Track Testing: LeCont tyre compounds

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We were at the international track of Viterbo. Asphalt temperature was 37°C

LeCont tire compounds
After our studies on weights last month, as promised we finally managed to put up an interesting track test on tire compounds. Tires, as we know, are one of the major parameters that act on kart performance. LeCont is an important company that works 100% on performance tires. Racing tires for cars, karts and mini motorbikes are studied and offered by the Italian firm.

Which tires to test

LeCont kindly and quickly sent us a set of three different tires named LH01, LH03 and LH02, together with a set of rain tires. These last ones have not been part of our test. The three LH tires go from the ones with the softer compounds (LH01) to the hardest (LH02). Such hardness is measured in IRHD grades. So LH01 tires have 48 IRHD, LH03 have 54 IRHD and finally LH02 have 60 IRHD, shifting in steps of 6 IRHD grades. The three types of tires are also recognisable from the coloured line that runs along the entire diameter of the thread. Yellow for LH02, green for LH03 and blue for LH01. Dimensions are 11×7.10-5 for rear tires and 10×4.50-5 for front ones. The LH tires in general are made to be simple to use and have good lasting performance. They are made with polyester and have quite a soft structure that works quite well with low grip track, but maybe is not as performing as other racing tires with high grip tracks and rubber on the asphalt and with high temperatures. Also prices as indicated on the Internet (www.lecont.com) site are pretty interesting with cost of a set of LH02 equal to 125€, LH03 139€ and LH01 145€.

Start of testing – LH02

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Rear LH02 tyres indicating practically no wear except for some diagonal lines in the internal area of the tread just toward the axle hub. The very smooth surface indicates low grip

Considering that all three sets of tires had the same structure, differing only in tire compound, the idea was to understand how a difference in tire compound hardness can act on tire performance and on lap times. We mounted the first set of tires starting from the hardest ones, the LH02, the yellow lined. Inflating pressure set at 0.65 bar. We know that for LH tires LeCont indicates a 0.84 – 0.87 bar working pressure.

We were at the International track of Viterbo. Asphalt temperature measured equal to 37°C.

The were no karts on the track except us, so very low grip. This was the reason to have 0.65 bar instead of a more traditional 0.6. First laps I needed to find the right pace, also trying to get the feeling both with the tires and the track. Grip was not particularly high and performance was acceptable, but not astonishing. Balance of the kart was good and no particular defect was shown by the tires, with grip quite constant from the first laps and no sudden loss of grip at any time. Good performance entering the curves, but some limits in traction and generally on rear tires having limited grip especially along fast curves. Lap times started from high values both for my need to warm up and for the need of the tires to warm up!

1° lap 1.04”68

2° lap 1.04”25

3° lap 1.03”16

4° lap 1.03”10

5° lap 1.02”57

6° lap 1.02”15

7° lap 1.02”01 (best lap with LH02)

After the 7th lap, times were more or less constant. The hardness of the compound was evident all the way. Good overall performance by the LH02 tires, but the need to have long lasting tires with harder compound had on the other hand some limits on a low grip track and especially when lateral acceleration on fast curves asked for high lateral grip. Braking performance anyway was also pretty good. After around fifteen laps tire thread showed very good resistance to wear, which is the main aim of the LH02 tires.

LH03

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Rear LH03 tyre with grainy tread surface indicating much greater grip compared to the LH02. Still just a little wear in the internal area of the tread indicated by small diagonal lines

We then quickly changed to softer tires, the green LH03 tires. 6 IRHD degrees less of compound hardness compared to the LH02. Starting pressure at 0.6 bar. Already in the first laps I felt performance was extremely higher. Grip was greater with the tires doing all the job to obtain grip even with a track asphalt still almost completely without rubber cover. Traction and lateral grip were greatly improved and lap times quickly confirmed my feelings.

1° lap 1.02”03

2° lap 1.01”70

3° lap 1.01”18

4° lap 1.01”39

5° lap 1.01”00 (best lap with LH03)

6° lap 1.01”09

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Front LH03 tyres with slightly grainy surface and no real wear

Laps times went on constantly after lap 6. Great difference was evident especially at the end of the great straight of the start, where the very fast right turn needs great grip, especially on rear tires, so that speed can be kept high without releasing the accelerator for too long. Rear tires with good grip slide just slightly towards the external part of the curve permitting the kart to turn following the right trajectory. With the yellow LH02 tires such curve was pretty hard and speed had to be reduced too much.

LH01

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Rear LH01 tyres with grainy tread surface indicating good grip but also visible wear effect in the internal area of the tread with greater diagonal lines formed. The balance between performance and wear (20 laps) is still very good

Final testing was done with the blue LH01 tires. Another 6 IRHD degrees reduction for the softer tires of the lot. As said IRHD intervals from LH02 to LH03 to LH01 are equal to 6 degrees. Starting pressure set again to 0.6 bar. The feeling in the first laps was of great easiness in driving the kart. High grip, just slightly, as driving sensation, greater then the LH03 tires. But the astonishing performance came from the fact that high grip left the kart free to smoothly run along curves and exit them. Pushing harder and harder lap times decreased constantly. Braking and entering curves was great and also traction and lateral grip given by the tires was excellent. When the limit entering corners was somehow passed, the front tires slid laterally, but performance was not impacted too much and control of the kart was always possible.

1° lap 1.01”02

2° lap 1.01”00

3° lap 1.00”80

4° lap 1.00”41

5° lap 1.00”72

6° lap 1.00”70

7° lap 1.00”20

8° lap 59”90 (best lap with LH01)

9° lap 1.00”01

So finally the blue tires gave, as predictable, the best performance. And incredibly enough lap time difference was very similar, around 1 second (1”), between LH02 and LH03 and between LH03 and LH01. So it is as if 6 degrees of IRHD are equal, at least on Viterbo track and with Rok kart, to 1 second. Wear of the blue and green tires was also very low and so performance seems to be very good and combined with longevity of the tires. Only front tires showed some wear of the thread because of lateral sliding when pushing really hard entering the curves. This aspect could though most probably be solved acting on chassis setup. We will surely see that in future issues.

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The front LH01 tyre with good grip indicated by the tyre surface but also rubber being ripped by excessive sliding when pushing hard for performance. Lines both diagonal and longitudinal are present in a wider area of the tread. Set-up should be improved