[Tejas@perioimpl]

Originally Posted by Samurai

You were trying to get 10.5J rim for a 31x10.5 tyre? The ideal rim width for 10.5 tyre would be 7.5 to 9 inches. So your current rims are perfect.

Couldn't get 10.5j rims so bought these tyres else I would have bought the 11.5 ones.

[Samurai]

The ideal rim width for 11.5 inch tyre would be 8 - 9.5 inches. Good thing you didn't get the 10.5J rims. BTW, 11.5 inch wide tyres on a Classic is extreme, too much rolling resistance and unsprung weight for the XDP engine.

[Tejas@perioimpl]

Originally Posted by Samurai

The ideal rim width for 11.5 inch tyre would be 8 - 9.5 inches. Good thing you didn't get the 10.5J rims. BTW, 11.5 inch wide tyres on a Classic is extreme, too much rolling resistance and unsprung weight for the XDP engine.

True. That does make sense. Worked out good for me!

But, I'm seriously considering change of axles.

[AVR]

Originally Posted by Tejas@perioimpl

@4x4addict
AVR, what's the offset of the rims?

Don't know actually. More like an ArKane question to me.
Though I know that the 235s are just about as much as what the rims can handle because I see very minimal spacing on the inside and the tyres rub on the inside on full-turns.

Would spacers work or do I really need to change to alloys?

Adi

[harjeev]

Originally Posted by Tejas@perioimpl

My bighorns are 31" x 10.5 x 15

Thanks for the update. I too am thinking of 31 x 10.5 15's but am leaning on MAXXIS Trepedors. (dont have the budget for the Bighorns) But still lets see.

My original alloys were 6.5J with positive offset. I had to change them. I could not find a 10.5J rim so settled for 8.5J negative offset rally rims.

I'll go for something similar.

I'm running the stock 4.88 dif. I have not noticed any significant difference / reduction in performance as of now. However, i have done a lot of slush runs and not major climbs, etc to feel the need to change to 5.38. Maybe after monsoons when i shift to dif terrain requiring more torque i may feel a difference.

Any idea if I can change the MM550 diff ratios to 5.38. I think that the standard in the army is 4.88 and the one on my 3B is 5.38. Also would it be a simple conversion or is complicated??

The lift is scary no doubt and you are always scared of tipping over (although the jeep is stable, it's a mental block). I don't corner at fast speeds at all. I'm seriously considering shifting to mm550 axles which are 3" wider than the classic ones. It's help a bit with the stability.

Exactly my thoughts. As I would be lifting the vehicle by 3" (tyres) & 4" shackles I would have to compensate it with wider axles and wider tyres. So i'll get approx 4.5" from wider tyres and another 3" from the MM550 axles. Even when I put -ve offset alloys that would also increase the track width to some extent. Shouldn't it???

Also shouldn't the shocks also be replaced. Cauz after all this is done, the ride height would have increased by 7". This will drastically reduce the travel of the OEM shocks! I am no expert so am I making sense or have succeeded in making a fool of myself

The lift and bigger tyres are a boon 100%. The ramp over angle has drastically improved!

So thats your stamp of approval. Thanks.
I am currently gathering info and would most likely start the modifications once I have my LHD 3B back from the workshop which should be later this year. Will have to wait till then

Originally Posted by 4x4addict

@harjeev: Shackle lift will only increase your body height but the lowest point in your diff and GC will not change. Only larger tires will increase your GC and improve your overhangs/rampover angles. When you put larger tires a shackle lift helps prevent the larger tires fowling with the body. A shackle lift alone is not very useful in my opinion.

Thanks Tini. I would go for shackle lift only when I change the tyres

Originally Posted by genesis

@Harjeev: Dont forget to budget for the power steering that you will have to put in to steer the bighorns!

Will definitely do that too? I am either thinking a PS or the normal steering box of a Bolero. I've heard that they work really well too. But drove a PS fitted MM550 the other day and it definitely is a boon!!! Who knows ;-)



@Tejas:
Buddy I read that you also changed the mounting and/or position of the shock absorbers. Any specific reason for that?

[Tejas@perioimpl]

Originally Posted by harjeev

Any idea if I can change the MM550 diff ratios to 5.38. I think that the standard in the army is 4.88 and the one on my 3B is 5.38. Also would it be a simple conversion or is complicated??

Nope. It's not complicated. You can get the LSD version.

Even when I put -ve offset alloys that would also increase the track width to some extent. Shouldn't it???

Hardly makes a difference

Also shouldn't the shocks also be replaced. Cauz after all this is done, the ride height would have increased by 7". This will drastically reduce the travel of the OEM shocks!

I'm not facing any issues.

I am either thinking a PS or the normal steering box of a Bolero. I've heard that they work really well too. But drove a PS fitted MM550 the other day and it definitely is a boon!!!

If you fit the bolero box, make sure the pulley used is of a larger diameter. Otherwise the steering becomes too sensitive and is scary at highway speeds.

@Tejas:
Buddy I read that you also changed the mounting and/or position of the shock absorbers. Any specific reason for that?

Did not change it. I was thinking of changing it if travel was an issue. Since it isn't, no point in messing about.

@Adi: Spacers not recommended for offroading.

