1690T reduction ratios ...

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Miranda
Posts: 2
Joined: Mon Apr 08, 2019 6:55 pm
Location: Cornwall

1690T reduction ratios ...

Post by Miranda » Fri Apr 12, 2019 8:39 pm

So the serial number plate on my 1690T states that the reduction ratio is 10/49.



I thought the available final drive options were 11/58 and 9/59 or are we talking different things?

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GeoffDEAL
Posts: 404
Joined: Tue Jan 27, 2009 8:25 am
Location: New Zealand

Re: 1690T reduction ratios ...

Post by GeoffDEAL » Fri Apr 12, 2019 10:45 pm

Hi Miranda the Ser plate on my 1690t has no ratio numbers for some reason but the ratio is marked on the center of the axel and is 9-59 with 18-4--38 tyres. A friend has a 4wd 1690 no turbo and is fitted with 34" back wheels with 24" front would seem to be wrong for back to front gearing. Will see what other 1690t have with reduction ratios.

Ian
Posts: 48
Joined: Wed Oct 03, 2018 12:03 pm
Location: Dumfries and Galloway

Re: 1690T reduction ratios ...

Post by Ian » Wed May 01, 2019 10:11 am

I have a fairly early 1690 here in the UK fitted with 24" fronts and 34" rears with tires 13.6x12x24 and 18.4x15x 34 fitted and this is correct by the operators manual I have no idea what the reductions are as the plate is missing

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GeoffDEAL
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Location: New Zealand

Re: 1690T reduction ratios ...

Post by GeoffDEAL » Wed May 01, 2019 10:28 am

Hi Ian the ratio should be stamped on the center of the back axel sometimes a bit hard to see with the paint.

Ian
Posts: 48
Joined: Wed Oct 03, 2018 12:03 pm
Location: Dumfries and Galloway

Re: 1690T reduction ratios ...

Post by Ian » Fri May 24, 2019 1:48 pm

And to update this I have now found the reduction stamp on the hub it is very difficult to see it's fitted with the fast reductions hence why it will clock around 20 mph on 18.4x34s

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GeoffDEAL
Posts: 404
Joined: Tue Jan 27, 2009 8:25 am
Location: New Zealand

Re: 1690T reduction ratios ...

Post by GeoffDEAL » Sat May 25, 2019 10:41 am

The 1690t with 18.4 --38 have 14.9 --24 front tyres where the 34" rears have 13.6 -24 fronts to keep the ratio correct also there can be different profile of the back and front tyres depending on what tyres are fitted.

Ian
Posts: 48
Joined: Wed Oct 03, 2018 12:03 pm
Location: Dumfries and Galloway

Re: 1690T reduction ratios ...

Post by Ian » Sat Jun 01, 2019 8:05 am

Geoff yes as per fitted to my 1690

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