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RepRoduced fRom AutocAR 28 jAnuARy 2009

T h e o r i g i n a l car weekly

Cheap tyres the real cost

tyre test

highlightssafety

concerns


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Cheap imports|Tyre test 2009

WW.AUTOCAR.CO.Uk 28 JANUARY 2009 28 JANUARY 2009 WWW.AUTOCAR.CO.Uk

Our man was stunnedby Contis advantage

over the bargains

Tyres are a distress purchasefor many car owners, so whenthe time comes to replacethem its no surprise thatmany motorists shop on price.But by buying cheap tyres, are

you sacrificing primary safety?We heard from our hosts at Continental

Tyres Contidrom test facility last yearhat they had tested cheap Far Easternmports and got some scary results. Athe time we thought this was interesting

but probably not of huge significance,because of low sales volumes in the UK.

Wrong. Accurate official statisticsdont exist, but cheap import tyres fromChina and Taiwan account for around afifth of all passenger car tyres currentlysold, many of them via the internet. Thatmakes their performance well worthesting.

In order to earn the circled E on theirsidewall, tyres have to pass the ECE R30

CONFIDENCE INTERVALSBecause lap times an braing istances

for each tyre are not exactly the same

each time you measure them, we use

stanar statistical methos to calculate

the confience intervals shown in the

charts. We can be 90 per cent certain thatha we repeate each test a very large

number of times, the true mean (average)

woul have fallen within this range.

Each tyre is score accoring to

how many others it beats in each test.

The scoring system is six points for the

test winner, five points for secon best

an so on. In the case of a tie, the pointsfor the tyres places are ivie equally

between them.

high-speed test, which ensures they cancarry a specified percentage of their ratedload at close to their rated maximum speed

without failure.But there are no statutory tests of

braking, handling or aquaplaningperformance, and even the R30 testis considered inadequate by many carmakers. In other words, just because atyre can legally be sold in the UK, that isno guarantee of its performance in safety-critical aspects of normal driving.

So just how capable are cheap importtyres from China and Taiwan? We chosea popular tyre size 205/55 R16 andreturned to Contidrom with a Golf 1.9TDI to find out by pitting five brands (GTRadial, Linglong, Nankang, Triangle and

Wanli) against Contis own PremiumContact 2. The imports were all purchasedin Germany and the Contis were selectedat random from a distribution centre. Theresults were an eye-opener.

how and whereContinentals Hanover test facility

the Contidrom proved such a success

on our 2007 test that we could thin

of no better place for this years action.

With a 2.4-mile dry circuit, 1.1-mile wet

trac and objective test areas, the

Contidrom is one the worlds most

advanced tyre test facilities.Unlie in previous years, where we

used two test cars (one front-wheel

drive, the other RWD), in testing budget

tyres we opted for just a front-driver.

We chose VWs Golf 1.9 TDI as the ideal

example of a typical family hatchbac.

Crunching the numbers (on his ninth

tyre test) was keith Howard, and in thedriving seat was Jamie Corstorphine.

cheAp tyResthe real cost

Howardslaptop nearly melted when it came to thewet handling results

Is bargain rubber from the Far East really ashrewd investment? We have our doubts aftertesting five of the leading low-cost optionsSTORY JAMIE CORSTORPHINE, kEITH HOWARd PHOTOGRAPHY STUART PRICE


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WET HANDLING

WET BRAkING AQUAPLANING (LONGITUDINAL)WET CIRCLE AQUAPLANING (LATERAL)

yre test 2009 | Cheap imports

Continental

4240

Worse BetterCritical speed (mph)

44 4 6 525048 54

GT Radial

Linglong

Nankang

Triangle

=1st

=3rd

=3rd

5th

6th

Wanli

Confidenceinterval

=1st

Wanli

0 .2 4 0 .2 6 0 .2 8 0 .3 0 0 .3 2 0 .3 4 0 .3 6 0 .3 8 0 .4 0 0 .4 2

Worse BetterResiduallateralacceleration(g)

GT Radial

Linglong

Triangle

Nankang

2nd

3rd

4th

5th

6th

ConfidenceintervalContinental 1st

Nankang

32 3430

Better WorseBraking distance (m)

36 38 40 42

GT Radial

Wanli

Triangle

Linglong

2nd

=3rd

=3rd

5th

6th

Continental

Confidenceinterval

1st

Nankang

0.450.40

Worse BetterLateral acceleration (g)

