jester
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| posted on 19/4/21 at 08:01 PM |
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Sylva Striker Track day tyre pressures
Hi
All
Looking at doing a track day shorty.This will be my first track day in my striker.I am after adivce on tyre pressures for the striker
Tyres are Yokahama A539 185/60/13 80H
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CosKev3
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| posted on 19/4/21 at 08:31 PM |
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What do you run on the road?
Try 18psi and see how it feels
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peter030371
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| posted on 19/4/21 at 09:29 PM |
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I have used A539 tyres for one wet track day on my Striker. Started at 18psi (cold) but it was so cold that day I went up a couple more psi which
improved grip a little. It was like driving on ice though and wish I had kept my r888 on for the day.
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jester
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| posted on 19/4/21 at 11:36 PM |
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quote:
Originally posted by CosKev3
What do you run on the road?
Try 18psi and see how it feels
 18psi Oh dear
I have Just brought a new double barrel foot pump. As the last single barrel fell apart on me. The gauge was out on that as well it seams.
It was reading only 9psi on all four tyre. on the new foot pump.
I have only had it stored away for 6 months as well.The tyres allways seamed to grip well on the road
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jester
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| posted on 19/4/21 at 11:46 PM |
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quote:
Originally posted by peter030371
I have used A539 tyres for one wet track day on my Striker. Started at 18psi (cold) but it was so cold that day I went up a couple more psi which
improved grip a little. It was like driving on ice though and wish I had kept my r888 on for the day.
Umm
That's the second person that's said 18psi now or there about's.
Not alot of people like the A539 very much I have a second set that came on an another set of alloys I brought for my work in progress Tango
Jester
Are the r888 that good then
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obfripper
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| posted on 20/4/21 at 06:59 AM |
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I run 16psi cold pressure all round as a base setting but that is with r888r and ar1 semi slick type tyres.
The a539 is relatively hard in comparison, so may need even less pressure to warm up sufficently. If you have a ir thermometer, check across the tread
after a handful of decent laps (fast but not sliding/drifting), if the centre is hottest reduce the pressure, if the outer and inner edges are hottest
increase the pressure. Anything below 10°c difference is pretty good.
If there is a significant difference between outer and inner edges, then your geometry needs adjustment, make the best of how it is setup on the
day.
When the tyre has warmed up expect the pressure to rise to around 20psi.
If it's wet those tyres will be a handful, you can still have some fun but they will be difficult to get any heat into. Increasing the pressure
as peter suggests will decrease the contact patch and increase the pressure on the tread within that patch - this increases the available grip in the
same way as using a narrower tyre does in the wet and reduces the chance of aquaplaning.
If you have adjustable shocks, go a click or two softer for wet conditions, if it's dry then go with your road settings to start with and if
neccesary go a click or two harder to sharpen up the feel.
Dave
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The Knobs
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| posted on 20/4/21 at 07:25 AM |
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18 cold is a good pressure I use that with 888s
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peter030371
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| posted on 20/4/21 at 07:50 AM |
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quote:
Originally posted by jester
Not alot of people like the A539 very much I have a second set that came on an another set of alloys I brought for my work in progress Tango
Jester
Are the r888 that good then
I remember when they came out the A539 was 'the tyre to have for road use' but I think the only other option then was the A048R.
Then along came Toyo with the R888, now replaced with the R888R.
In the late 90's early 00's I had A048 which I then wore out on track days so switched to the R888 to try something different (and they
were cheaper). In the dry the A048 were a little quicker and more predictable than the R888 but not by very much. My current Striker I put on a new
set of R888r and from memory I would say they are just as quick as the A048R.
I only tried the A539 for one day as heavy rain was forecast, as others have said very hard but then the set i borrowed was >5 years with zero
miles on them. I think I would have been better off sticking with my then R888 Toyos. The A539 seemed to lack grip and slide very easily even when I
did get some heat in them later in the day as things dried out a little.
