[shankar.balan]

Originally Posted by Crosscountryman

I'm attaching the concerned part of 2021 Brochure of Thar when I bought mine. It may help answer Q1

These are exactly the same details written in the brochure which I have with me. Mine is a Feb 2021 Thar.

[dhanushs]

Originally Posted by Blooming Flower

Would you please throw more lights on the actuation sequence detail of BLD and MLD in rear when situation demands? In which manner M&M programmed it in the control module? Is this why BLD kick-in time is longish 3 seconds so that MLD gets precedence?

BLD is always in action when wheel slips. Consider it as a traction aid. When a wheel starts slipping, brakes are applied to the slipping wheel. This will transfer the braked torque to the wheel with traction or the other wheel.

MLD is a mechanical locking device. It locks the axles once the locking conditions are met. Then both axles turn at the same speed. The beauty of BLD is that it allows both axles to turn in different speeds still providing traction and hence maintaining the line of the vehicle.

Originally Posted by cool_dube

Since BLD is software gimmickry, it will always take precedence over the mechanical MLD. Possible scenarios in which BLD will "give up" (and hand things over to MLD) - when brakes overheat due to repeated application of BLD or sensor failure.

Software Gimmickry you say?
Well.. Can you explain more on situations where BLD will give up?

Also, have you experienced a situation where brakes have overheated? Or Sensors have failed? Would like learn more hence...

[cool_dube]

Originally Posted by dhanushs

Software Gimmickry you say?

Ah, maybe inappropriate choice of word What I meant to say was that BLD being a software "aid", should be more sensitive in terms of kicking in prior to MLD. Of course it depends on the tuning but I'd presume that as soon as BLD detects a wheel-slip, it would start applying brakes to that wheel, thereby causing transfer of torque to the other wheel on that axle. This should happen much prior to difference in rotation speed across both wheels crosses 100 rpm (which, I understand, is the trigger condition for MLD to lock). Hence, my inference that BLD should be able to "handle the situation" almost every time, without MLD being required to intervene.

Well.. Can you explain more on situations where BLD will give up? Also, have you experienced a situation where brakes have overheated? Or Sensors have failed? Would like learn more hence

Brakes do overheat in case of very frequent application, akin to what happens when hill decent control takes over. Sensor failure is, of course, an extreme condition and highly unlikely to occur. I cannot envisage any other scenario under which MLD would kick in prior to BLD. Please let us know, if you do.

PS - just my thoughts based on limited knowledge on these topics. Please feel free to add/correct, as appropriate

[dhanushs]

Originally Posted by cool_dube

...

Brakes do overheat in case of very frequent application, akin to what happens when hill decent control takes over. Sensor failure is, of course, an extreme condition and highly unlikely to occur. I cannot envisage any other scenario under which MLD would kick in prior to BLD. Please let us know, if you do.

..

So you were pointing to conditions when BLD kicks in before MLD? If so, its always.
Also, the short interval where BLD works in real life doesnt heat up the brakes. And the sensors.

[Blooming Flower]

Originally Posted by dhanushs

BLD is always in action when wheel slips. Consider it as a traction aid. When a wheel starts slipping, brakes are applied to the slipping wheel. This will transfer the braked torque to the wheel with traction or the other wheel.

MLD is a mechanical locking device. It locks the axles once the locking conditions are met. Then both axles turn at the same speed. The beauty of BLD is that it allows both axles to turn in different speeds still providing traction and hence maintaining the line of the vehicle.

I would like to get the followings clarified as per my understanding.

1. BLD is part of an ESP system (ESP = TC+BLD), and it always stays on even if ESP is off by the manual application of the provided switch. I believe the switch only disables the TC part of ESP, not BLD.

2. BLD may kick-in in microseconds as per the controller programming depending on the wheel slip situation to provide traction on the slipping wheel by modulating the brakes at the individual wheel, whereas TC does the same by modulating the engine torque.

3. As MLD (Eaton one) has no manual override/control mechanism, and it only gets activated through centrifugal action in the differential by sensing 100 rpm rotational speed difference between the wheels in an axle, it's safe to assume BLD may engage before MLD kicks in.

4. If point no. 3 is satisfied, only 3 combinations may exist.

(a) BLD serves the purpose before a mechanically robust mechanism of MLD is in place.

(b) Even if BLD kicks in before there can be a 100rpm difference leading to MLD engagement.

(c) BLD and MLD can work simultaneously.

In either case, one of the systems is rendered redundant. Even, if the situation (b) takes place at all, it makes the intent of BLD null and void. And in the case of (c), I fail to eliminate the conflict between these two systems to serve a single purpose.

