Andy D
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| posted on 13/5/10 at 07:01 AM |
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A048s R888s and lap times
A couple of questions for folks racing on 1b tyres, Yokohama A048s or Toyo R888.
At what point in the tread wear do you notice a drop in performance? And when do you reckon they give their best lap times?
Anyone's opinions appreciated, cheers.
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MK9R
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| posted on 13/5/10 at 07:30 AM |
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i find times drop off once the wedding is showing 
I change mine once i am wearing out the wear markers, and performance doesn't seem any worse at this point than when they are new. The
peformance is more related to how many heat cycles the tyres have done, but to honest we (RGB) get through all of the tyres apart from the inside
front far before the heat cycle seems to come into play. The one thing I do notice is that the more wear on the tyre, the shorter amount of time the
tyre seems to last before its starts going off in a race.
As a gauge if i start the year with 4 new tyres, i have to change the rears set and outside front once during the season, and maybe another rear set
right near the end . Thats a season of 14 races with some extra test days added in.
Cheers Austen
RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk
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Andy D
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| posted on 13/5/10 at 07:49 AM |
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quote:
The one thing I do notice is that the more wear on the tyre, the shorter amount of time the tyre seems to last before its starts going off in a race.
I think that's what I'm suspecting..
My son was racing his Civic at Croft last weekend. On Saturday he was quicker than he'd ever been round the circuit, but the following day
he was slower. Not by a huge amount, but I noticed the front tyres are partially down past the wear bars.
I'm thinking you need a certain amount of tread depth to generate heat?
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MK9R
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| posted on 13/5/10 at 07:52 AM |
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quote:
Originally posted by Andy D
quote:
The one thing I do notice is that the more wear on the tyre, the shorter amount of time the tyre seems to last before its starts going off in a race.
I think that's what I'm suspecting..
My son was racing his Civic at Croft last weekend. On Saturday he was quicker than he'd ever been round the circuit, but the following day
he was slower. Not by a huge amount, but I noticed the front tyres are partially down past the wear bars.
I'm thinking you need a certain amount of tread depth to generate heat?
I think its more that you need a certain amount of rubber on the tyre to stop it over heating. The tyres seem to over heat quicker the more they are
worn/used
[Edited on 13/5/10 by MK9R]
Cheers Austen
RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk
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GMPMotorsport
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| posted on 13/5/10 at 07:54 AM |
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It really does depend on how hard you drive, we use the A048 and I got through 3 sets during the season but that didn't include a set kept just
for wet racing, I do buff them up after each race which I find helps a lot, HTH.
www.gmpdevelopments.co.uk
www.gmpmotorsport.co.uk
ARDS Instructer.
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GMPMotorsport
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| posted on 13/5/10 at 07:56 AM |
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quote:
Originally posted by MK9R
quote:
Originally posted by Andy D
quote:
The one thing I do notice is that the more wear on the tyre, the shorter amount of time the tyre seems to last before its starts going off in a race.
I think that's what I'm suspecting..
My son was racing his Civic at Croft last weekend. On Saturday he was quicker than he'd ever been round the circuit, but the following day
he was slower. Not by a huge amount, but I noticed the front tyres are partially down past the wear bars.
I'm thinking you need a certain amount of tread depth to generate heat?
I think its more that you need a certain amount of rubber on the tyre to stop it over heating. The tyres seem to over heat quicker the more they are
worn/used
[Edited on 13/5/10 by MK9R]
It is a very fine line, the more tread you have the more the rubber moves around creating to much heat hence the reason for slick tyres.
[Edited on 13/5/10 by GMPMotorsport]
www.gmpdevelopments.co.uk
www.gmpmotorsport.co.uk
ARDS Instructer.
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Andy D
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| posted on 13/5/10 at 08:10 AM |
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quote:
It is a very fine line, the more tread you have the more the rubber moves around creating to much heat hence the reason for slick tyres.
Isn't that more of a problem with proper road 1a tyres, hence sprinters have them buffed down? I would have thought 1bs being a bit more track
focussed, have less tread to start with, to prevent overheating..
