R/C107 Differential Ratios

The R/C107 models had an extremely long production run – 18 years.   There were a variety of different models and specification changes.   This included the differential ratios that can have a big impact on the performance and economy of the vehicle.

In compiling the table below, I have tried to research the various country specific variants.   It is possible I have missed a few.  Please indicate in the comments below if that is the case.

The SL and SLC of the year had the same mechanical specification (at least during the SLCs production run).   The only exception was the 450SLC 5.0 where there was no equivalent 450SL 5.0 until the facelift and the 500SL model.   
R/C107 Differential Ratios

Many of the same aspects that were covered in the W126 table are applicable here.   As with the W126, the V8 models received the larger (1.3l) case.    Also, as with the W126 models, Mercedes-Benz went on a fuel efficiency drive during 1981 which is why the V8 cars got revised ratios.   The project was called the “Energy Program” and included other changes such as the revised Bore/Stroke of the 380 engine.

Early in the first generation production, the 450 models moved from a 3.07 ratio to 3.06.   This was achieved by changing from a 46:15 gear set to a 52:17 gear set.   This was more of a minor specification change than any real impact on the car.

From the long term ownership of a 450SLC, I think the chosen ratio works well for that car.   I’m not as sure of some of the other ratios.   My view is that some of the later ratios were too tall.   They probably worked a bit better for the home market on the Autobahn than in countries with lower speed limits.

Model / YearDifferential RatioSpeed at 1,000 RPM (4th)RPM at 100km/h
First Generationwww.classicjalopy.com
280SL (107.042)
280SLC (107.022)
5 Speed Manual (to June 1976)
HK
RSA (to May 1976)
3.9231.7
3155
280SL (107.042)
280SLC (107.022)
3.6933.72967
350SL (107.043)
350SLC (107.023)
3.4635.02857
450SL (107.044)
450SLC (107.024)
To Dec 1973
3.0739.52532
450SL (107.044)
450SLC (107.024)
From Jan 1974
3.0639.62525
450SLC 5.0 (107.026)2.7244.52247
450SL (107.044)
450SLC (107.024)
USA 1980
2.6545.72188
Second Generationwww.classicjalopy.com
280SL (107.042)
280SLC (107.022)
3.5833.13021
380SL (107.045)
380SLC (107.025)
(1980-1981)
AUS, SE 1981-1985
3.2737.02703
500SL (107.046)
500SLC (107.026)
(1980-1981)
2.7244.52247
380SL (107.045)
(1981-1985)
2.4749.02041
500SL (107.046)
(1981-1985)
2.2454.11848
Third Generationwww.classicjalopy.com
300SL (107.041)3.4635.32833
560SL (107.048)
USA, AUS, J only
2.4749.42024
420SL (107.047)
500SL (107.046)
2.2454.51835

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