ajg_e
Member Since: 04 Mar 2011
Location: Blue Mountains NSW
Posts: 14
  
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| suspension in tight tolerance for wheel alignment? |
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G’day,
SWMBO is taking the disco for a wheel alignment tomorrow, as I just had the control arm bushes and ball joints changed. 
I have read about tight tolerance mode and agree I should select it first. No problems there except it’s about 30km to the tyre place. My question is can she drive normally with tight tolerance mode selected?
Any help appreciated
Regards
Andrew
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 26th Sep 2011 11:47 am |
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BBS SPY
Site Sponsor
Member Since: 15 Jun 2007
Location: Sunny Cyprus
Posts: 3054
  
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Hiya Andrew
Yea driving about in Tight Tolerance mode is absolutely no problem for that kind of distance.
And well done to you for recognizing you need to have it in this mode for the best wheel alighnment results.
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| 26th Sep 2011 7:04 pm |
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disconewbie79
Member Since: 10 Apr 2011
Location: Sheffield
Posts: 82
 
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Hi guys please tell me what is tight tolerance mode? Until this post I have never heard of it. How do I select it in my car??And what does it do?? I have an 05 manual. cheers
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| 26th Sep 2011 8:06 pm |
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BBS SPY
Site Sponsor
Member Since: 15 Jun 2007
Location: Sunny Cyprus
Posts: 3054
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Hiya disconewbie79
Tight Tolerance mode is a special mode that according to Land Rover, any of their vehciles needs to be in for the best physical wheel alignment result. This mode is only possible to be entered into and exited out of using good specialist Land Rover diagnostic equipment and although many Wheel alignment centres profess to do this, i have my doubts that they actually do this significant step.
Try to appreciate that the EAS system of any Land Rover is designed to allow some tolerance.
This effectively means that at any one time the weight distribution of your vehicle might not be 100% equally spread over all four wheels. Across one axle for example, when you roll it onto the wheel alignment jig, one side might presently be taking 30% of the weight and the other the remaining 70%. Physical adjustments made on this basis will certainly not be right when after you roll it off the jig and the EAS decides to reverse the weight distribution to the opposite.
Tight Tolerance mode effectively makes the EAS system work much harder than normal to produce a near 50 / 50 weight distribution at all times and therefore produce more accurate than normal physical wheel alighnment adjustments.
It's not a mode you would want to run in continually, as i expressed to the OP as it makes the EAS system and valves work overtime and might possibly lead to premature wear out.
You also need to be sure yor EAS system is absolutely working correctly and properly calibrated which can be affected by any physical problems
So the best results are obtainable as follows.
1) Check your suspension totally, inspect each and every bush for any amount of wear and slop. Change anything suspect or as required.
2) re calibrate the EAS system heights and ensure it is performing 100% as it should be.
3) Put the EAS into tight tolerance mode.
4) Have a physical wheel alignment performed with adjustments done as required.
5) Put the EAS into normal running mode
I hope this helps
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| 27th Sep 2011 7:06 pm |
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hgrimmett
Member Since: 11 Oct 2009
Location: Bledlow
Posts: 901
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Thanks BBS,
one objection I heard recently was that since you don't drive it in TTM then why set it up in TTM? Surely you may as well set it up without TTM because if it makes that much difference then you'll likey lose the precision element of the alignment as soon as you start driving it. Does that make any sense? I know what I'm trying to say!  -------------------------------------------------------------------
D4 '15 (64) Se Tech Indus Silver
Tesla Model Y LR (22)
Audi TT Roadster 225 (52)
Tesla Model 3 LR (70) (gone)
Porsche Boxster '96 2.5 5spd project (P)
Mini R52 S (54)
BMW 330e eDrive MSport '16 (gone)
D3 '07 (56) XS TDV6 Buckingham Blue (gone)
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| 27th Sep 2011 8:00 pm |
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geoff.
Member Since: 24 Jan 2010
Location: West kent
Posts: 8531
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H
as you well know i have the equipment to put in to TTM and also have access to a hunter machine and what i can say is there is a difference when done in TTM as to normal mode.
don't forget its not just the toe in or toe out its also caster and camber alighment and thrust angles that need doing and if the veh is not sitting square or level these can't be done properly , hope this helps
so colin (BBS) is quite correct in saying to get the best results have it all checked
Geoff
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| 27th Sep 2011 8:10 pm |
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disconewbie79
Member Since: 10 Apr 2011
Location: Sheffield
Posts: 82
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Thanks for telling me I didn't realise it was so complicated!! Do you think I will need this done if I have driven on tyres that were not balanced properly??
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| 27th Sep 2011 11:16 pm |
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BBS SPY
Site Sponsor
Member Since: 15 Jun 2007
Location: Sunny Cyprus
Posts: 3054
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hgrimmett
To make the EAS enter TTM you have to be able to negotiate past very sophisticated anti access rolling code algorythms. This is something we (BBS) have due justification to invest sufficient amounts of money and effort to be able to do, and so provide the capability within our equipments functionality, just as we provide CCF editing amongst many other reasons.
