[Spitfire]

Originally Posted by Samurai

But one has to keep in mind that SWB has less tolerance towards any kind of lifts, it can increase the body roll easily.

1" spacers with a 235 profile tyre.

1" == 25mm

235 - 215(stock on CL/CJ) == 20mm

Total increase would be 25 + 10 == 35

35 x 2 == 70 mm increase in total track.

i.e 1680 + 70 == 1750mm which is about the track width of a MM540/50.

Or is that going overboard? That was the plan to offset body roll. But the SPOA never happened.

[ex670c]

Originally Posted by svsantosh

My 2cents here (I am a newbie to jeeps, so please feel free to ROFL if its stupid)

1) Hummer Technology:

I remember reading some where that Hummer's GC is acheived by the drive shaft not driving the center of the HUB like ALL other vehicle's on the road. It instead drives a 'sort of' 2nd transfer case which is conected to the wheels... See Hummer front axle pic and 'CAD' pic below.

2) Now - if someone can break their skull out and design something similar on a Jeep Chassis (I made a DUMB Picture using Ganesh's gbanavar chassis) it MAY increase the GC.

That is PORTAL AXLEs they are of 2 Basic Hub Configurations.
1) Reduction Hub with no drop, so no increase in GC like TATRA813/815, MAN630A/Shaktiman.

2) Reduction Hub with drop, increase in GC like Volkswagen Type 18, Styer Halflinger (IFS & IRS), Styer Pinzgauer (IFS & IRS), Mercedes Unimog & Unimog Trucks & Volvo C303

Normally the portal Hubs have an Additional reduction of 2:1 and the differential ratio is between 2:1 to 3:1

Regards,

Arka

[GTO]

Thanks a ton, Arka! Your inputs have helped me jot down a concrete plan for the Classic.

Originally Posted by ex670c

I believe your JEEP is running 4.27:1 as you had changed it earlier.

She was running a 4.2 on the 2.1 engine. Now, she's on a 4.8.

Improves the front track and the vehicle follows with in that track i.e less steering wander.

Got it, will do.

The MM540 Rear Axle/Housing can be fitted - but not worth the trouble.

Deleted

Bilstein Shocks - Better rebound.

Any model number? Where do I source?

The max size on a CJ3B/CJ5 stock is 7.50X16 i.e 31", with out trimming the rear fenders/wheel arches.

That's what I'll stick to then.

241mm

That kind of GC makes my mouth water

PS - Check your XD3P if it is a XD3PU then get a MM550XD FIP rated 76bhp at 4600rpm & 15.5kgm

Will do.

[DirtyDan]

Another idea is not to raise the vehicle but to lower the ground. I am working on a demo package for this right now.

[DesertKing]

Interesting topic. Last week I drove my MM540on mix terrain (mainly rocks) almost for 7 hrs. I found that sometimes the belly of the engine and other times the gearbox skid plate touches the rocks so easily. My Jeep is having 31 x 10.5 and I wonder that even climbing on a 12 inch single step can be a problem. The only solutions is to increase the clearance of belly (not differential). This is my daily drive, otherwise I was thinking to go for SPoA set up.

I need to know if somebody on T-BHP already done SPoA on MM540. Will this increase body roll to greater extend that sharp turn on speed becomes dangerous.

[ex670c]

Hi GTO,

The Bilstein 5100 series for CJ5 =
F4-B46-0250H0 & F4B46-0260H0


Regards,

Arka

[Ym-enjn]

Originally Posted by khan_sultan

From a pure off-roading perspective I don't think one would be too worried about speedo error etc etc.

Khan the only thing to worry is if there is a radar speed check going on, you’ll see you are at 60 kmph but your actual speed is fast and can result in a ticket. I always slow my spedo-speed to 50 at spots where there is more probability of an interceptor.

GTO if you use a good negative offset rim you can easily use a 31" height tyre in CL340+. That by itself will make a huge difference in your jeep which I guess is currently running on 215x75, may be experts can give an exact figure of lift. Try it for this season. You'll get a fair idea and also not miss rain and winter OTRs.

My 31x10.5x15 tyres have improved GC a lot (though these ones are temp arrangement as no good tyre options in this size are avaible in Jaipur) and don't rub upper inner or side walls on stock setup, the rim pushes them out.

[DesertKing]

Originally Posted by Ym-enjn

My 31x10.5x15 tyres have improved GC a lot (though these ones are temp arrangement as no good tyre options in this size are avaible in Jaipur) and don't rub upper inner or side walls on stock setup, the rim pushes them out.

I saw these tyres in Jodhpur having good AT design (I do not remember the brand but I guess it was Goodyear). If intrested do give me a call.