If your A539 are old tyres (have you checked the date code?) then the best upgrade you can do to your car, almost irrespective of everything else, is
to get some FRESH semi-slick tyres such as R888R. If you have never driven with fresh semi-slick tyres in a lightweight car the grip available will
amaze you 
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yogibear1969
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| posted on 20/4/21 at 10:57 AM |
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quote:
Originally posted by jester
quote:
Originally posted by peter030371
I have used A539 tyres for one wet track day on my Striker. Started at 18psi (cold) but it was so cold that day I went up a couple more psi which
improved grip a little. It was like driving on ice though and wish I had kept my r888 on for the day.
Umm
That's the second person that's said 18psi now or there about's.
Not alot of people like the A539 very much I have a second set that came on an another set of alloys I brought for my work in progress Tango
Jester
Are the r888 that good then
My A539's went quite hard after 3-4 years! Need to drive more obviously!
Edd
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pmc_3
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| posted on 20/4/21 at 02:59 PM |
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Pressure gauges on foot pumps are really inaccurate buy yourself a separate gauge for setting them.
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peter030371
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| posted on 20/4/21 at 04:08 PM |
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quote:
Originally posted by pmc_3
Pressure gauges on foot pumps are really inaccurate buy yourself a separate gauge for setting them.
That is a very good point. I have 4 pumps at home plus a 'proper' tyre inflator on the airline at work. As we design and build TPMS
devices we have the kit to measure them to silly accuracies. All the pumps and the inflator are massively out. I hate mechanical gauges as one
knock/drop and they will be out for ever. I got a Longacre Standard Digital Tyre Pressure Gauge for about £50 and when calibrated at work in 2019 it
was within 0.15psi of the actual pressure. I really should take it back in and check it again but I doubt it has drifted at all....digital gauges
should either work well or not at all 
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procomp
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| posted on 20/4/21 at 04:36 PM |
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The Yoko A539 is the Locost race championship tyre in 13" 185 60. Tyre pressures vary across the grid from 16psi to 28psi.
personally id start at 25psi cold.
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jester
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| posted on 20/4/21 at 08:54 PM |
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Thanks everyone
I have ordered myself a digital tyre gauge as well now
Looks like a tyre change when there A539 have worn out then
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ian locostzx9rc2
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| posted on 20/4/21 at 09:42 PM |
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I ran my Nankang ns2r on my striker at 18 psi cold on trackdays and ran about 20/22 psi on the road
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bi22le
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| posted on 20/4/21 at 11:12 PM |
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Top advice here, ready?
Buy a separate pressure gauge and listen to Procomp!!
I run 18 cold on R888R, I have never used A539 so can't comment on those.
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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peter030371
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| posted on 21/4/21 at 08:18 AM |
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quote:
Originally posted by bi22le
Top advice here, ready?
Buy a separate pressure gauge and listen to Procomp!!
Procomp probably have more experience than as all added together but the range he gave is HUGE. In the lowcost they are all very similar cars so why
such a wide range? Car setup? Driver style/preference? Track type?
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pmc_3
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| posted on 21/4/21 at 12:41 PM |
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quote:
Originally posted by peter030371
quote:
Originally posted by bi22le
Top advice here, ready?
Buy a separate pressure gauge and listen to Procomp!!
Procomp probably have more experience than as all added together but the range he gave is HUGE. In the lowcost they are all very similar cars so why
such a wide range? Car setup? Driver style/preference? Track type?
The weather conditions would play a big part in it as it's the only tyre they are allowed to use.
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procomp
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| posted on 21/4/21 at 07:06 PM |
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Huge range in locost because as in the vast majority of cases some use too stiff a damper / spring and soft tyre pressure to compensate for being too
stiff.
If done properly with dampers and springs you can use the tyre pressures the tyre was designed to use to get the best performance out of it.
I do tyre testing in various race championships for Yokohama, Avon, Toyo.
Were running our new Caterham at castle combe next week to test the brand new AVON ZZR's with Avon motorsport division before they finally go
into production.
It's all part of what i do when dealing with suspension, tyre development, setups, dampers, springs, Etc Etc it all plays a big part in the
development of cars for various championships wether it be basic Locost, British GT or GT Cup.
[Edited on 21/4/21 by procomp]
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