Street tires on track (Z212, Z1, MX)

[turtl631]

My Kumho MXs are fairly worn and probably won't last me more than a few more lapping days. I'll need something new (17x9 all around), and I'm sticking with street tires to avoid covering up mistakes and save money. My 245/40 MXs have done me well, but I'm considering trying something new also. By all accounts the MX is at the bottom of the barrel in terms of ultimate grip and sidewall rigidity compared to the other sticky street tires. A DE instructor with a E36 328i that was just awesome on track runs the Z212s, and makes a pretty convincing case for them on bimmerforums. The biggest size is 245/40, so I'd be running the same size as now, although the Z212 is a little wider I believe. The other option I'm considering is the Dunlop Z1. There's a 255/40/17 of the new Star Spec Z1 out, but this compound is supposed to work better at low temps than the old Z1, so I'm surmising it may have more of a tendency to overheat. They also seem to cost a bit more than the Z212s. Anyone have any good input for this? I think I can get a set of 245/40 Z212s shipped for under $550.

[Def]

Go with RT615's. The Z212's aren't bad, but they're more expensive than the RT615's and I feel the Falkens have a very slight edge in ultimate grip at the expense of a little less tread life. They're a little loud, and kind of suck in heavy rain, but besides that no major issues.

[a_ahmed]

the direzzas are not bad from what I heard of people's testimony on a number of different forums. Just a thought

[turtl631]

Well, the Direzzas are a little pricier than I'd like. It looks like I could get Z212s in 245/40 for around $520 shipped, and 615s in 255/40 for around $550 shipped. With my fat S14 and 245s or 255s, I'm just a little concerned about the greasy sensation everyone talks about. I've never really experienced this firsthand, but it sounds like an annoyance for sure. Would going oversized, like a 275/40, help keep this at bay? I really don't like that size much, they cost more, and the gearing hit/fender rubbing would be gay, but I could deal with that if the tires were more consistent.

[Def]

I don't think you'll have a problem with 255/40 RT615s or 245/40 Z212's. 275/40s are gay, and make it hard to get the CG of your car down to a reasonable level.


I still say go for the RT615s - my gut feeling is the sidewall is stiffer than all the others.

[turtl631]

Well, it's decided- four 295/40/17 MXs have been ordered.













...kidding, that would probably feel disgusting. Maybe if I sell my car and buy a Stang to run AI. I'll probably go with the 255 615s, unless coin is really tight and the Z212s seem like the sound choice at the time. After years of owning 240s, it's time to hop on the Falken bandwagon. I wish my wheels were a bit wider, but you can't beat the cost of my MB Weapons, and 17x9 should be a pretty good fit for the 255s.

[a_ahmed]

I think you're going with the right choice 17x9+ 255/40/17 falkens :)

[2Fass240us]

What did you end up buying?

I have Z212's on my car and like them. I never felt like they got greasy, but admittedly have very little experience with UHP street tires. As an additional data point, my instructor drove my car at Expo last July and said it had tons of grip.

[turtl631]

Nothing yet. My MXs will last a few events, which I won't be doing until June at the earliest. I think I'm leaning towards the 615s, if only to get an additional 10mm of width since Z212s aren't offered in 255/40.

[OHH]

Although not cheap I am gonna try Bridgestone Re-o1r's. 245/40-17 and 255/40-17. From my understanding they are very similar in grip to the RT-615 however they are most consistent over their entire life. I currently am running RE050A pole positions. I love them sticky and very predictable. The Re-o1s are suppose to be even better.

[raen419]

Iirc, the RE01R is stickier than the RT615, and obviously doesn't last as long, but handles heat a lot better as well.

[spool_sample]

Iirc, the RE01R is stickier than the RT615, and obviously doesn't last as long, but handles heat a lot better as well.

Are you basing this off of experience?

As I've owned both tires, I can say the RE01Rs will outlast RT615s and they are not much better at handling heat, all other things being equal.

I will agree the REs are stickier, though. But considering the outrageous prices Tire Rack is charging for them now, I decided it was better to save 50% of my money rather than have 5-10% more grip, especially since I really need R-compounds to be competitive in my class, anyway.

IMO, 90% of people looking for street tires are going to be fine with 615s.

[OHH]

From the reports I read it jives with what spool_sample said. Soon as summer hits I can give my own thoughts on the RE's

I was going to get RT-615's but as fate would have it I needed a winter job and I got one at a tire place, one that was owned by Bridgestone/firestone.

They had an employee deal thing goin on so I got my Re-01's at half of list so as you could imagine I couldnt pass the deal up. If that would not of happend I would indeed have 615's

[Def]

Nothing yet. My MXs will last a few events, which I won't be doing until June at the earliest. I think I'm leaning towards the 615s, if only to get an additional 10mm of width since Z212s aren't offered in 255/40.

255/40 615s will look pretty meaty on a 17x9" wheel. I have 235/40 Z212's on my front 17x9" and the tire is very close to being square on the wheel. In fact, I'm pretty much sold on 235/40s on 9" wheels, the response is much better by getting the tire spring rate up with the slight stretch.

[Epstein]

I'm running the 615's in 255/40 on a 17x9. Yes, they're beefy. You can see it on page 2 of my "sweet forum" intro thread.

[raen419]

Are you basing this off of experience?
Yes.
Not my personal experience, but from observing others last season who ran on RE01Rs and RT615s the RT615 lasted a bit longer....and iirc, those two guys only ran them at the track. Never on the street.

And yes, RT615 is a better street tire, imo.

[ecugrad]

Yes.
Not my personal experience, but from observing others last season who ran on RE01Rs and RT615s the RT615 lasted a bit longer....and iirc, those two guys only ran them at the track. Never on the street.

And yes, RT615 is a better street tire, imo.

Were your RE01R's shaved? Shaving them extended the life for several of my local autox buddies.

[raen419]

Read again bro. NOT MINE. Someone else's. Iirc, they weren't shaved...but that was idk....13 months ago. I saw them at every event and rode w/ both guys a few times, and saw the results of both toward the end of the season.