[DHABHAR.BEHRAM]

Dear GTO - sorry I could not reply earlier, it was all work as usual (sigh!). My recommendation is that whatever you do, please do not sacrifice reliability or you will once again land up like your last experience with the petrol engine. Look at it a little differently. Go for the 5.38:1 conversion from 4.88:1, then go for larger tyres but please be clear on the road speed v/s engine rpm. The tyres must not offset the ratio or you will gain nothing. I have given you the formula for calculating. Also remember that you have an inherent advantage of having the fuel tank inside the vehicle so there is no chance of tank breakage by underfloor hitting. So, thinking differently, you must drive offroad in the lightest car that it can be so the change to the suspension height is minimum. The stance of the car on road must hold off road. Tharein lies the secret. Things like SPOA can be done and it will excite you to think in such a direction but it has to be done properly. Garage method is not recommended because the complete steering geometry changes, with it the handling will change. Alternately you can think of increasing the shackle dimension slightly. A 20 mm increase gives a phenomenal advantge in terms of stance. Try it out but do it properly, articulate the car and observe what happens.

When are you coming to Devlali? When do we meet?

Best regards,

Behram Dhabhar

[GTO]

Originally Posted by DesertKing

I found that sometimes the belly of the engine and other times the gearbox skid plate touches the rocks so easily.

Exactly! I want to increase the difficulty level of Mumbai OTRs, taking GC on top of the wish list.

Originally Posted by DirtyDan

Another idea is not to raise the vehicle but to lower the ground. I am working on a demo package for this right now.

Ever the witty double D. You find your 4x4 yet?

Originally Posted by ex670c

Hi GTO,

The Bilstein 5100 series for CJ5 =
F4-B46-0250H0 & F4B46-0260H0

Thanks Arka!

Originally Posted by Ym-enjn

GTO if you use a good negative offset rim you can easily use a 31" height tyre in CL340+.

Appreciate the tip.

Originally Posted by DHABHAR.BEHRAM

My recommendation is that whatever you do, please do not sacrifice reliability or you will once again land up like your last experience with the petrol engine.

And what a sorry experience it was. Funny you should mention that, today marks the 1st anniversary of my 2.5 engine thread. I intend to put up a 12 month update by the evening.

The tyres must not offset the ratio or you will gain nothing.

Gotcha.

I have given you the formula for calculating.

Would you please put it up here for everyone elses benefit?

Also remember that you have an inherent advantage of having the fuel tank inside the vehicle so there is no chance of tank breakage by underfloor hitting.

The many design touches that go into making the CJ3B a competent offroader amaze me. Not to mention, someone thought of this unique fuel tank position 5 decades ago!

Things like SPOA can be done and it will excite you to think in such a direction but it has to be done properly.

With gurus like yourself & Arka to watch over my Jeep, do I have to worry about a "proper" job? As complicated as the SPOA is, a part of me is still willing.

Alternately you can think of increasing the shackle dimension slightly. A 20 mm increase gives a phenomenal advantge in terms of stance. Try it out but do it properly, articulate the car and observe what happens.

Can you please elaborate on how to go about this?

When are you coming to Devlali? When do we meet?

Soon, real soon.

[GTO]

Road speed (kms / hr) = (engine rpm * 2 *3.1416 * dynamic rolling radius (meters) * 60) / (gear ratio * axle ratio * 1000)

Behram asks to keep this formula in mind before tyre upgrades.

[rhandle]

Originally Posted by ex670c

8) For a 31" tyre you will get 31-28 = 3" by 2 = 1.5" at least, so from 8" you get 9.5" = 241mm . That is Gurkha Territory

Regards,

Arka

Hi Arka,

Am running 275x70x16 now on Gurkha and that height is more than 31x10.5x15.

Extra height of tyre can be seen in below picture!

[ex670c]

Originally Posted by rhandle

Hi Arka,

Am running 275x70x16 now on Gurkha and that height is more than 31x10.5x15.

Extra height of tyre can be seen in below picture!

Hi Rahul,

Measure the tyre height(diameter) with a tape when they are fitted in the vehicle. (Static Loaded)


275-70-16 = 31.15inches

31-10.5-15 = 30-31" on 8.5" wide Rim.

7.50X16 = 31" = but when fitted in an MM550XD is actually 30.5'-31" depending on the brand of the tyre, Apollo Bullets being the tallest.

Regards,

Arka

[GTO]

Am running 275x70x16 now on Gurkha and that height is more than 31x10.5x15.

Of course it would! 31x10.5x15 is like 267mm with a smaller sidewall on 15 inchers.

[RedMM340]

GTO,

Keep in mind that a little scrap on the underbody is o.k. As long as the scraps/impacts are on skidplates and crossmembers there is no damage done.

A great deal of suggestions and analysis has been done here, but I would suggest that you simply go +1 on the tire size and see how your jeep works.