Myles Posted June 15, 2014 Share Posted June 15, 2014 I bought some open-ended wheel nuts for the Caterham this week (from Westfield! as I needed a couple of bits for my Megabird too... ) The car has always been on closed nuts until now. I fitted one set and them immediately removed them - only half of the thread is used The closed nuts clearly use the same amount of thread (I counted the turns to be sure) - so I'm sure they would be as safe as the scruffy old ones - but I didn't want to give my mot man any pause for thought..... Wheels are Minators - should I bother going to the trouble of fitting longer studs - the existing setup has seen me through 40k of hard touring and track days just fine.... Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted June 15, 2014 Member Share Posted June 15, 2014 What's the thread length of the nut and the diameter of the stud? Jonathan Link to comment Share on other sites More sharing options...
Wrightpayne Posted June 15, 2014 Share Posted June 15, 2014 Hi Mine was exactly the same as yours - there has been discussion about this before. I put new discs on mine a few years ago and put the longer studs in for peace of mind. The end of the stud now flush with the top of the open ended wheel nut. I also remember seeing sprint cars with 2 or 3 cm of thread sticking through the nut presumably for easy addition of spacers?? Ian Link to comment Share on other sites More sharing options...
revilla Posted June 15, 2014 Share Posted June 15, 2014 My car is exactly the same. I was worried and had a chat with Nick Potter about it. He said it might look alarming but was quite normal on these cars and in the many years he had been around them he had never known it lead to a failure. There certainly wasn't a general history of the nuts coming loose on the shorter studs. Link to comment Share on other sites More sharing options...
6speedmanual Posted June 15, 2014 Share Posted June 15, 2014 Turn the nuts down in a lathe so the unused section is removed. Saves total, rotating and unsprung mass. Peter Link to comment Share on other sites More sharing options...
Myles Posted June 15, 2014 Author Share Posted June 15, 2014 Thanks. Peter - if I turned these down, there probably wouldn't be much of the flats left to gain a purchase! I'll check them out again when I've got through this mot - the Westie has the same nuts - I think the studs are shy there too, but not by as much. When all is said and done, I'd never have spotted this if I'd stuck with closed nuts - so any remedial work will wait until the next big rebuild, most likely... Link to comment Share on other sites More sharing options...
2GBR Posted June 15, 2014 Share Posted June 15, 2014 Just because a wheel has not fallen off a car means it is good engineering practice, But certainly does not require many threads to do the job Link to comment Share on other sites More sharing options...
ECR Posted June 15, 2014 Share Posted June 15, 2014 Chew this over ..... 😬 Thread engagement length. In general, according to Machine Design magazine, the minimum recommended length of engagement is 0.75 to 1 times the bolt major diameter for threading into steel and other materials of comparable hardness; and 1 to 1.5 times the bolt major diameter for threading into brass, cast iron, and aluminium. These lengths of engagement specified are for full threads engaged, not overall bolt length. Regarding partial threads in the chamfers on the ends of internal or external threads, FED-STD-H28/2B, 1991, Sect. 7.7.2, p. 61, specifies that approximately half the countersink or chamfer depth may be included in the length of engagement calculation. For a 12mm x 1.5 pitch nut that equates to 6 complete turns of the nut (9mm of engagement - .75d) - MINIMUM acceptable 8 complete turns of the nut (12mm of engagement - 1d) 12 complete turns of the nut (18mm of engagement - 1.5d) MSA standard Link to comment Share on other sites More sharing options...
rgrigsby Posted June 15, 2014 Share Posted June 15, 2014 Good advice above, FWIW whilst I've never had a problem with Barnby alloys when I bought a set of CXR wheels a few years ago the rears were very marginal so I ended up fitting long studs. I've got open ended up wheel nuts as well but I don't think the stud actually comes all the way through the wheel even with the longer stud fitted. Link to comment Share on other sites More sharing options...
Mankee Posted June 15, 2014 Share Posted June 15, 2014 I was going to post in your wheel nut thread from a few days ago, but never got round to it. I originally had 32mm length studs, but after upgrading my front hubs (complete with longer studs), changing rear calipers etc., I have fitted the normal Caterham/Redline 40mm studs to the rears as well, as I need to run 3mm spacers with 7J Minators in order to clear the brakes and ARB drop links. Having open-ended nuts allows you to see how little thread engagement there is with the short studs and I'm much happier with the 40mm studs, especially at the back, although they will be untested until tomorrow. Link to comment Share on other sites More sharing options...
Myles Posted June 16, 2014 Author Share Posted June 16, 2014 Thanks. ECR - I counted approx 6.5 to 7 turns on the nuts on the front wheel! Didn't try them on the rear... Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted June 16, 2014 Member Share Posted June 16, 2014 Rule of thumb for common materials (as well as MSA regulation, as ECR says) is that thread engagement length should be 1.5x bolt (stud) diameter. At least two turns of thread should be protruding through the nut. Jonathan Link to comment Share on other sites More sharing options...
Jason Plato Posted June 16, 2014 Share Posted June 16, 2014 been like this for 20 years or more its not right but its proven to be OK. Longer studs fix the non existent problem Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now