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Sedan rubber tire wear issues—help a noob.

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Sedan rubber tire wear issues—help a noob.

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Old 03-10-2019, 07:42 PM
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Default Sedan rubber tire wear issues—help a noob.

I am having an issue today that I'd love some feedback on. Long and short of it is my jaco blues, BRAND NEW for today's black carpet racing, are already starting to cone. My previous sets did not do this. I had a traction rolling issue and did two three things:

1) Lowered ride height to around 5 front 5.5 rear (started at 5.25 and 5.75) This is the ride height I tend to run in general. I don't remember why I raised the car, but it wasn't super significant, and I don't get carpet residue on my chassis at 5mm front, so why not.

2) Went from -2 camber that I normally run to -1 all around.

3) Extended my sidewall CA glue up a little higher based on some feedback from others, even though the CA was basically where I normally run it on the other sets, albeit they were old and this is my first NEW set of tires on this 3racing evo advance 2k18 chassis in 25.5 TC.

So, perhaps I'm just looking for some confirmation bias here, but I'm thinking the -1 camber in front is what did this, and the INSIDE tire for our high speed sweeper coned the worst, where as the outside tire had a TON of rubber buildup (like a ring) I had to keep soaking in lighter fluid and scraping off. I did not have time (since I'm getting my son into racing and I have three cars to prep) to try anything else, I just needed the traction rolling GONE for racing.

Is this a symptom of too little negative camber? The car drives amazing—like 2nd place and fast lap out of the main amazing... no complaints. I'm just traditionally an off-road guy, so, I really don't have the experience to know how to respond to this, and at $40 a pop, I can't be blow'n through sedan tires quick.

For now, I've gone back to -2 all around, cleaned up / extended the sidewall CA, and swapped the front tires left/right and will scrub them in in practice next race day. Wondering if I should be at -3?! Seems crazy.

Thanks in advance!

Wayne
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Old 03-11-2019, 05:23 AM
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Most of the changes you made should have decreased wear.

Jaco tire have been known to fluctuate in hardness. It's possible you might have bought a set from a really soft batch.
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Old 03-11-2019, 06:31 AM
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I've never run the Jaco tyres but have had a similar issue with other soft carpet tyres. The solution was the additive - using spider blue for 5mins rather than WD40 made the tyres less sticky, so the car almost glides round the track. Somehow this happens in such a way that it actually improved laptimes whilst reducing tyre wear and grip roll.
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Old 03-11-2019, 06:55 AM
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This is my first season running touring car on black carpet. I've only been using Jaco blues. My experience has been after 5 runs they're showing wear. After 10-15 runs they're pretty well junk. The car will still run a halfway decent lap on old tires, but the balance changes so you start chasing problems you shouldn't be, and it becomes numb to setup changes. I just setup the car so it drives the best and produces the fastest laptimes... tires aren't going to last anyways. Higher traction seems to be easier on the tires than sliding on a lower grip track.
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Old 03-11-2019, 09:09 AM
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Still don't understand why black carpet tracks haven't went with a harder tire. I think gluing sidewalls sucks. Traction rolling also sucks. Why are tracks still using the same tires that were run on grey carpet? Why not switch to a 36 and outlaw gluing sidewalls?
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Old 03-11-2019, 10:17 AM
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I was thinking about that too. Here's the explanation I came up with.

Stickier tires make cars faster. Since we're rolling over in corners, we're obviously no longer traction limited in corners, but we are still traction limited on acceleration. Racers will want stickier tires until the cars wheelie.

