Tyre companies have sought to prove the merits of their rival wares in assorted ways over the years. There was now Tory MP Ian Mills launching the Dunlop Denovo at Paul Ricard in the seventies, or BF Goodrich making its European debut at the same French circuit. More recently journalists have been invited to Jarama to assess the P700 and P600 Pirelli series.
But it was BF Goodrich which started the instant comparison tests in my European experience, the Americans allowing a wide choice at Estoril last year and a primarily Pirelli P7/P6 alternative at the Ricard debut of that company’s TA low-profile rubber (then glassfibre-belted rather than today’s steelbelted TA2 and TA-R1 series).
From the promotional viewpoint there is always a risk that the journalistic assessors will both destroy the machinery and dislike the product. The British contingent are good boys in the first respect, but I must say I came away from Estoril liking a Dunlop D40 cover over any other for wet-weather use! The second generation Goodrich put on a convincing display, wet or dry, and I still prefer to go production racing on that American rubber: however my own road cars were delivered on, and remain happily in use with, Michelin MXV and Bridgestone RE71 .
I have just attended a most painstaking, and painfully honest, back-to-back comparison. “Painfully honest” because the host’s performance product was not always the fastest assistant around a deserted and dry Brands Hatch Indy circuit.
The occasion was Firestone’s British launch of “four new passenger tyre lines, each designed to meet the increasingly demanding performance requirements of the motorist.”
We tried only the lower profile covers, the glamour-line entitled Firehawk SV, V-rated to 150 mph in 50 or 55 aspect ratios.
Also on hand were Firehawk 660 in 185/60 R14 upon an Escort XR3i, and the same sizing, but HR-coded upon Alfa’s nimble 1.7 33. Competitive brands I had time to assess fully on the Escort were Dunlop D8, Pirelli P600, and Michelin MXV. Time ran out on the Alfa 33 session, with just the Pirelli P600 assessed against the day sponsor’s 660. Armed with the knowledge that a V-rated 660 has been approved for “OE” (Original Equipment) status on Porsche’s four-cylinder non-turbo models, we worked the unmodified XR3i around Brands Hatch. The track was in outstanding condition after June rain, basking in July’s strong sunshine. This was perfect terrain for trying the four tyre choices listed above, including the Firestones which replace the S-660, a cover the company admits was subject to criticism for “a rather harsh ride.”
Independent RAC timekeepers and an Amstrad 512 computer system kept track of our forays, with tyre pressures raised only an average 5 psi over the recommended road pressures.
Aside from retaining firm pressure on the brake pedal of the SCS anti-lock system in the Escort — which knocks the pedal back and forth with alarming variations at Brand Hatch speeds—the Ford provided a straightforward comparison with consistent speeds from its hoarse CVH and now reassuring suspension. The XR3i was unexpectedly fast on 105 bhp when compared to the 118 bhp Alfa 33 and the 156 bhp Alfa 75s, the latter chosen re employ the SV Firestone in 195/50 VR 15 sizing.
The conscientious computer told us that Dunlop D8s allowed the fastest laps, with 1min 2.9sec their best (68.88 mph average speed), and 1min 3.6sec the worst. Equipped by Pirelli, the best tour was lmin 3.2sec and the slowest 1min 2.8sec. Shod by Michelin, the times ranged from 1min 3.8sec to 1min 4.5sec, whilst the Firestone 660 covers were the most consistent with two opening laps at 1min 4.1sec, a 1rnin 3.7sec and two closing laps at 1min 3.4sec.
Thus the slowest time recorded by that small red Ford around the pleasurable curves and crests of this admirable driving challenge was 67.18 mph — the latter recorded on Michelin MXV which were the only covers not to show signs of excessive shoulder wear after vigorous circuit employment . “You pays your money and takes your choice” of speed versus durability.
Unfortunately a small front-end vibration on the Alfa 33 demanded rectification, so we did not have time to more than establish its slight superiority of half a second per lap over the Ford’s best, at 62.4-second laps (69.44 mph) on both Firestones and Pirelli P600 in eleven completed laps.
Although I actually started the day with the glorious sounds of Alfa’s 2.5-litre V6, I have saved the proverbial best to last. I drove two examples— one in black, sporting the Veloce appellation in respect of the extra body panels. Former FF1600 Champion of Brands Andy Ackerley demonstrated this car with persuasive and self-deprecating skill. “I thought it was front-drive until I found I could do this with it . . .” Pause for accelerator to be lifted on the 85 mph approach to Clearways . . the be-spoilered Romeo turns sharply into the apex kerbing, opposite lock holding it ready for the firm braking needed as the ensuing slide ceases and the need to turn right becomes apparent.
Thoroughly sold on the Alfa as a morning test bench, I worked through five sets of covers: the competitive brands listed earlier, plus two runs of the Firestone SVs because the first set’s lap time bonus was accompanied by worse understeer than expected, and because I wanted to ensure that any increased track knowledge was included in the Firestone data.
Using the notebook and lap times supplied, it was possible to come to some tyre testing conclusions. First of all, a straightforward road car on today’s low profile rubber is now much more at home on a circuit than even the Seventies equivalent machine.
For example, Paddock Bend is approached at just about 100 mph and 5800 rpm in fourth gear. Brake toward the looming tyre barrier and turn right, downhill. Unless there was a mistake in line the car coped on full throttle around this testing combination, existing 4600 rpm and some 85 mph.
I am not pretending that is fast by formula car standards, just highlighting how rapid road cars have progressed in alliance with suspension tailored to 50-series tyres. By the end of the day our guides, Mr Ackerley and former ATS Formula One occupant Slim Borgudd, were looking forward to laps beneath the minute barrier in these Alfas.
Our laps did not yield less than 61.5 seconds (70.4 mph), and that was on the Firestone SV 195:50 casings. Furthermore the sponsor’s tyres provided more routine laps beneath 62sec, nudging 69 mph average for a course which includes a 40-50 mph U-bend. Second fastest were a set of Goodyear Eagle NCT’s (61.7). Then, a scant tenth adrift, were Bridgetstone RE71s, on which Ackerley and I had also completed the passenger laps. These Japanese covers were just 0.3sec slower than the Firestones and equally consistent. Slowest, to general and in absolute lap time, were Pirelli’s P700 in a band from the 1 min 2.9sec to lmin 3.4sec.
Since I am sure many will feel statistics can be made to support any argument, I will also note in purely subjective manner which tyres I preferred on the Alfa 75 and Escort XR, the only models in which I completed a minimum of five timed laps on each brand.
For the 75 I favoured the feeling of crisp and eager compliance with the driver’s wishes which came from the Goodyear Eagles. The security of the Firestones could not be denied, nor could a noticeable rpm boost at Paddock and Clearways compared to the Bridgestones.
On the Ford I clearly preferred the 660 Firestone, but I cannot tell you whether it has improved the ride over the S-660. . . Brands is not that bumpy! To be honest I didn’t like the Ford much on any of the non-Firestone covers. Yet the Dunlop achieved the best time (underlining the importance of independent timing) and is also likely to provide a good ride, assuming previous experience with D4/D40 family is a good indicator of D8 character. JW