Smithy77 Posted April 7, 2015 Share Posted April 7, 2015 Jonathan,Finally got round to measuring my studs over the weekend and can confirm:Front stud length fron hub = 28mmRear stud length from hub = 21mmand by measuring the amounth of 'clean' thread it looks like the rears engage about 9mm of threadI'm not sure on the diameter of the stud to do your rule of thumb calculation, but it would appear I am below the limit of 1.5 x stud diameter??Do I have anything to worry about? I'm guessing the car did 4/5 seasons of motor racing with its current set up, and presumably with no wheel nut issues... Link to comment Share on other sites More sharing options...
Mike-360R Posted September 7, 2023 Share Posted September 7, 2023 Just 're-opening' this thread having searched for wheel nut torque settings after a conversation with a few members at the Donnington track day this week. All of us had the 15" Orcus alloys on relatively new cars - three Duratec and one Sigma. The latest Caterham build manual for Duratec (Edition 2.0 - page 187) states the wheel nuts should be torqued to 85Nm. However, the rest of the guys at the track torqued theirs to 75Nm (which I have also seen mentioned in this thread).Just wondering what the latest general consensus / advice is as it may appear I am over-torquing mine. For info, I use copper-slip grease on the threads. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted September 7, 2023 Member Share Posted September 7, 2023 The recommendations in the Assembly Guide have changed from 75 Nm to 85 Nm (as you say). Discussions in the past had commented that 75 Nm seemed a bit low.I don't expect that there's much experimental evidence either way.Jonathan Link to comment Share on other sites More sharing options...
Dixa1225 Posted September 7, 2023 Share Posted September 7, 2023 Should be 85NM , do not use copper slip on the threads. Link to comment Share on other sites More sharing options...
Mike-360R Posted September 7, 2023 Share Posted September 7, 2023 Thanks #28, #29. I'll stick to the 85Nm and clean up the threads when the wheels are off next. Link to comment Share on other sites More sharing options...
John Vine Posted September 7, 2023 Share Posted September 7, 2023 Up till now, I've tightened to 75Nm (2008-era 15" anthracites). If CC now recommend 85, I'm happy to move to that.I don't lube the threads at all, due to the risk of over-stretching the stud before reaching the specified torque. But I do make sure the threads are really clean.JV Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted September 7, 2023 Share Posted September 7, 2023 The M12 studs should be safe to at least 120Nm without damage. I have found the rear wheel nuts loosen by about 30Nm on the track as the hubs heat up (no noticeable change to the fronts). I torque to 85Nm before a track day, then ensure they are at 75Nm when hot after coming off the track. Link to comment Share on other sites More sharing options...
Guy Lowe Posted September 7, 2023 Share Posted September 7, 2023 DO NOT LUBE THE STUDS Link to comment Share on other sites More sharing options...
DW199 Posted September 7, 2023 Share Posted September 7, 2023 I torque to 85Nm before a track day, then ensure they are at 75Nm when hot after coming off the track.What is the reason for the lower torque when hot? Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted September 7, 2023 Share Posted September 7, 2023 What is the reason for the lower torque when hot?I think differential expansion of the hub and brake disk and possibly the use of the alloy cones on the wheel nuts. It is quite consistent and has always done it when the rear hubs and brakes get really hot. I find the loosening torque when the wheels cool down again is pretty close to 85Nm, if the hot tightening torque is kept at 75Nm. Link to comment Share on other sites More sharing options...
CAT170 Posted September 10, 2023 Share Posted September 10, 2023 I have been fortunate to own a number of new cars and each one has had a small amount of lubrication on the wheel studs/nuts or bolts from new. I don't know what they use but can say that whatever it is it lasts for years, and if you have your car serviced regularly then the manufacturer's advice is correct. On other cars I've fixed which had no or almost no lubrication I applied a small amount of oil or copper slip and then wipe it - a completely dry thread is not going to be a good idea. Below is a link to an interesting video but I suggest jumping to 2 mins and stopping at 5 mins as although I agree with him and think he is a competent and honest engineer, he is usually rather non PC and a bit Marmite. Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted September 10, 2023 Leadership Team Share Posted September 10, 2023 Only on Blatchat could we run to four pages on how tight you should tighten your nuts! Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted September 11, 2023 Member Share Posted September 11, 2023 IIUC from previous threads about threads there seem to be two separate points:1 Whether it's a good idea or not to put anything on them.2 If you do then the book torque setting will no longer be optimal. Jonathan Link to comment Share on other sites More sharing options...
John Vine Posted September 11, 2023 Share Posted September 11, 2023 #38: If you do then the book torque setting will no longer be optimal. Absolutely. This table gives a good idea of the torque reduction required for lubed threads.JV Link to comment Share on other sites More sharing options...
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