astra sxi 56 reg, just had it's first service in nov 9,500mls was told wheel alignment was out.
seen as the weather is getting colder and snow is on the way i thought best have good tread on the front,
checked fronts at 4mm rears at 7mm so swapped about, these wheel's were not removed in the service! i had to whack one off with my rubber mallet & cleaned up hubs with wire brush and a coat of copperslip to make this much easier if i get a puncture,
i think it's a bit poor that a main dealer does not remove wheels and clean the hubs as a precaution as they know alloy wheels corrode on the hubs, just wondered how many of you folk with cars of 1 yr-2 yrs that have not removed those wheels yet? maybe best get them done before you get a flat in a snow drift!!
tracking done pressure checked car drives spot on..
Edited by Dynamic Dave on 11/12/2007 at 21:15
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I bought alloys/fat tyres just after I bought my car.My remedy then is to fit the original steel wheels with plastic hubcaps and skinny tyres on for the winter and put the alloys with fat tyres back on in the spring. I have done this for the last 5 years and the alloys still look like new. Expensive I know and the car doesn't look that great in winter but its a nice compromise between winter safety and summer good looks.
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It came standard with alloys so no steel wheels not even sure if they do any, i do wash it every 2wks so to wash salt off & gave them a scrub when i took them off.
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>>cleaned up hubs with wire brush and a coat of copperslip to make this much easier if i get a puncture,
Is it a good idea to put a grease btween the wheel and the hub?
I thought friction was involved here, and even with what would only be very small movement, could this cause future problems?
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Is it a good idea to put a grease btween the wheel and the hub?
Some snipquoting taken place
I had new tyres fitted today to the Corolla and noticed the hubs were copperslip coated - last service was at the Toyota main dealer so presumably this is their standard practice when alloys are fitted.
Edited by Dynamic Dave on 11/12/2007 at 21:18
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>Is it a good idea to put a grease btween the wheel and the hub?
A very interesting question, but I've never given it a moment's thought. Here's a quick calc to estimate the required co-efficient of friction between the two parts. As ever, there are some necessary assumptions, and the input data I have used is at the top of the calc. As per usual, I am not claiming any exactness, but it's close enough to give a rough idea.
bolt_dia=12e-3; % 12mm bolts bolt_torque=100; % 100 Nm torque No_bolts=5; % 5 bolts in pattern bolt_PCD=120e-3; % 120mm PCD rim_dia=14; % 14 inch rims tyre_width=205; % 205mm tyre section width aspect=60; % aspect ratio % car_mass=1000; % car mass (kg) L_front=0.7; % proportion of car mass on front axle mu_tyre_road=1; % coefficient of friction between tyre & road
>>% To estimate the total clamp load pressing the wheel against the hubclamp_load=No_bolts*bolt_torque/(0.2*bolt_dia)
clamp_load =
2.0833e+005
>>% To estimate the rolling radius of the wheelRolling_radius=(1/1000)*(((rim_dia*25.4)/2)+(tyre_width*(aspect/100)))
Rolling_radius =
0.3008
>>% To estimate a braking force - assuming lock up with 70% of car's mass on frontbraking_force=car_mass*L_front*9.81*mu_tyre_road/2
braking_force =
3.4335e+003
>>%Use rolling radius to estimate braking torquebraking_torque=braking_force*Rolling_radius
braking_torque =
1.0328e+003
>>%estimate required hub/wheel coefficient of friction to avoid slippagemu_required=braking_torque/(clamp_load*(bolt_PCD/2))
mu_required =
0.0826
For a dry connection, the required coefficient will be easily exceeded, and especially so if the two parts corrode together, and there will be no slippage.
However, based on the calc, I could easily believe that if grease is used, slippage is likely under extremes of braking and acceleration. The first part of the joint that's going to suffer under this movement is the bolt, which will be subject to extra shear and bending loading (beyond any that's there due to normal tolerance mismatch). Sudden bolt failure due to fatigue would be the likely result.
So, I would say that for cars which are going to be regularly used in extremis that greasing the interface is a bad idea. If the car is used in extremis, the wheels will be changed regularly, and so corrosion isn't a problem.
For cars under "normal" use, then I don't see a big problem with using some grease. It is likely to avoid a service problem, and in "normal" use slippage will not be a regular occurrence.
I wonder if police pursuit vehicles and vehicles like Top Gears SIARPC vehicles use a greased interface?
Number_Cruncher
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Is there a problem?
With one exception all my Vauxhalls, from '85 to '07, had alloy wheels that were only taken off when necessary - most years the annual service consisted of oil & filter change plus MOT, relying on brake wear warning devices for pad replacement - not once, in 22 years, did an alloy stick on the steel or cast iron hubs.
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Well what can i say i must have only seen mine do it in the last 20yrs of been in the motor trade!
It's common for alloys that don't come off often, my point was this car is newish a small amount when fitted would have been a good idea!
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