Rennsports RS2 Cold Tearing-Ideas??

[Trackho]

I am running into an interesting issue with the rear RS2

During the really hot trackdays they are fine, however when it cools down 85ish---the rear is starting to cold tear-- I am running 32/30 for the track--have Ohlins suspension, bla, bla, bla---I heard somewhere that a little more comp damening might help--any ideas---

BTW-Running 2:05 ish at T-Hill

 

[Trackho]

yeah, yeah yeah---you Dunlop guys are all the same---Im thinking about it---this tearing is getting old---Ill try backing off the comp a tad---Thanks

 

[MrCrash]

I've shredded all three brands on the back of my SV. Interesting that Scott speaks of backing out on the compression, the cause of the tearing in my case was a lack of low speed compression damping. The rear shock would compress / collapse suddenly under the load placed on it by a corner, then suddenly get into a working range of the valving and spring that would effectively prevent the shock from compressing any further. This would abruptly load on the contact patch, shredding the tire.

I brought my Fox shock to Phil at Aftershocks, and had him add low speed compression so the shock would compress more gradually than it did, while still retaining the light high speed compression for compliance over bumps. This finally stopped the tearing, as the midcorner load would gradually feed into the shock then into the contact patch as the rear suspension compressed in a more controlled manner, as opposed to just collapsing, effectively bottoming, then suddenly overwhelming the contact patch.

Two rear tires a weekend at Willow Springs on a 76 hp SV650 was outright ridiculous.

I'm bumped up compression on the shocks of street bikes that were showing tearing, it seemed to improve the wear characteristics.

 

[Holeshot]

I talked to a freind who runs 1:56's at T-hill and he said he went real real light on rebound dampening and that solved his problem of tearing...

for what it's worth I suppose.

 

[MrCrash]

Scott, I've always known you to be immaculate in your racebike preparation, it doesn't surprise me that you've never had cold tearing problems. I figure Jim has a lot of experience with GSX-Rs, and that you only benefit from that.

My problems came on a "prototype" Fox Shock, I was told it was the first SV shock they ever sold back in 1999. It was probably just a GSX-R shock, I struggled to get that thing working right for a year.

Also, with regards to tearing Metzelers, I was still showing a bit of ragged wear when running the soft compound rear at Willow Springs, even after the revalve. Bumping up to the medium compound (actually the Daytona dual compound with the right side Medium, left side Soft) elimianted the wear at that track.

 

[Trackho]

Thanks guys interseting things to try--seems odd that it is more prevalent w/ lower ambient temp--than comp/rebound adj--but now I can dick w/it

 

[Trackho]

Got a Brand New Tire RS2

OK---so I guess theanswer is lighter on the rebound any final words--it was recommended that I try 28 psi in the rear as well---to heat the tire up more

 

[MackeyStingray]

would running such a low temp make the tire wear excessively?

 

[Robert R1]

would running such a low temp make the tire wear excessively?

A tire that get's cold tearing has much less life than one with lower pressure. It's a necessary compromise. Nothing more annoying that wasting a new rear due to cold tearing.