0.50 0.55 0.650.60 0.70

GT Radial

Wanli

Linglong

Triangle

=2nd

=2nd

4th

=5th

=5th

Continental

Confidenceinterval

1st

On average, it rains 200 days a year in theUK. Which makes having a tyre that works

well in wet conditions a priority and the wethandling test one of the most relevant that

we conduct.The results make for disturbing

reading. Our Golf is hardly the last wordin performance its 104bhp is barelyenough to break traction, even out of thetightest hairpin and the wet circuit is nottremendously long (a lap takes aroundone and a half minutes), yet the differencein time between the Chinese tyres and theContinental is staggering.

Equipped with the best-performingChinese tyre, the Nankangs, the Golf

was three seconds a lap slower than withthe Continental, but with the worst, theTriangles, it lapped a scarcely believableeight seconds slower. An eight-second gapin something as humble as a diesel Golf isall the evidence you could ever need thattyres matter, not only in terms of lap times

but also in how quickly you can stop or turnwhen it really matters. Wearing the Contis,the Golf felt more agile, stopped quicker andsteered with more feel than with any of ourfive Far Eastern brands.

The Nankangs not only produced thequickest lap time but also got closest to theContis in terms of feedback. They producedless outright grip than the control tyres,

but the balance between front and reargrip was even, while the fall-off in grip waspredictable and gradual.

Swapping to the GT Radials lost anothereight-tenths of second, but this doesnt fullyexplain how different the Golf felt. Gone

was the balance, replaced by an awkwardyo-yoing sensation as the car slipped firstfrom the front and then the rear. Althoughthe GT Radials didnt struggle for traction,under braking and in mid-corner they hadmarkedly less grip than the Nankangs, andit fell away with little warning.

While the Wanlis proved slower again,subjectively they felt more stable, balancedand communicative than the GT Radials.The grip levels were actually lower,hence the slower lap, but it was easier tocomfortably work the car up to the limit andthe resulting slip was more controllable.

Put simply, the Linglong and Trianglewere in a different, much lower league, andthey both recorded similarly poor lap times.

Although the Linglongs provided goodsteering feel and balance, the shortage ofgrip was truly staggering; the sensation wasnot unlike driving on ice. This caused anissue not only through the corners but alsounder braking and under power.

But the wooden spoon goes to theTriangles, not only for recording the slowestlap but also for providing the least satisfyingdrive by some margin. Their main downfall

was an inability to deal with longitudinaland lateral forces simultaneously. Touchthe throttle mid-corner and the Golf wouldslip wide; brake in anything but a straightline and the ABS came juddering in. Theresulting lap was not only slow but alsoscrappy and inconsistent.

To get a handle on the g ulf in ability,consider that in one 50mph corner theTriangles were 8mph slower and generated0.2gless. That might not sound like a lot,

but it could be the difference betweenstaying on the road and leaving it.

We hooe up an aapte Aui A4 to

Contiroms rail-guie system for the wet

braing test. The braing istance is measure

from 80-20m/h (50-12mph) on an asphalt

surface an then extrapolate to zero to

eliminate ABS inconsistencies at low spees.

Seven runs are mae an the highest an

lowest results eliminate for the analysis.

The ifference between the best (the Conti)an the worst (the Linglong) was 8.5m. It woul

probably have been even larger ha the test

been conucte on a lower-friction surface.

This test is conucte on a large asphalt circle

with a raius of 200m. Aroun it is a 20m long

by 5m wie section of staning water, with a

epth of 6mm. The test begins at a spee of

55m/h (37mph), which is increase in 5m/h

(3mph) increments to 95m/h (59mph). Lateral

acceleration through the water at all the spees

is average; the higher this figure, the better

the tyre resists aquaplaning uring cornering.Trea compoun is a factor in this test, so the

Wanli coulnt match the Conti. The worst tyre

in a eep mi-corner pule was the Nanang.

This is a test of cornering grip in the wet, in

which the test car (a specially instrumente

Aui A4) is riven as fast as possible aroun a

wet asphalt circle of 50m iameter. Seven laps

are time, the fastest an slowest eliminate,

an times for the remaining five laps then

converte into lateral acceleration in g.

The Conti wale this test, pulling 28 per cent

higher lateral acceleration than the Triangle;thats equivalent to a 13 per cent ifference in

cornering spee. Unsurprisingly, the correlation

with the wet hanling results was very close.

