Tyre wear problem

[GSVR]

I was wondering what other racers have done when their tyres start wearing like the one on in this picture. Once this happens your tyre just gets worse and worse.

What causes it? What is the technical term for this kind of wear?

At the time this happend it was at Manfield on test days and my bike wasn't the only one it was happening to.

I will post my solution to the problem that I have stuck to for the rest of the time I was racing but recent ideas have me thinking there may be a better solution.

Any input greatly appreciated.

This was on my old SV650 with Std frontend with emulators and from memory a way to soft GSXR rear shock. The tyre was a fresh new Pirelli Diablo Superbike slick SC1. The track was Manfeild before any resealing work had been done.

[Clivoris]

Is it what happens when you leave the pub and give a cold tyre too much wrist?:innocent:

[Ivan]

I was wondering what other racers have done when their tyres start wearing like the one on in this picture. Once this happens your tyre just gets worse and worse.

What causes it? What is the technical term for this kind of wear?

At the time this happend it was at Manfield on test days and my bike wasn't the only one it was happening to.

I will post my solution to the problem that I have stuck to for the rest of the time I was racing but recent ideas have me thinking there may be a better solution.

Any input greatly appreciated.

This was on my old SV650 with Std frontend with emulators and from memory a way to soft GSXR rear shock. The tyre was a fresh new Pirelli Diablo Superbike slick SC1. The track was Manfeild before any resealing work had been done.


Im Sure that is because you do not have enough preload on the suspension thats what myne looked like on my 125 before we adjusted the preload

[Sketchy_Racer]

Yeah looks like it's too saggy in the rear, possibly a bit of cold tear also (made worse by to much squat) raise preload, and up tyre pressure.

.... Sketchy_Racer doessss know what he's talking about [tui add here]

[GSVR]

Im Sure that is because you do not have enough preload on the suspension thats what myne looked like on my 125 before we adjusted the preload


Yeah looks like it's too saggy in the rear, possibly a bit of cold tear also (made worse by to much squat) raise preload, and up tyre pressure.

.... Sketchy_Racer doessss know what he's talking about [tui add here]


Great thanks for the replies. Tyre pressure helped in the past but not with this these tyres.

I'll add a bit more now.


At the same time Glen Williams had just started racing his Old SV650 and he had it set up with his old ZX10 rear shock and an USD frontend. His rear tyre was just like mine as well but much worse. I think this may have been before he sent it away to be revalved. His bike was not ideal but would have been miles better set up than mine.

Oh one more thing the wear/ damage for the righthanders was alot less than for the 2 lefthanders. 2 corners created more wear than the other 5? on Manfield.

[Ivan]

Great thanks for the replies. Tyre pressure helped in the past but not with this these tyres.

I'll add a bit more now.


At the same time Glen Williams had just started racing his Old SV650 and he had it set up with his old ZX10 rear shock and an USD frontend. His rear tyre was just like mine as well but much worse. I think this may have been before he sent it away to be revalved. His bike was not ideal but would have been miles better set up than mine.

Oh one more thing the wear/ damage for the righthanders was alot less than for the 2 lefthanders. 2 corners created more wear than the other 5? on Manfield.

YipCauseManfield is right handers the right hand sideof the tire stays hot but becuase of the 2 lefts you hardly get any heat in them tires that why Alot of guys bin it in these left hand corners as thetires are a shit load corner when you look at Manfield the rights are very long and flowing so you on the edge of the tire for a while putting alot of heat into it and then down the straight heats the center but the left during all this is cooling off then all of a sudden you back onto a left again slightly colder tire and possibly cold Tearing the tire as the tire is to cold?? Thats a guess as to why someone like Shaun Or Robert will know but Im just thinking from my opinion what it could be but im no expert at this

[Robert Taylor]

Yeah looks like it's too saggy in the rear, possibly a bit of cold tear also (made worse by to much squat) raise preload, and up tyre pressure.

.... Sketchy_Racer doessss know what he's talking about [tui add here]

Manipulating spring preload and tyre pressure will often get rid of and minimise the problem but it is usually not skinning the cat correctly.

