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Hey guys quick question. 5th gear is overdrive so is the final ratio 4.5 with overdrive or is the 4.5 reduced to a smaller number with overdrive engaged?
 

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Hey guys quick question. 5th gear is overdrive so is the final ratio 4.5 with overdrive or is the 4.5 reduced to a smaller number with overdrive engaged?
If I did the calculation correctly (been a long time) the 0.707 5th gear times the the final drive ratio of 4.529 should give you a 3.202 gear in 5th aka overdrive.

smart car Gear ratios:
1st (3.308)
2nd (1.913)
3rd (1.258)
4th (0.943)
5th (0.707)


Reverse:
(3.231)

Final drive:
(4.529)
 

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Thanks opec, I can get a better idea why the guy was wanting a higher ratio.
I know that since I put the turbo on my 1st gear is about useless.
However I don't see myself machining up a whole new set of gears either!
 

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Thanks opec, I can get a better idea why the guy was wanting a higher ratio.
I know that since I put the turbo on my 1st gear is about useless.
However I don't see myself machining up a whole new set of gears either!
It's just not worth it for a car that's most likely not going to last more than 5 years IMO.
 

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It's just not worth it for a car that's most likely not going to last more than 5 years IMO.
I don't know how you drive or maintain your car but I hope mine will last a lot longer than 5 years, my old 280zx lasted over 22 years and I was told it wouldn't last 5.:pWhen I sold it it had a rusted through floorboard but the guy who bought it repaired it, repainted the car,and told me he got it insured it for over $15,000 ,about what it sold for new.:DI intend for my smart to last at least as long but, Who knows?:rolleyes:
 

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I don't know how you drive or maintain your car but I hope mine will last a lot longer than 5 years, my old 280zx lasted over 22 years and I was told it wouldn't last 5.:pWhen I sold it it had a rusted through floorboard but the guy who bought it repaired it, repainted the car,and told me he got it insured it for over $15,000 ,about what it sold for new.:DI intend for my smart to last at least as long but, Who knows?:rolleyes:
I drive the crap out of all my cars and I don't see my Brabus lasting more than 5 years and it'll be on it's way to the bone yard.

I have more faith in my 25 year old Fiero GT with a 3400 X-engine than I'll ever have in my smart, plus the fact that we get scalped whenever we need/want parts or accesories for these turds is the main reason I say after 5 years most will be off to the bone yard!
 

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Barney: Well... it's probably geared that low because of the automatic clutch. could you imagine how many clutch plates people would fry if the clutch had to be released even more slowly if you just released the gas pedal to creep forward in traffic?
 

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Useless?

Thanks opec, I can get a better idea why the guy was wanting a higher ratio.
I know that since I put the turbo on my 1st gear is about useless.
However I don't see myself machining up a whole new set of gears either!
So why Barney, does the turbo make your 1st gear about useless. I thought it already was about useless, without a turbo?
Just needing more info.
Rich
 

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Discussion Starter · #31 ·
Use taller tires, it would effectively raise the gear ratio w/o taking anything apart but will affect the speedometer.
I put taller tires on the car and either the ABS braking system or the electronic stabilization program shut the car down. After about a 1/4 mile the car would only do about 5 mph and I KNOW IT WAS NOT THE TIRES THEMSELVES DOING IT. It was some kind of electrically (computer) control issue.
 

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I put taller tires on the car and either the ABS braking system or the electronic stabilization program shut the car down. After about a 1/4 mile the car would only do about 5 mph and I KNOW IT WAS NOT THE TIRES THEMSELVES DOING IT. It was some kind of electrically (computer) control issue.
You probably need the same diameter all around to keep the esp from messing up or maybe pull fuse 11 to disable the esp .
 

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Has anyone changed the rear gear ratio? ...
To go all the way back, there are two (sic) "rear gear ratios" (aka "final-drive ratios")for the 451. All gassers (pure, passion, pulse, BRABUS) have the same - 4.53:1. Diesels have 4.16:1, a bit taller. But then, a diesel also has a bit more torque to turn it over.
 

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I put taller tires on the car and either the ABS braking system or the electronic stabilization program shut the car down. After about a 1/4 mile the car would only do about 5 mph and I KNOW IT WAS NOT THE TIRES THEMSELVES DOING IT. It was some kind of electrically (computer) control issue.
What size tires did you have on each corner?
 

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Discussion Starter · #37 ·
The car only has 71 hp but I can go up hill at 2500rpm all day long. I have to shift out of 1st gear after one car length so what good is it. I can drive on a flat road at 1200 to 1500 rpm so why sit at 3500 rpm? I have nine cars so if I want power I will drive the 67 Mustang or the older Chrysler with a REAL HEMI in it. It costs me $45 to drive the hemi to work so this smart is JUST about gas mileage period. Don't care what it looks like or sounds like. Just get me 50 plus miles per gallon.
 

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Discussion Starter · #38 ·
I left the original tires on the front and put 70 series on the back. That would have dropped the revolutions per mile by I believe 100. I think the low rider style 55 series goes around about 900 turns a mile and the 70 series about 800 turns a mile if I remember correctly. All I care about is gas mileage period. I am not road racing just straight line driving 110 miles a day.
 

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Discussion Starter · #39 ·
I use regular oil in my eight older cars and change it every 2,000 miles and they last forever. I run Royal Purple in the smart and change it every 5,000 miles so I hope the car lasts another 8 years until I retire. My Toyota pickup and Miata both went 300,000 miles and only used a half quart of oil between oil changes. I sold those and they still ran. One guy bought the Miata and drove it cross county from my house. I hope the smart lasts for 8 years. Then I can drive the 64 vw bug as the daily driver and the big finned gas hogs about once a month.
 

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You've got to use similar diameter tires all 4 corners or the computer goes wonky. Jwight had that problem a while ago. All I can tell ya for sure is that I've had rears on the front (tires and wheels) for over a year, with no mileage penalty. Going to a 70 series tire all around is easily done under those parameters, providing they fit in front.
 
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