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Old 9th September 2009, 14:25   #91
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Originally Posted by Samurai View Post
..
MM550 could approach the last part much faster than CJ340 because MM550 would bounce lot lesser than CJ340 during the approach.

The reason why I couldn't never gain enough speed in any gear was because of the bouncing over uneven surface.
Yes, very true. I did notice that the 340 was bouncing and was not able to gather consistent momentum whereas the 550 was not bouncing that much and was able to get momentum.

However, to reflect again on day 1, the lightweight gypsy with 1.0L engine came bouncing all over with 20 years old MRF Zigma tyres on the slope where both the jeeps had to be winched out. BUT to be fair to the jeeps, siddu had built momentum some 100/150 mts away itself from the incline.

The key was momentum -- which ever way you achieved it.

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That last hill section didn't have enough traction even for Mud tyres on the spider. Even the spider Gypsy had to use momentum rather than traction, you drove that part, so you know it.
Vijay tried to 'crawl' in 1st Low and it did not make it. With 2nd L and momentum, it went up easily.

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...

The NDMS however is the undisputed king of all terrain when worn by a CJ3B petrol jeep. The jeep has to be light and the engine needs to have the power/torque needed (both low and high).

The NDMS may even fail with a CL340 due to the heavier engine, and resulting overall GVW of the vehicle.
Hence is the vehicle dimension and vehicle weight which killed it. NOT the tyres.

...540s and Cl340's (2.1 and Inter) are better off with ATS, or MT tyres.
Choose NDMS only if you have a petrol cj3b jeep, for all else stick to a more modern tread pattern
Wow, that's quite an insight and must say that it makes sense. Thanks for sharing this perspective.

Last edited by khan_sultan : 9th September 2009 at 14:28.
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Old 9th September 2009, 14:35   #92
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Originally Posted by DKG View Post
I have my doubts about a heavier car having any advantages offroad as compared to a lighter vehicle. Traction should benefit on account of tyre tread design and not vehicle weight. A heavier car will need a more powerful engine (usually implying a heavier engine on account of higher displacement) - doesn't add up.

Given the weight of a vehicle one needs to purely focus on tyre choice to optimise its performance offroad. The 600x16 seems perfect for cars the size of the CJ3B. Anything larger should wear atleast 700's if not 750

Its fair to say that most of us who were not there cannot guage the terrain from pictures and comment about why the NDMS didn't work. So far on trails in forests my CJ3B with 600x16 NDMS works brilliantly. BTW they are brand new MRF's

I agree 100% @DKG. For off-roading a lighter vehicle will always be leagues ahead (at the expense of ride quality off-course).
A heavier vehicle will ride better on all surfaces, and will probably be safer,...but in off-roading (slush, sand, hillclimbs, water crossings) this very trait is a big, big disadvantage.

The engine, tyre, GVW, dimension combo would certainly be important but still as an average a light and nimble vehicle with the correct gearing and tyres will always triumph.
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Old 9th September 2009, 14:37   #93
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Ahh! Guys we are going off topic on this thread. lets stick to this thread with report and more pics from Sree's cam and Sharat's Cam.
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Old 9th September 2009, 14:41   #94
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Ahh! Guys we are going off topic on this thread. lets stick to this thread with report and more pics from Sree's cam and Sharat's Cam.
Yes, getting too techy. May be lets move these to 4x4 tech section.
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Old 9th September 2009, 14:48   #95
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Yes, getting too techy. May be lets move these to 4x4 tech section.
Your welcome to Sir !

But you know what,.. if we have to learn all the ropes on off-roading from one's own mistakes this lifetime aint going to be enough considering the diverse topography we have in our beautiful country.

For example I would'nt be able to drive on the fantastic terrain you guys have down south.

So, I think we all learn tonnes from other peoples expieriences even if its a thread on excursions. Cheers All !!.... out
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Old 9th September 2009, 14:53   #96
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Originally Posted by khan_sultan View Post
However, to reflect again on day 1, the lightweight gypsy with 1.0L engine came bouncing all over with 20 years old MRF Zigma tyres on the slope where both the jeeps had to be winched out. BUT to be fair to the jeeps, siddu had built momentum some 100/150 mts away itself from the incline.
K_S, there was no way we could use momentum on day 1. There were huge ruts and rocks there which probably would damage under body parts of Jeeps. Being a light weight Gypsy, it will bounce all over the place instead of hitting under body, hence siddu's momentum trick worked out with out any damage to the vehicle. But day 2 was different, the terrain was steap but had no rocks / ruts which could damage inderbody parts, hence relatively safe to use momentum. Plus, i took a new path instead of beaten path after having an inspection on foot for hidden roacks undernethe the tall grass. 2 times i used gypsy technic to clear obstacle in day 2. the fisrt hill climb and second hill climb.

