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Fitting bigger wheels:
245/75-16 on a Stock Discovery
What - No Lift?
There is a common misconception that you will have to "lift" the vehicle to be able to fit taller and bigger wheels. It is also believed that if you fit taller springs ("suspension lift"), there will be no rubbing and no need for cutting the wings. Bigger wheels "fill" the wheel arches more than stock 29", and the belief is that taller springs will prevent the wheels from rubbing the wings.
This is all wrong! Fact is a suspension lift will allow more articulation until it rubs, it will not remove the rubbing problem. Rubbing is mainly determined by the size of the wheel in relation to the wheel arch size.
Rubbing occurs when the wheel is pushed into its wheel well when axle is flexing, i.e. it is the articulation of a bigger wheel that causes the problem. To prevent a bigger wheel from rubbing, fitting taller axle bump stops will do the business (which will reduce articulation upwards). If the axle is allowed to flex, some metal cutting will be needed to fit bigger wheels.
The size fitted is only moderately larger than stock, and according to other Discovery-owners experience, should not need any taller bump stops, and only slight cutting of rear wing - it is even reported that no cutting is needed (though this probably depends on the make of the tyre)!
To be able to check for rubbing, you will have to check on a ramp or on the trail. Using a trolley jack to lift a wheel will not put the weight on an axle as what occurs when flexing going uphill and most of the weight is redistributed to the rear axle.
245/75-16
The 30,6" sized wheels being fitted should come on quite easily. This tyre size is a very popular size in the US, and are ususally fitted with a moderate suspension lift of 1-2". Fitting taller springs will increase articulation, i.e. giving the vehicle even better offroad performance.
These wheels are pretty wide and chunky, are reasonably tall, and really enhance the looks of a Discovery. Though a bit of suspension lift on the vehicle will give a bit more balance between tyre and wheel well, there is no problem running this tyre on an otherwise stock suspended vehicle.
Taller wheels spell less accelleration (and increased top speed). The discoverys speedometer read ~87 km/h when actually running 80km/h, so at 6% speed change, the taller wheels should in fact give a more accurate reading...
As seen on this picture, the difference between the old/worn 205/80-16 and the new 245/75-16 are approximately 4 - 4,5 cm. This moderately taller tyre will increase ground clearance by ~2cm over stock.
Cutting of the wings
Likely spots of rubbing according to others experience on this size are: Front: Spoiler/apron. Rear: Wing aft of wheel.
the discovery had no spoiler/apron, so attention was turned to the rear wings. Browsing internet pages showed a horizontal cut of 4-4,5 cm was needed to fit the rather large 32" tyres like 235/85-16. To fit 245s, only the horizontal lip (not the vertical wing itself) is necessary, according to many users.
It seems lots of people fit these tyres without cutting the wing - but if you do not cut, and you really need it, you might ruin your precious new tyres. Cutting too much is better than too little, and one large cut would make the wing ready for even bigger tyres at a later stage. So the cut intended for 32" tyres were decided, even if a much smaller piece of metal should suffice (or even no metal cutting might be needed, as reported by several owners).
A straight line was drawn from the rubbing strip (or where it would have been) downwards.
This is known as the Camel Trophy Cut, as this was the cut made by Land Rover Special Vehicles to be able to fit 7.00-16 wheels on Camel Trophy Discoveries.
The blue masking tape shows where to cut (aft of the tape). RH side pictured.
Firstly, an electric jigsaw was tried, but the wing vibrated violently, so a clean and straight cut was impossible. An electric nibbler also proved useless. The old plate cutting scissor, on the contrary, achieved a straight and clean cut (LH side pictured). An angle grinder, or even better a Dremel would probably have been more suited for the job. The burrs were then removed to create a more tidy look.
Rubbing on Radius Arm
Next step was to check if the taller and wider wheels where rubbing on the front radius arms at full lock. To do this, place axle on axle stands, and turn from lock to lock.
RH side was OK, but the LH wheel definetly rubbed on the LH radius arm.
To avoid this rubbing, you simply turn the steering lock screw on the opposing side (in front of the swivel housing). As the LH wheel rubbed, the lock stop on the RH side (pictured) had to be turned a few turns until there was a clearance of 20mm, which is the factory spec clearance.
This job done within two minutes after jacking!
Conclusion
The overall appearance of the vehicle is enhanced, with a more aggressive and purposeful look - it really looks like an offroader fit for fight!
A rather large piece of the wing was cut, enabling for the fitment of 32" at a later stage. When I come around to it, I will bend some aluminium treadplate to fill from wheel arch to rear quarterpanel, beneath the rubbing strip. This will conceal the rather rough leading edge of the RH side cut, and also the dented and bent part of the lower wing. The allowance of fitting 32" wheels made this rather large cut necessary, though a small and largely invisible piece would have done the trick.
Offroading, the increased height under diff/axles was a very convenient modification. The BFG All Terrain pattern definetly had a better grip on rocks and mud than the Michelin XPCs.
On road, there is slightly more noise - the vehicle seems to roll a bit rougher. Tarmac performance is still good, and I do not feel I have sacrificed anything for the sake of offroad performance.
