Rear End Gear Ratio

[chrisraven]

Hi there I have a 2009 GL1800 and found that if I stay around 100 klms an hour the mileage is ok. I get about 315 klms to a tank of gas. This summer I went up to Kelowna from Abbotsford and was on the Coquilhalla highway. I was cruising around 130 to 140 clicks and found I only got 200 klms before needing gas. Which meant I had to stop at Merrit to gas up or I would not have reached Kelowna.

I was wondering if anyone has experimented with the rear dif to change the gear ratios so we get more mileage out of less gas. There are cars out there that have smaller engines then we have so we certainly do not need the horsepower to move us along. I thought about a 20 to 30 percent overdrive type gearing would give us much better economy while not impeading the performance.

Would like input across the board. Thanks in advance.

Chris

[WingAdmin]

Hi there I have a 2009 GL1800 and found that if I stay around 100 klms an hour the mileage is ok. I get about 315 klms to a tank of gas. This summer I went up to Kelowna from Abbotsford and was on the Coquilhalla highway. I was cruising around 130 to 140 clicks and found I only got 200 klms before needing gas. Which meant I had to stop at Merrit to gas up or I would not have reached Kelowna.

I was wondering if anyone has experimented with the rear dif to change the gear ratios so we get more mileage out of less gas. There are cars out there that have smaller engines then we have so we certainly do not need the horsepower to move us along. I thought about a 20 to 30 percent overdrive type gearing would give us much better economy while not impeading the performance.

Would like input across the board. Thanks in advance.

Chris

It's not down to gear ratios, it's down to aerodynamics. A small car can get away with a smaller engine and get better mileage because it is aerodynamically efficient, and does not take much power to push through the air.

Motorcycles, especially BIG motorcycles, are NOT aerodynamically efficient. They take more power to push down the road than you need for a small car. And the amount of power required goes up exponentially as speed increases - which is why your mileage drops so precipitously as you ride faster and faster.

Your range is pretty close to correct for a GL1800 - a bit on the low side, but definitely in the ballpark.

[chrisraven]

While I know that aerodynamics does enter into the equation for gas mileage. The 1800 seems to have quite a bit of spare power that I think could be more efficiently used in producing a better mileage. I am looking at taking quite a long trip across Canada, starting from Alaska and ending in St Johns Newfoundland. The stretches between gas stations is quite a distance on some of the northern roads across the Canadian provinces. I realize that to travel across Canada on the major routes would not be that big a problem, however my planned route is not that simple. I am trying to find a solution to the mileage situation that does not tie up valuable cargo space with a gasoline can of undetermined size and weight. At any rate I am looking forward to my trip and the experiences of the north.

Thanks for your reply I do appreciate your input.

Chris

[mweddy@gmail.com]

Goldwing cruise, 70 MPH, 3000 RPM. Chevy Tahoe cruise, 70 MPH, 2000 RPM. Chevy K1500 Pickup cruise, 70 MPH, 2000 RPM. The Tahoe is a heavy ****, 6800 GVWR, with a 5.3 liter V8, and not real aerodynamic. (still better than a motorcycle). I agree, there is plenty of power to gear the bikes a little taller. I was able to drop the RPM's a little by switching to a 180/70/16 rear tire, which is a little taller than the original 180/60/16. It also cleaned up the speedometer inaccuracy. I have not found gear sets for the Goldwing to change the gear ratio, but if you find one, please post it. By the way, I used my GPS to verify speed so that all of my measurements were the same.

[chrisraven]

Hi there: thanks for the input. I have a 2009 Avalanche with a 5.3 liter engine (327CI) and I can easily cruise along at 110 to 120 kms while only at 2100 RPM. I get great gas mileage, in the range of 800 kms per tankful.

I was thinking of finding an old rear end from a scrap 1800 and remanufacturing the gears into something that would actually give me the ratios that I am after. However finding a rear end has not been to easy since most people want money for their old parts. All I need is an old unit that is intact, the casing can be broken and the gears can be well worn, it does not matter, what is important is knowing the dimensions and physical implications of what I am trying to do.

If anyone out there knows someone with a rearend they want to give away or lend me for some time please let me know or send me a message.

Thanks in advance.

Chris

[mweddy@gmail.com]

There are lots of final drives available on ebay. (leftovers from trike conversions) Here is one for $75 with free shipping:
http://www.ebay.com/itm/172100671812?it ... m=&vxp=mtr