final drive ratio 4.521:1 alternatives??

[gearhead9]

Wondering if any gearing options are available for the smart car. I see the epa mileages are only 33/41 which is not bad around town, but pretty pathetic on the highway (for an 1808 lb car)where most of my mileage would be. Is the gearing for this car only available in the 4.529:1 final drive ratio, or can a buyer give up some of the 0-60 acceleration in favor of better mileage on the highway, with a different (optional) final drive ratio?

[burtandnancy]

You can gain a little with a tire change...

[RussBarnes]

I installed Michelin 185/60-15 radials and they are one inch larger diameter = 4.4% higher gear ration. I notice it slows the acceleration and need to put my foot harder into it, which reduces whatever I gain. And while maybe in Iowa at 55 with no AC I could tap the 50's. with my one day a week 104 miles on Interstate at 75 and probably 30% city the rest of the week I am still only at 41. I was a couple mpg higher with my Doug Thorley we couldn't take the noise.

P.S., I have four equal tires on now and maybe the larger tires on the front are sucking mpg away. But the ride is softer and the cornering is many times better.

[1959_Imperial]

I am looking for the same solution which is to get some taller gears. I run Royal Purple oil, a K &N air filter and I can get 45 to 48 miles per gallon. Most of my driving is on the freeway (62,000 miles in 2 years). I just ordered 70 series tires and just got an exhaust system so I hope to gain a few more mpg.

[IH8OPEC]

Originally Posted by 1959_Imperial

I am looking for the same solution which is to get some taller gears. I run Royal Purple oil, a K &N air filter and I can get 45 to 48 miles per gallon. Most of my driving is on the freeway (62,000 miles in 2 years). I just ordered 70 series tires and just got an exhaust system so I hope to gain a few more mpg.

[gabe1475]

Originally Posted by RussBarnes

I installed Michelin 185/60-15 radials and they are one inch larger diameter = 4.4% higher gear ration. I notice it slows the acceleration and need to put my foot harder into it, which reduces whatever I gain. And while maybe in Iowa at 55 with no AC I could tap the 50's. with my one day a week 104 miles on Interstate at 75 and probably 30% city the rest of the week I am still only at 41. I was a couple mpg higher with my Doug Thorley we couldn't take the noise.

P.S., I have four equal tires on now and maybe the larger tires on the front are sucking mpg away. But the ride is softer and the cornering is many times better.

What kind of a drop did you notice in RPM?

[jwight]

Originally Posted by gearhead9

Wondering if any gearing options are available for the smart car. I see the epa mileages are only 33/41 which is not bad around town, but pretty pathetic on the highway (for an 1808 lb car)where most of my mileage would be. Is the gearing for this car only available in the 4.529:1 final drive ratio, or can a buyer give up some of the 0-60 acceleration in favor of better mileage on the highway, with a different (optional) final drive ratio?

Just my .02: the car is what it is, an 1808 lb car with a 70 hp engine and a 5 speed transmission. So far, the highest EPA mileage rating of any gas powered non-hybrid in the US. Using hypermiling techniques some people have hit 50 mpg but that's the exception. Driven like any other car, low 40s on the highway is about right. Driven hard, mid-30s are probably about all you can expect.

Want higher mpg - hybrids are it for now.

[dennyrex]

yeah, for freeway-moslty driving, to improve mpg, maybe you want to invest in a windtunnel ;-)

[RussBarnes]

Originally Posted by gabe1475

What kind of a drop did you notice in RPM?

Love to answer, but I did the tire swap before I installed the scangauge so I don't have a clue.

[RVGRINGO]

I found the answer without even looking for it: We bought a 2007 Passion with the standard 60 HP Mercedes engine and six speed transmission. We're happy! From what we can see, the 2008-10 smarts offer no advantages & seem to have some unresolved 'concerns', according to these forums.