Author Topic: Reading your tyre wear  (Read 1126 times)

Online sfcpiet

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Re: Reading your tyre wear
« Reply #15 on: December 02, 2019, 15:41 »
Look at the wear indicators on the tyres of the yellow bike. Check that rebound.

?

Lots of rubber left on the slick, pity it is well past its best before date...

The BT012 was photographed after a blistering hot event in Spa.  Can be hot as hell there... or miserably cold and wet, all in a single weekend.

I prefer to have supple suspension with decent travel, a lot easier on the tyres.  Although the bike is considerably quicker than I am, nobody has ever complained I was getting in their way... ;D

piet
180s feel quick, 120s are...      If it ain't broke, fix it till it is.

"A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics"  Georg Fitch 1916

Offline Laverdalothar

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Re: Reading your tyre wear
« Reply #16 on: December 02, 2019, 15:59 »
?
Although the bike is considerably quicker than I am, nobody has ever complained I was getting in their way... ;D

piet

Not even after you overtook me, I agree...  :-[

 :-*

I agree that also my bike was set to 2,2 bar for the race-track (rear), as per recommendation from Bridgestone btw...

already tons of grip and great handling with the GSX-R-Rims and the 150/70-18 BT012SS. Shame they do not deliver them anymore to Germany these days...   :'(

« Last Edit: December 02, 2019, 16:00 by Laverdalothar »
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1000 SFC 1985 #2934 currently under restoration
1000 SFC Preproduction bike 1985 #0001 *sold*
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Offline Tippie

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Re: Reading your tyre wear
« Reply #17 on: December 02, 2019, 16:13 »
I wouldn't complain about the look of that rear slick. What do you see wrong with it Carlo?
SF2 17483 (race)
SF2 17424 (road)
An Australian living near Oslo in Norway

Offline Laverdalothar

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Re: Reading your tyre wear
« Reply #18 on: December 02, 2019, 16:21 »
I don't think he means the slick, he means the other pic... there are partually blank parts on the side-wall, just as described in the video for wrong shiming of the suspension... also one edge of the "profile cut" is building up material while the other side looks washed out. this also indicates something's wrong/not ideal with the suspension.

I think for the track days we do on our old bikes, the tire looks great. sure it could be better, but would the rider recognize it? propably not... 
750 SF(0) 1971 #9934 *sold*
1000 SFC Classic 1989 #3367 *sold*
1000 SFC 1985 #2934 currently under restoration
1000 SFC Preproduction bike 1985 #0001 *sold*
1200 Jota 1981 #7474
750 S-Formula 2000 #1602
1000 Motoplast - currently under construction

Offline Vince

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Re: Reading your tyre wear
« Reply #19 on: December 02, 2019, 18:12 »
I am keen to see my tyres after watching the full video, shame I am 600ks away.It's good to have some empirical evidence to obsess about with suspension and tyre pressure effects. 10,000 more posts coming soon

Offline Jo

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Re: Reading your tyre wear
« Reply #20 on: December 03, 2019, 15:39 »
Not entirely true.

Road use gets tyre temps nowhere close to what would be attained on a forcefull track run.

If the bike has the power and the rider the speed on the track, the tyre will quickly reach a proper operating temperature and pressure will rise to a "normal" level if it has been reduced beforehand.  If not, pressure will rise to abnormal heights, causing all sorts of havok, especially playing tricks on the suspension.

When riding Spa on the 3C in warm to hot conditions, rear pressure was set at around 2.0-2.2bar in the 150/70 BT012S, measuring imediately after leaving the track showed a very normal and healthy 2.7-2.8bar, the pressure I would normally use on the road.  Tyre performance was perfect, as expected.  Wet conditions called for slightly raised pressures as not enough heat could be generated.  I also had the oppurtunity to run a set of slicks on the old banger, pressures needed to be reduced even further.  The performance these things offer cannot be described, it needs to be experienced! ;D

Hard to overheat tyres at the pace our bikes are capable of, slight blueing at the edges can be considered quite normal after temps have returned to ambient.  Have yet to see a Lav that has managed to blister its tyres, provided they were run at appropriate pressures.

Badly chewed up tyres after track runs are not always the result of incorrect pressures, properly working suspensions go a long way to help reduce tyre wear.

piet



My experiences were based on my Aprilia RSV and as rule-of-thumb estimate Iíve transferred this (maybe to much) in general. For example, the frequently
driven Pilot Power gets very quickly out of its temperature range when it is used on a racetrack:

 ???

It also makes a difference whether you drive in Spa or Oschersleben, in Spa I measured a lower delta between cold and warm tires, obviously because
of the relatively long track in combination with the two high-speed sections.