This is part of the reason why our equipment costs a bit more than pocket money and why folks like Geoff Invest in it and extoll it's many virtues and capabilities over anything else, and IMHO opinion quite rightly so.
It is understandable that manufacturers of vast make / model wheel alignment equipment do not have due justification to do the same, just for one function on a handful of models and so instead resort to providing a plethora of pacifying excuses and objections to answer the need for supplying the ability to enter / Exit TTM in their equipment. Only but hoping a vehicle driven on the Ramp might be about right. Trust me i asked and have heard even better whoppers than yours.,
The fact is that that the EAS system in normal running mode, constantly allows a limited degree of flexibility of the vehicles weight distribution between all four wheels at any point in time. Imagine trying to aim a gun sight to a point that could already be off in any direction by up to 30 % (just an imaginary figure).
TTM locks the EAS sytem to stop it allowing this for this exact reason.
If you truly believe otherwise, almost always some story from someone who can't provide TTM capabilities and imagine that Land Rover introduced the TTM just for the fun of it, then that's totally up to you. 
disconewbie79
Yea sorry its a bit more complex than you thought.
unbalanced tyres should not cause a problem and as long as you have no doubts as to your EAS systems correct functioning you should be OK
However i should state that the height sensors are prone to problems and don't actually cost much, typically less than 15 GBP per corner.
If i had issues i would replace all four, re calibrate the heights, put the EAS into TTM, have the alignment done, exit EAS TTM and have a well earned cuppa knowing it is as right as it could possibly be.
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| 28th Sep 2011 6:57 pm |
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ajg_e
Member Since: 04 Mar 2011
Location: Blue Mountains NSW
Posts: 14
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Hi all
Thanks for your responses to my original post.
I put the car in TTM with my Faultmate. SWMBO took the car for the wheel alignment when she returned I changed it back all good.
This was an added bonus of the faultmate and this forum because I did realise you needed TTM for a wheel alignment.
Once again Thanks
Regards
Andrew
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| 30th Sep 2011 11:03 pm |
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hgrimmett
Member Since: 11 Oct 2009
Location: Bledlow
Posts: 901
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Sorry guys, I'm not a disbeliever I'm happy to be taught!  -------------------------------------------------------------------
D4 '15 (64) Se Tech Indus Silver
Tesla Model Y LR (22)
Audi TT Roadster 225 (52)
Tesla Model 3 LR (70) (gone)
Porsche Boxster '96 2.5 5spd project (P)
Mini R52 S (54)
BMW 330e eDrive MSport '16 (gone)
D3 '07 (56) XS TDV6 Buckingham Blue (gone)
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| 1st Oct 2011 12:30 am |
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BBS SPY
Site Sponsor
Member Since: 15 Jun 2007
Location: Sunny Cyprus
Posts: 3054
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Nice one Andrew
glad you appreciated and got to use the TTM function
hgrimmett
No worries, i am happy to teach anyone willing to learn. 
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| 1st Oct 2011 7:09 pm |
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leroymusic00
Member Since: 12 Jan 2021
Location: Carlisle
Posts: 143
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BBS SPY wrote:Hiya disconewbie79
Tight Tolerance mode is a special mode that according to Land Rover, any of their vehciles needs to be in for the best physical wheel alignment result. This mode is only possible to be entered into and exited out of using good specialist Land Rover diagnostic equipment and although many Wheel alignment centres profess to do this, i have my doubts that they actually do this significant step.
Try to appreciate that the EAS system of any Land Rover is designed to allow some tolerance.
This effectively means that at any one time the weight distribution of your vehicle might not be 100% equally spread over all four wheels. Across one axle for example, when you roll it onto the wheel alignment jig, one side might presently be taking 30% of the weight and the other the remaining 70%. Physical adjustments made on this basis will certainly not be right when after you roll it off the jig and the EAS decides to reverse the weight distribution to the opposite.
If you purchase an Autel unit, about £40, you can select Normal and Tight tolerance from your phone.
Tight Tolerance mode effectively makes the EAS system work much harder than normal to produce a near 50 / 50 weight distribution at all times and therefore produce more accurate than normal physical wheel alighnment adjustments.
It's not a mode you would want to run in continually, as i expressed to the OP as it makes the EAS system and valves work overtime and might possibly lead to premature wear out.
You also need to be sure yor EAS system is absolutely working correctly and properly calibrated which can be affected by any physical problems
So the best results are obtainable as follows.
1) Check your suspension totally, inspect each and every bush for any amount of wear and slop. Change anything suspect or as required.
2) re calibrate the EAS system heights and ensure it is performing 100% as it should be.
3) Put the EAS into tight tolerance mode.
4) Have a physical wheel alignment performed with adjustments done as required.
5) Put the EAS into normal running mode
I hope this helps
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| 5th Mar 2021 8:29 pm |
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L319
Member Since: 14 Dec 2013
Location: Herefordshire
Posts: 2080
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I used to work at Land Rover and I know that getting the air suspension algorithm correct proved very time consuming . Its not just height adjustment its also load adjustment. If you imagine a static situation, you can end up with two diagonal wheels taking most of the load and the other two just stopping if falling one way or the other . Adding the dynamics of movement to it as well just adds further complications.
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| 6th Mar 2021 12:57 pm |
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