost of todays Wings for a net loss over time for most :?:
Not me :!:
For those that realy demand higher MPG why not get a HD or Oil-Head Beemer that are proven. Or why not simply get a smaller bike with less cross-section, ie wind resistance, or Mega-Scooter?
As one who has put over 230K miles on two GL1800s. I tend to agree more with Jerry and others question of what exactly you would gain from this conversion. Honda doesn't always do things right, but there are some things I think they are spot on, final gear ratios and mufflers. Trying to improve upon either IMO is a waste of time. More MPG, get a scooter.
Ed Jenkins, Pawnee, Il
07, 43,000 miles
Ed Jenkins, Pawnee, Il
07, 43,000 miles
Of course you won't SHOW lower RPMs. When you go to 70 series, your speedometer reads closer to your actual speed than before. When it says 60 mph, you are actually doing about 60, instead of 56...Gwingbuzz said:
So your RPMs for your actual speed are lower.
Would I spend good money for taller gears? No, but I'll be switching to 70s to get the same benefit, once I need tires, as well as having more cornering clearance.
I don't really care if I get better fuel economy or not, but I'd like the RPMs to be reduced at high speed.
I do expect to see an improvement in true fuel economy though. That's not part of the decision though.
Gl1800 final drive gear ratio change
Im impressed. You guys are all over this and I just posted it. There seems to be a consensus that the r's on the GL1800 dont really need to be as high as they are. Yes it may effect 1/4 mile times but im 57 and when i want hair raising acceleration i climb into my Toyota matrix. I agree with many that breaking into the tranny is just not a viable option. I dont want to go too far down in rpms so 500 seems like a nice round number. If the 500 works who knows maybe Ill have another set made for a 750 drop. Like others I have found the bikes best mpg to be under 3k. Since I can basically leave it in 5th gear down to 25 mph or lower on occasion I believe this bike could easily have a taller gear set. Ive had other road cruisers from harley and honda etc. and this GL pulls like a freight train from real low r's so i feel to ride at high r's on the interstate is just not required. I can tell you this much. The gears will be of equal or better quality (they wont be chinese), they will be made in the u.s.a., any new bearings (if needed) and/or any other parts will be genuine Honda. From the different Honda shops i have spoken with I have found they have never had to fix a GL1800 Final drive except for one that was flawed from manufacture and had cracked. I have no intention of altering that kind of reliability. My bike will get the first set and my rides can usually cover 2 to 4 states on any given day and I dont like to trailer my bike around. I have a complete final drive and swing arm for study and have already met with a gear company. I will keep you posted as to how things are going. It may be a month or so before i have anything of interest to post. There is of course up front design and prototype costs but since there appears to be quite a bit of interest in this idea it may be worth continuing. Gas isnt going to get any cheaper. Ride safe. tp
Im impressed. You guys are all over this and I just posted it. There seems to be a consensus that the r's on the GL1800 dont really need to be as high as they are. Yes it may effect 1/4 mile times but im 57 and when i want hair raising acceleration i climb into my Toyota matrix. I agree with many that breaking into the tranny is just not a viable option. I dont want to go too far down in rpms so 500 seems like a nice round number. If the 500 works who knows maybe Ill have another set made for a 750 drop. Like others I have found the bikes best mpg to be under 3k. Since I can basically leave it in 5th gear down to 25 mph or lower on occasion I believe this bike could easily have a taller gear set. Ive had other road cruisers from harley and honda etc. and this GL pulls like a freight train from real low r's so i feel to ride at high r's on the interstate is just not required. I can tell you this much. The gears will be of equal or better quality (they wont be chinese), they will be made in the u.s.a., any new bearings (if needed) and/or any other parts will be genuine Honda. From the different Honda shops i have spoken with I have found they have never had to fix a GL1800 Final drive except for one that was flawed from manufacture and had cracked. I have no intention of altering that kind of reliability. My bike will get the first set and my rides can usually cover 2 to 4 states on any given day and I dont like to trailer my bike around. I have a complete final drive and swing arm for study and have already met with a gear company. I will keep you posted as to how things are going. It may be a month or so before i have anything of interest to post. There is of course up front design and prototype costs but since there appears to be quite a bit of interest in this idea it may be worth continuing. Gas isnt going to get any cheaper. Ride safe. tp
tp If you are realy serious about the project while your working on it note that there have been quite a few reports on the large bearing going out that takes the major brunt of the load with the single sided swingarm. The failures are similar to the ones that are happening on the LT's and for the same reason.
