Tony Whitley Posted January 31, 2011 Share Posted January 31, 2011 Trying to explain why my car snapped 90 degrees on a straight, dry road when being driven "normally" (i.e. not expecting anything untoward because I wasn't anywhere near the limit). It happened less than 200 yds from setting off with no warning so I'm thinking the tyre had a slow puncture. I think I remember hearing that LSDs will do this if one tyre is giving less grip than the other and I can see it in theory, can anyone confirm this or am I talking rubbish? Link to comment Share on other sites More sharing options...
Piers Rendell Posted January 31, 2011 Share Posted January 31, 2011 Something very similar happened to me, when the De Dion tube broke. Have a close look at it. Link to comment Share on other sites More sharing options...
Tony Whitley Posted January 31, 2011 Author Share Posted January 31, 2011 I checked that thanks, it looks OK. Link to comment Share on other sites More sharing options...
MADMALC Posted January 31, 2011 Share Posted January 31, 2011 Check the rear radius arm/arms for attachment. My watts linkage rear bolt did undo it's self two turns in only a few miles. Loctited and regularly finger checked now. S7MAD Link to comment Share on other sites More sharing options...
Wight Skipper Posted February 1, 2011 Share Posted February 1, 2011 Were you accelerating? Link to comment Share on other sites More sharing options...
Sheds Moderator Posted February 1, 2011 Share Posted February 1, 2011 The LSD thing is when you are accelerating out of a corner. If you have an open diff then when one wheel starts spinning all the power goes to it and the other one freewheels. As a result only one wheel has lost traction and the other one steers you round the corner. In a similar situation with an LSD one wheel starts spinning and the power is maintained to the other wheel. If that too breaks traction then you have 2 spinning wheels and that end of the car will go straight on. If it's RWD then the car will be sideways very quickly. Link to comment Share on other sites More sharing options...
Tony Whitley Posted February 1, 2011 Author Share Posted February 1, 2011 Yes, I was accelerating, firmly but nothing excessive as the engine / night / tyres were cold though it was dry, I had just changed up to 3rd. BOSS, something like that is theory I'm working to but I'm fairly sure I was already round the slight bend (not enough to put any great load on the tyre, I was only doing 20-30, just changed from 1st to 2nd). I had a slight sense of a loss of traction (forwards not sideways) when I let the clutch in in 2nd gear but other than that nothing felt wrong. If the NSR tyre was soft and started spinning forwards the LSD would suddenly put all power through the OSR and that would have to cope with all the load of accelerating the car. The car will easily break traction of both rear tyres on a dry warm road if the up-change to 3rd is clumsy so if a single tyre was asked to cope with normal acceleration I can see that it would not have much chance. I'll check the radius arms later, I hadn't thought of that Link to comment Share on other sites More sharing options...
bstark Posted February 1, 2011 Share Posted February 1, 2011 In a straight line I have had this on a dual carriageway in close zero degree temperatures, and a slippery wet road. The road was uphill and the camber was enough for the car to snap violently in 2nd. I gathered it all up but it took me both lanes to do it, which was a bit of a worry. It was extremely slippery though as touching the throttle afterwards lightly was enough for the back to step out. Just wondering if there was a bit of oil around for you? Bob Stark Supersprinter Link to comment Share on other sites More sharing options...
Tony Whitley Posted February 1, 2011 Author Share Posted February 1, 2011 A few degrees above zero and dry as a bone but otherwise your experience sounds similar. In a fraction of a second I was travelling sideways, out of control, at no point did I have any chance of making any difference. We checked the road at the time (11 pm) and I went back yesterday in daylight - clean as a whistle. Link to comment Share on other sites More sharing options...
Mr Locust Posted February 1, 2011 Share Posted February 1, 2011 If the NSR tyre was under inflated, the rolling radius would also tend to decrease. In conjunction with heavy acceleration that would take quite a bit of load off the OSF tyre. Depending on steering geometry that could give quite a change to the car feel. Could that pull on the steering be what you experienced? Ian Green and Silver Roadsport 😬 My Flickr Photos Blatchatters Flickr Pool Link to comment Share on other sites More sharing options...
rj Posted February 1, 2011 Share Posted February 1, 2011 If you have a puncture you'll have rear end steering, but not 90 deg out of nothing. Link to comment Share on other sites More sharing options...
Wight Skipper Posted February 1, 2011 Share Posted February 1, 2011 Also add a bit of spilt diesel into the mix maybe... Link to comment Share on other sites More sharing options...
bstark Posted February 2, 2011 Share Posted February 2, 2011 Tony, It's a scary feeling isn't it . What I would say is that whenever I have had something broken on a car / tyre gone etc. then I can definitely feel it in normal driving afterwards. In my case it was definitely the road conditions and the car has been fine since. How does yours feel? Bob Stark Supersprinter Link to comment Share on other sites More sharing options...
Tony Whitley Posted February 2, 2011 Author Share Posted February 2, 2011 If feels not very well ☹️ Approximately two seconds after snapping sideways it hit the kerb of a side road on the other side of the road, breaking 3 wheels and bending bits of the N/S suspension I didn't have time to feel scared, it was snap / oh **** / bang. pics Link to comment Share on other sites More sharing options...
peterg Posted February 2, 2011 Share Posted February 2, 2011 Have you checked the front? it might not be the back end at all, maybe something broke on the front steering/suspension/brakes? just a thought and probably not it at all but worth a careful check over Link to comment Share on other sites More sharing options...
Tony Whitley Posted February 2, 2011 Author Share Posted February 2, 2011 I do have a lot of toe out (15 deg or so) which seems more than can be explained by the deranged front wishbones. I haven't tried straightening out the suspension yet to see if the wheels then point in the right direction, I was waiting until the insurance inspector had seen the car. Link to comment Share on other sites More sharing options...
peterg Posted February 2, 2011 Share Posted February 2, 2011 Broken steering rack? mounts? etc Link to comment Share on other sites More sharing options...
bstark Posted February 2, 2011 Share Posted February 2, 2011 Ouch! Given damage has been done its probably best to have a 7 specialist go over the whole car and see if they spot anything... Bad luck Bob Stark Supersprinter Link to comment Share on other sites More sharing options...
Tony Whitley Posted February 2, 2011 Author Share Posted February 2, 2011 Definitely, it's in hand. Link to comment Share on other sites More sharing options...
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