On gravelled roads, though, the wider wheels seem to "float" more than the narrower 205/80-16. Curving must definetly be done at a lower speed than on stock width wheels. This was also feared, which is why 215/85-16 (same height) would have been my first choice if I had to pay the full price for a set of wheels.
Steering is about the same, no improvement nor worsened "feel"; but the turning radius has increased - not too helpful on the trail... Nevertheless: I am totally satisfied with the fitment of the taller tyres, though narrower profile would probably have suited me better. Beware though: On these pictures the BFG A/T 245/75-16 are fitted to Rostyle steel wheels. These rims are Range Rover wheels 6" wide. The BFG recommends the tyres fitted to rims 6,5"-7,5", so fitting these tyres onto Rostyle is not recommended. The tyres will be swapped onto standard Discovery steel wheels (7" wide) as soon as I've got these shotblasted, primed and painted.
245/75-16 on a Stock Discovery
The standard fitment 29" wheels bellies a stock Discovery when a Defender 90/110 keeps going on its almost 32" wheels. The difference of close to 3 inches leaves the differential housing on a Discovery 3-4 cm closer to the feared rocks. Contrary to common belief, it is not necessary to fit taller springs to fit the bigger wheels. The discovery has now received "as-new" BF Goodrich All Terrain wheels sized 245/75-16 (~30,6") - a size that fits a bog standard suspension Discovery - perhaps with some metal work...What - No Lift?
There is a common misconception that you will have to "lift" the vehicle to be able to fit taller and bigger wheels. It is also believed that if you fit taller springs ("suspension lift"), there will be no rubbing and no need for cutting the wings. Bigger wheels "fill" the wheel arches more than stock 29", and the belief is that taller springs will prevent the wheels from rubbing the wings.
This is all wrong! Fact is a suspension lift will allow more articulation until it rubs, it will not remove the rubbing problem. Rubbing is mainly determined by the size of the wheel in relation to the wheel arch size.
The size fitted is only moderately larger than stock, and according to other Discovery-owners experience, should not need any taller bump stops, and only slight cutting of rear wing - it is even reported that no cutting is needed (though this probably depends on the make of the tyre)!
To be able to check for rubbing, you will have to check on a ramp or on the trail. Using a trolley jack to lift a wheel will not put the weight on an axle as what occurs when flexing going uphill and most of the weight is redistributed to the rear axle.
245/75-16
The 30,6" sized wheels being fitted should come on quite easily. This tyre size is a very popular size in the US, and are ususally fitted with a moderate suspension lift of 1-2". Fitting taller springs will increase articulation, i.e. giving the vehicle even better offroad performance.
These wheels are pretty wide and chunky, are reasonably tall, and really enhance the looks of a Discovery. Though a bit of suspension lift on the vehicle will give a bit more balance between tyre and wheel well, there is no problem running this tyre on an otherwise stock suspended vehicle.
Taller wheels spell less accelleration (and increased top speed). The discoverys speedometer read ~87 km/h when actually running 80km/h, so at 6% speed change, the taller wheels should in fact give a more accurate reading...
Cutting of the wings
Likely spots of rubbing according to others experience on this size are: Front: Spoiler/apron. Rear: Wing aft of wheel.
the discovery had no spoiler/apron, so attention was turned to the rear wings. Browsing internet pages showed a horizontal cut of 4-4,5 cm was needed to fit the rather large 32" tyres like 235/85-16. To fit 245s, only the horizontal lip (not the vertical wing itself) is necessary, according to many users.
A straight line was drawn from the rubbing strip (or where it would have been) downwards.
This is known as the Camel Trophy Cut, as this was the cut made by Land Rover Special Vehicles to be able to fit 7.00-16 wheels on Camel Trophy Discoveries.
The blue masking tape shows where to cut (aft of the tape). RH side pictured.
Next step was to check if the taller and wider wheels where rubbing on the front radius arms at full lock. To do this, place axle on axle stands, and turn from lock to lock.
RH side was OK, but the LH wheel definetly rubbed on the LH radius arm.
This job done within two minutes after jacking!
Conclusion
The overall appearance of the vehicle is enhanced, with a more aggressive and purposeful look - it really looks like an offroader fit for fight!
Offroading, the increased height under diff/axles was a very convenient modification. The BFG All Terrain pattern definetly had a better grip on rocks and mud than the Michelin XPCs.
On road, there is slightly more noise - the vehicle seems to roll a bit rougher. Tarmac performance is still good, and I do not feel I have sacrificed anything for the sake of offroad performance.
On gravelled roads, though, the wider wheels seem to "float" more than the narrower 205/80-16. Curving must definetly be done at a lower speed than on stock width wheels. This was also feared, which is why 215/85-16 (same height) would have been my first choice if I had to pay the full price for a set of wheels.
Steering is about the same, no improvement nor worsened "feel"; but the turning radius has increased - not too helpful on the trail... Nevertheless: I am totally satisfied with the fitment of the taller tyres, though narrower profile would probably have suited me better. Beware though: On these pictures the BFG A/T 245/75-16 are fitted to Rostyle steel wheels. These rims are Range Rover wheels 6" wide. The BFG recommends the tyres fitted to rims 6,5"-7,5", so fitting these tyres onto Rostyle is not recommended. The tyres will be swapped onto standard Discovery steel wheels (7" wide) as soon as I've got these shotblasted, primed and painted.
