Kumho XS Vs. Falken Rt615K

[Adrian_Visser]

Who has run both of these tires? I am looking for some sticky summers this year and it looks like in a 215 45 r16 these are my only options barring running 225 50 r 16's which apparently will cause wheel well rub.

Has anyone run both and could give an opinion?

From what I have heard falken Azenis Rt 615's get pretty greasy when hot but what about the Rt 615k? It seems to be quite a different tire.

Kumho XS's I have not heard much about other than they aren't much good when very cold or in the rain.

Opinions?

[FredK]

Any of these extreme performance tires will suck in the rain or cold.

I've only run the RT-615 while autocrossing and I found them to be a pretty good tire, except when wet. The K compound was to improve the high temperature performance.

In the extreme performance category, 225/45R16 Toyo R1R are a viable option.

What is your intended use?

[Jb325is]

XS's do suck REALLY bad in cold weather. I have R1R's and they are fantastic. I haven't run them too much on the road but when I did they were pretty good, but I never drove on them in cold weather.

[nrubenstein]

I would run the 205/50 Dunlop Z1s, or the 225/45 R1Rs. The RT615s are mediocre, and you are way too far north to enjoy the Kumho XS. The XS is literally the worst tire I have ever driven on in the wet/cold.

The only time I recommend the XS is if it is ALWAYS above 80 (preferably higher) and ALWAYS dry. If you can meet those conditions, they are fantastic. If not, they are horrible.

[Adrian_Visser]

Thanks guys I totally brushed over the R1R's thinking they were DOT R comps. I think I'll go with those. How much of a difference in grip would there be between a 205 and a 225 of the same tire anyway?

I guess dimension wise the 225 is 9% wider than the 205, does that mean 9% better grip?

Edit: Forgot to mention, use wise I plan to auto-x quite a bit and do a few HPDE's.

[nrubenstein]

No, it means like 1-2% better grip. If you're lucky. Small differences in width aren't that big a deal.

[Adrian_Visser]

No, it means like 1-2% better grip. If you're lucky. Small differences in width aren't that big a deal.

I see well maybe the Starspecs are still an option then. Thanks for the info, all this tire stuff is new to me.

[SkinnyVT]

The RT615s are mediocre

Now is this statement based on the old 615's or the new compound used in the 615k?

[acolella76]

Similar thread i started on bf.c, thought i'd share: http://forums.bimmerforums.com/forum....php?t=1595482

[Adrian_Visser]

Similar thread i started on bf.c, thought i'd share: http://forums.bimmerforums.com/forum....php?t=1595482

Hey thanks, that is exactly what I'm trying to decide on. The Starspecs were my first choice, then I started worrying about widths and got confused.