[Tejas@perioimpl]

Few issues:

Overheating still happens when driven fast (~90kmph) or at 60kmph with 4 passengers or on ghat sections. The radiator is new, coolant level doesn't change and the radiator cap is as per specifications. The electric fan manages to control the temp from approx 95 to 85-90 but is not enough.

A lasts few OTRs made me realize the disadvantage of the 31" with my XDP engine and 4.88 difs. The engine just can't take it! I need to get a better engine or change to 5.38.

[garrett_t16]

DCM is the way to go buddy !

[Samurai]

Do you have the thermostat? My thermostat was recently removed and it never crosses 60, in fact it remains firmly at 40-45 while driving in rains. I don't have electric fan either.

How's your water pump?

My Jeep heating problem became so severe at one time, I had to move all the heating related posts to a separate thread, which itself turned out to be 11 pages long. It even gave birth to two more cooling test run threads.

https://www.team-bhp.com/forum/techn...blem-jeep.html

[gsferrari]

Originally Posted by Tejas@perioimpl

A lasts few OTRs made me realize the disadvantage of the 31" with my XDP engine and 4.88 difs. The engine just can't take it! I need to get a better engine or change to 5.38.

Just to understand this better what you are saying is that your wheel makes 1 full rotation for every 4.88 rotations of the transmission output. As the wheel diameter increases this means you cover more distance with every rotation. Therefore 4.88 rotations is now doing more work than with smaller wheels and therefore the engine is struggling.

So if you increase wheel diameter then it is better to increase the diff-ratio to 5.38 so that instead of 4.88, 5.38 rotations are needed for the same distance which makes it easier on the engine (less torque required and therefore more in store for tackling obstacles).

Do I have this concept sorted out here?

[Tejas@perioimpl]

Originally Posted by Samurai

Do you have the thermostat? My thermostat was recently removed and it never crosses 60, in fact it remains firmly at 40-45 while driving in rains. I don't have electric fan either.

How's your water pump?

My Jeep heating problem became so severe at one time, I had to move all the heating related posts to a separate thread, which itself turned out to be 11 pages long. It even gave birth to two more cooling test run threads.

https://www.team-bhp.com/forum/techn...blem-jeep.html

1. Thermostat is not there. Has been removed.
2. Sometimes crossed 80 in rains. But has always overheated on highway runs. Never during the actual OTR.
3. Water pump is fine as of now. You've read my water pump issues earlier on.
4. Am going through your quoted thread

Originally Posted by gsferrari

Just to understand this better what you are saying is that your wheel makes 1 full rotation for every 4.88 rotations of the transmission output. As the wheel diameter increases this means you cover more distance with every rotation. Therefore 4.88 rotations is now doing more work than with smaller wheels and therefore the engine is struggling.

So if you increase wheel diameter then it is better to increase the diff-ratio to 5.38 so that instead of 4.88, 5.38 rotations are needed for the same distance which makes it easier on the engine (less torque required and therefore more in store for tackling obstacles).

Do I have this concept sorted out here?

Yes.

Originally Posted by The Wolf

Get your injectors cleaned and fuel pump calibrated if its been a while. Feel the injector nozzles with your fingers for any back/abnormal pulse.
Change the clutch. It may be new but sometimes water entry and heavy OTR'ing may prematurely destroy your clutch.
Check all grease points especially star joints.
Jack up your jeep in neutral and check if all the tyres are rotating freely.
LBNTL, check the oil pressure, anything under 3bar isnt great.

For a swb- XDP 4.90 with 4.88 DR should fairly take you anywhere without too much pain plus manage a 100kmph on the speedo on highways.

5.38 will help a bit but your tyres have nothing to do with your overheating.

Everything was checked. It's elementary my dear Watson.

The car goes very freely on the hghway with good acceleration. It's the fact that it starts heating up fast as well.

I never said that 5.38 and overheating are related.

Overheating is one issue. And the other issue i'm facing is that the engine & 4.88 combo can't take the 31"ers during offroading. I'm getting a serious drop in power.

[Samurai]

Originally Posted by Tejas@perioimpl

1. Thermostat is not there. Has been removed.
2. Sometimes crossed 80 in rains. But has always overheated on highway runs. Never during the actual OTR.

Hitting 80 in rains without thermostat and with electric fan? There is definitely a major issue here.

Keep the radiator cap open and start the engine, do you see bubbles in the radiator water?

Originally Posted by The Wolf

Change the clutch. It may be new but sometimes water entry and heavy OTR'ing may prematurely destroy your clutch.

Is this true? Jeepers never do half-clutching in offroading, why should clutch go bad in offroading?

[Tejas@perioimpl]

Originally Posted by Samurai

Hitting 80 in rains without thermostat and with electric fan? There is definitely a major issue here.

Keep the radiator cap open and start the engine, do you see bubbles in the radiator water?

Checked that. Even BD did all that checking a few months ago. No issues and thus ruled out gasket issue. However he did recommend a degassing tank. That though will not solve the overheating issue, will just be a good preventive measure against gas buildup.

[garrett_t16]

@tejas i just checked with rajeev my DR is 4.27 !!\
so it should do much much more than 60 on the expressway right ?

[Tejas@perioimpl]

Originally Posted by garrett_t16

@tejas i just checked with rajeev my DR is 4.27 !!\
so it should do much much more than 60 on the expressway right ?

Yup, easily. Hell, your XD3P with 4.27 has more power than my XDP with 4.88! Time to put on my thinking hat...