Live action from FUMANCHU182.

[fumanchu182]

I keep flopping back and forth between getting MT ETR in 305/45R17 again or going to the 315/50R17.

You've had both and our cars were setup similar. Which did you like best? I'm on the stock 2.62 gear if that's a variable.

Got my tire guy looking for both to see what's available and will probably snag some next week.

I think for the power you are putting down a 305 is perfectly fine and it matches the 2.62 well, do you notice wheel slip? With a 315 youll launch well, no slip but might bog or shift all the way into sixth in the traps. Also need spacers and longer studs. But Ive heard the racestars clear better. Im currently running the hoosier dbr which is 29.5/10.5r17. They are the truth. When I convert to 15s I’ll go back to the ET Streets and run the radial pros.

 

[vortecd]

I think for the power you are putting down a 305 is perfectly fine and it matches the 2.62 well, do you notice wheel slip? With a 315 youll launch well, no slip but might bog or shift all the way into sixth in the traps. Also need spacers and longer studs. But Ive heard the racestars clear better. Im currently running the hoosier dbr which is 29.5/10.5r17. They are the truth. When I convert to 15s I’ll go back to the ET Streets and run the radial pros.

I'm not doing the spacers to fit my 315s, a 3 pound hammer will make the room for them. I'm not going to play that hit or miss on traction game

 

[jonx96]

I'm not doing the spacers to fit my 315s, a 3 pound hammer will make the room for them. I'm not going to play that hit or miss on traction game

You saw last year the struggle I had chasing a personal best. Prep wasn’t the greatest but for that time of year prep isn’t always the best. The 305 I wasted 3 track days in a row last year

 

[jonx96]

But a 305 will hook. I proved that. But there were a lot of wasted track days for that to happen

 

[DavidKFla]

305 45r-18 Street Rs hook great on my car. An occasional slip but you will get that when you're getting wheel speed.

 

[Speedy!]

@fumanchu182 set his best 60' as far as I know on the 305s with a 1.37. He had 3.09 as well for that.

I've set a 1.42 with a bunch of mid 1.4s on the 305s and 2.62 gear. Prep has to be on point though.

What I'm struggling with is whether a 315 will let me put more power down earlier to make up for the difference in diameter vs just pulling some power with the 305s when prep isnt stellar. I'm afraid itll be a wash.

Maybe @vortecd can let us know. He's pretty methodical at the track.

 

[vortecd]

@fumanchu182 set his best 60' as far as I know on the 305s with a 1.37. He had 3.09 as well for that.

I've set a 1.42 with a bunch of mid 1.4s on the 305s and 2.62 gear. Prep has to be on point though.

What I'm struggling with is whether a 315 will let me put more power down earlier to make up for the difference in diameter vs just pulling some power with the 305s when prep isnt stellar. I'm afraid itll be a wash.

Maybe @vortecd can let us know. He's pretty methodical at the track.

My car hooked 99% of the time running mid 10s and slower. Add 150hp and it is a different ball game. The prep for the race I was at is always good but the temps were higher then I normally run in.

Ron tested the 305s to the 315s a few years back when running 10 teens and they were pretty close. I do think the test would have been way different if he were running 9.7s

 

[DavidKFla]

I do things differently than you guys since I index race. Low 60' doesn't work for me. I have a 3.09 gear and over 4600 lbs.

 

[Mean Cat]

HP level & track prep is the key. More HP & 315's = more consistency.

Stock boost 305's work better with 2.62 but will work with 3.09 also to a point.

Higher boost 315's work better with 3.09 to take up some of the gear loss of the taller tire.

Launch style will be a factor too, I like to just hammer it to the floor, no time wasted. Hook & Book.



.

 

[Speedy!]

My car hooked 99% of the time running mid 10s and slower. Add 150hp and it is a different ball game. The prep for the race I was at is always good but the temps were higher then I normally run in.

Ron tested the 305s to the 315s a few years back when running 10 teens and they were pretty close. I do think the test would have been way different if he were running 9.7s

I recently checked out Ron's testing. We need to consider that was in his Demon which had 3.09 gears. I'm actually very surprised the 60' wasn't quite a bit better with the 305 considering the gearing but is what it is.