Whatever that means to making the cars corner reasonably.
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Old 03-11-2019, 11:03 AM
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Originally Posted by malkiy View Post
Still don't understand why black carpet tracks haven't went with a harder tire. I think gluing sidewalls sucks. Traction rolling also sucks. Why are tracks still using the same tires that were run on grey carpet? Why not switch to a 36 and outlaw gluing sidewalls?
As I understand it, it's just the sidewall deforming and rolling over, like not enough tire pressure. On the off-road world, we had to go to different inserts when this happened, but on on-road, people glue the sidewalls so they don't stick when it rolls over. Not sure if 36s will fix it, but gravity USGT tires don't suffer from this
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Old 03-11-2019, 04:18 PM
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I bet your lighter fluid tire cleaning method has something to do with the rubber being broken down too much.Setup wise you can try different Ackerman positions to adjust the scrub. You might be overdriving the car too - there's a finer line between overdriving and underdriving in onroad compared to offroad. Just my .02..
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Old 03-11-2019, 04:20 PM
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duplicate
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Old 03-11-2019, 04:46 PM
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I found it helped a lot to get advice from the local more experienced racers when I had new issues. See if the other racers are experiencing the same thing or what they might be doing setup and tire prep wise to not have the same issues? Otherwise, it may just be a super soft batch of tire, and a little too much trigger pulling.
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Old 03-12-2019, 08:24 AM
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Originally Posted by Dane View Post
I bet your lighter fluid tire cleaning method has something to do with the rubber being broken down too much.Setup wise you can try different Ackerman positions to adjust the scrub. You might be overdriving the car too - there's a finer line between overdriving and underdriving in onroad compared to offroad. Just my .02..
Oh there's no question I'm over driving. I have to setup the car for that. I promise you I will always over drive my cars
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Old 03-12-2019, 08:27 AM
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Originally Posted by Dane View Post
I bet your lighter fluid tire cleaning method has something to do with the rubber being broken down too much.Setup wise you can try different Ackerman positions to adjust the scrub. You might be overdriving the car too - there's a finer line between overdriving and underdriving in onroad compared to offroad. Just my .02..
We all do the same lighter fluid cleaning at our track.
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Old 03-12-2019, 08:42 AM
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Unlike most cars, the Advance 2k18 has some anti-Ackerman on the steering. Works great on higher speed corners, especially asphalt. It gives less slip angle on the inside tyre which should yield more friction when it is lightly loaded, as well as decreased wear.
What steering D/R are you running on your transmitter? I find I have to turn it down a lot on this car, to about 75%, even on tight indoor tracks. Running too much steering angle will just cook your front tyres and can actually give you less steering.
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Old 03-12-2019, 08:54 AM
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Originally Posted by LzREngineering View Post
Unlike most cars, the Advance 2k18 has some anti-Ackerman on the steering. Works great on higher speed corners, especially asphalt. It gives less slip angle on the inside tyre which should yield more friction when it is lightly loaded, as well as decreased wear.
What steering D/R are you running on your transmitter? I find I have to turn it down a lot on this car, to about 75%, even on tight indoor tracks. Running too much steering angle will just cook your front tyres and can actually give you less steering.
Just off of full lock. Might have to try that. Keep in mind though that my old tires didn't do this. Really thinking the camber was the killer, but I'll try the dual rates just to see. Our track literally has 3 180s in a row in the current layout, so, I like me some steering.
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Old 03-19-2019, 07:30 AM
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So, to follow up. I tried turning down dual rates—no good. The car definitely needs near full throw for our field of 180s. I set my camber back to -2, then -2.5, back to -2, and it was obviously steering city. I rode on two wheels through our full speed sweeper a few times during the first half of the 3rd qualifier and my car was just super tippy. I was competitive in the main, coming seconds behind 1st, but the car was a real hand-full. Tire wear looked much better though. Took some advice and glued way further up the sidewalls and about half way up the bend toward the contact patch and went back for another day of practice with my son and had a chance to run the car between rounds of teaching him how to drive. WOW is all I can say. The CA glue further up the sidewall made the car insanely good. No push, nothing, smooth responsive non jerky turn in. I'll have to report back over time but my theory is the tire's edge was being abused with our super sticky track and not enough sidewall glue. I'll report back after some time, but I'm really thinking that I just needed to stick with -2 camber and some higher sidewall gluing.
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