Comments:

1) The motion ratio that the SV650 linkage imparts is sufficiently different to that in the ( K1 to K4 ? ) GSXR1000. Compared to the GSXR for any given distance of wheel movement the shock shaft is moved less on the SV. The linkage is less aggressive on the SV therefore the shock shaft moves at a slower speed. Damping in such shocks is velocity dependent, if you move it slower ( as in this case ) it has less damping. That is one of the compelling reasons the shock feels soft to you.

2) Has the shock ever been apart? Much like a car tyre lets its pressurised air migrate through the rubber over time exactly the same happens in these oem shocks that use a bladder. The nitrogen pressure migrates through the rubber into the oil. If it has never been apart it will well and truly be a ''milkshake'' by now, softer again and it will go off more quickly.

3) Even for the GSXR ( which has a more aggressive linkage ) that shock is too soft. We happen to have dyno'd these in the past. Compared to a well sorted racing shock the initial damping at very low shaft speed has a very lazy build up because there is too much bypass bleed through the main shaft. STOP RIGHT NOW thinking about closing off the low speed compression adjuster, that actually has very little influence over the first initial part of very slow speed shaft travel. You may fudge it a little, that is all. The compression adjuster works on shaft displacement only and is a bypass bleed for oil into the reservoir, that part of the damping mechanism accounts for only 12 to 13% of total damping force. On the main shaft the bypass jet is handling a much greater volume of total flow, but of course the shock has to be stripped to manipulate its size.

4) Allied with that the shim stack opens too early and allows it to squat too readily, this means that the rear end sinks into its stroke too readily pre compressing the spring too much. So there is more spring force, its engaging a little too early on the rising rate part of the linkage and that overloads the tyre.

5 ) The tyre is also a part of the suspension action but there is a fine window where it is going to work, it varies from track to track, temperature, gearing, all sorts of variables. Too hard suspension and the tyre is compressing too much and ''scrubbing the loaded contact surface. Too soft suspension and it squats and becomes hard ( oversimplistically ) delivering a similiar result.

6 ) Another cause of scewing tyres can be too much rebound damping and I dont mean just on the clicker I mean on the shim stack. THE CLICKERS are not some magical device that changes the character of the shock immensely. Kyle Key was stressing his front tyre at the Pukekohe Nationals, we analysed that it was happening while working low in its stroke through ( especially )turn 1. It was essentially being held down too aggressively instead of recovering as quickly as it should. That was causing harshness and was making the tyre do too much of the absorption action. ( I am glad he had Ohlins cartridges fitted rather than anything else because they are dramatically user friendly to make quick internal setting changes ) And anyway how do you know whether the rebound calibration in that GSXR shock is in any way suitable for the motion ratio that the SV linkage imparts on it? I hope you havent been misled by another forum?

7 ) I am guessing that your personal stats are roughly conversant with the spring rate on that GSXR. Many people would fit a firmer spring which is also often the wrong way to skin the cat and will result in harshness over the more abrupt bumps.

As I stated somewhere in another thread springs are more about position, damping is about controlling rate of change of position.............. the rate of change of position in that GSXR shock is clearly lacking, especially in compression.

Just for relevant information we will be up and running modifying standard shocks such as this very soon. As we have a huge database of Ohlins damping curves for popular models of bikes. So we have a huge helping hand in knowing what force curves are required / mods required. Whilst this sort of oem modification work wont attain the same performance as our beloveed Swedish stuff it is going to give great bang for buck for club riders.

[GSVR]

Yep. Well the conclusion was reached that the SC1 compound was too soft and I've been useing SC2s ever since and the wear is really good getting lots of riding out of a tyre. Becuase I'm so tight I even tried an SC3 but found it was abit slippery for even someone as slow as myself.

What I would like to know if anyone racing SVs has had any luck with soft compound tyres. I might get some new tyres soon so even changing brand is a possibility.

Or maybe an SC1 is usable with the right suspension and tyre pressure!

[GSVR]

Thanks for the reply Robert. I will read your post several times to get the most out of it.

