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RT-615's - Reinforced or normal sidewalls?

4K views 21 replies 7 participants last post by  Auto-X-ZTS 
#1 ·
I'm looking at these for auto-x and was wondering if someone had experience with these.

Apparently there are 215/40/17's that have reinforced sidewalls (my current size tire) and 215/45/17's with "normal" sidewalls, which of course is the SVT tire size and a recommended favorite around here, as you should all know.

So, what would suit the track better? I would assume reinforced but that's why I'm asking the question, I can only assume and you know what they say about assuming. I have never run 45's either, so I'm not even sure if I would rub or not (pretty mild drop). I didn't have any problems with a 40 series.
 
#2 ·
The reinforced sidewall will help your turn in, especially in the Focus which is not particularly light. Under hard lateral load the sidewall can roll over, which screws up the contact patch and therefor your grip situation, a stiffer sidewall helps to mitigate that. They will also ride stiffer on the road, if they're only track tires there's no big deal.
 
#3 ·
I have run the 215/40-17 Azenis, and the sidewall is very stiff. The problem I found with Azeni's as track tires was heat management.

The Dunlop Z1's are on closeout at Tire Rack - 215/40s are something like $85 (new spec tire on the way from Dunlop). I was very pleased with these as track tires, so they may be worth a look.
 
#4 ·
I don't care about my ride, I ride with the shocks cranked down on crap roads all the time so it's all good.

Are the Dunlops STS legal? That's what I need. I'm aware of the heat issues but I'm looking for something I can use on the track and street. I only have one set of good rims.
 
#7 ·
Yes, they are STS legal. If these will be your only tires, I would worry a little about a 40-profile tire if you have bad roads. I still haven't taken them off after the track event, but I don't have crappy city streets to deal with.

I think the Dunlops are also said to be markedly better in the rain than the Azenis.
 
#5 ·
i have them on the front of my car and the side wall is hella stiff. i love them tho. good tire in my view. plus if i'm not mistaken going to a 40 instead of a 45 should bump your gearing up a little and help acceleration. thats what i did with mine went up to a 205-50-15 from a 195-60-15. you can tell the difference. pulls alot harder or at least it feels like it does on the good old ass dyno.
 
#6 ·
about the driving on the road, i had put my on a few weeks ago and it has rained like hell since i did this and i have had no problems with them. they are amazingly good in the rain. had a few problems with the ice/snow mix the other morning but thats a givin. what kinda struts and shocks you running? i have agx's as stiff as they go.
 
#8 ·
Haha we're in a drought now so yeah...

I'm on Koni shocks and springs, the drop is "1.6" but it looks only a little lower than an SVT honestly. I run 40's no problem right now on these streets so no worries there. The roads aren't really bad bad, just uncomfortable. I'll take a look at the Dunlops. How long do they last compared to the Azenis? I've been told to expect around 10K with use as mixed track/street tires.
 
#9 ·
i'm not to sure there. i have only had mine for a little while now. they are nice tires tho. i'm still able to mess around a little when its wet out. the only issue i have with them is they do like to spin in first gear. but then again we have not broke 60 since i put them on so that could be part of my problem.
 
#10 ·
As far as the Dunlops, they haven't performed very well at any events I've been to.
The Azenis RT-615 have been a much better choice.
I've seen the Dunlops chunk up pretty good.
I think the reason the Dunlops are attractive now is due to the closeout prices.
At full tread depth down to 1/2, the Azenis stick pretty damn well in the rain.
Below that...be careful.

For your car, a 215/40 is closer to the stock gearing.
But...
The 215/45 Azeni runs quite a bit wider than the 215/40.
I'm not sure why, but it's close to a 1/2 inch.
But, it's also taller and heavier. [dunno]

If you spin the tires a lot coming out of a corner, the taller tire will help.
But then again, so will letting up on the gas a bit. [;)]

I'm assuming you have aftermarket wheels??
Meaning...low offset? (40-42mm)
If so, with the 1.6" drop, you most likely will rub on heavy bumps with the 215/45,
unless you're running some pretty high camber numbers in the front.

And...remember, there are other choices...
Bridgestone RE-01R
http://www.focusfanatics.com/forum/showthread.php?t=149887
Kumho is coming out with a new tire...
http://swmtscca.org/forum/viewtopic.php?t=724
^^^Ah man...I got on my soap box in that thread. [paranoid]
 
#11 ·
Offset is 42.

Weight and gearing are very sensitive subjects for me being an automagic driver. That's also why I burn tires now, because if I don't, I come out of corners in 3rd gear at 2,000 RPM. I need more seat time to figure out a better way to circumvent that.

I'm not going to shave the tires, I want them to last and I'm not that "serious" about it yet, especially with me being so slow. [hihi]

Also I have a feeling 1.6 is not really accurate. Take a look in my gallery, it looks more like a stock SVT drop to be honest, probably around 1". I have about 2" gap in front and more in back.

Thanks for the input Doug, you really know your stuff.