Your car will be a great test since you've run both and have used both 2.62 and 3.09s as well.

Every race I've competed in the 305s had no problem because the track was properly prepped and I was only shooting for a 10.00. It's those regular TNT days where I've had problems but Beech Bend is doing these private race tire only TNT now with great prep so I'll probably be focusing on those.

 

[DavidKFla]

What are you guys testing for? A particular event, class or your personal best?
Do any of you race?

 

[fumanchu182]

What are you guys testing for? A particular event, class or your personal best?
Do any of you race?

N/T Grudge this year and MHSH events. Won the Oct MSHS 10.0 class this year and am shooting for the 9.5 class again, or even faster...

 

[Speedy!]

I'm testing for what will give the best and most consistent 60' times on a A8 Hellcat with 2.62 gears between a 305/45R17 and a 315/50R17.

My theory is that "best" and "most consistent" may be mutually exclusive for these tire sizes with the afore mentioned car setup.

I race in 10.00 classes where a DOT tire is required.

 

[fumanchu182]

I'm testing for what will give the best and most consistent 60' times on a A8 Hellcat with 2.62 gears between a 305/45R17 and a 315/50R17.

My theory is that "best" and "most consistent" may be mutually exclusive for these tire sizes with the afore mentioned car setup.

I race in 10.00 classes where a DOT tire is required.

The most consistent will be a tire that hooks no matter the surface. Thats the DBR. ET Street Rs because of the stiffer sidewall are very prep dependent. Once a radial slips thats it. Radial slicks are designed to slip then hook. This is not to be confused with Bias Ply Slicks (yes radial slicks are a thing). Also the 315s are unobtanium. If you are with the 2.62 I’d stick with the 305. Or be crafty, do a 15” conversion, Im about to run 315/60r15. 😂

 

[Speedy!]

The Hoosier DBR is not DOT approved in my race classes require it.

 

[fumanchu182]

The Hoosier DBR is not DOT approved in my race classes require it.

305 or 315 it is for you. Lemme ask you this, what are your 60’ averages?

 

[Speedy!]

Overall average on a prepped surface is around 1.48 if I had to guess.

Without prep all bets are off. I somehow managed a 9.8x ET with a 1.67 60'. I'm still not sure how I managed that.

 

[fumanchu182]

Overall average on a prepped surface is around 1.48 if I had to guess.

Without prep all bets are off. I somehow managed a 9.8x ET with a 1.67 60'. I'm still not sure how I managed that.

It was your backhalf, must have had a great tune and great air. If you are looking for a better 60' then prep is the key to success with no matter what ET Street R you use, just because of the way a prepped surface is better for the radial construction and compound. Also you mentioned you like to leave soft, up that timing, will instantly get your 60' moving and if you are blowing the tires off, leave at idle. I've decided what I'm going to run. Mickey Thomspons ET Street Radial Pro, 275/60r15, will be depenendent on the surface but due to the bigger side wall I can air down and hit it harder if necessary to get it to bite. With the 309 it's going to be screaming in first gear but that's what I want.

I honestly think if you have the AAD suspension like I do, but still have the 2.62, the 305 is the right size tire for you, prep will be key. This is the fun part of racing. Lets say you start at 18psi, on your first few test hits at an event you air up till you slip and then go right back down in PSI, then hook and book.

 

[jonx96]

I agree @fumanchu182 a 305 can hook I've done 1.4 60s and a 1.38 60ft. The thing for me there are days or events where track prep is perfect. In which case I was getting very annoyed. Unless the track you race at is perfect 90% of the time I think more track days are wasted on the 305. The day I did the 1.38 60 I went back up an hour later and completely blew the tires off the car. Over that hour track prep was beat down pretty bad.
Where @Speedy! races is an interesting track since it is right next to a river. I believe when I was there last year there were talks about how the track is really greasy from the river until the sun starts to beat down on it.

 

[DavidKFla]

There's different adjustments in the car that you can make to help overcome bad track conditions. Suspension, traction, etc.

Anytime you're at the track and street cars are there you have to expect a shitty track.