from low bottom to top in sequence

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Offline Bjornung

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from low bottom to top in sequence
- Jun 09, 2021 - 10:39
Warning - this is probably not useful to know for anyone... :tic:

Feeling bored and not motivated to do what I should do I  happened to think about a conversation I was involved with the other day.
It was claimed by an individual that cars with a manual gearbox was designed for optimum performance to always use ALL available gears in sequence when starting up.
Of course I disagreed with that -  and the discussion was not LR related at all.
But - today - I began to wonder if that was possible to do at all in my 86" with OD installed.

Not feeling like trying out in practice, for a good reason it turned out ,once I had done figuring out what was needed.
I am absolutely sure that this has been figured out before by someone, but here is my findings.

A total of around more than 30 separate gear stick movement would be required!  ;D

I really hope someone is not going to point out that I did a mistake, because then I have to go over all of this once more. :embarrassed:  :undecided:  :(

oh well. how to waste some time, but fun still...

Bjørnung
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Offline fifty seven

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Re: from low bottom to top in sequence
Reply #1 - Jun 09, 2021 - 10:59
Knowing precise wheel speed at peak torque is always useful,  particularly when pulling a mangel wurzel harvester  or reaper-binder across a rough field...as everyone does today. :tic:
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Offline craggle

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Re: from low bottom to top in sequence
Reply #2 - Jun 09, 2021 - 11:05
Be interesting to see that chart with the output gear ratio on it to see if any of the gears match.

i.e. does 1st high range equal 3rd low range for example?

Craig.

Online antarmike

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Re: from low bottom to top in sequence
Reply #3 - Jun 09, 2021 - 11:41
Be interesting to see that chart with the output gear ratio on it to see if any of the gears match.

i.e. does 1st high range equal 3rd low range for example?

Craig.


Online antarmike

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Re: from low bottom to top in sequence
Reply #4 - Jun 09, 2021 - 12:06
Be interesting to see that chart with the output gear ratio on it to see if any of the gears match.

i.e. does 1st high range equal 3rd low range for example?

Craig.
This for slightly later info from Fairey....


Offline Bjornung

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Re: from low bottom to top in sequence
Reply #5 - Jun 09, 2021 - 12:34
Be interesting to see that chart with the output gear ratio on it to see if any of the gears match.
i.e. does 1st high range equal 3rd low range for example?
Craig.

Well, I did put in all the ratios of diff, H/L, OD, etc (my 86" on 7.00X16 tyres) in  spreadsheet and calculated so hopefully it should be correct.  :smiley:
I did also plot speed versus gear/rpm and also plotted torque curve, but that was just for my own to see what the rpm was in various gears and speeds.

Bjørnung

Offline Bjornung

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Re: from low bottom to top in sequence
Reply #6 - Jun 09, 2021 - 13:01
Forgot to attach picture...

Here now with overall ratios.


Bjørnung

Offline alan reid

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Re: from low bottom to top in sequence
Reply #7 - Jun 09, 2021 - 14:12
Thought it was only recommended to use o/d  in 3rd and top  ( too much torque input)
Having suffered the calamity of a broken gearstick 100 miles from home, found a usable spread of gears by fumbling the main box into 3rd. Then used 3rd low, 3rd high and 3rd o/ d.
Reverse to be avoided at all cost

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Online antarmike

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Re: from low bottom to top in sequence
Reply #8 - Jun 09, 2021 - 16:30
Thought it was only recommended to use o/d  in 3rd and top  ( too much torque input)
Having suffered the calamity of a broken gearstick 100 miles from home, found a usable spread of gears by fumbling the main box into 3rd. Then used 3rd low, 3rd high and 3rd o/ d.
Reverse to be avoided at all cost

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That is a popular misconception.

The Fairey Overdrive for the LT95 Gearbox (One Tonne 101" FC, V8 Stage 1, and RRC) was only supposed to be used in 3rd and 4th, but the series LT76 O.D. was available for use in every gear, (including reverse).








However if the vehicle has had an engine conversion, V8, Tdi, Perkins 4203 or others, it might be prudent to limit the use of lower gears with overdrive??

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Offline Bjornung

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Re: from low bottom to top in sequence
Reply #9 - Jun 09, 2021 - 16:49
On my 86" I personally only use OD in 4. and 3. At higher speeds, except when I forget I am in OD and use it in all gears, like the other day when I feared for a while the engine had lost power.

Bjørnung

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Offline Andy80 Moderator

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Re: from low bottom to top in sequence
Reply #10 - Jun 09, 2021 - 18:36
I had a 2a Lightweight with a RV8 and used use an overdrive in 2nd around town without detrimental effect.

 :tongue:

Offline pdes

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Re: from low bottom to top in sequence
Reply #11 - Jun 09, 2021 - 22:41
Similar with Roamerdrive.  OK in all gears.

 http://roamerdrive.com/ss_overdrive.html


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Online Trakgrip

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Re: from low bottom to top in sequence
Reply #12 - Jun 10, 2021 - 10:13
I have Fairey ODs on one of my 80"s and my 86" and have always used it in all gears when appropriate. Especially when towing, there are times when using it as a splitter to provide intermediate gears is extremely useful, as it can be if you are towing up a steep hill in low box and would run out of gears without a range change (in my experience it is generally not possible to change from say low third to high first on the move on a hill since you will have stopped by the time you are back in gear).

I used to find that changing up whilst reversing was a good party piece with passengers who didn't understand the delights of the transmission. Of course it is even more fun in a 'Mog....

Offline Graeme Trade Advertiser

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Re: from low bottom to top in sequence
Reply #13 - Jun 10, 2021 - 12:33
I once worked with an ex-squaddie who had had to drive a 'Very Top Brass' across Salisbury Plain in an Austin Champ.  The VTB's aide missed a turning, and my friend was told to stop and go back.  He did... by putting the Champ into reverse on its separate lever.  He then set off backwards, changing up on the main box as necessary.  The VTB was silent for a while, but when they resumed forward motion on the correct track, couldn't hold it in any longer...

"Driver...?"  "Sah!"  "You changed up whilst going backwards?"  "Yes, sah!"  "How did you do that?"  "With this lever here, sah!"  "Can you do that?"  "Yes, sah... I just did!"

The puzzled VTB went quiet for the rest of the journey.
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