Running with Slicks

[redjohnuk]

Hi all

Has anyone experienced wheel nut torque / security changing (tightening or loosening) when running slicks on a track day. Car is set up for ZZR's but have tried running std width (6") slicks without changing the suspension set up. After an extended run found the offside nuts really tight and scarily the nearside a bit loose!!!

Happened more than once.....

Any thoughts/observations would be welcome.

Thanks

[Ivaan]

I'd check the mating faces of the wheel, where it contact the hub. If you don't use that set of wheels regularly, you might have some degradation ? 

[Jonathan Kay]

Open or closed nuts?

How much torque are you using?

Jonathan

[redjohnuk]

Hi, all faces have been chemically cleaned, they’re closed nuts and 85nm torque.

[Duckpit]

Never had that problem

[aerobod - near CYYC]

I have had this problem when changing the wheels when the hubs are hot, typically when changing from wets to slicks or vice-versa between sessions when the hubs have not cooled down enough. Really requires a few laps then come in to re-torque the nuts. No problems with the nuts losing torque if the hubs are cool or only slightly warm when tightening the nuts. I do check nut tightness at 75Nm before each (normally 20 minute) session as a matter of course.

The rear hubs on my car are hotter than the fronts after a cool-down lap and take longer to cool due to the much more restricted air flow around the rear wheels. If I have to change wheels between track sessions, I try to get the wheels off as soon as I get back to the paddock and wait as long as possible to put the other wheels on before going out for another session, even if just leaving the rear wheels off if I only have a single jack to lift under the a-frame link to the de-Dion tube.

[redjohnuk]

That’s very interesting.... have you ever experienced one side getting tighter? 

I know technically it shouldn’t happen.  

I do find that when on a day with 20min sessions I can overlook coming in to recheck!!!

 

 

 

[aerobod - near CYYC]

Never had any tighten, but I’ve lost up to 20Nm of torque after about 12km of lapping when mounting wheels on hot hubs. In 2015 I did see someone with a VW, who had changed wheels for a session, lose all 5 wheel bolts - luckily he just was driving through the paddock wondering why he had a clunking sound, the wheel stayed in the wheel arch and we helped him locate the trail of bolts back to the track exit.

[redjohnuk]

Thanks for the feed back.

Think I’ll change the studs and nuts so I’ve a good basis to start from and keep a closer eye on it . Strange though I’ve been doing track days for years and never had this ‘issue’ before.

cheers