Point is that IF I were going to invest any $$$ in changing the R&P in one of my final drives I would also want to install a higher load capacity bearing with it to hopefully prevent a problem that could take out the $$$ and time that were put into it.
Do a search and you will find that the reported failures are at various mileages and not related directly to loads like trailers or high mile bikes.
Point is that IF I were going to invest any $$$ in changing the R&P in one of my final drives I would also want to install a higher load capacity bearing with it to hopefully prevent a problem that could take out the $$$ and time that were put into it.
Do a search and you will find that the reported failures are at various mileages and not related directly to loads like trailers or high mile bikes.
I think the whole idea is kind of silly. The GL1800 will cruise at 100 all day (not that I would ever go that fast, officer) - what more could I want? Th cost of this kind of mod would sure buy a lot of gas.
Look at the amount of money people put into chrome and other non-functional add-ons. At least this would be functional...
tp, you're too funny, Toyota Matrix indeed.... LOL
I know exactly what you mean I have one as a runabout myself. But otherwise brilliant I hasten to add.
John
I know exactly what you mean I have one as a runabout myself. But otherwise brilliant I hasten to add.
John
I drive 25000 miles a year
I calculate about $350 savings per year at $4 a gallon. at that rate it wouldn't take long to pay for a set of reasonably priced gears. Since I plan to wear our at least 2 more bikes before I quit riding. so I see 3 sets purchased for me. I'm not looking to make a major savings but I think the less wear and tear on my bike and wallet would be good. I definately feel I would come out ahead as long as the price was reasonable.
Mike
CA1V
Victorville, CA
I calculate about $350 savings per year at $4 a gallon. at that rate it wouldn't take long to pay for a set of reasonably priced gears. Since I plan to wear our at least 2 more bikes before I quit riding. so I see 3 sets purchased for me. I'm not looking to make a major savings but I think the less wear and tear on my bike and wallet would be good. I definately feel I would come out ahead as long as the price was reasonable.
Mike
CA1V
Victorville, CA
Just another redneck here but I agree that the final drive would be the one to change if one did change the gearing.
I also think 500 rpm would be a little much in lowering the rpm at say 60mph. I like maybe 300 rpm.
Think the whole gear trans set could stand this because 1st is a little low geared.
Just thinking which doesn't happen as often anymore.
Barney
I also think 500 rpm would be a little much in lowering the rpm at say 60mph. I like maybe 300 rpm.
Think the whole gear trans set could stand this because 1st is a little low geared.
Just thinking which doesn't happen as often anymore.
Barney
Caution:
I recall years ago that a group of people agitated for a taller 5th gear for the Valkyrie. Someone came up with a taller gear that required replacing the 5th gear in the tranny. IOW not cheap.
It did not work.
It reduced the RPMs as desired but had no positive affect on MPG.
Moral of the story was that there are lots of other considerations in the equation. Where you are in the torque curve at highway speed for example. Also, in our bikes, I would not be surprised to discover that the engine management computer would need tweaking to make the engine efficient at the lower RPM point.
In fact, convincing someone to crack the engine control unit and learn how to reprogram it would probably be a much more productive use of time.
I recall years ago that a group of people agitated for a taller 5th gear for the Valkyrie. Someone came up with a taller gear that required replacing the 5th gear in the tranny. IOW not cheap.
It did not work.
It reduced the RPMs as desired but had no positive affect on MPG.
Moral of the story was that there are lots of other considerations in the equation. Where you are in the torque curve at highway speed for example. Also, in our bikes, I would not be surprised to discover that the engine management computer would need tweaking to make the engine efficient at the lower RPM point.
In fact, convincing someone to crack the engine control unit and learn how to reprogram it would probably be a much more productive use of time.
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