[White trash]

Question Gary. What time of the year was it?

[TonyB]

My back tyre has developed a very similar wear pattern on the left hand side from riding at Ruapuna. A few people looked at it and said that the shock is bottoming out- though looking at Roberts answer its not likely to be quite that simple!

Nice pic BTW- its not all that easy to get a decent pic of wear like that

[Robert Taylor]

Yep. Well the conclusion was reached that the SC1 compound was too soft and I've been useing SC2s ever since and the wear is really good getting lots of riding out of a tyre. Becuase I'm so tight I even tried an SC3 but found it was abit slippery for even someone as slow as myself.

What I would like to know if anyone racing SVs has had any luck with soft compound tyres. I might get some new tyres soon so even changing brand is a possibility.

Or maybe an SC1 is usable with the right suspension and tyre pressure!

Not on every track! Teretonga ( for example ) is the worst track and there is a specific dynamic that is causing it.

[GSVR]

Question Gary. What time of the year was it?

I think it would have been between the 2nd and 3rd rounds of the Vic Club meetings in 2006. Funny how I still have the tyre.

With the Pirellis it seems you can go SC0 on the front no worrys but the SC2 was the softest compound that worked on the back.

[Robert Taylor]

I think it would have been between the 2nd and 3rd rounds of the Vic Club meetings in 2006. Funny how I still have the tyre.

With the Pirellis it seems you can go SC0 on the front no worrys but the SC2 was the softest compound that worked on the back.

You could actually get an SC1 to work but the shock and its spec has to be right on the money. Many tyre wear problems are blamed on the tyres when very often its a suspension and set up problem. But generally yes the SC2s are more forgiving re set up.

Its quite a good system really...we blame the tyre guys and the tyre guys blame us!

[White trash]

I think it would have been between the 2nd and 3rd rounds of the Vic Club meetings in 2006. Funny how I still have the tyre.

With the Pirellis it seems you can go SC0 on the front no worrys but the SC2 was the softest compound that worked on the back.
So bloody cold then? A contributing factor in conjunction with the incorrect suspension would have to be that the tyre wasn't anywhere near it's operating temperature.

[KS34]

Looks like cold tearing to me, have you got tyre warmers? did they get up to temp?

[Robert Taylor]

So bloody cold then? A contributing factor in conjunction with the incorrect suspension would have to be that the tyre wasn't anywhere near it's operating temperature.

That is 100% correct. Please though dont start an argument about tyre warmers!

[Tony.OK]

Not all is caused by "cold" tyres...............linky (http://www.crstuning.com/tire-wear.html)

[GSVR]

So bloody cold then? A contributing factor in conjunction with the incorrect suspension would have to be that the tyre wasn't anywhere near it's operating temperature.

Don't recall it was that cold but the track surface probably was.

Personally I think they might be great if you can afford to put a new one on after every race. But then who wants to pay $300 a race for a 0.2 sec improvement in laptimes. Possibly coming out of the hairpin was the only place the SV had enough power to deal to the tyre.

Would be nice to try an SC1.5

[GSVR]

Not all is caused by "cold" tyres...............linky (http://www.crstuning.com/tire-wear.html)

Great link but all those wear marks are running with the tyre mine are more across the tyre.

Thanks Tony actually the pictures of your tyres got me thinking on this.

A question for the 600 guys. Does a 190 wear any better then a 180 or is the difference unnoticable?

[Robert Taylor]

Don't recall it was that cold but the track surface probably was.

Personally I think they might be great if you can afford to put a new one on after every race. But then who wants to pay $300 a race for a 0.2 sec improvement in laptimes. Possibly coming out of the hairpin was the only place the SV had enough power to deal to the tyre.

Would be nice to try an SC1.5

Your choice is to either take steps to fix the sources of the problem or to band aid it. The first option will ultimately make you faster and I believe that is a good part of the mentality of road racing.

Option 1 Average tyres and great suspension equals average lap times

Option 2 Great tyres and average suspension equals average lap times

Option 3 Great tyres and great suspension equals great lap times

Most people I know prefer option 3.

