Dan

[greenSEtrike]

I have 94 1500 SE with a Motor Trike Coupe kit, it has a Ford Rear with 3.08 gears and my highway fuel mileage is worse than terrible. Will a 2.73 gear help my milage and high rpm @ highway speeds? I am ready to change out the gears if the difference warrants the cost. Any help will be greatly appreciated.

 

[Lucky]

My kit is a coupe on a 90SE. My mileage is in the low thirties. At the time I had mine done I did not know that were other choices. I ask about it when I found out and was told that with the lower gear I would have to be constantly having to shift gears. I am very intrested in what you find out.RIDE SAFE

 

[greenSEtrike]

I have gotten conflicting opinions from guys in car shops, some say the 2.73 gears will drop my rpm's considerably and others say it won't make that much difference. I don't know who to believe. I sent an e-mail to Motor Trike Christmas eve asking their opinion since they engineered our rigs and as yet have not gotten a reply. At 70 the the interstate I get about 23.7 @ 80 I get 20, and that is kicking up 3800 to3900 RPM. That just isn't right. Below 60 I get between 32 and 35. Makes no sence to me.

 

[Lucky]

MOTOR TRIKE is a member here maybe they will offer an opinion. I think you may have other probs. mine duz not drop that much.27-28 is about as it gets.

 

[rhino 2]

I have gotten conflicting opinions from guys in car shops, some say the 2.73 gears will drop my rpm's considerably and others say it won't make that much difference. I don't know who to believe. I sent an e-mail to Motor Trike Christmas eve asking their opinion since they engineered our rigs and as yet have not gotten a reply. At 70 the the interstate I get about 23.7 @ 80 I get 20, and that is kicking up 3800 to3900 RPM. That just isn't right. Below 60 I get between 32 and 35. Makes no sence to me.

I would think with 273's you would have to slip the clutch to get off at an stop.
Besides at70/80 mph your fighting drag/wind more than gears.
308's are quite high to begin with.

 

[harvey]

On a GL1500 it seem the good to bad mpg is at 3500 rpm

 

[Tip Schwartzbeck]

I added a set of home built trike wings - made a nice difference.
Might be worth checking into,
Good luck and safe triking!,
Tip

 

[aussietriker]

the difference between the 2.73 & the 3.08,s is the rev,s the motor will be pulling at 60 mph.e.g 2.73 will be say 2700 opposed to the 3.08 @ say 3200 rpm. another way of looking at the difference is say the 2.73 at full throttle you are doing say 120mph against the 3.08 @ 97 mph. your mileage problem sounds like your running to rich . as the motor goes faster it requires more fuel to acheive speed so the amount of fuel being used gets higher.i personally would be checking the fuel circut first to make sure thats all ok before changing diff ratio,s. have you checked your air filter to see if its dirty or not. airflow affects fuel economy big time.

 

[greenSEtrike]

Thanks for the reply Aussie. I had to get the carbs rebuilt when I got it a few months ago, since it sat so much they were gummed up or somthing, it wouldn't idle. They were completely rebuilt with stock jets etc. I don't know how they set, rich or lean, but it seems to run quite well, its just bad milage @ highway speeds. I talked to a mechanic today and he said the 2.73 gears would drop my rpm's about 500rpm's versus the 3.08's. At 60 i'm turning 3000rpm's with the 3.08 gears, I like the idea of 25 or 26hundred @ 60. That would have to improve my milage. I have a price of $400, parts and labor, to swap out the rear end gears.

 

[Darrell]

If you don't mind a little more input, I will tell you that my basis of knowledge is automotive, (I am a retired mechanic) not motorcycles. That said, your problem, in my opinion, is probably not the gearing. If you look at the two ratios, you will see that there is only about 10% difference in them. That means that if air resistance were not a factor, on level ground you might logically expect 10% better fuel economy. Unfortunately, there are hills, and there is wind resistance. To get an idea of how large a factor the wind is, the next time you are going down the road at 35, hold your arm out in the wind with the palm downward, then try it with the palm straight forward. Now, repeat the test at 75 mph. Now think about all the frontal area your trike has.
I think it goes without saying that it is harder to push the trike up a hill than it is to push it down one so I won't go into that.
With the 2.73's the engine is going to work harder to maintain your speed on hills and at interstate speeds. The harder an engine works, the more fuel it will use. Fuel usage is far more dependent on load than it is on RPM. While there is no way you can truly know how it would work in your particular application, with your personal driving patterns, I think that there is a distinct possibility that you might even get poorer fuel economy as a result of this change.
No matter what, my opinion is free, so you are getting your money's worth on my advice.
Ride well and safely, Darrell

 

[greenSEtrike]

Thanks for input Darrell. I appreciate all the input I can get. I realize there is a lot of drag with the fenders and all, I just can't figure out why my milage is so bad. I have 3 friends with identicle bikes and they all claim 30+mpg. They also all say they aren't turning near the rpms at those speeds that I am. By the way, I live in SW Florida so we don't have any hills, just a few bumps in the road. I have gotten so many different opinions, i don;t know what the H___ to do. I guess I'll just save my money so I can but a little more gas and just deal with it. Thanks.

 

[jim peacock]

I have a 96 1500 se with a 06 lehman kit with floor boards.
Normail riding around below 65 34 to 36 mpg.
Interstate pulling a escapade se trailer running 65 to 70 mph.,30 to 32 mpg.
:wave4::wave4::wave4::wave4:

 

[greenSEtrike]

Jim, do you have a solid rear end or independent? do you know what gear ratio you have in the rear axel?