This test is also conucte using the rail-guie

system, but with the cars left wheels running

in a water epth of 7mm. As the car enters the

staning water, the river accelerates an the

instruments recor at what spee the riven

left wheel reaches a slip ratio of 15 per cent. The

higher this spee, the better the aquaplaning

resistance of the tyre.

It was surprising that the Wanli tie with theConti here but then its trea pattern is lifte

from the dunlop SP9000. The rest, particularly

the Triangle, performe poorly by comparison.

weT handling

Nankang

85 86 87 88 89 90 91 92 93 94 95 96

Better Worse

97

GT Radial

Wanli

Linglong

Triangle

2nd

=3rd

=3rd

5th

6th

Continental

Confidenceinterval

1st

Laptime (sec)

Contis offered betterwet lap times as wellas far more feedbac

onti rubber was a full eight seconds quicker than the Triangles The wet handling circuit exposed huge gaps inthe tyres abilities

il-guidedAudiA4wasused forstraight-line aquaplaning tests Extradose of bravery pills wasrequiredfor some of theflyinglaps


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Cheap imports|Tyre test 2009

28 JANUARY 2009 WWW.AUTOCAR.CO.UkWW.AUTOCAR.CO.Uk 28 JANUARY 2009

HIGH-SPEED TESTSMany car maers consier the manatory

ECE R30 high-spee test to be inaequate

an specify proceures of their own inwhich the loa or maximum spee are

raise, the inflation pressure roppe

or the camber angle increase. Our

five import tyres were teste at Contis

engineering HQ accoring to VWs

requirements, which all original tyre

fitments on its cars have to pass. Four of

the five (GT Raial, Linglong, Nanangan Triangle) faile the test because of

structural failure, the most ramatic being

that of the GT Raial (left).

The spread of times for the dry circuit wasmuch narrower than for the wet, at 2.6sec

between the Contis and the Linglongs, butthe subjective differences were big enough.

Again the Nankangs came out top ofour budget tyres; they ran the Contis veryclosely, and on one lap they even posted aquicker time. The Nankangs most strikingcharacteristic was how iron-fisted they felt,giving the Golf a safe, solid feel and meatysteering. However, the Nankangs couldntmatch the Contis delicate, balanced feel,

which allowed the Golf to be workedthrough the more demanding corners.

If we turned in with too much speed,the Nankangs gave no option apart fromgetting completely off the throttle andsacrificing speed hence the variation inlap times and the slower average.

The GT Radials produced the nextquickest time, 0.6sec behind the Nankangs.

While the outright grip produced was notfar off that of the Contis, the fall-off in grip

was more sudden and the steering wasuncommunicative. The GT Radials neededto settle momentarily before delivering fullgrip; similarly, if you suddenly backed offthe throttle mid-corner, there was a lot moremovement from the rear end.

The Triangles produced reasonableoutright grip but became spiky near theedge of adhesion. In particular, oncefront-end grip had been breached theTriangles understeered wider and moresuddenly than with any of the quicker tyres.In lift-off situations they produced some(acceptable) rear movement.

Wearing the Wanlis, the Golf felt like adifferent car, with noticeably less grip, moremovement through the direction changesand more throttle control required to keepthe car on line. The Wanlis also struggledunder braking, with less initial bite andgreater ABS intrusion. That they almostmatched the Triangles time is down to alinear, predictable fall-off in adhesion.

Soggy and unresponsive are two wordsto describe the Linglongs. We could pointto the traction problems exiting the hairpin,or the tendency to drift wide under powerthrough long corners. But the biggest issue

was instability turning into faster corners.Be anything but super-smooth and the Golfcould slide quite sharply from the rear, oftenrequiring opposite lock in 80mph-pluscorners. On a test track it was entertaining,

but you wouldnt desire it for road use.

dry handling

Far Eastern tyres weremore at ease in the

dry, but still not great

Aggressive behaviourwiththe Linglongs was rewarded with therearendbreaingaway,oftenat speeds of morethan80mph.