Enough said

[HDTboy]

Great link but all those wear marks are running with the tyre mine are more across the tyre.

Thanks Tony actually the pictures of your tyres got me thinking on this.

A question for the 600 guys. Does a 190 wear any better then a 180 or is the difference unnoticable?

From what I've seen (not a lot), running a 190/55 is more about increasing the side grip available, and helping turn the bike quicker due to the tyre being taller than a 180/55. Moreso when fitted to a 5.5 inch rim instead of the 6 inch rims on the 1000s

[GSVR]

From what I've seen (not a lot), running a 190/55 is more about increasing the side grip available, and helping turn the bike quicker due to the tyre being taller than a 180/55. Moreso when fitted to a 5.5 inch rim instead of the 6 inch rims on the 1000s

Yep a 190/55 is going to be alot taller than a 160/60 when fitted to a 4.5 inch rim.

[HDTboy]

You'd need to ask Karl Morgan about that

[GSVR]

You'd need to ask Karl Morgan about that

I'm just wondering how close it will be to the chain or will I have to grind one side off a bit.

[cowpoos]

I was wondering what other racers have done when their tyres start wearing like the one on in this picture. Once this happens your tyre just gets worse and worse.

What causes it? What is the technical term for this kind of wear?

At the time this happend it was at Manfield on test days and my bike wasn't the only one it was happening to.

I will post my solution to the problem that I have stuck to for the rest of the time I was racing but recent ideas have me thinking there may be a better solution.

Any input greatly appreciated.

This was on my old SV650 with Std frontend with emulators and from memory a way to soft GSXR rear shock. The tyre was a fresh new Pirelli Diablo Superbike slick SC1. The track was Manfeild before any resealing work had been done.
have you worked out this is because of the bikes shit suspension yet??? or do you believe you could fix it with pressures and compound changes??

[budda]

Bridgestones work well on SV's - anyone else on here tried 'em ?

[GSVR]

Bridgestones work well on SV's - anyone else on here tried 'em ?

I haven't found a tyre thats bad on an SV just different handling characteristics, wear, and performance.

The SV being a very low powered commuter doesn't eat tyres. Just get the right tyre for the track conditions ie temp etc, how long you want them to last, and weather conditions.

SV you can use very soft fronts and they wear well but be careful putting soft stuff on the back in cold winter conditions when the tracks suface is cold or you will get wear like pictured in the first post (Cold shearing)

Approriate this thread has been dredged (its a year old) as its getting near the Vic Clubs winter series. If I was running Pirrelli slicks on my SV I'd be useing an SC0 or SC1 front and an SC2 rear on any cold day. And tyrewarmers of course.

I run these at trackdays and they last for ages and my bikes got a standard rear shock in it.

[cowpoos]

If I was running Pirrelli slicks on my SV I'd be useing an SC0 or SC1 front and an SC2 rear on any cold day. And tyrewarmers of course.


changed your tune again??

[GSVR]

changed your tune again??

If you are refering to Tyrewarmers. If the rules allow for something that can help you then of course you will use it.

I think for example ProTwins would have been a far more interesting class and would of added diversity from the other classes if it was a control street tyre that could handle wet and dry conditions and also had no tyrewarmers (just like streetstock). Oh and also standard shocks with only spring and oil changes. But dogbones allowed to be shortened to improve steering.

I've been on this same tune like a broken record for some time now just ask anyone who races that I talk to often.

[Robert Taylor]

I haven't found a tyre thats bad on an SV just different handling characteristics, wear, and performance.

The SV being a very low powered commuter doesn't eat tyres. Just get the right tyre for the track conditions ie temp etc, how long you want them to last, and weather conditions.

SV you can use very soft fronts and they wear well but be careful putting soft stuff on the back in cold winter conditions when the tracks suface is cold or you will get wear like pictured in the first post (Cold shearing)

Approriate this thread has been dredged (its a year old) as its getting near the Vic Clubs winter series. If I was running Pirrelli slicks on my SV I'd be useing an SC0 or SC1 front and an SC2 rear on any cold day. And tyrewarmers of course.

