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Skipping gears in shifting

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South San Frncisco, california, USA   USA
Mon freres,
In driving the TR6 4 speed, is it safe, appropriate, or objectionable
deleterious to gearbox clutch to skip gears, ie: First to third,
second to fourth... when in proper rev band?
thinking of saving clutch pedal strokes.
Sorry if this is too pedestrian question, but the wife doesn't know,
neither cat nor bird will tell me, sitting there casting smug look.

thanks

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tapkaJohnD Avatar
tapkaJohnD John Davies
Lancaster, Lancashire, UK   GBR
It's called "short-shifting"

Of course there can be reason to do it, but in the higher gear, your revs will be lower than they would beif you changed up into the intermediate gear, so you need to take them higher in the lower gear, or you risk bogging down, well off the cam.
But say, using the low gear to accelerate and overtake, then cruise straight away, every reason to short shift.

John



Edited 1 time(s). Last edit at 2017-10-25 03:56 PM by tapkaJohnD.

South San Frncisco, california, USA   USA
thanks! it is past ten pm in Lancashire I think,
54 f in London...end october...mmm... couldnt help
slipping this side door mention global warming.
UK can be beautiful this time of year.
sorry i guess this off topic. next time ill go to the pub.
wes

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Tonyfixit Avatar
Tonyfixit Tony M
Duncan, British Columbia, Canada   CAN
I do it sometimes accelerating on a steepish downhill with my truck. Slowing down I will often stay in high gear until I decide what appropriate lower gear to select, then double clutch down to that.

Double clutching is not saving pedal strokes though.

Are you doing this for personal comfort (leg muscles ) or to save your clutch?

South San Frncisco, california, USA   USA
mmm, Tony, after reading your reply I took the machine for a short stroll 12 miles, fair bit of stopsigns...
but also these half and quartermile free stretches... and examined this more close.
Neutral to 4th is 4 clutch strokes. Neutral to 1 to 3 to 4 or 1 to 2 to 4 is three clutch strokes...
and one wants to do it without bogging...(which probably takes its own toll on clutch drivetrain
engine not so happy for a few seconds)
So normal is four strokes, skipping one is three...all in all not saving much.
I guess from time to time in nice conditions is ok.

After a longer drive, say an hour or two, it is a bit of a workout, being a 1950 model myself.
I'll also say, since I feel I have the engine running issues sorted out, (for a whole two months now!)
the shifting has improved. And since getting new tires, two weeks ago... everything is related...
The clutch action, while heavy still, is more predictable and car is all around steadier behaved.
I still need to do trailing arm bushings and springs, and rexamine my lever shock valving and oil...
but things are greatly improved.
Thanks for making me think more on this....I was more wondering if skipping gears messed with gear synchro rings and such.

regardez
wes

Uberxy Avatar
Uberxy Steve Fox
Va, Charlottesville, USA   USA
I don't skip gears in my 6 much, but when I had a big-torque BMW M5, I would get up to motorway speed in second and then go directly to sixth. I also rarely used first except when starting uphill. First clutch lasted 90k miles.

Also, when I was racing SCCA and SVRA, I learned from Mark Donahues book to not downshift thru the gears; that is, if coming up to a second gear corner in 4th gear, one would brake in 4th until reaching 2nd gear speed, and then downshift from 4th to 2nd directly. Saves wear and tear on car and driver, and makes for smoother driving.



SR
73 TR6



Edited 1 time(s). Last edit at 2017-10-25 10:18 PM by Uberxy.

Tonyfixit Avatar
Tonyfixit Tony M
Duncan, British Columbia, Canada   CAN
In reply to # 1494116 by wes gray Thanks for making me think more on this....I was more wondering if skipping gears messed with gear synchro rings and such.

regardez
wes

You transmission does not care what previous gear was selected, just that the relitive speed of the gears is (more of less) syncronised. So, if for instance, you change from 2nd to 4th you may make a slower gear change, spending an extra half second in neutral just to allow the gears to slow to a more suitable speed, before pulling back into 4th.

Skipping gears going down is a bit more involved, this may involve selecting neutral, lifting the clutch pedal, blipping the gas, and pushing the clutch pedal down again befor selecting the lower gear.