This was funon the test trac, but you wouldntwant it ona B-roadOne infivenewtyressoldin Ukis cheaprubber from the Far Eas

t

GTRadial rubberfailedVWs specified tyre tests

Nankang

108107

Better WorseLaptime (sec)

109 110 111 112

GT Radial

Triangle

Wanli

Linglong

=2nd

=2nd

=4th

=4th

=4th

Continental

Confidenceinterval

1st

Nankang

37 3836

Better WorseBraking distance (m)

39 40 41 42 43 44

GT Radial

Triangle

Wanli

Linglong

2nd

=3rd

=3rd

=5th

=5th

Continental

Confidenceinterval

1st

DRY BRAkING

DRY HANDLING

dry braing is measure at Contirom on

an asphalt surface from an initial spee of

110m/h (69mph), with the braing istancerecore from 100m/h (62mph) to rest. Seven

runs are mae on each tyre, an the highest an

lowest results are eliminate to leave five runs

for the analysis.

This test usually results in a close grouping;

last year the istance between best an worst

was a little over three metres. But this year the

winning Conti stoppe a full 5.5m shorter thanthe last-place Linglong. With Linglongs fitte,

the test car was still oing more than 20mph at

the point where the Conti ha stoppe.


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We were expecting the bargain tyres

in this test to fall short of the

Continental reference rubber, but wewerent prepared for just how wide

the gap was. The Conti easily topped

the final ranings, but there was little

good news below it.

Best of the rest overall was the GT

Radial, because of its consistent

performance. But a wet lap time

3.4sec adrift of the Contis indicatesjust how far even it fell short. And

remember, other premium tyres may

be superior to the Conti; that was

certainly the case in our test last year.

In many of the disciplines the

Nanang was closest to the German

tyre, but poor performance in the two

Right turnLeft turn

Acceleration

Lateralacceleration(g)

1.01.0

1.0

0.5

0.5

0.5

0

0

0.5 1.0

Longitudinalacceleration(

g)

Braking

0 500 1000 1500 2000 2500 3000 3500

Distance(feet)

0

5

10

15

20

25

30

35

40

45

50

55

60

65

Speed (mph)

Triangle

Continental

31.7m

40.2m

Continental

Linglong

25m 40m30m20 35m

Stilldoing27.8mph

VerdicTBRAkING Best and worst wet braking distances from 50mph

TRACk GRIPSpeed differential between best and worst on wet circuit

PRICE DH WH DB WB ALo ALa WC TOTAL

Conti 75.83 6 6 6 6 5.5 6 6 41.5

GT Radial 58.65 4.5 4 3.5 3.5 3.5 4 4.5 27.5

Nankang 55.20 4.5 5 5 5 2 1 4.5 27

Wanli 51.41 2 3 1.5 3.5 5.5 5 3 23.5

Linglong 52.44 2 1.5 1.5 1 3.5 3 1.5 14

Triangle 51.06 2 1.5 3.5 2 1 2 1.5 13.5

CORNERINGLateral/longitudinal g-forces

on wet circuit: Conti (blue) vs Triangle (red)FINAL RESULTSPrices supplied by blackcircles.com (0845 620 2000) and include valve, fitting and balancing

key: dH = ry hanling; WH = wet hanling; dB = ry braing; WB = wet braing; ALo = aquaplaning longituinal;ALa = aquaplaning lateral; WC = wet circle

Corstorphine gave the Linglongs afair stab under wet braing but the result was similar to a bad chase scenein The Sw

eeney

This scene was replicated around 200timesduring our tyre testTime to crunch numbers: Corstorphine and Howard hitthe data

Wet braing: Linglong-shod Golfwas still doing 27.8mph at the pointwhere it had stopped on Contis

A humble Golf TDIwas our unglamorousassistant for the day

Thans to Eurotunnel (www.eurotunnel.com, 08705 353535)

WWW.AUTOCAR.CO.Uk 28 JANUARY 2009

aquaplaning tests dropped it down to

third position overall.

With its tread pattern copiedfrom Dunlop, the Wanli performed

well in the aquaplaning tests. But it

was less competent elsewhere,

notably in the dry braing, and

dropped to fourth.

Little thats positive can be said

about the Linglong and Triangle, which

posted greatly inferior results. Asyourself: on a wet road in particular,

would you lie the car behind (let

alone your own) to be fitted with a

state-of-the-art premium tyre or a

cheap import? Having seen how the

cut-price tyres in this test performed,

were in no doubt about our answer.


6/6

When you really need to stop.

Full stop.

ContiSportContact 3 225/45 R17 Y

TyresMarch 2008

www.c

onti-online.c

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