Which DR for 18" wheels?

Discussion in 'SRT Hellcat Performance' started by BlackbirdWS6, Apr 29, 2016.

  1. BlackbirdWS6

    BlackbirdWS6 Gold Member

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    I tried doing a thorough search but wasn't able to find a thread discussing this topic. I am going to be getting a set of dedicated wheels for drag racing (18x10). The 2 options I see for a DR from Mickey Thompson are the S/S 305/40/18 and the Street R 305/45/18.

    The Street R would be taller and reduce my gear ratio perhaps making it slower than the S/S if both hook. The Street R would be easier to hook up but again, if both provide the traction off the line, the S/S would likely result in quicker times (tire also weighs less too).

    My Charger is bone stock but will have an aluminum DS put in before it sees the track with a sticky tire. I honestly don't plan to swap the rear to a 3.09 or add more power to the car.

    Let me know your thoughts.
     
    Last edited: Apr 29, 2016
  2. Link

    Link Silver Member

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    MY MT's are a 305-45-18 on 10in rims, don't remember if they are street R. I got the recommendation from TC.
     
  3. TNCHARGER

    TNCHARGER SRT Hellcat Supporter Gold Supporting Member

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    If you want a tire that will hook at the track get the ET Street II 305/45/18 R....make sure to get the "R" as the regular ET Street II hooks great but nothing like the "R" .....not enough hieghth difference to make any real difference in gear ratio...
     
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  4. BlackbirdWS6

    BlackbirdWS6 Gold Member

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    Street S/S does not come in a 305/45 so must be the Street R?

    I am not seeing a ET Street II listed on the website. Mickey Thompson Performance Tires & Wheels

    I see only the Street R and Street S/S. Both sizes (305/45 Street R) and (305/40 Street S/S) use the R2 compound.
     
  5. TNCHARGER

    TNCHARGER SRT Hellcat Supporter Gold Supporting Member

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    Seems they changed their web site since I ordered my set. It appears they dropped the ET Street II and now have the R and SS. I wondered why they didn't do that earlier.

    At any rate the R tire is superior for the track. The SS is similar to the ET Street II with a better street tread. The SS would be a better choice if you are going to run it on the street and track. The R is still going to hook much better though at the track.

    If you decide on the R and order thru a vendor make sure you are not getting the old standard ET Street II....if they have the R it may be listed under ET Street II "R" as mine were when I ordered them last year.
     
  6. dragrcr

    dragrcr Gold Member

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    First of all the S/S is not lighter. I think you got confused. But no biggie as it is only 1 pound. But on the SS that extra pound is probably the steel belts which is "bad weight", since it is the farthest from the center of the axle.

    I have actually run BOTH of those tires. If you run on a decent track and you do not add mods or the 3.09 Diff, I would definitely run the 305/40 S/S. I think I got 47 passes out of them but I run at Irwindale and that track is a challenge causing me to have to do massive burnouts. I expect you could easily get 20 more passes at a good track.

    The "R" is definitely a more serious tire and should be considered for someone with mods and the 3.09 gear. I will say my best 60 foots with both tires have been about the SAME. 1.56. But I actually did a 1.559 last night with the "R" at Irwindale in 300 feet worse DA. So the "R" is showing that is will probably exceed the S/S slightly in overall ability. I have the 3.09's now and have run both tires with the 3.09's and all the 1.56's have been with the 3.09's. Also, I would have never ran the taller "R"s with the 2.62 gears.

    Pic of the car launching is with the S/S's....
    . LAUNCH CROP.jpg DSCN1889.JPG DSCN1999.JPG DSCN1621.JPG
     
  7. BlackbirdWS6

    BlackbirdWS6 Gold Member

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    Thanks for the thorough response and pics. Regarding the weight, I figured a little shorter tire in the same width would be lighter but I wasn't intending this to mean it was of any significant difference. I am leaning towards the S/S since I don't plan on switching to the 3.09 unless I somehow grenade the stock rear. I've seen folks break the case but not the internals.

    Did you have any issues with the tire spinning on the rim? I may proactively have these glued when mounted just to avoid a potential issue.
     
  8. dragrcr

    dragrcr Gold Member

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    Oh god yes. Even at 35PSI on my first street drive rolling into it at the top of SECOND gear a couple times they moved about 2" on the rim. As with all setups it seems to diminish as the tires thermal cycle and the lubricant used to seat the beads dries out. But at the Drags (Irwindale) I had to go way down on pressure to get it to hook. Sometimes as low as 13 PSI. Needless to say the tires easily went 180 deg and beyond! The problem is when the heavy spot on the tire matches up with the weights they added to counter balance it. Then it is SHAKE CITY.

    With the ET Street "R"s I chose to balance the wheel ONLY with the TPMS sensor. They each took 2.0 and 2.5 ounces exactly opposite the TPMS sensor. Then mounted the tires with no further balancing. So far it is smooth for the most part, but not always. I am not sure why but I think these tires can flat spot in a very short time and will sometimes shake during a run depending if they are synchronized or not. I don't think the S/S's will do that. On the way home from Fomoso last time driving 130 miles sometimes on glass smooth highway they were smooth......even though they did shake on a few runs that day.

    You can glue them on if you want. But, I was afraid of what it would be like if they slipped anyways? Would it disrupt the seal? Or what will it be like then next time they are dismounted? Will the beads have to be carefully cleaned with solvent? Will the Tire Monkey do a good job? Will they leak air after the second mounting etc etc.....SO MANY questions. I chose to do what I know works.

    I have seen some wheels with a bead lock on one side. Not sure how this would work if one side slips and the other does not. Will it tweak the tire caucus? Eee Gads!

    As a side note a company that makes custom forged wheels like my Forgelines, FINSPEED offers bead seat knurling to lock the tire to the wheel. It is a STEAL at $40 per wheel.

    KNURLED BEAD SEAT
    The Knurled Bead Seat option increases friction in the contact areas where the wheel meets the tire, and limits tire slippage under heavy braking and acceleration. This option is highly recommended for track use.

    $40 per wheel finspeed-options-knurled-bead-seat.jpg
     
  9. BlackbirdWS6

    BlackbirdWS6 Gold Member

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    That's a nice feature for sure and def a steal at $40. I'm still undecided on wheels so the tire is actually the easy part. I think I'm set on the S/S tires unless others have a recommendation the other way.
     

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