Tachodisc for 560SL

Dear all, 

I'm doing tachodisc conversation for my 560SL, 1987.
What is right tachodics number for 560SL ?
We have Canadian 560SL with KM tachodisc number 1157.
Mr Trunz confirmed and send me disc 1157, but it is different than canadian one.
Mr Trunz has ebay offer for 560SL disc with number 8901, which is similar to canadian. 
I'm little bit confused and asking for your opinion. 

BR 
Stan 

 

Hi Stan,

what is the issue with that disc? 107 542 89 01 is not what I know from 560 SL . I know 107 542 90 01, 98 89 01 , 11 57, 12 57 .

Hi , 

I'm little bit confused, because Mr. Trunz send me 1157 disc, but you can see on the picture 
red marks for the shifts are not printed correct, also there are 2 white marks below 20 km/h, 
I don't know where have to start speedo pointer. 
I found ebay offer (also from Gunter Trunz ) for disc 8901 (I have only picture of the disc, meanwhile Mr. Trunz erase it from ebay) 
and this 8901 has marks exactly as our original Canadian 1157.

BR 
Stan 


  

Hi Stan,

it is an illusion to believe that you just swap speedometer discs without measuring and adjusting speedometer electronically afterwards. Even if the speedometer you want to convert has the same scaling as the one you want to create you still have to adjust. Remember that European speedometers must show advanced speed while US will show values Plus/Minus real speed. So whenever I converted a speedometer I have adjusted electronics to reflect that. And you cannot know what happened to old speedometer, Is it really the one that is written there or is it a different one. You have to check and adjust according to k-Values. There are 2 resistors that let you adjust scaling. Sometimes people have even played with needle and springs so much that it will be non-linear.

The only easy thing on speedometer are those 5 gears. If they run smoothly they will be exact. But even there it is a good idea to check them at higher speeds. I have seen cases where they would work perfectly at 60 km/h and slow their operation at 200 km/h. And you should change counting form Miles to Km by a factor of 1.609 . Last I add stickers with new k-value and with the conversion of miles to km documented.

Remember this is a measurement instrument. It needs precision and calibration. Otherwise you risk high speed tickets or angry truck drivers behind you.

Hi Stan,

and sorry 107 542 89 01 is the correct disc for early 560 SL speedometers. I had a twist from 89 to 98 in my memory. However: Calibrating your speedometer after swapping disc is a Must in my eyes. Swapping gears is easy and exact but needle is more sensitive and was already during manufacturing something that VDO had to do on each speedometer separately.

But now I understand why Günter has added these 2 marks. He has compared original 12 57 disc and original 11 57 disc and seen that 11 57 spread is larger than 12 58 spread. These 2 addtl marks below 20 km/h and above 240 km/h are there to compensate that.

Whether you use 107 542 11 57 or 107 542 89 01 disc is a matter of taste. Or you can decide to replace 90 01 with 89 01 and 12 57 with 11 57 . That is a matter of taste. If I was Günter I would only have produced one of the 2 discs, most probably the later 11 57 .

Moin Moin
Hello Stan
Where the problem ,new day new lack ,the new disc is available in Neuss
DHL RR 7287 9682 7DE
best regards
Günter Trunz

Dear Mr Trunz, 

thanks for fast action 
It’s pleasure to work with you.
Also, thank you Volker for detail explanation 
about convertion of speedometer.
I changed all 5 gears of speedometer already
(ordered them from cabriodoc) and waiting new tachodisc to install entire cluster.
I’m included in common order for such gears in forum and will get them when are available.

I believe such discution is very helpfull
for owners of 560SL, because increased import from USA.


Best regards
from Bulgaria
Stan