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-   -   Front Tyre Wear Query (http://forums.sv650.org/showthread.php?t=145901)

Tim in Belgium 29-01-10 10:28 PM

Front Tyre Wear Query
 
Quick Intro: I ride the Nurburgring a lot, 270 laps last year, approx 225 on the GSXR, as well as TDs at Spa, Zandvoort and Zolder. Now let the story begin:

My last weekend at the Ring 2009 was great, great weather, great company, great lap times, an amusing weekend etc.

What was not so great was the wear to my front tyre. Normally I get 2+ weekends from a rear and more from a front.

The last weekend I did about 41 laps on a new front and it is just about beyond what I'd call safe for riding on.

The tyer in question is a BT-002, soft front 120/70.

The weekend was end of August, hot during the day but cold first thing. On the Friday I did a few laps scrubbing in the new tyre, came in measured hot pressure and let down to bridgestone recommended hot pressure (I can't remember what that is, something like 28-30 PSI IIRC).

I then went out and did 2 laps, with some flagging at an accident. I then went out again for a storming session, new PB BTG in the lowish 8s, new Juanjo time (race chrono) best of sub 8.

A great weekend followed., lots of laps, plenty in the mid 8's etc. No complaints from me about the bike.

Just looking at the tyres I took off after 41 laps and the front is done in on the right shoulder, it has really fifty penced pieced with a pronounced wearing/scrubbing, feeling the tyre it is remarkably thin here.

A clear view of the RHS with wear:

http://inlinethumb04.webshots.com/22...600x600Q85.jpg


A view of the LHS much less extreme wear:

http://inlinethumb60.webshots.com/45...600x600Q85.jpg

Some more shots of the digging out of the RHS:

http://inlinethumb27.webshots.com/43...600x600Q85.jpg

http://inlinethumb13.webshots.com/14...600x600Q85.jpg

Notice how it almost "troughs" on the RHS:

http://inlinethumb55.webshots.com/46...600x600Q85.jpg

The pics really don't do true justice, but I was wondering if there is any possible reasons for this extra wear over normal, somepossible ones follos:

1) My pace was slightly faster (but not that much really, and a lot below what these tyres/this bike could do).

2) My cornering lean angle is too static, only ever roll to a certain angle on the bike and no further, causing this ramp effect in the tyre.

3) The tyres were too low in pressure on the cold mornings, or too high in pressure on the hot afternoons, I only set my pressures once and then felt happy, leaving it for the rest of the weekend.

4) It was an old stock tyre, bought in the UK, but they had stopped being produced.

5) There is some deficiency in my bike's suspension.

Some conmbination of the above.

Am I expecting too much from my tyre? Is there some other explanation? Answers on a post card, or reply below...

Not terribly interesting but it's winter.....

Berlin 29-01-10 10:44 PM

Re: Front Tyre Wear Query
 
Hot tear Tim. Not enough Air in the tyre. See more info here...
http://www.feelthetrack.com/tire-wear.html
also look fopr the video where he explains tyre wear on Youtube. (search "two clicks out")

Tim in Belgium 31-01-10 12:28 PM

Re: Front Tyre Wear Query
 
Chears for that Berlin, it could well be the case.

Red Herring 31-01-10 12:58 PM

Re: Front Tyre Wear Query
 
Looks fairly average to me Tim. Don't forget that as soon as you take the tyre off the rim the profile changes so don't worry about the "digging" or "troughs". Wear like that on a front tyre is often indicative of heavy braking cranked over and if you think your way around the ring (like you don't know the way!) there are several places where you're gong to be doing that on the right hand side (into Aremberg for example, or Bergwerk) from quite high speed. Of course it might also be that you're better on right handers that lefts.... which is typically British of you!

Tim in Belgium 31-01-10 01:04 PM

Re: Front Tyre Wear Query
 
The Ring always wears tyres a lot more on the RHS, so that's not my concern, more the rate of wear compared to all of my other trips, I thought the type of wear may be a clue to why it was accelerated this time. It could be that I was just being more aggressive that weekend, or could be some pressure/suspension set up.

Red Herring 31-01-10 02:44 PM

Re: Front Tyre Wear Query
 
I suspect it's just the way you are going that little bit quicker, unless you have specifically changed a tyre/suspension setting. Generally when we learn our way around a track we get down to a base time fairly quickly, then we trim bits off it by trying that little bit harder in places. Getting on the throttle harder and sooner (the slow in quick out approach) is the safest and most popular way so rear tyres get a hard time at first, then we try braking harder and later but keeping the same entry speeds, before finally when we get really confident somewhere (and the Ring takes years to get here) we start going in hard on the brakes. This last stage is the hardest on the front tyre as you are often scrubbing/drifting it all the way to the apex, and it may be that you have now arrived here, hence the sudden increase in your front tyre wear.
Far be it for me to tell you how to ride the Ring Tim, but if you are at this point you're going to need lady Luck on your side because eventually you're going to need some reserve going in to deal with the unexpected, that's what makes the ring so unique and exciting, and a killer!

yorkie_chris 31-01-10 03:29 PM

Re: Front Tyre Wear Query
 
What were your new hot pressures after you let some air out?

It will change more than with just amount of air directly, as less air will allow more flex.

Tim in Belgium 31-01-10 03:31 PM

Re: Front Tyre Wear Query
 
I honestly can't remember, but they were from Bridgestone for this specific tyre/compound. I'm thinking I set them on a hot afternoon, so when going out on a cold morning the diffrence was too great and they were too low in pressure.

I.e I caused a lot of the wear in a few laps.

yorkie_chris 31-01-10 04:01 PM

Re: Front Tyre Wear Query
 
Looking at K6-600 fork valving, it seems pretty light. But that is about as far from an experienced and scietific viewpoint as you can get. Not least because yours could be totally different :-P

Chewie 12-03-10 03:34 PM

Re: Front Tyre Wear Query
 
My front bridgestone has gone the same was as this tyre after 5000 miles or so! all done on the road.


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