Selecting 1st gear at speed
Discussion
Whilst watching some youtube clips recently, sTiff Needle was driving a 911 through some S bends and on one hairpin bend he said: "I need 1st gear for this one". He must have been doing about 50-60mph on corner entry. How does 1st gear physically engage at that speed, and why don't the rear wheels lock up when the clutch re-engages?
In nearly every FWD road car (and some RWD) I've driven, 1st gear physically won't go in if the car is moving, even at 5-10mph! I need schooling on gearboxes I think!
In nearly every FWD road car (and some RWD) I've driven, 1st gear physically won't go in if the car is moving, even at 5-10mph! I need schooling on gearboxes I think!
1 to 2 is often the biggest gearing step-change in the 'box.
Needs a mighty, and finely-judged, throttle blip to rev-match on the way down, else it won't go-in because you're asking too much of the 1st Gear synchro cones to instantaneaously accelerate the input shaft and clutch disc (think: inertia) and they'll baulk (sic).
The real problem is breathlessly rushing it all in anticipation, rather than letting it snick-in just-right when matched. Even in my BEC, dog-box and all, this is a private source of delight when it goes just right. One of those liminal rewards for the challenge of driving a manual well. you know.
(as opposed to worrying about bragging rights and on-paper acceleration figures vs auto/and my-Golf-R DSG and similar tediou_zzzzzz.)
Needs a mighty, and finely-judged, throttle blip to rev-match on the way down, else it won't go-in because you're asking too much of the 1st Gear synchro cones to instantaneaously accelerate the input shaft and clutch disc (think: inertia) and they'll baulk (sic).
The real problem is breathlessly rushing it all in anticipation, rather than letting it snick-in just-right when matched. Even in my BEC, dog-box and all, this is a private source of delight when it goes just right. One of those liminal rewards for the challenge of driving a manual well. you know.
(as opposed to worrying about bragging rights and on-paper acceleration figures vs auto/and my-Golf-R DSG and similar tediou_zzzzzz.)
Edited by Huff on Friday 17th July 21:57
Random fact of the week: Tiffany Dell disintegrated the carbon fibre prop on "my" DB9R at Silverstone by down changing too early! (gear box is at back, with engine speed prop running forwards to engine, downshifting with clutch disengaged to early over sped prop to around 12Krpm, at which point it exploded! (dog box, so you get pretty much any gear you ask for, even if you didn't really want it ;-)
Remember, so sporting cars run a much taller 1st gear compared to more cooking cars. Really fast stuff can often crack 60mph in 1st!
Remember, so sporting cars run a much taller 1st gear compared to more cooking cars. Really fast stuff can often crack 60mph in 1st!
Ouch!
Not a risk I'd considered but makes sense with an aft g/box.
Fortunately on my wee toy the prop is at 'normal speeds' and attached to a 3.44:1 quaife diff; also short, yet still two-part with a centre bearing.
First is good for a hair over 60...
Not a risk I'd considered but makes sense with an aft g/box.
Fortunately on my wee toy the prop is at 'normal speeds' and attached to a 3.44:1 quaife diff; also short, yet still two-part with a centre bearing.
First is good for a hair over 60...
Edited by Huff on Friday 17th July 22:23
Max_Torque said:
Random fact of the week: Tiffany Dell disintegrated the carbon fibre prop on "my" DB9R at Silverstone by down changing too early! (gear box is at back, with engine speed prop running forwards to engine, downshifting with clutch disengaged to early over sped prop to around 12Krpm, at which point it exploded! (dog box, so you get pretty much any gear you ask for, even if you didn't really want it ;-)
Remember, so sporting cars run a much taller 1st gear compared to more cooking cars. Really fast stuff can often crack 60mph in 1st!
And people say carbon fibre is great !...think I'll stick with steel lolRemember, so sporting cars run a much taller 1st gear compared to more cooking cars. Really fast stuff can often crack 60mph in 1st!
stevieturbo said:
Max_Torque said:
Random fact of the week: Tiffany Dell disintegrated the carbon fibre prop on "my" DB9R at Silverstone by down changing too early! (gear box is at back, with engine speed prop running forwards to engine, downshifting with clutch disengaged to early over sped prop to around 12Krpm, at which point it exploded! (dog box, so you get pretty much any gear you ask for, even if you didn't really want it ;-)
Remember, so sporting cars run a much taller 1st gear compared to more cooking cars. Really fast stuff can often crack 60mph in 1st!
And people say carbon fibre is great !...think I'll stick with steel lolRemember, so sporting cars run a much taller 1st gear compared to more cooking cars. Really fast stuff can often crack 60mph in 1st!
stevieturbo said:
Max_Torque said:
Random fact of the week: Tiffany Dell disintegrated the carbon fibre prop on "my" DB9R at Silverstone by down changing too early! (gear box is at back, with engine speed prop running forwards to engine, downshifting with clutch disengaged to early over sped prop to around 12Krpm, at which point it exploded! (dog box, so you get pretty much any gear you ask for, even if you didn't really want it ;-)
Remember, so sporting cars run a much taller 1st gear compared to more cooking cars. Really fast stuff can often crack 60mph in 1st!
And people say carbon fibre is great !...think I'll stick with steel lolRemember, so sporting cars run a much taller 1st gear compared to more cooking cars. Really fast stuff can often crack 60mph in 1st!
here you can me see engaging 1st a few times at reasonable speeds on a run up the mountains. This was on the Loser (mountain) Berg Trophy in Austria. A consistency event, not a race.
https://www.youtube.com/watch?v=Xa9lsbGLdQg&fe...
To answer any questions why I am not fully on it on the straights: a big percentage of this road has on one side cliffs or steep declines up to several hundred meter deep.
Any sane person keeps speeds down and has fun in the turns.
https://www.youtube.com/watch?v=Xa9lsbGLdQg&fe...
To answer any questions why I am not fully on it on the straights: a big percentage of this road has on one side cliffs or steep declines up to several hundred meter deep.
Any sane person keeps speeds down and has fun in the turns.
GrumpyTwig said:
I've always found double declutching to be pretty mandatory for 1st, otherwise you get one or two things happening, a crunch from the box and/or massive drive train shunt.
Modern cars have synchromesh so double declutching does nothing over the first declutch.What car do you use that needs double declutching as it sounds like synvromesh is out.
The Spruce goose said:
GrumpyTwig said:
I've always found double declutching to be pretty mandatory for 1st, otherwise you get one or two things happening, a crunch from the box and/or massive drive train shunt.
Modern cars have synchromesh so double declutching does nothing over the first declutch.What car do you use that needs double declutching as it sounds like synvromesh is out.
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