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procomp
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| posted on 13/5/10 at 09:13 AM |
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Hi
The better rubber is on the outer. Once down towards the end of life your using the not so good rubber.
Best but gets expensive way is to fit new scrubbed tyres every 3-4 races.
Cheers Matt
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progers
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| posted on 13/5/10 at 09:28 AM |
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What he siad ^^
I find the first race with new rubber (O48's) the tyres are definitely quicker by a few tenths, they then level out and perform pretty
consistently until they get too worn/too many heat cycles. I make 2 sets last a season with maybe an extra rear nearside if I'm feeling flush
- Paul
[Edited on 13/5/10 by progers]
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Andy D
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| posted on 13/5/10 at 10:04 AM |
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Well we've had four races and the fronts wont do another.  Rears will probably last all year. (800+kg fwd car)
So it's new tyres for the next race and a new lap record.  ... or maybe not!
Thanks chaps, any more comments welcome. 
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bi22le
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| posted on 13/5/10 at 10:59 AM |
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When I brought my Striker I got a set of A048s that are pretty much on the wear bars all of the way across the wheel (even wear on all four corners).
Im doing a track day on them on Saturday. Ill be running 18PSI. Does this sound about right and safe?
What does heat cycles mean? I have a blue colour to the outside of two of the wheels I take it this is due to lots of heat. Again is this a
problem.
Thanks for the info and sorry to hijack the post alittle. The responses of this may help the OP any way.
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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progers
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| posted on 13/5/10 at 12:53 PM |
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16-18psi is a good place to start. O48's work best when around 22psi hot. Just measure the pressures when you come in from a session and
equalise them to 21/22 all round (some tyres will heat up more than others)
Regarding the wear, they will be fine, us racers are worrying about tenths of a lap time, for trackdays just wear the buggers out :-)
Blueing on the edge is pretty common, its normal. Heat cycling erefers to how many times the tyres have been warmed up and cooled down again. The more
cycles, the more the rubber tends to degrade. Again, we are being a bit pedantic here, worn O48's will be much, much better than a normal summer
tyre on a track.
Cheers
Paul
P.S. I have a bunch of part worn 48's (185/13 and 205/13) that people can have for £10 each - just need to collect them from Norfolk!
[Edited on 13/5/10 by progers]
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Andy D
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| posted on 13/5/10 at 01:55 PM |
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quote:
P.S. I have a bunch of part worn 48's (185/13 and 205/13) that people can have for £10 each - just need to collect them from Norfolk!
Bloody hell! I've just spent over £300 on those very sizes for my Westy this afternoon. ..out of interest, how much like is there left in
them?
[Edited on 13/5/10 by Andy D]
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andylancaster3000
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| posted on 13/5/10 at 02:09 PM |
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out of interest, how much like is there left in them?
I'd be interested too
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MK9R
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| posted on 13/5/10 at 02:11 PM |
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can you use all the grip up of a tyre, if so Paul will have rung them dry
Cheers Austen
RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk
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andylancaster3000
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| posted on 13/5/10 at 02:14 PM |
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Actually, following on from this. Assuming you haven't put a vast number cycles through them, what is the shelf life of them? (48s that is)
Obviously it depends on what conditions they're kept in but just as a ball park, when have people noticed them going off?
I haven't had enough seat time of late to be able to tell
[Edited on 13/5/10 by andylancaster3000]
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progers
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| posted on 13/5/10 at 03:53 PM |
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All the tyres I have are about half worn i.e 1-2mm above the wear bar. Still plenty of life in them, just past their best for racing
- Paul
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procomp
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| posted on 13/5/10 at 04:12 PM |
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Hi
Shelf life of around 12 months. Definitely replace at start of a season.
All the above info really applies to the Yokohama 048'S. The Toyo 888's are to be treated as a totally different tyre altogether. Yokos
are designed to run at 22-24 Psi with construction to allow the tyre to work well. They are effectively a cut slick in basic terms rather than a road
tyre with a lookalike tread pattern.
Cheers Matt
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