I run these at trackdays and they last for ages and my bikes got a standard rear shock in it.

Try opening the throttle earlier and holding it on longer like the fast guys in front of you, read the tyres again.

[GSVR]

Try opening the throttle earlier and holding it on longer like the fast guys in front of you, read the tyres again.

Yeah like thats ever going to happen. What about putting Terry or Glen on my bike and see how long it takes them to ruin a tyre. Now that would be a comprehensive test.

Sort of like getting Gixxeracer to do a tyre test on a Streetstock bike right?

[Robert Taylor]

Yeah like thats ever going to happen. What about putting Terry or Glen on my bike and see how long it takes them to ruin a tyre. Now that would be a comprehensive test.

Sort of like getting Gixxeracer to do a tyre test on a Streetstock bike right?

Suffice to say the three riders you mention are more motivated than you about going fast and will have the right equipment to do so.

[GSVR]

Suffice to say the three riders you mention are more motivated than you about going fast and will have the right equipment to do so.

I don't think so. If two or them were really motivated they wouldn't be riding commuter bikes right? PT

[Robert Taylor]

i don't think so. If two or them were really motivated they wouldn't be riding commuter bikes right? Pt

twist twist twist ad infinitum

[Mishy]

You could actually get an SC1 to work but the shock and its spec has to be right on the money. Many tyre wear problems are blamed on the tyres when very often its a suspension and set up problem. But generally yes the SC2s are more forgiving re set up.

Its quite a good system really...we blame the tyre guys and the tyre guys blame us!

Bingo, I do it all the time .. . . . . . . . . :devil2:

Soft tyres are far more prone to the type of tearing we are lookig at here. There are many many possible causes/cures for this, but often the underlying problem is the same - too little temperature in the tyre, which leads to a lack of compound flexibility (tyre is below it's temperature corridor, and the polymers have not attained glass transition temperature) In a very soft tyre which has a high volume of stiffener in the compound, this mostly rules them out in cool conditions
Another (common) underlying problem is an imbalance between the load applied and the wheel force at that end of the bike. Suspension and geometry matter a WHOLE heap here, but poor tyre choice can also be the culprit.
All the Conti running SV650 riders at Nationals this year (Conti ran 2 and 3) ran Medium rear tyres. We only had one meeting where i think a soft would have been a genuinely better choice for any of them
It seems simplistic, but a well performing strong compound tyre will provide better grip than a torn soft one.

[Shaun P]

What are conti's like compared to say pirellis?

[CHOPPA]

Ive found 2 solutions for this problem! The first solution is to turn the tyre around :msn-wink: and the other solution was to change to DUNLOP :first:

RT would be good to talk to but we could never sort the problem out on cold Taupo on pirellis but it doesnt seem to be a problem on Dunlops

[Mishy]

What are conti's like compared to say pirellis?

Not that much in it, the Conti front tyre carcase is a bit stronger though, and the rear seems better dampened.

[GSVR]

Don't want to make any assumptions or presumptions here....

Do you think Contis race tyres are more like Dunlop race tyres in their construction and charactistics than Pirellis?

[Robert Taylor]

Don't want to make any assumptions or presumptions here....

Do you think Contis race tyres are more like Dunlop race tyres in their construction and charactistics than Pirellis?

They are actually somewhere inbetween the two, Hamish will be able to elaborate further.

[Mishy]

They are actually somewhere inbetween the two, Hamish will be able to elaborate further.


Quite right mate :) The carcase of the front Conti in particular is more rigid and stable than the Pirelli, but more supple than the Dunny. It's kind of the same for the rear, but the Conti and P model are a bit closer. There are still significant differences though, and the Conti seems to have a bit more control in that area. In general the Dunny's are pretty rigid, and transfer force, and dampen quite differently to all the others. Robert would testify to how much that affects suspension damping and spring solutions - it's quite a big deal, and really needs someone other than me to cover it properly.
You could write pages on that stuff though . . . . . . . . .