1) Samurai was able to clear the first hill clime in 2L crawl where as my gearing was taller than of a CJ340. 2L was too slow for me and 1L even slower. Hence i reveresed to the first hill for getting the benifit of moementum from incline in 3L the moment i hit the foot hill to be cleared, i pressed hard and cleared it.

2) The second hill was also cleared in a similiar way, reversed as much as i could, 3L, fully pressed cluch, gas the engine to a good RPM, release the cluch suddenly hence you have a sudden start and zoom to top of the hill and at almost top, flick to 2L for clearing last hurdle.

There was one abservation i made here, when you are stalled on a steep inclice, you should quickly enguaage reverse gear and use engine power to roll back. It was very tough for Samurai for doing this since it was a KMT90 - non syncro. A fully enguaged cluch for few seconds on that incline meanse - suicide. I have seen Samurai's vehicle rolling down dangerously, Samurai any thought how you managed here?

Thanks
--Sree--
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Old 9th September 2009, 14:57   #97
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Yes, getting too techy. May be lets move these to 4x4 tech section.
We are talking offroading techniques, not mechanically technical issues. So I don't think it is offtopic.
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Old 9th September 2009, 14:58   #98
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Originally Posted by mjothi View Post
Yes, getting too techy. May be lets move these to 4x4 tech section.
Mjothi, each terrain needs different technic, here we have a live example to discuss and clear the things, i think its ok to have lil technical discussion here.

Thanks
--Sree--
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Old 9th September 2009, 15:12   #99
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Originally Posted by sreerajunnithan View Post
There was one abservation i made here, when you are stalled on a steep inclice, you should quickly enguaage reverse gear and use engine power to roll back. It was very tough for Samurai for doing this since it was a KMT90 - non syncro. A fully enguaged cluch for few seconds on that incline meanse - suicide. I have seen Samurai's vehicle rolling down dangerously, Samurai any thought how you managed here?
True, that was one moment I really cursed for not having hand brake or disc brakes. Eventhough I had fully floored the brakes at the stall point, the Jeep still rolled back when I depressed the clutch. Because of all the water crossings, the drum brakes were mostly at 50% efficiency. But at that steepness, it was no good at all.

Since brakes were useless, I had two choices.
1) If the engine was on, I had to keep the tyres spinning to stay there. Some people may have wondered why I was spinning away to glory while talking to people on top. I just wanted to stay there.
2) If the engine was off, I had to remain in gear. Moment I depress the clutch to engage reverse, it starts sliding. When it is sliding I can't engage reverse because it is non-synchro mesh. It angrily protested with a kat-kat-kat sound whenever I tried and kicked the gear lever back.
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Old 9th September 2009, 15:17   #100
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Originally Posted by sreerajunnithan View Post
1) Samurai was able to clear the first hill clime in 2L crawl where as my gearing was taller than of a CJ340. 2L was too slow for me and 1L even slower. Hence i reveresed to the first hill for getting the benifit of moementum from incline in 3L the moment i hit the foot hill to be cleared, i pressed hard and cleared it.
2L on sharat's jeep must be slower than yours i think as Sharat's jeep crown pinion ration is 5.38.

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Originally Posted by sreerajunnithan View Post
2) There was one abservation i made here, when you are stalled on a steep inclice, you should quickly enguaage reverse gear and use engine power to roll back. It was very tough for Samurai for doing this since it was a KMT90 - non syncro. A fully enguaged cluch for few seconds on that incline meanse - suicide. I have seen Samurai's vehicle rolling down dangerously, Samurai any thought how you managed here?

