Goodyear British Off Road Championship

Tyre technology

Bruce Tigwell, multiple British Off Road Champion tries Goodyear's Wrangler MT/R

Goodyear has for a long time now, shown more than a passing interest in our sport. They have supported the Hillrally for three years and seem to have carefully considered what sort of terrain we traverse and what is required from a competition off road tyre.

It may well be that their newly announced Wrangler MT/R tyre will take over as 'the' tyre to use for competition. It's early days yet but so far three drivers I know of have done battle in vehicles shod with MT/R's and all have been seriously impressed.

The only entrant in The Hillrally to run Goodyear's latest rubber was Glen McKeith. He had many a drama on the rally, but none were attributable to the tyres! A head-on collision and myriad mechanical fixes hampered his event progress a little, but he did not get a puncture and his MT/Rs looked fresh, right to the end. Even in deep mud the grip was good and the gravel tracks were a dream.

I spoke to Glen about the performance characteristics of the MT/Rs at The Hillrally, and his enthusiasm led me to Steve Phillips, Goodyear's Product Manager, who offered me a set to try at the next safari, two weeks later, at Glyn-Neath.

Before having the tyres fitted I though it best to look into the technical aspect of the tyre's construction, to try and understand why it should be so good. I was reluctant to risk running an 'unknown to me' tyre without carefully checking its credentials carefully, and I'm sure most competitors would want to do the same.

This obliging manufacturer kindly sent me through a full technical specification, outlining construction and design features, which seemed perfectly matched to the sort of things we do.

Built for the job

Simon Dowdeswell uses MT/Rs Photo ©Gavin Lodge

It seems that the design team at Goodyear have taken a clean sheet of paper, as it were, and created a tyre that incorporates all the features that are important to off road competitors. What they have created may well give optimum performance in all off road conditions.

Features that I would regard as important are, above all, puncture resistance, then grip in all conditions, predictable handling and finally long tyre life. It sounds simple enough, but so far I've yet to come across a tyre that fulfils all these criteria. The MT/R design team, however, would appear to have satisfied this tall order.

To make the tyre as puncture resistant as possible the tread pattern area has beneath it, two high tensile steel belts. Under them and including the sidewalls are three high modulus polyester plies.

A unique feature of this tyre is the sidewall compound, which is different from the long life very durable, tread pattern rubber. Incorporating their own 'Durawall' puncture resistant technology, Goodyear have developed a special compound, which is to tyres what Teflon is to frying pans. Rocks and sharp objects just seem to slip off, not even marking the sidewalls.

Rallye De Cimes enthusiasts will know that at that rocky event, on some stages the top competitors grease their tyre sidewalls. This only lasts for a short distance, but has the effect of slipping off the sharp rocks which might otherwise shred sidewalls. It seems that MT/Rs achieve the same effect, but without the grease.

Proof of the pudding - Glen McKeith - Hillrally - no punctures, myself - Glyn-Neath - no punctures, Mike Wolfe - Long Valley Stage Rally - no punctures.

To achieve an all conditions grip design, Goodyear have created a unique, infinitely varied and very open tread pattern, featuring inclined hook shaped centre lugs, heavy shoulder blocks, wide tapered grooves, radial cuts and sipes and optimum tread compound.

The sidewalls have large and varied lugs, which extend about half way down the sidewalls towards the bead. The effect of these can really be felt when either trying to climb out of in-line ruts or in deep mud.

The tread pattern itself has a similar layout to many currently used pure mud tyres, but has many more sharp edges. Tread depth is deep and the tread contact area is about 50% of the total surface area, again like many currently used mud tyres.

The design detail ensures best possible grip in all conditions we normally encounter. The carcass design and tread compound ensures stable and predictable handling on all surfaces, including tarmac, and long tyre tread life.

Put them to the test

Julian Mendelsohn's new Bowler is MT/R equipped Photo ©Gavin Lodge

Having bravely decided to run the MT/Rs tubeless as recommended by Goodyear, I pumped them up to 32psi, because they looked and felt right at that pressure!

