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Axle ratio

Posted: Wed Oct 31, 2018 5:19 pm
by mnha440
My LA14/2 1939 model has a 5.25:1 axle fitted. I have a standard 5:1 spare, but I doubt it is worth changing for 5% difference. For modern road conditions I would like a ratio of around 4.3 or 4.5:1. I have found a gearcutter who will make me a cwp for an eye watering sum which is out of the question. I don't like re-inventing the wheel so thought that there might be some words of wisdom on the Forum! Any ideas? Mike.

Re: Axle ratio

Posted: Wed Oct 31, 2018 8:37 pm
by classiclife
Hello Mike,

Have you tried Guest Gear Services, or was that the company that made your eyes water ?? !!

If not, they are based in Chesham, Buckinghamshire via 01494.794.667

Best wishes.

Richard.

Re: Axle ratio

Posted: Wed Oct 31, 2018 9:19 pm
by qantasqf1
FWIW if you go through with this to complete the job the speedo drive gear ratio will need changing too. The higher ratio rear axle implies the gearbox output shaft rotates at reduced RPM for the same road speed so the speedo drive ratio must be increased by the same factor,
In other words the speedo will indicate a lower speed than the car is actually travelling if the original speedo gear ratio remains unaltered. Just saying...!

Re: Axle ratio

Posted: Thu Nov 01, 2018 9:05 am
by mnha440
Thank you Richard you have "guest" it!

I am not too concerned by the speedo issue as an alternative pinion gear can be made relatively cheaply. I actually run with a sat nav so have an accurate read out anyway.

An overdrive is another way to go, I wonder if any one has experience of fitting one to this chassis or Daimler equivalent?

Mike.m

Re: Axle ratio

Posted: Thu Nov 01, 2018 9:55 am
by JT7196
Good morning Mike, I have just checked my Data Base and have been unable to find your Lanchester listed, would you be kind enough to send me the following details
Date of 1st Registration
Reg No
Chassis No
Eng No
Body type
Body / Int colours
Your contact details
Please send to:-
alan.wheatley63@gmail.com

Cheers Al ( DLOC Registrar )

Re: Axle ratio

Posted: Thu Nov 01, 2018 11:29 am
by JT7196
Hi Mike, yes you are quite correct, I actually have it listed twice !! so need to get my listings updated !!

Cheers Al :D

Re: Axle ratio

Posted: Thu Nov 01, 2018 2:25 pm
by Sydsmith
Just thinking aloud here Mike but I wonder if you will gain anything by changing the ratio.

My V8 250 manual overdrive achieves a higher speed in fourth than in overdrive. I have always presumed whilst engine rev's are reduced, the torque the engine produces is insufficient to drive the higher gear.

So if it is increased speed you want, I suspect you might not get what you want after a lot of work, if it is lower revs for a given speed, it would work of course.

I am not sure but I seem to recall some clever member of the old forum fitting an overdrive to a 30's Daimler, might be worth a search on the old forum. Syd

Re: Axle ratio

Posted: Thu Nov 01, 2018 2:41 pm
by mnha440
Thanks Syd I will check out the old forum, haven't been there yet. I'm looking for lower revs at 45/50 mph Mike.

Re: Axle ratio

Posted: Thu Nov 01, 2018 10:25 pm
by Marcel Renshaw
I have a friend who is fitting a Laycock overdrive to his 1934 Daimler 15.