Many high-end vehicles only depend on the BLD system to emulate the result of an MLD. In that case, should I assume the BLD system in Thar/ Scorpio N is not robust enough?

Originally Posted by cool_dube

Since BLD is software gimmickry, it will always take precedence over the mechanical MLD. Possible scenarios in which BLD will "give up" (and hand things over to MLD) - when brakes overheat due to repeated application of BLD or sensor failure.

IIRC, Your previous post mentions BLD only works in the front axle.

Now, if the brakes overheat to meet the action of BLD, I really doubt the credibility of the Mahindra brakes system. If this result is extrapolated to real-life high-speed driving situations, the design of the brake system wouldn't have been fail-safe at all. I safely can ascertain this is not the case here.

And for the 'gimmickry' part-- Nowadays, most of the modern logic-controlled systems in a vehicle are capable enough to replace age-old mechanical systems and they are evolving at a rapid pace. Looking at the current scenario of the application of electronics and logic in automobile systems, 'gimmick' seems no more justifiable, I think.

[cool_dube]

Originally Posted by dhanushs

So you were pointing to conditions when BLD kicks in before MLD? If so, its always.

Yes, that is what I was referring to. So, under what circumstances would MLD kick in on a BLD-enabled axle? Will it ever? If it won't then MLD is more of a fallback system, in case BLD fails, right?

Originally Posted by dhanushs

Also, the short interval where BLD works in real life doesnt heat up the brakes. And the sensors.

That is good to know.

Originally Posted by Blooming Flower

IIRC, Your previous post mentions BLD only works in the front axle.

That was my understanding, but based on recent posts from more knowledgeable members, I stand corrected. BLD is indeed enabled for both axles on the all-new Thar.

Originally Posted by Blooming Flower

Now, if the brakes overheat to meet the action of BLD, I really doubt the credibility of the Mahindra brakes system.

It has nothing to do with credibility. It is basic physics. Braking occurs due to friction and friction generates heat. Any intelligent system will pull the plug on the whole thing rather than frying the brakes! If one is in a situation where BLD is kicking in constantly, even if for short intervals, there are chances of brakes overheating.

If this result is extrapolated to real-life high-speed driving situations, the design of the brake system wouldn't have been fail-safe at all. I safely can ascertain this is not the case here.

Brakes overheating is a real-life scenario. Try coming down a steep ghat road without engine braking.

Looking at the current scenario of the application of electronics and logic in automobile systems, 'gimmick' seems no more justifiable, I think.

Please read my succeeding post - I did admit to inappropriate usage of that word.

[dhanushs]

Originally Posted by Blooming Flower

I would like to get the followings clarified as per my understanding.

1. BLD is part of an ESP system (ESP = TC+BLD), and it always stays on even if ESP is off by the manual application of the provided switch. I believe the switch only disables the TC part of ESP, not BLD.

Even though BLD uses the ESP hardware, consider it as a system working separately.

2. BLD may kick-in in microseconds as per the controller programming depending on the wheel slip situation to provide traction on the slipping wheel by modulating the brakes at the individual wheel, whereas TC does the same by modulating the engine torque.

3. As MLD (Eaton one) has no manual override/control mechanism, and it only gets activated through centrifugal action in the differential by sensing 100 rpm rotational speed difference between the wheels in an axle, it's safe to assume BLD may engage before MLD kicks in.

100 rpm is an approx value. If speed is considered, it kicks in approx at 10kmph. Again approx since the conditions are variable.

(a) BLD serves the purpose before a mechanically robust mechanism of MLD is in place.

BLD is different. MLD is different. If MLD is there BLD will aid before MLD kicks in. If not, it will try and do MLD's work.

(b) Even if BLD kicks in before there can be a 100rpm difference leading to MLD engagement.

True.

(c) BLD and MLD can work simultaneously.

BLD works when there is a difference in wheel speed. When MLD is engaged, there is no difference in wheel speed, so, no need for BLD.

Many high-end vehicles only depend on the BLD system to emulate the result of an MLD. In that case, should I assume the BLD system in Thar/ Scorpio N is not robust enough?

It is robust enough. Also, Mechanical locking and brake locking are two different things. Both has it's own advantages and disadvantages.

Originally Posted by cool_dube

Yes, that is what I was referring to. So, under what circumstances would MLD kick in on a BLD-enabled axle? Will it ever? If it won't then MLD is more of a fallback system, in case BLD fails, right?

Like mentioned earlier. Consider both systems seperate. Doesnt depend on each other to work.

[dhanushs]

Originally Posted by cool_dube

...
Please read my succeeding post - I did admit to inappropriate usage of that word.

