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Post by chisbur on Sept 8, 2022 14:16:15 GMT 12
Hi there, do aftermarket rear wheel LSD's require certification? I don't see any exemptions for these in the VIRM.
I have a LSD here that is quite tight and causes a bit of binding/skipping on the wheels when doing slow turns in a small radius (e.g. on a service station forecourt or carpark).
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Post by Chris on Sept 8, 2022 17:21:31 GMT 12
Hi there, do aftermarket rear wheel LSD's require certification? I don't see any exemptions for these in the VIRM. I have a LSD here that is quite tight and causes a bit of binding/skipping on the wheels when doing slow turns in a small radius (e.g. on a service station forecourt or carpark). Hi Chisbur, a fitment of an LSD head does not require certification provided that only the differential centre is changed and the OE axle housing is retained. Or if the axle housing is replaced then the axle housing must fit the vehicle without adaptation, and there may be no change to the OE suspension geometry, plus it must retain unmodified OE drive-shafts(s), and there can be no changes made to the OE brake system. Where you might come unstuck, is an overly tight LSD, if the vehicle requires unreasonable force to steer the vehicle because the diff is so tight, then these are grounds to fail a WoF. Similarly, if the vehicle does not handle safely under normal conditions of road use, then it is also a reason for rejection. As a WoF inspector cannot dismantle the vehicle for a WoF inspection, a good method for them to test this would be a roadtest with a couple of decent roundabouts. If it feels unnatural (ie: it wants to steer off the road) then I imagine that could be reasonable grounds to fail a WoF. Keeping in mind that this is a subjective test based on the WoF inspectors experience and if they feel it is unsafe, then the onus is on the owner of the vehicle to show otherwise. If the inspector is suggesting that the diff feels locked (or the diff is so tight that it is effectively locked) You could demonstrate it is not locked with a breakaway test or similar by lifting one side of the vehicle and measuring how much force it takes for the wheel in the air to turn with the other wheel on the ground. Hopefully that helps Chris |
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Post by chisbur on Sept 8, 2022 20:42:14 GMT 12
Thanks for the response Chris,
Based off this statement, am I correct in saying that vehicles without a center diff (e.g. a RWD in this case) would therefore still require a certification?
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Post by Chris on Sept 9, 2022 7:33:06 GMT 12
Thanks for the response Chris, Based off this statement, am I correct in saying that vehicles without a center diff (e.g. a RWD in this case) would therefore still require a certification? Not sure what you mean by "center diff"? Do you mean the centre diff has been removed and its been converted from 4WD to RWD? |
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Post by chisbur on Sept 9, 2022 8:22:56 GMT 12
No conversion - just a standard RWD setup. Engine at front, drive line down the middle and differential at the rear.
My mistake though -I've just re-read your post. I was interpreting 'diff centre' as a 'centre diff' (as used in 4WD/AWD vehicles)
Thanks.
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