The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: youngjohn on July 31, 2014, 11:52:27 AM

Title: Speedo gearing
Post by: youngjohn on July 31, 2014, 11:52:27 AM

Does anyone know what the speedo gearing is on an '83 R65?
Thanks

Title: Re: Speedo gearing
Post by: Barry on July 31, 2014, 01:12:03 PM

The speedo ratio is the number of cable revolutions for 1 mile travelled and therefore the correct ratio depends on which final drive you have.

Check your final drive ratio against this list.

Title: Re: Speedo gearing
Post by: nhmaf on July 31, 2014, 01:24:44 PM

The "speedo ratio" value in the right column of Barry's chart will often have a "W" in front of it, and will be in small font at the bottom of the speedometer dial/face.

Look for the final drive ratio stamped into the grey metal top surface of your final drive, near where it bolts onto the swingarm housing in which the driveshaft passes.   e.g. "32 / 9" .... this would be used with a "W1318" speedometer.

Some R65s came with 31/9 final drives and some came with 32/9 final drives, and some had their final drives swapped out by previous owners over the years.  And, sometimes speedometers were swapped out rather than being repaired, as the odometer function does have a tendency to fail on these, and not everyone payed close enough attention to the various ratios.

Title: Re: Speedo gearing
Post by: arvo92 on July 31, 2014, 02:16:51 PM

Wow... ratios.

Something I never thought about when I swapped my final drive for an item from R80. I need to start looking into the ratios then :)

I am truly amazed something like this has ever been created. Huh, every time I think it is purely Lego, it is not!

Title: Re: Speedo gearing
Post by: Barry on July 31, 2014, 03:43:17 PM

For completeness I should have mentioned that a metric speedo will have different ratio. Just multiply the speed ratios in the table by 0.62137

Title: Re: Speedo gearing
Post by: Tony Smith on July 31, 2014, 06:01:49 PM

Quote

For completeness I should have mentioned that a metric speedo will have different ratio. Just multiply the speed ratios in the table by 0.62137

I have a speedo fitted for the sole purpose of passing my State's roadworthy test regime and to fill what would otherwise be a large hole in the instrument binnacle. A GPS or my phone will give me accurate speed monitoring (On my R100 and on the XT I have 40, 60 80 & 100kph in top gear discretely marked on the tacho as well, I will do the same on the R65 when it is put in the road (real soon now)).

Title: Re: Speedo gearing
Post by: youngjohn on August 01, 2014, 04:13:37 AM

Thanks for info - problem sorted.