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• Cooper Discoverer STT Review

Discoverer STT's are Cooper's premium "high void traction tire", with an 80% leaning towards off-road use. That said, these tyres really pack a lot of punches with the remaining 20% that is assigned to on-road driving.

STT's have been specifically created by Cooper to work on SUVs, 4x4s and of-course, the mighty Land Rover. The tyre  features a 3-ply carcass construction, tear / chunk resistant rubber compound and a centre 'traction zone'. In the real world, that makes for a very tough, rugged tyre, resistant to impact and tyre bruising.

Features

1. DEEP BUTTRESS LUGS STTs feature a deep, aggressive tread pattern, that extends down the sidewall of the tyre (on both sides). This increases the wheels effectiveness on soft surfaces but also helps find grip when rock crawling.
2. RIM FLANGE PROTECTOR Around the inner diameter of the tyre, Cooper have placed some flange protectors to rebuff knocks and scrapes when off-road and also add a little to the 'look' of the tyre. The flange protectors are chunky and feature a small moulded knight on them.
3. TAPERED STONE EJECTORS In between the lugs sit some moulded ribs that are designed to prevent stones and debris from lodging in this area. These again serve two purposes, as they also aid soft surface traction.
4. SUPER TRACTION TREAD Cooper have put a lot of research and effort into creating tread that offer abundant grip when you most need it. The combination of deep buttress lugs, notched and scalloped shoulder lugs and the centre traction zone make this one very grippy, composed tyre, on or off-road.
5. ARMOR-TEK3 CARCASS CONSTRUCTION The carcass around which the grip is moulded is made from two heavy duty radial polyester body plies and one angled body ply, giving protection and resistance to breaks, chunking and bruising.

Don't think that the above is just marketing jargon. During our testing, it quickly became apparent that this tyre is rugged, hard-wearing and affordable.

Test

As always, we fitted the review samples to our Defender. The tyres came mounted on 17" Predator wheels from John Craddocks (review coming shortly) and we went for 265 / 70 R17 (to match the alloys). Fitting is a simple affair and as always you should follow Land Rover directions when jacking and removing wheels. These are quite 'bulky' to be handling, so you may have to resort to sitting down on the ground and using your chins and legs to manhandle them into place.

Once bolted on, these tyres look mean. They instantly give a standard Defender much more 'butch' presence. Be careful when choosing tyre sizes and widths though, any more than 265/70 and you may end up needing extended wheel arches to comply with road regulations. Larger sizes could also start to rub on the wheel liner, so make sure to adjust your bump stops appropriately.

On-road

We jumped straight into the truck after fitting and headed off on a test-route. Straight-away, you'll notice the difference on-road. With only 20% on-road bias, we're quite impressed with handling. We were expecting a horrendous ride,  sluggish steering and a deafening tyre drone - but got none of the above. Firstly, the ride is a shade more 'floaty' than standard tyres - when braking and cornering at first you might notice this. On wet roads, the rear end does feel a little light, but has never been anywhere near a concern, just more of a sensation.

Use on new Defenders

Since upgrading to our TDCi, which has more sound proofing and a slightly quieter engine, we have noticed a low frequency grumble from these tyres, though it's very slight and hardly audible.

We've found the tyres to be brilliant otherwise. Road noise is present, it's going to be with so many grooves and lugs. However, it's not horrendous. Sort of like a quiet hum in the background. The noise worsens on the motorway, but is overshadowed by the engine and other motorway speed related clunks and groans.

The tyres have seen around 2,000 miles of use in 2 months and have been worn in now. Grip is better than at first and all 4 corners seem to be wearing perfectly. The tread hasn't been scrubbed away by the 1,800 miles we've done on-road and those 1,800 miles haven't been the equivalent of ear-based torture. The only handling issue now is tight corners, but it's not the tyre themselves, just the size. Expect your turning circle to be around 30 or 40 feet now, or get some wheel spacers to offset the wider turning circle.

We must admit to being completely over the moon when we awoke last Saturday to find 3 or 4 inches of snow that has accumulated over the week to 2 feet in some areas around Yorkshire. This has given us chance to drive approximately 400 miles on the cold, wet and icy stuff. As you'll see from wednesdays pictures, we got stuck once (because I wasn't looking where I was going) and then again yesterday up a very steep hill that had claimed a Saabs wheel (just torn it off when the driver collided with a wall).

Tyre tread

Again this was driver error, I forgot to engage diff-lock before things got difficult. Still, once engaged the tyres gripped hard-packed snow and fresh snow alike to claw our way back up the side of a 3:1 or 4:1 incline. Once at the top, the Police had closed the road off and we had to move some cones to continue on our journey. For some reason, nobody had thought to close the road off at the bottom.

After spending at least 20 hours driving in the wintery conditions this week, we've been unable to lose grip completely, even when trying to do so around quiet country lanes. Hard cornering on snow at 15 mph feels very composed and the rear feels quite planted. This shows the difference between on and off-road biased tyres. We managed to do a 180 degree spin whilst trying to park a Suzuki Swift last night.

The performance we've seen this week has been brilliant. Pedestrians have stopped and literally done double takes as we safely drove past at reasonable speeds in the snow. We towed a 2-tonne van (fully loaded with tools) sideways on sheer ice with no problems what so ever. The truck has even taken us into snow banks and through mounds and has just kept going. This has all been down to the tyres and the most part, excellent snow-driving techniques 🙂

Off-road

We have had a jolly good time taking to some greenlanes during the weather, although it's not needed as even busy A-roads have been turned into desolate arctic trails, covered in 6 inches of snow. In -5 temperatures, the Landy confidently pulled us up long, steep hills strewn with boulders, ruts and rocks. It was literally like being sat in a very slow, bumpy train. We just kept going and going.

Likewise, before all the snow came, mud, wet grass and the like provided no drama for these excellent tyres.

We ordered our review samples from John Craddocks Ltd. Service was excellent and the staff are very helpful. Visit John Craddocks.

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