Go Back   Team-BHP > Buckle Up > 4x4 & Off-Roading > 4x4 Technical


Reply
 
Thread Tools Search this Thread
Old 15th July 2009, 14:09   #16
Senior - BHPian
 
Spitfire's Avatar
 
Join Date: Jul 2006
Location: Panaji - Goa/Bangalore - Karnataka
Posts: 3,240
Thanked: 600 Times
Default

Quote:
Originally Posted by Samurai View Post
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.

Last edited by Spitfire : 15th July 2009 at 14:21.
Spitfire is offline   Reply With Quote
Old 15th July 2009, 16:44   #17
Senior - BHPian
 
ex670c's Avatar
 
Join Date: Nov 2004
Location: Chennai
Posts: 2,454
Thanked: 1,789 Times
Default

Quote:
Originally Posted by svsantosh View Post
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
ex670c is offline   Reply With Quote
Old 15th July 2009, 19:44   #18
GTO
Team-BHP Support
 
GTO's Avatar
 
Join Date: Feb 2004
Location: Bombay
Posts: 46,561
Thanked: 80,342 Times
Default

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

Quote:
Originally Posted by ex670c View Post
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.

Quote:
Improves the front track and the vehicle follows with in that track i.e less steering wander.
Got it, will do.

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

Quote:
Bilstein Shocks - Better rebound.
Any model number? Where do I source?

Quote:
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.

Quote:
241mm
That kind of GC makes my mouth water

Quote:
PS - Check your XD3P if it is a XD3PU then get a MM550XD FIP rated 76bhp at 4600rpm & 15.5kgm
Will do.
GTO is offline   Reply With Quote
Old 16th July 2009, 07:58   #19
Senior - BHPian
 
DirtyDan's Avatar
 
Join Date: Jul 2007
Location: Dharamsala
Posts: 1,781
Thanked: 694 Times
Default

Another idea is not to raise the vehicle but to lower the ground. I am working on a demo package for this right now.
DirtyDan is offline   (1) Thanks Reply With Quote
Old 16th July 2009, 08:40   #20
BHPian
 
DesertKing's Avatar
 
Join Date: Mar 2008
Location: Jodhpur, Rajasthan
Posts: 460
Thanked: 18 Times
Default

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.
DesertKing is offline   Reply With Quote
Old 16th July 2009, 10:10   #21
Senior - BHPian
 
ex670c's Avatar
 
Join Date: Nov 2004
Location: Chennai
Posts: 2,454
Thanked: 1,789 Times
Default Bilstein 5100

Hi GTO,

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


Regards,

Arka
ex670c is offline   (2) Thanks Reply With Quote
Old 16th July 2009, 22:04   #22
Senior - BHPian
 
Ym-enjn's Avatar
 
Join Date: Jun 2008
Location: Jaipur
Posts: 1,039
Thanked: 54 Times
Default

Quote:
Originally Posted by khan_sultan View Post
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.

Last edited by Ym-enjn : 16th July 2009 at 22:07.
Ym-enjn is offline   Reply With Quote
Old 18th July 2009, 05:04   #23
BHPian
 
DesertKing's Avatar
 
Join Date: Mar 2008
Location: Jodhpur, Rajasthan
Posts: 460
Thanked: 18 Times
Default

Quote:
Originally Posted by Ym-enjn View Post
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.
DesertKing is offline   Reply With Quote
Old 20th July 2009, 11:17   #24
Distinguished - BHPian
 
Join Date: Jul 2007
Location: MUMBAI
Posts: 3,059
Thanked: 4,571 Times
Default

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
DHABHAR.BEHRAM is offline   Reply With Quote
Old 20th July 2009, 15:45   #25
GTO
Team-BHP Support
 
GTO's Avatar
 
Join Date: Feb 2004
Location: Bombay
Posts: 46,561
Thanked: 80,342 Times
Default

Quote:
Originally Posted by DesertKing View Post
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.

Quote:
Originally Posted by DirtyDan View Post
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?

Quote:
Originally Posted by ex670c View Post
Hi GTO,

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

Quote:
Originally Posted by Ym-enjn View Post
GTO if you use a good negative offset rim you can easily use a 31" height tyre in CL340+.
Appreciate the tip.

Quote:
Originally Posted by DHABHAR.BEHRAM View Post
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.

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

Quote:
I have given you the formula for calculating.
Would you please put it up here for everyone elses benefit?

Quote:
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!

Quote:
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.

Quote:
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?

Quote:
When are you coming to Devlali? When do we meet?
Soon, real soon.
GTO is offline   Reply With Quote
Old 23rd July 2009, 19:17   #26
GTO
Team-BHP Support
 
GTO's Avatar
 
Join Date: Feb 2004
Location: Bombay
Posts: 46,561
Thanked: 80,342 Times
Default

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.
GTO is offline   Reply With Quote
Old 25th July 2009, 15:51   #27
BHPian
 
rhandle's Avatar
 
Join Date: Dec 2006
Location: Ghaziabad
Posts: 554
Thanked: 105 Times
Default

Quote:
Originally Posted by ex670c View Post

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!
Raising a Jeep's ground clearance : Options?-23062009310.jpg
rhandle is offline   Reply With Quote
Old 25th July 2009, 16:24   #28
Senior - BHPian
 
ex670c's Avatar
 
Join Date: Nov 2004
Location: Chennai
Posts: 2,454
Thanked: 1,789 Times
Default Tyre height

Quote:
Originally Posted by rhandle View Post
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
ex670c is offline   Reply With Quote
Old 25th July 2009, 16:28   #29
GTO
Team-BHP Support
 
GTO's Avatar
 
Join Date: Feb 2004
Location: Bombay
Posts: 46,561
Thanked: 80,342 Times
Default

Quote:
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.
GTO is offline   Reply With Quote
Old 25th July 2009, 23:14   #30
BHPian
 
RedMM340's Avatar
 
Join Date: Apr 2008
Location: on the move
Posts: 459
Thanked: 22 Times
Default

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.
RedMM340 is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Optimum ground clearance of a Car? & how it is measured... skamb Technical Stuff 84 17th May 2017 22:36
Raising a Tata Marina's Ground Clearance vivek.singh.73 Modifications & Accessories 27 8th September 2013 21:43
Ground Clearance cartech Technical Stuff 35 10th November 2012 10:41
NHC ZX - Ground Clearance venkatrx The Indian Car Scene 17 30th July 2009 20:22
NHC Zx Ground Clearance and Ride quality mahesh4sure The Indian Car Scene 8 24th February 2006 11:39


All times are GMT +5.5. The time now is 17:50.

Copyright 2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks