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Is 55 lbft really enough?


Andrew

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I had my tyres changed yesterday and asked the garage to torque the wheel nuts up to 55 lbft as per the owners manual. The mechanic said that 80 - 90 lbft was more usual. I did a couple of the nuts up to 55 lbft using his torque wrench and I have to say I agreed with him. If I'd been changing a tyre at home using a normal wrench I would have done them up a lot tighter. The wheels are 14" minilite style (two gates) alloys.

So is 55 ftlb enough, do I usually do them up too tight or am I just worrying too much?!

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I have found (on my car anyway) that anything less than 55lbft is too little and the nuts work loose on track days. Anything more on an alloy wheel is too much and over time will damage them.

 

My humble advice is to buy a good quality torque wrench. 15 quid will buy you one that will screw your nuts up (ooer!) a treat. Halfords do some lurvely ones with a good torque range for 45 quid and that's where I'd start.

 

Of course if anyone follows my advice and sh*gs their wheels up or they fall off don't come running to me. This isn't America you know.

 

Davebo

C7 CAR

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Is 55 lbft enough. Is more going to damage thread?

The prev owner of my car had over tightened the wheel nuts on my car and pulled the threads.

This led to my little wheel off excursion last year at Abingdon.

Make sure you have steel inserts in the Ali wheels. My wheel did not this may

have contributed/compounded my problem.

Also check that the mating surfaces are completely clean.

 

I was not convinced by the 10mm of thread the nuts were using so popped longer studs and open ended racing nuts (22mm) on too. I saw that Alex W has this arrangement too.

 

I can't see why thread lock couldn't be used at 55lbft??? Any reason

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I must admit being a bit concerned about the short studs which are standard on my Superlight R. I would say that each nut can only get hold of about 10mm of thread. Looking at the postings on this thread I think I would be happy with some longer studs.

 

Has anyone got any recommendations about where to buy the longer studs and how easy is it to get the existing ones out?

 

Thanks, Andy

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On the lenngth of studs: MSA requirements are for 1.5 times the diameter of the stud for the wheelnut. Thus for 12mm studs 18mm should be visible.

 

On torque values I would set 55 ft/lbs as the upper limit. Much more risks stretched and weakened studs. From memory Caterham recommend between 45 and 55. I did about 20 sprints and hillclimbs last year with no trouble at all at 45 ft/lbs. But I do check the nuts regularly.

 

Longer studs are available from stores such as Burton Power and are quite easilyknocked out and replaced.

 

Hope this helps.

 

Barry

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One other thought occurs.

 

The torque values used also depend on whether there is any lubrication on the stud or not.

 

If there is lubrication, a given torque figure will be tighter than the same value where no lubrication is present (because less torque is required to overcome friction between stud and nut).

 

And another thing!!

 

Ital studs are thinner than Ford studs so they have less margin for error.

 

Looking back at this post I think I've probably just made it less clear - sorry.

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I got my longer studs and race nuts (oooh errr!) from Autocross.

Studs £1 each, nuts £1 something each.

You have to split the disk and hub on each wheel (De dion) to drift out and in the new studs. To remove the disk you need to undo the rear hub nut (tightened to 200lbft) don't forget the left hand side is a left hand thread.... and remove the calipers (two bolts). Halford do a suitable long torque wrench that goes up to 240 odd lbft for £50. Clean the hub nuts and thread and use plenty of threadlock or get new nyloc hubnuts if you are really pedantic.

The fronts are split pins with a castlelated nut. Tip...to remove the metal covers on the front hubs use a small sharp dot punch at a outward facig angle to tap around.

 

I agree with all that has been said about over tightening!

 

 

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I got my longer studs and race nuts (oooh errr!) from Autocross.

Studs £1 each, nuts £1 something each.

You have to split the disk and hub on each wheel (De dion) to drift out and in the new studs. To remove the disk you need to undo the rear hub nut (tightened to 200lbft) don't forget the left hand side is a left hand thread.... and remove the calipers (two bolts). Halfords do a suitable long torque wrench that goes up to 240 odd lbft for £50. Clean the hub nuts and hub threads and use plenty of threadlock or get new nyloc hubnuts if you are really pedantic.

The fronts are split pins with a castlelated nut. Tip...to remove the metal covers on the front hubs use a small sharp dot punch at a outward facig angle and drift around gently.

 

I agree with all that has been said about over tightening!

 

 

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