Tyres rubbing shocks

[GTRMikie]

When my van is stationary there is about one inch clearence between the rear inner tyre side wall (Yokos fitted to 5x10 wheels) and the shock absorber. However it is obvious that at some stage the tyre rubs on the shock absorber (paint rubbed off, tyre wall scuffed). There is no play in the suspension. Is this just due to body roll? I do not get the impression that the van is rolling all that much, however spirited my cornering is! I think the shocks are standard items. Would changing to something a bit stiffer cure this problem?

[tim-d]

Just to eliminate the obvious - could this be from a previous set of wheels & tyres? however sprited the cornering with an inch of clearance this just shouldn't occur and I don't think changing shocks would necessarily solve anything - chief suspect would be the radius arm or the subframe closing plate hole for the radius arm being ovalled - mark the nut with some tippex and indulge in some judicious experiemtal driving. .....disturbed tippex spells trouble...
One really simple thought though if all is fine from a subframe / radius arm perspective - have you had a flat lately? to get the tyre wall into contact with the shock would take some very low pressure & hefty cornering..............

[GTRMikie]

tim-d said:

One really simple thought though if all is fine from a subframe / radius arm perspective - have you had a flat lately? to get the tyre wall into contact with the shock would take some very low pressure & hefty cornering..............

I like the idea of the flat tyres. For some reason my rear tyres do seem to loose pressure quite quickly. I have yet to determine the cause of this, but it is highly likely that I have driven the van with low pressures. Even with pressures as low as 8psi they appear to be inflated but the gauge tells a different story! I will put some tape round the shocks, make sure the tyres are inflated, do some spirited cornering then check if the tape is scuffed. I'm not sure why the tyres lose pressure. The valves aren't leaking and there are no punctures so I must assume the seating on the rim is faulty. Anyone had this problem with Performance alloys and Yokohama tyres?

[tim-d]

strangely yes! I have some aged slotmags that kept losing pressure in about a fortnight but held steady at between 10 - 15 psi gave up on them in the end and put some steels on with no problems - have just had the tyres off the slots and all the internal rubberised paint has flaked off which I'm guessing may go a long way to explain the escaping pressure going to have these fully refurbed shortly but there is another option - for 10 inch wheels at least minispares have some inner tubes....................

[skyedriver]

Porous alloys or leaking past the seal between tyre & rim. The wheel may look ok but will probably be corroded where the tyre sits as water collects here. Some tyre places clean the rim up super good and apply a black sticky stuff (getting technical here) others just slap on a new tyre. One thing to try, blow up the tyre to about 45 or 50 then let it down again. Maybe even run it up & down the road. It might just reseat it.
Re shocker prob Mike, you haven't got super neggy camber on the back have you? As the tyre moves into the arch it wouldn't run parrallel with the shock?
If you run a flat tyre, I would have thought the profile at the top of the rotation would be little changed....it's only flat at the bottom remember. (said seriously)

[GTRMikie]

skyedriver said:

Re shocker prob Mike, you haven't got super neggy camber on the back have you? As the tyre moves into the arch it wouldn't run parrallel with the shock? If you run a flat tyre, I would have thought the profile at the top of the rotation would be little changed....it's only flat at the bottom remember. (said seriously)

All the geometry at the back is standard and there is no play in any of the bearings or bushes. I can see Tims point about soft tyres though, which will have more flexible side walls. When cornering hard, I think the whole tyre may deform into a conical shape with the hub nut at the point, although this will be more pronounced at the bottom. As long as the tyre is gripping the road, the wheel, and thus the body, move sideways but the tyre stays where it is and thus fouls the shock. Does that make sense or am I talking b******s?

[GTRMikie]

Just back from testing the "soft tyre" theory. Put some tape on the shocks where they had previously been rubbed, pumped the tyres up to 30psi then gave the van a good thrashing round my favourite twisty bits. Result, tape still intact therefore no rubbing. Tim's theory is thus proven! All I have to do now is stop the rear tyres from losing about 20psi every seven days!

[wildoliver]

if its porous alloys then bang a tube in.