MartinH Posted February 17, 2013 Share Posted February 17, 2013 When I was on the way to the CC Showroom send off this morning with the Penn gang... Slowing down for a mini roundabout and bang, crunch, g-r-i-n-d and my 🙆🏻 hits the floor. Next my near side rear wheel comes flying past me and unfortunately hits another Sevener in front and smashes his spare wheel carrier in. Apologies once again TrickyDicky ☹️ The wheel then carries on and hits another car crossing the roundabout side on and dents his door panel. How can this happen?? Forgotten to tighten up my nuts? Well, I am 99.999% sure they were all torqued up as per the manual. I also checked the other rear later today and they were all set correctly. On my way to the meet point I hit a 5" deep pothole with a big bang at about 30mph. I drove on another mile to the meet point and all seemed ok. The wheel then flew off about another mile after we all set off together on the blat. The pothole is my only explanation. Could this have caused it? Looking back I do remember a clunking when we drove off from the meet point but I thought it was something rattling in the boot. This must have been the wheel coming loose. By the way I don't have any copper grease or oil of any kind on the wheel studs. Has this happened to anyone else? The threads on the wheel studs look ok, as do the actual nuts but should I trust them again? Are there any super mega wheel nuts I can get that have a extra locking mechanism of any kind? I am now pretty paranoid that it could happen again! Not a good start to the season. 😔 Martin Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted February 17, 2013 Share Posted February 17, 2013 Could use medium strength threadlock on studs. It acts as anti-corrosion too. Sounds like the pothole impact is the cause. A lesson for us all to stop and check wheel security after such a hit ! Edited by - Stationary M25 Traveller on 17 Feb 2013 22:21:44 Link to comment Share on other sites More sharing options...
mic Posted February 17, 2013 Share Posted February 17, 2013 I'd be very surprised if the impact had caused the wheel to become loose, its more likely it was not tightened or some one has loosened it. Link to comment Share on other sites More sharing options...
Frying Pan Posted February 17, 2013 Share Posted February 17, 2013 Scary. Cant see how all four nuts could have worked loose hitting a pothole though -I think the 0.001% chance that you hadn't tightened them may be the cause. I'm always paranoid I've forgotten to do the obvious after working on my car... Edited by - 7heavensoon on 17 Feb 2013 22:43:57 Link to comment Share on other sites More sharing options...
Area Representative Paul Richards Posted February 17, 2013 Area Representative Share Posted February 17, 2013 Quoting mic: I'd be very surprised if the impact had caused the wheel to become loose, its more likely it was not tightened or some one has loosened it. Agree I've only known it happen when wheel nuts haven't been tighten properly. You haven't re-painted the wheels over winter have you? This could be a cause. Fresh paint will sometimes allow wheel nuts to loosen - need to re-torque after a couple of miles following painting. Link to comment Share on other sites More sharing options...
the_village_idiot Posted February 17, 2013 Share Posted February 17, 2013 Sounds scary! I think the likely story is they came loose because they were not fully torqued at some point- and perhaps the pothole was the catalyst. Either that or someone loosened them?! Have you used your 7 on the road a lot recently? At least the damage wasn't worse- god knows what would have happened if you had been doing 70moh- a freewheeling wheel at 70mph has a lot of momentium- Lorry wheels obliterate cars almost as bady as a head on motorbike would. On a side note- how much bolt thread protrudes from the alloys? Or to put it another way- how much nut thread is used by the bolts? Someone noted on mine it's perhaps 50-60% which seems a little low :s Edited by - the_village_idiot on 17 Feb 2013 23:30:05 Link to comment Share on other sites More sharing options...
Area Representative Nick Chan Posted February 17, 2013 Area Representative Share Posted February 17, 2013 I've know it happen when the wrong wheel nuts haven't been fitted and sleeved ones should have been used. The wheel has "rocked" on the studs and undone them. I can't believe this is the answer though for this problem unless you have changed rims and did need to use different nuts. I'd go with the wheel nuts not being tightened correctly on that corner Nick PS Really glad to hear that the damage caused was only very minor 😶🌫️ Link to comment Share on other sites More sharing options...
glasgow Posted February 17, 2013 Share Posted February 17, 2013 Sounds like the pothole impact is the cause. A lesson for us all to stop and check wheel security after such a hit ! Errmm, I thought wheel nuts are the only thing in the seven that matches tintop standards ... Eh, scary.... but anyway, good you are ok, Martin could have been worse.. Ahmed Link to comment Share on other sites More sharing options...
MartinH Posted February 17, 2013 Author Share Posted February 17, 2013 Thanks for the replies chaps. Just for the record, the wheels are original CC anthracites, not repainted. I have hardly used the car since Llandow in September. Been up on the stands while I worked on the engine. Fronts came off to give me more room to work in the garage and when they went back on few weeks ago, I torqued them all up including the rears. There seems to be plenty of thread operating on the nuts from memory but I will double check. I have the type with a little separate collar type washers. Cheers, M Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted February 18, 2013 Share Posted February 18, 2013 When I bought my car from CC it had 32mm long studs which only engaged in the nuts by a few threads ... with the anthracite wheels. I didn't like the thought of it at all, coming from an engineering background. CC wouldn't have it, so I bought and fitted 40mm long ones myself Link to comment Share on other sites More sharing options...
Jason Plato Posted February 18, 2013 Share Posted February 18, 2013 do you have closed ends on the wheel nuts ? - maybe you have bottomed out the wheel nut on the the stud ? giving a false sense of torque ..... if you follow ... Link to comment Share on other sites More sharing options...
