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Post by welshy1 on Nov 18, 2012 17:13:32 GMT
Just read a story over on another forum which reminded me.
The iva test requires a roll road brake test but cars equiped with an lsd should not be tested on a rolling road as when testing the one wheel the diff will try to spin the other wheel thats not turning potentialy damaging the diff it's the same for 4wd cars too.
So could you argue to not brake test the vehicle using the rolling road due to the lsd.
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Post by stevieboy on Nov 18, 2012 17:36:19 GMT
A rolling road will spin both wheels at the same speed, thus eliminating the lsd to operate, as it would on a slippy surface.
When the brakes are applied that will show the difference.
The problem with four wheel drives is that rolling roads are generally catered for only two wheels, so permanent four wheel drives are a problem, i have a discovery and my garage do a drive fast brake hard method on the open road to see if it stops in a straight line.
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Post by welshy1 on Nov 18, 2012 18:10:38 GMT
Not when checking for each side. Im sure the one roller doesn't operate when the other is being used will have to double check in work.
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Post by h5ngs on Nov 18, 2012 19:33:11 GMT
you only operate the brake rollers on one side unless testing both sides, also how many mx5s have been on the roads for the past 20 odd years with LSD which have had normal mot's every year and not had an issue, it damages 4x4 as it fooks the transfer box, turns 2 wheels when 2 are stationary but the LSD will be fine. Or that's the way i see it anyway  |
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Post by welshy1 on Nov 18, 2012 19:45:34 GMT
you only operate the brake rollers on one side unless testing both sides, also how many mx5s have been on the roads for the past 20 odd years with LSD which have had normal mot's every year and not had an issue, it damages 4x4 as it fooks the transfer box, turns 2 wheels when 2 are stationary but the LSD will be fine. Or that's the way i see it anyway I was always led to believe that to but over on another forum there have been a few cases of lsd being damaged by the use of the rollers can't say ive seen it myself. Also some mot testers have commented that any car with a lsd shouldn't be brake tested using the rollers. |
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Post by stevieboy on Nov 18, 2012 21:04:03 GMT
with lsd, traction control, sport mode, switchable auto, etc, etc
not heard any major issues with rolling roads.
iI personally wouldn't worry about it.
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Post by malcolmmazda on Nov 19, 2012 12:22:25 GMT
The MX-5 VLSD (older one) will be ok but some of the later Mk2 Torsen's have started disintegrating, possibly as a result of MOT tests. There are significant threads on the OC site etc
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glen
Newbie
Posts: 2
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Post by glen on Dec 4, 2012 20:57:06 GMT
I have been MOT tester for a number of years. Cars with lsd should not be tested on roller brake tester (both perm 4x4, standard 4x4 and 2 wheel drives with lsd may suffer damage). VOSA will be aware of this. If you inform the tester your car has a lsd they will probably use a decelerometer (G meter) to test brakes. All mot stations have to have them and vosa will be the same.
Hope this helps.
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Post by chizzy on Dec 6, 2012 7:16:55 GMT
Been an MOT tester for many years too, and totaly agree with Glen, cars with lsd have to have there brakes tested with decelerometer no matter if 4x4 or 2 wheel drive......just make sure you inform the tester in case he does not spot you got one
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