I am sure there are videos on YouTube showing this.

There was a recent post from a member who had fitted power assistance to their clutch pedal. Which really is not that hard or very costly to do.

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tapkaJohnD Avatar
tapkaJohnD John Davies
Lancaster, Lancashire, UK   GBR
"Double declutching" as described by Tony is wholly unnecessary in a 'modern' gearbox with constant mesh cogs a d synchromesh selection. Like your Spitfire 'box, except for first, unless its a later one. There is absolutely no advantage, even for a short shift down. All it will achieve is a little more time to slow the car before engaging the lower gear.
And "sparing the clutch"?? If your clutch can't tolerate Millions of uses, its poor quality or misassembled.
John

frostr6 Avatar
frostr6 Bill Connell
St. Paul, Minnesota, USA   USA
I used to skip gears and shift without the clutch pretty often in my old VW Beetle. It was a bit of a challenge and fun but i never really thought i was saving much clutch wear (and those engines are ridiculously easy to R&R anyway). I've never felt the need to do it in the TR6 partly because my syncros aren't that slick right now, and accelerating through the gears is half the fun.

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poolboy Avatar
poolboy Ken D
Sandy Hook, Mississippi, USA   USA
There have been times where I neglected to switch out of OD before coming to a stop.
With a J type, you don't notice until you shift from 2nd to 3rd and hit 3rd in OD..
That's not a good feeling when I'm trying to accelerate...so my feeling is don't skip gears.



Edited 1 time(s). Last edit at 2017-10-26 08:29 AM by poolboy.

South San Frncisco, california, USA   USA
i have come to agree that bypassing gears on acelleration from stops doesnt
accomolish much. thanks to all who have replied this subject.
(i just recently found and beat a number of vacuum leaks,
which when corrected, made adjustments to timing, mixture actually
meaningful and engine runs fine. Along with that new tires replacing
to iriginal tires, 36 thousand miles, but 43 years old... has made a huge difference
in the roadfeel of the car and goes back to an uncanny smoothness thru gears,.
i should journal thus subject...it would be longer.
thnks All.
wes

TRoutMac Avatar
TRoutMac Pete Chadwell
Bend, Oregon, USA   USA
My driving style isn't too concerned about economizing on clutch strokes, but is concerned about saving wear on the clutch disc and synchros. The hydraulics are relatively easy to replace if need be, but of course that cannot be said for changing the clutch or rebuilding the gearbox. Years ago I was driving the TR to a part-time job and did so for a period of two or three MONTHS (3 times a week) with a nearly disintegrated TO bearing. I only used the clutch to pull away from a stop. All shifting was done without disengaging the clutch, which seems to be pretty easy to do with the TR6 gearbox. I became pretty good at rev-matching for the downshift.

When I finally was able to buy the parts I needed, I pulled it all out and got everything straightened out. You wouldn't believe the TO bearing… man, it was messed-up!! But now I'm in the habit of double-clutch heel-toe downshifts to minimize wear on the clutch disc and (I think) synchros. But I NEVER stand at a light with the clutch released. That's not good practice in ANY car, but in a TR6 it's DEFINITELY to be avoided!! I leave it in neutral 'til the light changes.

I don't tend to use the engine for braking much… if I'm approaching a red light or stop sign and I know I'm going to come to a complete stop, I simply take it out of gear and use the brakes. Often times I don't even use the clutch to take it out of gear… if you move the lever to neutral at just the right moment--right when the throttle closes and torque reverses--then it'll slip out of gear easily and no harm done. It's a narrow window to get it into neutral though… too soon or too late and the torque moving through the 'box won't want you to move the lever. But if I figure I might get a green light before I come to a stop, I might downshift and use some engine braking.

At any rate, it's hard to imagine going from 4th to 2nd… the rev-match required might exceed the redline. Same with 3rd to 1st. And skipping gears on the upshift doesn't seem practical except in very unique circumstances. About the closest I ever come to that is when my light turns green when I've almost reached a complete stop, and I'm rolling slowly and decide to use the torquey 6 to pull away in 2nd gear when I might've downshifted to 1st.



Edited 1 time(s). Last edit at 2017-10-26 10:26 AM by TRoutMac.

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