Opti Grip Tire Temperature Monitoring

[Magpie]

I picked this product up quite a while ago with the intention of logging it via the Innovate system, however I have since moved away from Innovate to Haltech/Racepak.

The system is available to be purchased from here http://www.opti-grip.com/optigrip/Opti-Grip.html

What is in the pack? I also purchased the ability to log, this will be used in future using 'stuff' from Racepak. At the moment the system displays the real time non-contact temp. This is not as accurate as a pyrometer as the pyrometer takes an internal temp whereas the Opti Grip takes a surface temp. For the purposes of use surface temp are more than adequate.

IMG_0997 by Eipeip, on Flickr

IMG_0998 by Eipeip, on Flickr

Close up of the sensor. Sensors have a 1:1 ratio, that is the distance they cover is proportionate to the distance away from the target. Therefore to get an overall tyre temp the sensor would need to be about 6-8" away.
IMG_0999 by Eipeip, on Flickr

IMG_1001 by Eipeip, on Flickr

The interface to log if required
IMG_1002 by Eipeip, on Flickr

Install is rather simple. Pick a spot for the sensors and run the cables to the 'box'. Provide 12v to the 'box' and then connect the 'box' to the display.

Front sensor location
DSCN2958 by Eipeip, on Flickr

The front is angled down slightly
DSCN2959 by Eipeip, on Flickr

The rear. The sensor could be moved to the outside a bit so it gets more of the tyre
DSCN2962 by Eipeip, on Flickr

DSCN2961 by Eipeip, on Flickr

Just before taking the car out for a run (has not been dríven in a week)
IMG_1171 by Eipeip, on Flickr

After about 10 mins at 100 kmh. Interestingly they cooled down rather quickly when stopped. It was possible to see the difference when braking/accelerating/cornering. It is a little out of the way to see all the time, but glancing down is not a problem. I may move the display one day.
IMG_1182 by Eipeip, on Flickr

Overall it was a very quick install and I think it will be useful to get some information on how the tyres are working. I would say it is value for money as the kit is complete and works as described. Not sure when I will get the data logging part working as this will be very interesting.

[gslender]

I'd be looking to mount two on each front side, each with half the tyre patch in view of the sensor. That way you'd be logging tyre temps across the surface and discover handling or setup differences etc


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[greenMachine]

I think I would want three spot readings per tyre - outside shoulder, centre tread, and inside shoulder. That would require the sensors to be really close to the tyre, not an impossible ask but raising issues around the mounting structure and its resistance to debris.

Edit - I see that they now have a 'racer' setup with twelve sensors, but it does not specify whether it is still 1:1, be nice if it was narrowed down so they could be mounted on a bar 200 or so in front of the tyre. I see it can be (allegedly) used as 12 inputs to a data acquisition system, which makes it pretty attractive wherever the sensors have to be mounted. Has the mail to the North Pole closed yet?

[Magpie]

To mount the 3 sensors per tyre you would need a arm that moves with the suspension to ensure that the sensor measured in the same area all the time.



Or something like this.


I'm just after general temps. I have a tyre pyrometer that I use after a session, however after seeing how fast the tyre cools (on the outside) it will be interesting to see how quickly the internal temp of the tyre cools. May have to do a comparison. Take the internal and external temps, do a run to get everything hot, stop and take internal temps and then see how long it takes for the internal to match the external temp.

[Magpie]

Was never happy with where I mounted the sensors as they were too far away and not picking up the centre of the tyre. Further the sensors were prone to getting false readings off the brakes at the front. Plus I had a quite weekend.

The front sensors were moved down and pointing at the middle of the tyre (when on the ground)
IMG_1387[1] by Eipeip, on Flickr

IMG_1391[1] by Eipeip, on Flickr

The rears as well were moved to measure the middle of the tyre. May have to make a small shield to stop road 'crap' hitting the sensor.
IMG_1388[1] by Eipeip, on Flickr

IMG_1389[1] by Eipeip, on Flickr

[ManiacLachy]

I figure this was as good a place to post seeing as the topic is about monitoring tyre temperatures, rather than starting a new topic.

A friend was wondering about optimal tyre temps, grip, and getting the best lap. Does running around a track heat the tyres significantly enough to reduce their overall effective cornering grip? Would there be any benefit in backing off for a lap to bring the temps down before hitting a hard one aiming to turn in the best time?

Not talking about an MX-5 here, something with more power running Nitos.

[Magpie]

Hard question to provide a definitive answer on.

Does the person have a pyrometer and a good pressure gauge?

http://www.yokohama.com.au/News-and-Blog/2013/September/How-to-set-hot-tyre-pressures-in-race-tyres.aspx
http://949racing.com/using-a-tire-pyrometer-949-Racing.aspx
http://www.turnfast.com/tech_handling/handling_pressure2

Yes if you get the tyres too hot they will loose grip, however heat also increases tire pressure. The question about grip is the loss cause by the tyres being too hot or too much pressure. Too much pressure will cause the contact patch to shrink as the tyre starts to bulge in the middle.

Here is a video made by Opti Grip on tyre temps, the tyres do cool quickly, however the surface temp as well as tyre pressures and tyre type all impact how the heat/pressure is managed.



Here is another one, again the heat is generated when the tyre is working, that is loaded when it is just spinning very little heat is generated. Note this is only measuring the surface temp and not the internal temp. Over time tyres will suffer from heat soak so yes doing a 'slow' lap before a 'hot' lap may help, this is what a lot of time attack cars do. At JapNats the fastest 3 cars on the sprint did 22 laps between them! Where as the slower cars managed 21 laps EACH! Again the top 3 cars alternated between fast and slow laps.



This may help to understand the amount a tyre 'works' on the track

[Trackphotos]

Does running around a track heat the tyres significantly enough to reduce their overall effective cornering grip? Would there be any benefit in backing off for a lap to bring the temps down before hitting a hard one aiming to turn in the best time?

Not talking about an MX-5 here, something with more power running Nitos.

If you're talking about NT01 semi slicks, their optimum temperature is over 90c. Maybe on a very heavy car you might be able to overheat them during a few laps on a track, especially if you're either understeering through or powersliding out of every corner, but otherwise they should be fine. The pressure seems to be more important, the difference between 29psi hot and 32psi hot is significant on NT01s, regardless of the temperature. If you're talking about the performance road tyre range from Nitto, then yes, 3 or 5 hot laps can be enough to cook them. S-spec tyres (RSR, RS3, AD08R) are dual use tyres and as such have a lower temperature range before they get slippery. With R-specs the grip will be higher when they get hotter, with S-specs the grip will be at it's peak in the first one or two laps, before they cook. If the session is long enough to allow a cooldown lap in the middle, then yes it might get you more laps with higher grip than if you just keep going flat out from start to finish. A lot of the Time Attack guys running AD08Rs do this every session.

[ManiacLachy]

Thanks for the insights guys! I figured tyre pressure to be more important, but I'd never considered tyre temps and the effective heat range before. I shall pass the information along. He's running an A45 AMG, so ~1600kg, and yeah the NT01s.

[Magpie]

The driver also needs to be able to differentiate between tyres that are too hot/cold or over/under pressure, like knowing the difference for brake fade (pads, fluid or knockback). This article may help when looking at the tyres.

http://insideracingtechnology.com/tirebkexerpt3.htm

[Magpie]

This is another helpful article http://www.zcarclubq.org.au/race-tyre-management-tyre-pressures-temperature/

I have posted this photo before, but it shows the sort of graining that you get with tyre slippage. Further, learning to recognise what your tyres are telling you could save you from expensive mistakes
IMG_1367[1] by Eipeip, on Flickr