MartinH Posted February 18, 2013 Author Share Posted February 18, 2013 Cheers Dave. I do indeed have the nuts with the closed end - so yep - worth checking. I'll have a look tonight at how much internal thread they have and how much thread is required on the exposed studs to lock onto. Martin Link to comment Share on other sites More sharing options...
weeman Posted February 18, 2013 Share Posted February 18, 2013 Must have been scary. Happened to me once, in a friends newly rebuilt TR6, doing 70 ish down the A13. I think that whatever the cause, you're unlikely to ever know for sure. Of course check stud lengths and wheel nut types so as to eliminate them but the most likely answer is an oversight on your part. I'm sure you didn't want to hear that, but I bet most of us have done it (I certainly have) but were lucky enough for the wheel not to fall off. There's no shame in it. What do they say? "The man who never made a mistake never made anything" Link to comment Share on other sites More sharing options...
CB Posted February 18, 2013 Share Posted February 18, 2013 If I am on track, then I re-torque the wheel nuts after every session - they do seem to come loose (I assume due to the heating/cooling expansion cycle). I started doing this after I finished one track day and found some of them only finger tight having been fully torqued at the start of the day... Link to comment Share on other sites More sharing options...
Roadru77er Posted February 18, 2013 Share Posted February 18, 2013 While we're on this topic what should they be torqued up to? Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted February 18, 2013 Member Share Posted February 18, 2013 On mine it's 75 Nm. Jonathan Edited by - Jonathan Kay on 18 Feb 2013 09:00:08 Link to comment Share on other sites More sharing options...
Roger Ford Posted February 18, 2013 Share Posted February 18, 2013 Have you checked your torque wrench? Is it a cheap Black Spur or Silverline type, or something decent? It would need to be well out for them to come loose, but it's entirely possible. Link to comment Share on other sites More sharing options...
MartinH Posted February 18, 2013 Author Share Posted February 18, 2013 Think mine are 72. I can see how this is going and its fair enough to make assumptions and I am more than happy to recognise mistakes but I am pretty thorough about things like this. I am pretty sure I have never put the wheels back on without torqueing them immediately. I also torque up several times during the day at track days (last one in September last year) - although I must say I have never found them to be loose (maybe I am not trying hard 😬 enough!). I have two torque wrenches - both from the Halfords Professional range. One that goes up to about 60 and the other about 300 I think. I use the big one to get the 72. The smaller one (which I had with me yesterday) was clicking at its max on the other nuts I checked at the side of the road so I think I must have been tight enough and can assume the wrenches are ok). Link to comment Share on other sites More sharing options...
Swiss Tony Posted February 18, 2013 Share Posted February 18, 2013 Quoting Stationary M25 Traveller: When I bought my car from CC it had 32mm long studs which only engaged in the nuts by a few threads ... with the anthracite wheels. I didn't like the thought of it at all, coming from an engineering background. CC wouldn't have it, so I bought and fitted 40mm long ones myself You come from an engineering background but earlier in the thread you believe that driving over a pothole causes 4 wheelnuts to undo themselves 😳 To the OP - They weren't done up properly . We've all done it at some point Link to comment Share on other sites More sharing options...
CB Posted February 18, 2013 Share Posted February 18, 2013 "They weren't done up properly" - from my own experience I disagree. They can be torqued fully and come loose. I never had a problem with road usage and minilites, but the 8 spoke wheels and track use do it quite reliably for myself and others... Link to comment Share on other sites More sharing options...
Alan Reeves Posted February 18, 2013 Share Posted February 18, 2013 I had one fall of when a TR3A decades ago when I was a teen still.I constantly had to have the brakes bled ...After one of these sessions I went on a run and thought I had a wobble on a long right hander but when I hit the straight....bang, car droops to one side and a flash as a wheel goes past me and ends up in a parallel ditch... Yep I failed to re tighten the wheel. Found the wheel and no damage apart from scored the cart spring area. Link to comment Share on other sites More sharing options...
elie boone Posted February 18, 2013 Share Posted February 18, 2013 If potholes would undo wheelnuts no rally car would ever finish the event, one of the reasons wheelsnut can come un done at track days is that the paint on the wheel gets soft, so unless you have steel inserts in the wheel make sure the paint is removed where the nut fastens the wheel. Also i think 75 is a bit marginal on a DD ( M12 ) i always do them up between 9Mkg and 10Mkg Link to comment Share on other sites More sharing options...
Swiss Tony Posted February 18, 2013 Share Posted February 18, 2013 Quite, and the roads of the UK would be littered with cars ditched with wheels missing Link to comment Share on other sites More sharing options...
myothercarsa2cv Posted February 18, 2013 Share Posted February 18, 2013 Quoting elie boone: Also i think 75 is a bit marginal on a DD ( M12 ) i always do them up between 9Mkg and 10Mkg I thought it should be 75 ft lb? So 100 Nm (or 10 Mkg)... Link to comment Share on other sites More sharing options...
Myles Posted February 18, 2013 Share Posted February 18, 2013 Like many others, I've *almost* lost a wheel - and it was as a direct result of allowing myself to be distracted when going around the car to torque the wheels after some maintenance - I managed three and then must have wandered off. I've never known any of my minilite replicas to loosen themselves on either of my sevens (with c. 50-60k total mileage including trackdays) - but am happy to be persuaded this can be a regular problem with other designs. ...and unless I'm having a brain-fade - I always torque mine up to 55 lbft as per the manual... It has always seemed quite low when you remove a nut torqued to that level, but I've never had any problems... Link to comment Share on other sites More sharing options...
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