"Do not downshift into first when ... moving faster than 15 mph"

[Zooks527]

From the 2019 manual (v2):

I don't know when I would want to do this but, for sake of argument, 15 mph is 2200 rpm in my car (2019 GT MT PP1). How would downshifting into first at 16 mph (2350 rpm) from second (1525 rpm) do any damage to the clutch? There's a similar rpm spread between 2nd / 3rd around 25 mph, and I can't see anyone saying that you couldn't downshift in that condition.

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[Dfeeds]

Engine speed isn't everything. First gear has a different ratio than second and a lot more torque output because of that. It's why the car accelerates a lot faster in first at 2k rpm than fourth at 2k.

I have to really ease out of the clutch if I'm around 10 mph and I'm trying to engage first. If I don't the car jerks really hard. That's not good for any part of the drivetrain.

 

[Zelek]

I don't know anyone who would downshift to first unless you're literally in traffic barely moving off idle. I'm in second gear as long as I possibly can be before I go to neutral. First gear is very short and can be very jerky. I'm no engineer but I definitely would stick to what that manual states above.

 

[raptor17GT]

surely if you blip the throttle to rev match with the shift then it won't do any damage? I can think of one corner for doing that, uphill hairpin using a bit of oversteer to get the car around. Big blip and a downshift to first gear followed by corner. Second gear doesn't rotate the car at such low speed

http://www.rosswarmemorials.org.uk/ApplecrossNfo.htm

 

[Cobra Jet]

I don't know anyone who would downshift to first unless you're literally in traffic barely moving off idle. I'm in second gear as long as I possibly can be before I go to neutral. First gear is very short and can be very jerky. I'm no engineer but I definitely would stick to what that manual states above.

Exactly... and it wouldn't apply just to an S550, that's with ANY vehicle with a manual transmission... Having owned many Mustangs with a manual box and many other vehicles - I've never even thought of downshifting into 1st gear at all while at speed ... for what and why?

 

[Dr. Norts]

Exactly... and it wouldn't apply just to an S550, that's with ANY vehicle with a manual transmission... Having owned many Mustangs with a manual box and many other vehicles - I've never even thought of downshifting into 1st gear at all while at speed ... for what and why?

I don't understand the reasoning for this either. No need to go down into first unless your stopped and taking off from that stop.

Alot of manuals it's pretty difficult to downshift into first as compared to the other Gears.

Why would you want to do this anyways unless your going for a money shift lol.

 

[gadgtfreek]

We have speed humps in our historic area by the house, I always roll through these areas in second. I generally go over a speed hump around 8-10 mph and then just hit the throttle. It does fine in second and keeps me from shifting all the time.

I honestly hate first, shifting at 3k or so when cold, its there in a blink of an eye and it sucks as soon as you get going and caught at another redlight that requires starting in first again lol

 

[Zooks527]

I don't know anyone who would downshift to first unless you're literally in traffic barely moving off idle.

I've never even thought of downshifting into 1st gear at all while at speed ... for what and why?

Why would you want to do this anyways unless your going for a money shift lol.

Wonderful, all of us agree that we can't see when you want to do so, just as I said in the first post.

But, back to the question I asked, why would this damage the clutch? Not "might", not "could", but, per the manual, "will" damage the clutch.

 

[Zooks527]

Engine speed isn't everything. First gear has a different ratio than second a lot more torque output because of that. It's why the car accelerates a lot faster in first at 2k rpm than fourth at 2k.

But that elides the question of why there's no prohibition for downshifting across similar torque / gear ratio spreads in higher gears.

 

[Zelek]

Wonderful, all of us agree that we can't see when you want to do so, just as I said in the first post.

But, back to the question I asked, why would this damage the clutch? Not "might", not "could", but, per the manual, "will" damage the clutch.

The manual also probably states don't drink engine coolant too. Are you going to question that as well? I'm not one for arguing against a manufacturer's suggestion written in a technical document.

 

[Sivi70980]

This is interesting. Just put a new axle back on and the car sounds amazing! Because of this I will downshift (well, kind of) into 1st but I don't reengage the clutch till I'm stopped (stop sign) and get moving again. So I come up to the stop sign, clutch, first gear to let the auto rev match and new axle backs let everyone know I want attention, then when stopped, drive off like normal in 1st gear. Probably not what is meant by "downshifting into first gear".

 

[dx2]

Like it was already said, due to the very short gear ratio the velocity of the shafts will be much more different than switching between higher gears, so doing a switch into 1st with higher car speed often will burn the friction material down too quickly because of this difference in speed of the two shafts.
If they do not state the same warning in non-performance oriented models as well chances are they might have more service cases than usual and noticed that this might have been a frequent reason for premature clutch failure so the manual people at Ford placed a nice warning for the manual people into the manual.
ok, 2018+ has rev matching but it can be turned off.
And yes , to me the warning appears obviously unnecessary but so do other warnings like on coffee to go: caution burning hot coffee.

 

[526 HRSE]

Lol my car would die if i shifted into 6th at 50mph.

 

[Zooks527]

The manual also probably states don't drink engine coolant too. Are you going to question that as well? I'm not one for arguing against a manufacturer's suggestion written in a technical document.

And your goal in making a juvenile snarky reply to a legitimate technical questions is .......... ?

 

[Zelek]

And your goal in making a juvenile snarky reply to a legitimate technical questions is .......... ?

Ask stupid questions, get stupid answers.

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