1971 250C 70mph at 4,000rpm? - Page 2 - PeachParts Mercedes-Benz Forum

gear-head · #16 07-24-2013, 01:30 AM

Quote:

Originally Posted by ssk831

Yep, normal. You can install a lower ratio diff it it really bothers you. Will lose some around town power but could gain some highway mpg's.

'scuse me, you mean higher ratio. Numbers are lower. If you want your engine to turn lower r's at higher speeds, you want a higher gear ratio, i.e. numerically lower but actually higher ratio.
An example: 4:10 gear ratio is lower than 2:78's. If you have 4:10's, running down the highway at about 60mph your engine will be turning maybe 3500, a lot more r's than if you had a higher gear such as the afore metioned 2:78's which could probably have your engine turning in the neighborhood of 2200. The rpm's versus road speeds quoted here are approximations for demonstration purposes only, the actually numbers may vary a couple of hundred r's or so, for the road speeds quoted based upon the actual tire diameter used. Think about it. Do the math.

just a pet peeve of mine, been reading it all over this site for a very long time where nearly everyone calls out "need lower gears for lower engine rpm at freeway speeds" when just the exact opposite is true. I couldn't take it any longer, had to finally say sumpin!

caviterruptor · #17 07-25-2013, 09:59 AM

Quote:

Originally Posted by gear-head

'scuse me, you mean higher ratio. Numbers are lower. If you want your engine to turn lower r's at higher speeds, you want a higher gear ratio, i.e. numerically lower but actually higher ratio.
An example: 4:10 gear ratio is lower than 2:78's. If you have 4:10's, running down the highway at about 60mph your engine will be turning maybe 3500, a lot more r's than if you had a higher gear such as the afore metioned 2:78's which could probably have your engine turning in the neighborhood of 2200. The rpm's versus road speeds quoted here are approximations for demonstration purposes only, the actually numbers may vary a couple of hundred r's or so, for the road speeds quoted based upon the actual tire diameter used. Think about it. Do the math.

just a pet peeve of mine, been reading it all over this site for a very long time where nearly everyone calls out "need lower gears for lower engine rpm at freeway speeds" when just the exact opposite is true. I couldn't take it any longer, had to finally say sumpin!

Thanks for the clarification. Regarding parts for sale on this forum, still not getting it. Clearly I'm unfamiliar with any classifieds & the only reference to parts I see on this forum is Pelican Parts "New Parts Catalog". Can you be more specific as to how I can access the "parts for sale area" on this forum?