|Saturday, December 29, 2001||
AFTER all these years of driving in Himachal and the Himalayas one has found that the steepest climb over any pass is the one in Jalori. The pass itself in not high, only 3,223 metres above sea level, but after Khanag till the top of Jalori, you’ve 6 km of real steep gradient. Most vehicles heat up going up to Jalori. While coming down, if gears are not used to slow down, it is not unusual to see the brakes smoking, and possibly even the paintwork on the rims can get scorched due to intense heat that friction generates.
The saving grace is that just as the engine is about to get to the critical stage after covering 5-6 km, the car reaches the top. The engine gets a chance to idle, the outside air is cool and the strain is off the engine. A welcome respite. Even if the driver were to continue driving down hill, it would not strain the engine the same way as it does while coming up. The driver can continue without any problems. The engine will cool down automatically.
The other pass that
poses engine-heating problems is Tagalang La. At 5,360 metres above sea
level, it is the second highest motorable pass in the world. The lack of
oxygen also changes the fuel-air mixture combination. If the engine does
not fire perfectly, that too will contribute to the heating up of the
engine. The approach is almost 30 km long. This means about one hour of
grinding up in first or second gear. It is a common sight to see cars
pulled up on the side of the road, bonnet open, waiting for the engine
Incidentally, the drive from Rishikesh to Ladakh was in low gear most of the time. These were instructions from factory-trained engineers.
This meant that instead of being in first or second gear, High, we were in four-wheel drive, Low, so that we could breeze up in third or fourth gear going up Jalori or Khardung La . This kept the engine at the correct r.p.m. and not one of the 18 vehicles heated up.
This would be one of the greatest advantages of four- wheel drive and you also have the transfer case that allows you to use a lower gear.
Here is how it works. Your four-wheel-drive vehicle is in normal running mode i.e. two wheel drive and high. Your four-wheel-drive vehicle has two gear boxes plus a transfer case. You may now put the vehicle in four-wheel drive but still retain the same high gear ratio. In this mode, you have the front differential working for you as well as the rear. It may be necessary to lock the front hubs if the vehicle has Warner-type hubs. By putting the vehicle into a four-wheel drive mode, you have instantly improved the road holding, braking and traction.
This is what is required for off-road driving. If the front wheels get stuck, the rear wheels will push you out of whatever you were stuck in. In case the front wheels have cleared the obstacle and the rear wheels get stuck, the front wheels will put you out.
To negotiate a really rough terrain or long and steep climbs up a pass, engage a low gear. By engaging a low gear, you will bring into play a lower gear ratio. This will transmit extra power to the wheels.
It is recommended to use low and run in 3rd, 4th and 5th gear, rather than gears 1, 2, and 3 in high extreme conditions.
After the Isuzu Challenge I had an opportunity to go up Jalori in my Gypsy. I used the Isuzu formulae— Low and in 3rd or 4th. there was no heating up and I had a better gear ratio than the other two Gypsys which were in the convoy. I was able to pull way from them and make better time.
If you have a four-wheel- drive vehicle, make use of all that the manufacturer has given you. Your vehicle will perform better.