I would also like to add that any software function affecting physical components are implemented after countless hours of physical and digital evaluations and subsequent tune ups.

[Blooming Flower]

Originally Posted by cool_dube

Brakes overheating is a real-life scenario. Try coming down a steep ghat road without engine breaking.

I can't agree more. You are absolutely right. But, what I wanted to purport is the brakes will heat much while trying to stop a car from high speed as the duration and speed of slipping of the pads and liners/shoes with the disk and drum respectively are quite higher than the situation when the application of BLD is warranted. Leave alone the ghat roads, which is, of course, quite more intense than these two situations, and the heating resulting in possible brake failure is inevitable without engine braking.

Originally Posted by dhanushs

It is robust enough. Also, Mechanical locking and brake locking are two different things. Both has it's own advantages and disadvantages.

First, thanks for clarifying and validating my understanding.

The only thing I am not convinced of is 'it is robust enough'. Indeed, if it is, MLD is not at all required. Or the system for self-recovery in certain situations in the first lot is overengineered. Considering the pros and cons of the systems, I would have been convinced of the co-existence and requirement of the duo if the mechanically locking differential system had some manual on-demand control like Gurkha, G-wagon, LRs or Tfort.

[cool_dube]

Originally Posted by dhanushs

Consider both systems seperate. Doesnt depend on each other to work.

I understand that. My question is - given current state of respective tunes, can you think of a scenario where MLD will kick in prior to BLD?

Originally Posted by dhanushs

I would also like to add that any software function affecting physical components are implemented after countless hours of physical and digital evaluations and subsequent tune ups.

Goes without saying

Originally Posted by Blooming Flower

duration and speed of slipping of the pads and liners/shoes with the disk and drum respectively are quite higher than the situation when the application of BLD is warranted.

It depends on the trail. If there are frequent scenarios of wheels lifting off the surface, BLD will be in continuation operation. For instance, in HDC systems, speeds are quite low but these systems are designed to cut off in case of brakes' overheating.

[ph03n!x]

A lot of theory around BLD & MLD - all are theoretically correct. But I did a little practicals over the weekend, in my friend's farm.

I got my rear wheels to slip while climbing a sandy slope in 4H, and didn't revv too hard (to keep the MLD from engaging).

The wheels just kept spinning on, no BLD kicking in. I revv'd more, MLD kicked in with it's typical jerk and I climbed out.

I'll try the same with the front axle sometime.

Mine is an October 2020 Thar LX AT CT, and I've never seen BLD lock a rear wheel before MLD engages.

So they either work in tandem, with similar requirements (100 RPM difference) to engage - and BLD helps prolonging the MLD clutch maybe by holding the spinning wheel.

Or BLD is absent in my Thar's rear axle.

[navpreet318]

I think all of you are forgetting the initial information about the Thar 2020.

The MLD is present in the rear and the BLD acts only in the front. BLD is not present in the rear at all. This is from Day 1.

That have made some changes not with removal of MLD etc. I haven't followed that recently.

But the initial ones including mine from April 2021 are all with Rear MLD only and Front BLD only.

Bhpian Anshyuman has some great videos in his YouTube channel showing both in Action. Please do have a look.

[Urorobo]

Ergonomics of Thar

I have noticed a pain in my right scapular area ( right upper back below shoulder ) since the last two weeks. I have been driving my Thar and have done approx 800 km. All the miles are city driving only.

I am still not able to get the correct driving position . I am 178 cm tall and 75 Kg. Saw my ortho friend yesterday and told him this fact.

Have never had these issues in my other cars except TT. The TT gave me a stiff back as the driving position was low.

Being a surgeon my hands are my bread and butter especially the Right.

Any comments from fellow Thar owners and Ortho- Sport injury expert Car lovers.

Might have to stop driving the Thar

[MahindraThor]

Originally Posted by Urorobo

Any comments from fellow Thar owners and Ortho- Sport injury expert Car lovers.

Might have to stop driving the Thar

The origin of the right scapular pain is from your neck (cervical Spine), as the ride in the Thar is a little rutted. I suggest you to consider AVO suspension that will ease out some strain on the cervical spine and the subsequent scapular pain.

Keep driving Thar!!

[Urorobo]

Thank you @MahindraThor

That’s a very valuable but expensive prescription. Being a doctor I can appreciate your input. Prevention is better than cure.

Is it that the driving seat is not in line with the steering wheel but a bit off centre ? Not much to rest the hands on either side of the steering.

Will look into the suspension upgrade but if the car poses a risk to my neck or back then I might just as well go back to my Duster.

Beautiful car no doubt but don’t want it to be the literal pain in the neck.

Thanks a million