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View Full Version : please help with a strange setup issue.


2.7RS
2012.09.20, 01:46 PM
Went to Runes track yesterday with my mr03 mod.
see pictures.
http://i414.photobucket.com/albums/pp222/lmlindbo/DSC_0424_zpsd8b0ee20.jpg

http://i414.photobucket.com/albums/pp222/lmlindbo/DSC_0425_zpse76c2dbd.jpg

Started of with a newly trued X15's up front. on the second set of batteries it was flying, almost setting a new PB. After that I gradually lost my front grip. Most likely because of overheating. After a few more packs it was totaly useless with lack of front grip.
Then i tried a set of trued X20's. It oversteered like, well, a lot:). Turning down steering from 100% to something like 60% to be able to drive at all.

Any ideas whats causing understeer to the point that I run throug a set of X15 in a few packs, but oversteering to the extreeme with the X20's.

The track is very high grip. Tearing up the 15's. Almost all cars have some tracktionrolling issues.

Any ideas where to start tuning would be highly appreciated!

reaper
2012.09.20, 01:54 PM
Are there alot of fast sections on the track ? You seem to have alot of toe-out up front this on a fast course can scrub the tyres to hell

blt456
2012.09.20, 03:28 PM
I noticed that with the new batch of 15x pattern front tires, they provide lots of front grip. For example, my stock car was perfect with the previous batch of 15x tires. When my last set wore down, I put on a new set (new batch) and got oversteer. I did not change anything on my car and the tires were trued to the same diameter as the ones from the previous batch. The new 15x tires are very grippy and even on a medium grip rcp track, they provide too much grip.

I have raced on low, medium, high, and super high grip tracks all over the US. I have noticed that at every track, kyosho 30 slick front tires always work. I true them to different diameters depending on how much grip the track has. These tires are extremely consistent batch to batch. Maybe you should try these tires out.

DanDan
2012.09.20, 04:06 PM
I second what blt456 says on this matter. The new (post June 2012) 15x's are grippier & I would also suggest trying the Kyosho 30 fronts :)

2.7RS
2012.09.20, 04:54 PM
Thanks for the input.
But how come it understears on the new 15, and oversteers on the old 20. Shouldn't it be the other way around?

blt456
2012.09.20, 05:05 PM
It makes sense that way, but this has happened to me before with PN tires.
For example, in 2010 I tried PN 8 degree front slicks and PN 10 degree front slicks. The 8 degree slicks worked great at our track but I wanted to try out other tires, so I tried the 10 degree. The 10 degree tire was softer and also grained because it provided so much grip.

The only real way that I have been able to determine the grip levels of the PN front tires is by buying a few packs of each tire and trying them out. Sometimes some batches of tires provide more grip than the previous batch.

arch2b
2012.09.20, 05:25 PM
what is comes down to is manufacturing consistency. just because it has a shore rating of X doesn't mean it will behave as if such was true. GPM lost almost all their user base through a period of time where they flooded the market with bad batches of tires that were egregiously inconsistent with the shore rating given them. it absolutely killed their sales long term, where as they used to be the standard go to tire. right now it's kyosho 20/30's.

egonzalez
2012.09.20, 09:37 PM
I have experienced the same outcome with the new batch of 15x... They are just not the same tire compound/consistency. The new batch wear faster, decrease front bite, and actually shred after one or two batteries packs max. I found a local shop that runs carpet vs rcp that had like 5 set of the old 15x and I bought them all. The old batch is the way to go. :eek:

TheRinger
2012.09.22, 10:02 AM
what is comes down to is manufacturing consistency. just because it has a shore rating of X doesn't mean it will behave as if such was true. GPM lost almost all their user base through a period of time where they flooded the market with bad batches of tires that were egregiously inconsistent with the shore rating given them. it absolutely killed their sales long term, where as they used to be the standard go to tire. right now it's kyosho 20/30's.

Pretty much agree, I've tried every tire I can get my hands on and kyosho slicks work the best. PN tires are very inconsistent. The only tires I liked from PN were 15 fronts and 6 rear slicks and then stop using those when I Trued the 15 slick fronts and they literally melted while trueing them which they never did before with previous 15 slicks and the 6 slick rears came out fine. Try kyosho slick 30's in the front and 20 slicks in the rear. Been using that combo for years and works great. Though lately I've been trying the 20 slicks in the front and the 10 radials in the rear and they been working good.

2.7RS
2012.09.24, 02:56 AM
I'll look intop the tire-issues at a later time.
For now I have:
-Stiffened up the top-shock.
-Removed some preload from the front.

Result: 0,2 sek faster than my previous PB. A time set the last time the car felt good.

I managed to turn down the Steering DR to 78-79%, increasing front tire life.

Ok. Now you can go back to the tire-discussion...