2) Steering Wobbles on Braking/Cruising

These kind of can be due to any or more of the following :

i) Dynamically unbalanced Wheels - especially upfront. Rear ones also matter.

ii) Upset Wheel Alignment on one or more of its 4-principal constituents viz -i) Toe-in, ii) Castor, iii) Camber and iv) 'Offset'.

iii) Unevenly worn front Tyres.

iv) Worn-out Steering/Track Linkages/Suspension Bushes/Members.

v) Out of true Front Disc Brake Rotors. Re-machining them in local lathe shops can only make it worse as their 'run-out' tolerances are of the order of < 10 microns, which such shops can never achieve.

vi) Faulty/Worn out Caliper Assys OR sticky Hydraulic Piston/Rings thereof.

vii) Out of true Wheel Rims.

viii) Defective Engine/Gearbox Foundations.

3) Torque-Steer

Most Sensitive drivers at some time or the other experience that when accelerating hard, the car briefly pulls to a side for no apparent reason. Such a phenomenon is known as 'Torque-Steer' in auto lingo and afflicts practically all FWD Cars where the two drive-shaft lengths are inevitably unequal - due to the Power-Train layout.

In most such Cars, the RHS Drive Shaft is longer in length compared to the LHS one. Since the 2-DS's are made using the same 'shaft' material for reasons of mass-economy, their 'end to end torsional-stiffness' varies - being inversely proportional to their lengths - per elements of applied mechanics.

In other words, the longer/RHS-DS has lower torsional stiffness than the LHS one. Therefore, in the event of high torque/acceleration, the drive torque takes a fraction of a second longer to get transmitted to the RHS wheel, compared to the LHS one - tantamounting to it being 'effectively braked' for a while compared to the LHS one - hence the steering drag to the right.

This problem can be pretty annoying in high performance sports cars and to overcome it, designs are now available where the two drive shaft lengths are made equal. However, in mundane cases like ours, there are two possible solutions :

i) Grin and bear it, knowing what's causing it, or

ii) Make the RHS wheel 'toe-in' a shade higher than the LHS one - but ensuring that it's still within the OE tolerance specified. This should minimise the drag under hard acceleration, if not eliminate it.

Having done so, it'd be advisable to keep a close watch on any uneven/rapid wear of the two front tyres. If observed, take corrective action accordingly.

4) Side Drag in Cars

FYI, side-drag can be caused in a Car by any or more of the following :

i) Unequal 'cold' tyre pressures - either up front or rear.

ii) Asymmetrical tread patterns/different brands - particularly up front.

iii) Unequal wear up front - leading to difference in overall wheel dia's of > 2mm.

iv) 'X' rotation of Radial Tyres - which must be moved up and down on the same side only.

v) Difference in RH/LH 'Wheel Bases' of > 5mm, due to whatever reason - severe bumps or post accident repairs being most common.

vi) Faulty Wheel Alignment - by way of - a) Toe-in, b) Castor, c) Camber and d) 'Offset'.

e) Significant 'unequal' loading - especially upfront - say driver weighing 50 kgs and the passenger weighing > 75 kgs - more so in Cars lighter than say 750 kgs.

f) Heavy 'Crown/Camber' of the road surface - generally leaning excessively to the left.

g) Strong 'cross winds'.

h) 'Torque-Steer' - usually in Powerful/100 bhp/ton FWD Drive Cars - more pronounced while accelerating – as discussed above.

5) Altering OE Wheel Specs

Tampering with the OE Wheel Specs of a Stock Car is far from advisable - as they are arrived at after exhaustive R&D by the OEMs to give best possible results under the most trying conditions that an average motorist is likely to encounter.

On the otherhand, altering the designed 'Track' of a Car is a total NO-NO !

All these can even lead to annulment of your Warranty and hence the Insurance Cover - should something go wrong !

Anyway, there's an informative Article posted under our 'Infobank', titled 'Upsize but don't Oversize'. Pl Surf it and you'll get some 'safe' options for your Car - but at your own risks.

The basic funda there is of 'one-up' and 'one-down'. In other words, one can go for the next higher/wider 'foot print' but the next lower 'aspect ratio' too at the same time - maintaining the OE Rim size - such that the 'overall' Wheel Dia doesn't change beyond +/- 5 mm.

Wider 'foot-print' means better handling but at the cost of higher Fuel Consumption and stiffer steering at the same time. Lower 'Aspect Ratio' means a stiffer ride/more rim damage at the cost of better handling/body roll