As for the use of slicks and rain tires - yes, they make a big difference! I'll never forget the first full rain workout in Spa, when I decided to invest in rain
tires, unbelievable what's possible with them.



And what is a pure racing tyre? My CBR600 track bike uses tyres approved for supersport which are dot road tyres and recommended pressures for the track are 1.4rear/2.4front kpa, they work brilliantly. On the road they would need heaps more in the rear, and many people use these tyres on the road. My race SF on Conti attack cr tyres which are also dot road tyres have under 30psi front and rear, had I used high pressures, even higher than road as you suggest I would get absolutely nowhere. Vince's experience is very common, I thought I was a real hero first time I road at a racetrack, sliding the back out and going nowhere with cold road pressures.



These "Hypersport" tires you mention are actually road-legal racing tires. They should not be the first choice when driving on country roads or even in
the wet though.

Next, I want to put Contis on my Laverda, only that I do not intend to drive on the racetrack with her (in fact my suspension is the next big building site
I've to put my attention to).

In general, I have no experience on the racetrack with classic motorcycles, or with the tire dimensions used on classic bikes. I think that you have much
more idea about that ...


Cheers
Jo

« Last Edit: December 03, 2019, 15:52 by Jo »
Take people as they are - there aren't any others.

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Offline Paul Marx

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Re: Reading your tyre wear
« Reply #21 on: December 03, 2019, 15:58 »
Not very relevant for going on holiday or to the bakers  ;D

Paul

Offline Tippie

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Re: Reading your tyre wear
« Reply #22 on: December 03, 2019, 22:24 »
Jo, you are right they are road legal race tyres (basically slicks with some tread to be allowed in supersport racing). Yes they are lethal in the wet and shit unless in their operating temperature. It is a mistake for people to think that because they are a sticky race tyre they will be good for riding fast on the road, they can't get up to temperature.
SF2 17483 (race)
SF2 17424 (road)
An Australian living near Oslo in Norway

Offline cbertozz

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Re: Reading your tyre wear
« Reply #23 on: December 08, 2019, 12:38 »
I wouldn't complain about the look of that rear slick. What do you see wrong with it Carlo?

When we see comet tails on the wear holes trailing backwards it indicate not enough rebound (rebound too slow), so tyre staying down too long. You can ride all day like it but depending on your track you might see better tyre wear and improved handling characteristics with some more rebound (wind out a couple of clicks and see what happens).
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First owned in 1991, reacquired 2016.

Offline Piranha Brother 2

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Re: Reading your tyre wear
« Reply #24 on: December 10, 2019, 00:52 »
it indicate not enough rebound (rebound too slow)

Those two statements are opposites, Carlo. Not enough rebound = retracts/rebounds too fast (bounces). Too slow (= too much) rebound can be blamed if the rear continues to sink over a series of short sharp bumps or corrugations.
What ... leave it standard??!!

Offline Vince

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Re: Reading your tyre wear
« Reply #25 on: December 10, 2019, 02:38 »
In the dirtbike world that's called packing down, the shock gets another hit before its done its job on the first bump and this repeats till the shock bottoms and stays bottomed. That's why videoing or watching the bike from afar is a great way to see what's happening, it's easy to get it wrong just by your feel on the bike. Especially with short road bike suspension travel.

Offline cbertozz

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Re: Reading your tyre wear
« Reply #26 on: December 10, 2019, 05:27 »
Those two statements are opposites, Carlo. Not enough rebound = retracts/rebounds too fast (bounces). Too slow (= too much) rebound can be blamed if the rear continues to sink over a series of short sharp bumps or corrugations.

Too much rebound damping - too slow
Too much rebound - too fast.

Fully closed rebound circuit = maximum rebound damping = slow

Fully open rebound circuit = maximum rebound = fast

Itís all semantics
1978 Laverda Jota #6041
First owned in 1991, reacquired 2016.

Offline Jens

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Re: Reading your tyre wear
« Reply #27 on: December 10, 2019, 11:13 »
I installed recently these rubbers:







then I once drove around the cow pasture to control the fence.

Back home I checked the tire wear ----- but what the hell? Look at this:








Can someone read that tyre wear?


Cheers, Jens  ;)

Offline Vince

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Re: Reading your tyre wear
« Reply #28 on: December 10, 2019, 12:38 »
To much poo, less poo required

Offline Tippie

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Re: Reading your tyre wear
« Reply #29 on: December 10, 2019, 13:18 »
You really destroyed those K81s Jens. My Contis wear really well. This is after lapping just outside the class record, new rear damper units, fitted them as they came from Maxton. This tyres is three race meetings old. The tyres looked the same with the old Ohlins too. Used to chew the shit out of Avons but still always got a season out of them at least.
SF2 17483 (race)
SF2 17424 (road)
An Australian living near Oslo in Norway