Tire Decision

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Chubbs

Well-Known Member
I'm also running the Kumho V730's. That's a heck of a deal above!

I've got staggered fitment (255 rear, 225 front, 17" tires). Previous tires were RE71Rs. Compared to the bridgestones, the kumhos seem more temperature sensitve. I ran them earlier in the year at an autoX even where ambient temps were about 50 degrees, and the Kumhos might as well have been roller skates. They were just awful. I know all summer tires struggle when chilled, but these Kumhos were just hard as a brick, and completely worthless at those temps.

Last autox was about 70 degrees, and they were greatly improved. I've not yet had an event in the 90-100 degree range, but I really think they'll thrive in that environment. It doesn't seem like they've gotten warm at all yet, but it's hard to warm tires during a 1:30 autoX lap.

They aren't as loud as I expected given the crazy tread design, but the Goblin is so darn loud I'm not sure I'd notice anyway. I haven't tried them in the wet, and don't intend to. For the price, I think they are decent tires.

I'm not sure how your car is setup, but if you're running a rear sway bar (I am) I really feel like staggered fitment is a must. With the square bridgestone setup, the car was almost undrivable at the limit. Totally unpredictable and tail-happy. It was fun, until it wasn't.
 
Robinjo

Robinjo

Goblin Guru
Adding on to this discussion as I'm looking at tires again. Looking at Falken Azenis RT615K+ ($157), Falken Azenis RT660 ($177) or Khumo Ecsta V730 ($192) in 225-45R17. I'd like to hear feedback on them or if someone has a killer deal on another tire, let me know so I can look into it.

I will note I like the grip of the Khumo V730 but want to hear feedback if you have something I should be considering. Use is 95% street with maybe 1 or 2 autocross events a year.
 
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Rauq

Rauq

Goblin Guru
I've run nothing but RT615k+ on my Goblin, initially 225 square and now 245 on the rear. The fronts are original to my build and still holding up great, to the point that I'm expecting they will age out before they wear out. The 225s were great on the rear until I added the turbo and started spinning them more. I actually held onto them thinking they'd be spares for the front but ended up selling them when I realized I probably wasn't going to wear out the fronts. The 245 rears have been great for me, I've got a couple thousand street miles, a dozen autocrosses, a few track days, and a few drag strip hits on them. I've done 2.9s 0-60 on the street and 1.6 60' on the strip on them. I usually run 16psi front and 18psi rear.

Keep in mind that, if you want to be able to rotate tires left/right, they've got to be symmetrical tread, which, last I looked, only the RT651K+ and V730 are. If you're square, you can rotate front to back without being symmetrical, of course, but if you're staggered like I am now, you can only go left to right.

The only other tire I'd consider purchasing for my Goblin would be something even stickier on an extra set of wheels for track stuff. For an all-around tire, I'd buy another RT615K+ before anything else for my build.
 
Mahkoi

Mahkoi

Goblin Guru
I'm running the r615+ as well. As of now I'm 100% street driving on them but they grip well for what I do and I like them. I've also never had different tire on the car than those so they may suck and I just dont realize what I'm missing out on.
 
duthehustle93

duthehustle93

Well-Known Member
Robinjo said:
Adding on to this discussion as I'm looking at tires again. Looking at Falken Azenis RT615K+ ($157), Falken Azenis RT660 ($177) or Khumo Ecsta V730 ($192) in 225-45R17. I'd like to hear feedback on them or if someone has a killer deal on another tire, let me know so I can look into it.

I will note I like the grip of the Khumo V730 but want to hear feedback if you have something I should be considering. Use is 95% street with maybe 1 or 2 autocross events a year.
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All of these are decent compounds but it depends on your use case. The RT615K+ is a great compound, but it's the oldest, and especially in the last ~4 years the 200TW competition between manufacturers have resulted in serious improvements. Also, they now have an RT660+, which I haven't run yet so I can only comment on the "older" RT660. The RT660 is the softest compound, RT615K+ hardest, and the V730 is generally in the middle but on the slightly softer end.

Ranking these (in order of best to worst):
In terms of longevity/wear : RT615K+, V730, RT660
In terms of performance/grip: RT660, V730, RT615K+
Wet performance: RT660, RT615K+, V730
AutoX performance (performance w/o warmup): RT660, V730, RT615K+

In terms of price, I wouldn't spend more for a V730 over an RT660, but I would spend more for an RT660 or V730 over an RT615K+.
 
C

Chubbs

Well-Known Member
I'll chime in with an updated review of the V730. But first, keep in mind I've only ever had two tires on my goblin (RE71Rs and now these 730's), and they were different sizes....so it's hard to get a good comparison. Take this with a grain of salt.

The V730s are a little spooky and unpredictable to me. The Goblin is a little spooky and unpredictable by nature, so it's hard to tell how much of that is due to the car and to the tires, but the Kumhos don't seem to help. When the kumhos are "on", they are really great. Super tacky, and they communicate well. Very much like a go-kart tire. The front end of the goblin will chatter and "skip" a bit before it lets loose and understeers. And the rear provides lots of slip angle before it lets loose as well, which makes it predictable. on a 90+ degree summer day after 3 hard laps, there aren't many tires that I think would be better. So good news, right?

Not below a certain temperature. Like an on/off switch, if these things are cool they are treacherous. And that threshold is fairly high....I'd say below 80 degrees, these tires really don't work, and even then they require some abuse before they really get up to temp. Anything below 60 degrees, and just forget it. The goblin is a warm weather car anyway, so maybe these issues don't apply to you. But on the street, it's hard to get these things hot enough to work well.

So, if you're doing hard track duty in a warm climate, the Kumhos are going to be awesome for you. Plus, they look super cool (I know we don't choose tires based on looks, but they do look awesome!). For a street tire, I'd go with something less aggressive. A "lesser" tire is going to work better for you 90% of the time on the street, and even for light track duty. You really have to push these V730's hard before they respond well, and it's just really hard to do that safely most of the time. It's impossible to do it and stay on the right side of the law.
 
Robinjo

Robinjo

Goblin Guru
Thanks for the input everyone. I'm going to give the RT615K+ a go. Next set after that I'll have better information to provide. My biggest complaint on the V730 was longevity (which may be alignment caused). They gripped very well, I liked them a lot but did nee to be careful for the first 5 minutes of driving until they warmed up. I had zero incidents with them trying to come around, but again was careful until warm.

I strongly considered the RT660's but with the directional pattern it would not allow side to side rotation.
 
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Robinjo

Robinjo

Goblin Guru
Though this might be the case. Someone was going to give me a half used set of 255's but looks like it's too large. 225 or 235 look to be my sweet spot.
 
Markm

Markm

Well-Known Member
Eventually I’ll get some lighter wheels for the wife’s Goblin after she picks them out and will go from 225’s to 245 fronts 255 or 265 rears in anticipation of the new engine. I’ll most likely stay with the RT615K+ since we mostly just cruise around in it.
 
Robinjo

Robinjo

Goblin Guru
No, a guy is giving me a set of 255’s without wheels. I have 8” wheels and seeing if that will work on my wheels
 
Rttoys

Rttoys

Goblin Guru
Ok. Good. I was a little confused too. I wasn’t sure where 225s came into play. Free 255s, meh I’d run them
 
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