What would happen if...

What would happen if...

Author
Discussion

scorp

Original Poster:

8,783 posts

230 months

Thursday 22nd September 2005
quotequote all
... i select reverse gear while doing 70+ mph ?

I say this as a drive both a 6spd and a 5spd car and i know one day im going to have my dopey head on and attempt to move into 6th in the 5 speed (which would be reverse gear).



im not sure this is the right forum for these kinds of questions... sorry in advance.

>> Edited by scorp on Thursday 22 September 15:57

tvrgit

8,472 posts

253 months

Thursday 22nd September 2005
quotequote all
bad things...

expensive things...

although, since reverse has no synchro, it's unlikely you would be able to get it to engage unless you were very unlucky, although I suspect you would still knock a few teeth off several gearwheels...

agent006

12,043 posts

265 months

Thursday 22nd September 2005
quotequote all
Try going from 5th to reverse when stationary. The vast majority of gearboxes won't let you.

Don

28,377 posts

285 months

Thursday 22nd September 2005
quotequote all
agent006 said:
Try going from 5th to reverse when stationary. The vast majority of gearboxes won't let you.


But if you've got a Chimaera its mandatory...

Go figure.

Yes: If it was possible on the particular gearbox then very bad, very expensive and possibly quite terminal things would happen.

tonyhetherington

32,091 posts

251 months

Thursday 22nd September 2005
quotequote all
As others have said - I'd be surprised if you'd be able to actually get it in gear (physically the difference in ratios and the speed of the gearbox at those speeds would make it very difficult)...but basically, lots of metal would crunch and lots of of not-nice-noises would emminate from under your bum!

scorp

Original Poster:

8,783 posts

230 months

Thursday 22nd September 2005
quotequote all
Nice to know i won't be able to accomplish it, the 5spd is a Peugot (sp?) 106. Cheers.

7db

6,058 posts

231 months

Friday 23rd September 2005
quotequote all


This was the result of changing gear, and not matching revs:-

"19yr old City trader, spent his first year bonus on the car (insured 3rd party only on Dad's policy Shocked) and while meandering through Epping Forest, overtook (at around 40mph or so) a Honda Firestorm bike and then while changing from 2nd to 3rd, let all the revs die off (it was an SV with a lightened flywheel and even more power) and jumped off the clutch - net result 600 bhp fed the wrong way through the rear wheels and a spin into the trees"

tvrgit

8,472 posts

253 months

Friday 23rd September 2005
quotequote all
tvrgit said:
bad things...

expensive things...

7db said:
This was the result of changing gear, and not matching revs

Told ya!

carl_w

9,198 posts

259 months

Saturday 24th September 2005
quotequote all
IIRC a journalist did this to one of the press Jag XJ220s (or maybe an XJR9 or something). I believe it did one of those cartoon car impressions, where cogs and springs fall out from underneath and go bouncing down the road.

GravelBen

15,705 posts

231 months

Monday 26th September 2005
quotequote all
carl_w said:
IIRC a journalist did this to one of the press Jag XJ220s (or maybe an XJR9 or something). I believe it did one of those cartoon car impressions, where cogs and springs fall out from underneath and go bouncing down the road.


I've seen an evo7 or 8 doing that on video, was quite amusing(in a painful way), wasn't due to grabbing reverse, someone used to an evo3 was trying to see if it would do donuts from a standstill like the '3.

so he tried it: wind the revs up, wind some lock on, and drop the cluth, and........BANG! a few cogs roll out from under the car. oops. get out of car, apologise to owner...

zax

1,009 posts

264 months

Monday 26th September 2005
quotequote all
I had a couple of near things with this in a courtesy car (Smart ForFour), mainly because it's reverse is where my Honda's sixth gear is. Much crunching but it didn't engage. Of course I wasn't trying to force it, maybe if I had persisted? Selecting reverse normally was slightly stickier afterwards.

anniesdad

14,589 posts

239 months

Monday 26th September 2005
quotequote all
7db said:


This was the result of changing gear, and not matching revs:-

while changing from 2nd to 3rd, let all the revs die off (it was an SV with a lightened flywheel and even more power) and jumped off the clutch - net result 600 bhp fed the wrong way through the rear wheels and a spin into the trees"


He's going up a gear, how can this have caused the car a problem, surely he's just lost momentum, by letting the rev's die off?

jonnyb

2,590 posts

253 months

Wednesday 28th September 2005
quotequote all
carl_w said:
IIRC a journalist did this to one of the press Jag XJ220s (or maybe an XJR9 or something). I believe it did one of those cartoon car impressions, where cogs and springs fall out from underneath and go bouncing down the road.


The journo in question was flat out in second went to change up the third and got first instead! lifted clutch, sent the valves through the engine!! Apparently one landed about a mile away!

hallmark

129 posts

224 months

Thursday 29th September 2005
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I bought a stolen/recovered Subaru a couple of years ago that was jammed in reverse. When I stripped down the transmission, the 5th/Rev hub was shattered and the centre diff had welded itself together. The rear diff had also had all the teeth from the pinion ground away and the corners of all the crownwheel teeth knocked off.

At an educated guess, the driver had been trying to go from third into fourth, which wouldn't engage because the selector fork had worn away (previous owner resting their hand on the gearstick between changes). So instead of getting fourth, he managed to get reverse instead. Lift up clutch and Bang!

There's an interlock to prevent going from fifth to reverse, but I don't think it works from third to reverse - after all, the selectors would have travelled through neutral so the interlock wouldn't know anything was wrong.

BTW - in the Subaru, you could easily hit 100 in third if you were trying. God knows what speed the driver was doing when he got it wrong, but it must have come as some surprise!