I had no time to test at all until I got to Glyn-Neath; the first test was to be run one! Having walked the entire eight miles, declining several lifts, I was in full knowledge of how slippery the course would be, especially after heavy overnight dew. It was wet in varying degrees, from at best, damp gravel tracks, to at worst, deep muddy and rocky gullies.

Although confident of the design, I had no idea how the MT/R would behave in the continually varying conditions. For the first mile or so I was prudently cautious, but the car felt absolutely stable and secure. Pushing on a bit harder was no problem. Some very deep mud and water was dispensed with swiftly, without fuss and confidence was improving.

By the end of the first run I was quietly confident I could push harder and explore the performance envelope of these tyres a bit more.

During the next two runs I kept pushing harder, forcing the car into corners hard and taking slippery adverse cambers, with sharp rocks protruding, faster and faster. I was leaving braking later and later, being unsuccessful in getting the wheels to lock up.

The ultimate braking test came on the fourth lap, where red mist combined with driver error saw us approaching a 100 degree right hander far too fast. Preparing to overshoot I stood on the centre pedal - the car stopped and I turned right - just amazing grip- my flabber was gasted!!

This lap saw us fighting for second overall and our lap time was quick. I was really getting the hang of these tyres and went out on lap five really buzzed up and flying. I found it difficult to unstick the MT/Rs. They would break away on power curves predictably and on wet slippery adverse cambers gently let go, but only when pushed hard. I never managed to lock the wheels in a straight line, but then I didn't force the issue on the slippery bits.

Disaster struck on this lap. An unfortunate landing after a track crossing jump, into a large hole and a rock respectively, resulted in a broken left thumb for yours truly. I fumbled the next five miles or so (felt like 50 miles) to finish the lap in an agonisingly slow time. I was then banned from continuing with the final lap by the medic and 'others' so sat by while my regular co-driver, finished the event for me.

Despite spending the rest of the day whinging about my thumb to anyone who would listen, I did manage to carefully inspect all four tyres at the end of the event.

During the event we had broadsided several large and sharp rocks, some of which were embedded in the ground. The evidence of this was three bent and damaged steel wheel rims, two of which were badly scored with lumps missing.

The tyre walls on all four wheels were unmarked. The tread was sharp and the fronts were almost like new still, the rears were very slightly scuffed, the edges showing slight abrasion marks. There were no bulges or signs of carcass damage.

It is interesting that many other competitors had at least one puncture at this notoriously 'tyre eating' course, and because of its rocky nature, tyre wear is normally significant there.

Talking to very experienced Mike Wolfe (of Kingsley Cross Country) about these tyres before and after the event convinced him to try a set for a stage rally on the 5^th November, around the Long Valley area near Aldershot.

Now running the ex-Andy Sargeant lowered 90, complete with 'healthy' V8, Mike again put the MT/Rs through their paces. The stage comprised tarmac, gravel, mud, leaves and mostly in the wet. His only complaint was that he couldn't get the back to hang out on the corners, such was the grip.

High speed tarmac stability and lack of noise and vibration was impressive and like me he couldn't brake the MT/Rs. There were no punctures, no unwanted excitement and virtually no tyre wear. In Mike's words "very impressed".

The future

It will be interesting to see how these tyres perform during the next season, but the signs are good. I think other tyre manufacturers may need to dust off their drawing boards and enlist some serious design engineers if they want to stave off the challenge which Goodyear are currently presenting.

Another serious looking contender, which may challenge the MT/R is the Portugeuse Fedima Extreme tyre imported by David Simmonite. He witnessed these tyres in action in France and was impressed enough to bring them into the country for sale.

They certainly look right and have very strong sidewalls and a novel tread design, which appears ideal for our sport. It would be interesting to do some back to back testing with the MT/R.

I think it is likely that either or both of these tyres are set to move our sport on to bigger and better heights of off road performance and reliability.

The Goodyear Wrangler MT/R is the control tyre for the Goodyear British Off Road Championship.

Article by five times MSA British Off Road Champion, Bruce Tigwell.

Courtesy of Off Road Motorsport