Good stuff on all those other alternatives, but it appears they will break the bank more than Azenis. I'm probably going to stick with those. Looking forward to the disgusted look on the tire guy's face when he gets done mounting the stiff sidewalled Azenis. [rofl]

At least it's not as bad as the 225/50-16 Azenis I considered running on stock rims a few months ago. [poke]
 
#12 ·
WD40 As far as the Dunlops, they haven't performed very well at any events I've been to.
The Azenis RT-615 have been a much better choice.
I've seen the Dunlops chunk up pretty good.
I think the reason the Dunlops are attractive now is due to the closeout prices.
The Z1 won STU at the recent SD/NT...http://sccaforums.com/forums/8/259439/ShowThread.aspx#259439 :
At the San Diego National Tour this weekend, STU had the second largest class with 18 drivers from the western states. My codriver Tom K. put an excellent 2 days of driving together for a repeat win from last year. I was the fastest after 1st runs on Sat, had cone trouble, but was able to put a solid run in today to pull back up to close 4th trophy spot. Only 3 of us were able to break into the 60.xx sec., 2 of us on Dunlops.

The Dunlops were great today. They started to go off a little on the 4th run, we watered them down and they came back for run 5 and 6. We are still on full-treads. Other competitors were on fresh shaved Yokohamas, and Bridgestones.

Fun weekend!
I don't think a Falken shod car has won a National event since 2006...in STS, STX or STU.

Full-tread to full-tread, the Z1s have tested faster than the B-Stones (see TR test)...and the B-stones are generally considered faster than the Falkens...which is why all the National SpecCivics run them.

The B-stones have softish sidewalls...less of a problem on a 2000# Civic, more of a problem on a 2700# Focus. Might be OK for my 2300# ZX2. Thing is...there is no way I can beat a Civic on the same tires as a Civic (Jason Frank runs 205/45-16F and 195/50-15 R). I have a better Tq-to-weight ratio...but still lose on tire-to-weight if I run the same as them.

Back on topic...The beef, if there is one, on the Falkens is that they are not heat resisitant and that they have a very defined fall-off at 10/10ths of the envelope. They have great turn-in and slightly less overall grip than the B-stones...but if they are pushed too far, they are hard to reel back in. The heat thing can be somewhat dealt with by spraying.

I'll be on Z1s to start the season. 215/40-17s (7.5" wheel) on front and 195/55-15s (7.0" wheel) on back. The 215/40-17 is a wide tire and measures about 8 1/8"...which I believe is even wider than the Falken. The 195s measure 7 7/16"...about the same as a 205/50 Falken. Z1s are on closeout at TR and there is a $50 rebate for a set/4. The new Z1 "Star Spec" will be in very soon. It is basically the same tire with a revised compound that comes up to temp more quickly. Jury is out if that is good or not-so-much as it is unclear if overheating will now be an issue on a tire that was heretofore very tolerant of heat. Could be an issue on 2-driver cars or heavy cars: i.e. Focus.

Lastly...shaved tires can actually outlast unshaved tires if they are not street driven. They will also be faster.
 
#13 ·
I am street sriving them. I don't want to run 2 sets of rims. These will be my daily driver tires.

Also, I suck. [hihi] I'm a rookie. You won't see me at Nationals probably ever. So what would you say with that info?
 
#14 ·
Unshaved Z1s just won a NT on a heavy STU car...would bet they are faster. They are on close out and have a rebate, so they are likely cheaper than the Falkens.

So we have (likely) faster and (likely) cheaper...and awsome rain performance for the street.

...um, boy, I dunno what to say.[:)~]
 
#15 ·
I'm only going by what I've seen at events around this state.
And as I mentioned, the Dunlops have had a horrible showing from what I've seen.
Maybe it's the temps (we have a lot of 90°+ event days), maybe it's the cars (a couple STIs ran them, a Vette, don't remember what else),
or maybe it's the drivers pushing them too hard? [dunno]
Most of us that want to do well, are spraying our tires after each run at those (heat) events.
I'm definitely aware of the heat issues with the RT-615.

As far as Nationals, I only give the tire companies 1/2 credit for who wins what class.
Bridgestone has had a contingency package for quite a while.
Falken (IIRC) has never had one.
If you go to Nationals, and have a chance at placing, why wouldn't you run the tires that you can make some money on?

Course, with all that said...
Unless Falken comes out with a new tire, I'll be on something different once this set is wore out.
I do believe competition improves the bread, and as each company is coming out with a new tire they're getting better and better.
Falken set the benchmark a while ago with the RT-215, but it's since been surpassed by several tires now.

I'm still anxious to see what the new Kumho does.
 
#17 ·
As far as Nationals, I only give the tire companies 1/2 credit for who wins what class.
Bridgestone has had a contingency package for quite a while.
Falken (IIRC) has never had one.
If you go to Nationals, and have a chance at placing, why wouldn't you run the tires that you can make some money on?
If you are going to Nationals and know that 'you have a chance', more than likely you're going to put on the best that you can--contingency or not. Alot of testing, particularly by Andy Hollis, was done to show that the B-stones are several 1/10th faster on a 60second course. The $$$ is just gravey.



I'm still anxious to see what the new Kumho does.
As am I. I'll jump ship if they are faster...
 
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