Thanks
--Sree--
Sree, KMT90 is not fully non syncro. only 1st gear is non syncro. and i dont see any reason why one cannot change to reverse in KMT90 quickly. make sure all the wheels are held by brakes and shift it immediately to reverse and release the clutch and brake. and here anyways Samurai had stalled his jeep on the incline with forward gear. it is same as when held by the brakes.
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Old 9th September 2009, 15:20   #101
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Originally Posted by sreerajunnithan View Post
There was one abservation i made here, when you are stalled on a steep inclice, you should quickly enguaage reverse gear and use engine power to roll back. It was very tough for Samurai for doing this since it was a KMT90 - non syncro. A fully enguaged cluch for few seconds on that incline meanse - suicide. I have seen Samurai's vehicle rolling down dangerously, Samurai any thought how you managed here?

Thanks
--Sree--
A small correction here, reverse on any gearbox is a non syncro specially on BA10. You have to be quick to shift to reverse. Depends on your smoothness of gearbox, clutch and most important vehicle has to be stationary for a second atleast or must be dead slow!

Last edited by vinod_nookala : 9th September 2009 at 15:22.
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Old 9th September 2009, 15:26   #102
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Originally Posted by vinod_nookala View Post
A small correction here, reverse on any gearbox is a non syncro specially on BA10. You have to be quick to shift to reverse. Depends on your smoothness of gearbox, clutch and most important vehicle has to be stationary for a second atleast or must be dead slow!
mmm.... that make sense. I had brand new clutch assembly and shifting quickly to reverse gear was easy for me, coz of the less throw and smoothness of the GB. See guys we are learning

Thanks
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Old 9th September 2009, 15:26   #103
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Originally Posted by Samurai View Post
True, that was one moment I really cursed for not having hand brake or disc brakes. Eventhough I had fully floored the brakes at the stall point, the Jeep still rolled back when I depressed the clutch. Because of all the water crossings, the drum brakes were mostly at 50% efficiency. But at that steepness, it was no good at all.

Since brakes were useless, I had two choices.
1) If the engine was on, I had to keep the tyres spinning to stay there. Some people may have wondered why I was spinning away to glory while talking to people on top. I just wanted to stay there.
2) If the engine was off, I had to remain in gear. Moment I depress the clutch to engage reverse, it starts sliding. When it is sliding I can't engage reverse because it is non-synchro mesh. It angrily protested with a kat-kat-kat sound whenever I tried and kicked the gear lever back.
Oh, didn't knew your brakes were not effective. and btw keeping the tyres spinning to stay there was not a good idea as the spinning tyre will have less friction than a non spinning tyre. and the spinning tyre will not have any direction which could cause the vehicle to roll in any direction.
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Old 9th September 2009, 15:40   #104
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Hmm! good lot of interactions. Are there any more photographs/ videos? I must admit, I missed it for sure 3rd time in a row.

Must do this trail for sure, come what may.
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Old 9th September 2009, 15:40   #105
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Originally Posted by star_aqua View Post
Sree, KMT90 is not fully non syncro. only 1st gear is non syncro.
Both 1st and Reverse are non-synchro. So I couldn't shift to reverse while it was rolling back.


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Originally Posted by star_aqua View Post
and i dont see any reason why one cannot change to reverse in KMT90 quickly.
While it is moving? It kicked the lever back with kat-kat-kat sound.

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Originally Posted by star_aqua View Post
make sure all the wheels are held by brakes and shift it immediately to reverse and release the clutch and brake. and here anyways Samurai had stalled his jeep on the incline with forward gear. it is same as when held by the brakes.
Well, brakes were not good enough. It was rolling at full speed with brake pedal floored.

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Originally Posted by vinod_nookala View Post
A small correction here, reverse on any gearbox is a non syncro specially on BA10. You have to be quick to shift to reverse. Depends on your smoothness of gearbox, clutch and most important vehicle has to be stationary for a second atleast or must be dead slow!
BA10 is silky smooth compared to KMT90. Mine is really hard after all the operations it underwent.

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Originally Posted by star_aqua View Post
Oh, didn't knew your brakes were not effective. and btw keeping the tyres spinning to stay there was not a good idea as the spinning tyre will have less friction than a non spinning tyre. and the spinning tyre will not have any direction which could cause the vehicle to roll in any direction.
You are right, but tyres were not free spinning as in slush. There was just enough traction to retain me in place if I was revving. It stalled and switched off when I stopped revving.
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