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Descending hills


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Assuming a 4-speed slushbox, which is better for descending a steep hill: 2nd and intermittently braking, or 1st and braking a bit less?  1st gives more engine braking obviously but also makes the engine rev up to 4-5000rpm, not sure that's healthy for it to have all that torque coming from the wheels..

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5 minutes ago, m4rkw said:

Assuming a 4-speed slushbox, which is better for descending a steep hill: 2nd and intermittently braking, or 1st and braking a bit less?  1st gives more engine braking obviously but also makes the engine rev up to 4-5000rpm, not sure that's healthy for it to have all that torque coming from the wheels..

I`d use second personally with intermittent braking Mark.

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It depends how long the descent is. If you are in danger of overheating the brakes to the point they might fade then you want to use engine braking as much as possible to avoid that situation, otherwise let the brakes do the work - cheaper to replace pads and discs than transmissions.

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30 minutes ago, ColinBarber said:

It depends how long the descent is. If you are in danger of overheating the brakes to the point they might fade then you want to use engine braking as much as possible to avoid that situation, otherwise let the brakes do the work - cheaper to replace pads and discs than transmissions.

Same advise given by a Police Instructor I once knew.

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2 hours ago, ColinBarber said:

It depends how long the descent is. If you are in danger of overheating the brakes to the point they might fade then you want to use engine braking as much as possible to avoid that situation, otherwise let the brakes do the work - cheaper to replace pads and discs than transmissions.

You took me back nearly fifty years Colin, to when I first got that advice!

I had two Uncles who ran a ‘Under the Arches’ type auto shop and from whom I’d bought my first car.  Driving one of them around, I tried to impress with my driving skills by double-declutching on the approach to some lights.  ‘“What was that about!” he inquired.  He interrupted my explanation of the subtleties of gear box control by pointing out that brake shoes were a lot cheaper to replace than clutch plates.

I don’t think I ever did it again.

However, my Lexus manual does describe how long hill descents are better controlled by moving from the auto mode by using the paddles to select a lower gear.  It’s not something I have yet had the opportunity to try.  I’d hate to discover that it can go badly wrong.

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2 minutes ago, LenT said:

You took me back nearly fifty years Colin, to when I first got that advice!

I had two Uncles who ran a ‘Under the Arches’ type auto shop and from whom I’d bought my first car.  Driving one of them around, I tried to impress with my driving skills by double-declutching on the approach to some lights.  ‘“What was that about!” he inquired.  He interrupted my explanation of the subtleties of gear box control by pointing out that brake shoes were a lot cheaper to replace than clutch plates.

I don’t think I ever did it again.

However, my Lexus manual does describe how long hill descents are better controlled by moving from the auto mode by using the paddles to select a lower gear.  It’s not something I have yet had the opportunity to try.  I’d hate to discover that it can go badly wrong.

Manual Gear Selection works really well on my 450h Len and the Braking Effect is marvellous.

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2 hours ago, LenT said:

However, my Lexus manual does describe how long hill descents are better controlled by moving from the auto mode by using the paddles to select a lower gear.  It’s not something I have yet had the opportunity to try.  I’d hate to discover that it can go badly wrong.

Using a lower gear to assist the braking is fine, using the lowest gear instead of the brakes is taking it too far IMO.

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16 hours ago, LenT said:

  He interrupted my explanation of the subtleties of gear box control by pointing out that brake shoes were a lot cheaper to replace than clutch plates.

 

 

I worked on Sunblest bread vans during the summer holidays as soon as I passed my test. There I saw drivers double de clutching without touching the clutch pedal at all. They were able to sense the exact speed etc when the lever just jumped almost on its own.

I did manage to do it but mine were much more clumsy. As soon as I bought my own cars the novelty seemed to wear off !

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2 hours ago, stringbender said:

I worked on Sunblest bread vans during the summer holidays as soon as I passed my test. There I saw drivers double de clutching without touching the clutch pedal at all. 

That explains it, Alan.

I always thought that Sunblest loaves of the period seemed to come with an extra crunch.  🙂

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6 hours ago, stringbender said:

I worked on Sunblest bread vans during the summer holidays as soon as I passed my test. There I saw drivers double de clutching without touching the clutch pedal at all. They were able to sense the exact speed etc when the lever just jumped almost on its own.

I did manage to do it but mine were much more clumsy. As soon as I bought my own cars the novelty seemed to wear off !

You can just lean the lever towards the gear position from neutral and when the revs line up with the syncromesh it’ll pop in. Wouldn’t recommend making a habit of it though.

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1 hour ago, m4rkw said:

You can just lean the lever towards the gear position from neutral and when the revs line up with the syncromesh it’ll pop in. Wouldn’t recommend making a habit of it though.

One of my earlier cars was a 1929 Austin 16, (2.5L, straight six, 3 gears, no synchromesh on any, and external shoe handbrake on the prop shaft)

One becomes quite adept at changing gear with sufficient practice (!)

And every successful gear change felt SO good!!!

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For many years we had a Reliant Scimitar GTE. 

On a trip up to a wedding in the Midlands the hydraulics for the clutch failed. Not much we could do as we were in all our best clothes and needed to get to the wedding on time.

The way to do it with an old manual car is to turn off the engine, select 1st gear, handbrake off, turn the engine over which causes the car to move forward until the engine fires then away you go. Gear changes are then made by slipping the gear lever into neutral, adjusting engine speed to suit the new road speed then pushing gear lever into next gear. If done correctly you can make very smooth (and silent!) gear changes. The secret is to try to keep the car moving at all times by reading the road ahead and timing junctions and traffic lights so that you do not have to stop. The really interesting part was when we made a wrong turn into a cul de sac and had to do a three point turn. However we made it to the wedding, had a wonderful day and an uneventful journey back home.

JBP

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Yes they did indeed, John but ours was a manual 4-speed with overdrive on 3rd and 4th gears. You could actually pull away in 3rd gear (with a little bit of clutch slip) and then using the overdrive you could get up to 90 to 100 MPH without actually changing gear. Obviously this would only be done on private roads!!!

JBP

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40 minutes ago, JBPRX400h said:

Yes they did indeed, John but ours was a manual 4-speed with overdrive on 3rd and 4th gears. You could actually pull away in 3rd gear (with a little bit of clutch slip) and then using the overdrive you could get up to 90 to 100 MPH without actually changing gear. Obviously this would only be done on private roads!!!

JBP

Thanks John

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10 hours ago, JBPRX400h said:

For many years we had a Reliant Scimitar GTE. 

On a trip up to a wedding in the Midlands the hydraulics for the clutch failed. Not much we could do as we were in all our best clothes and needed to get to the wedding on time.

The way to do it with an old manual car is to turn off the engine, select 1st gear, handbrake off, turn the engine over which causes the car to move forward until the engine fires then away you go. Gear changes are then made by slipping the gear lever into neutral, adjusting engine speed to suit the new road speed then pushing gear lever into next gear. If done correctly you can make very smooth (and silent!) gear changes. The secret is to try to keep the car moving at all times by reading the road ahead and timing junctions and traffic lights so that you do not have to stop. The really interesting part was when we made a wrong turn into a cul de sac and had to do a three point turn. However we made it to the wedding, had a wonderful day and an uneventful journey back home.

JBP

I had to do the same when the clutch failed on my TR7.. good job the starter motor was strong.

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