Should I get 9" or 10" slicks?

Mike Puckett

SCCoA Member
I've ordered my new wheels. I went with the 15x8" over the 10". I've decided to go with the Hoosiers with either a 9" or a 10" tread width. Either will go on an 8" rim. I've been blowing off the 10.5" ET Streets which have a 9" tread and I'm wondering if the 10" tread would be better with the full slick. Both are 26" dia, both are DO6 compound, and there's only $5 difference in price. So, from the racers out there, which would you prefer?
 

BLOWN38

SCCoA Member
We have had good luck with the 28x10x16 on a 9" rim. They are C07 compound tho. 1.41 60' was the best. I know its not a stick dumping the clutch but it was a 2100 rpm at 10psi launch with a 100 shot on top of it.
 

aroot1

SCCoA Member
Not sure if the rim width will effect tire shape. If not, I've never heard anyone complain about having too much tire ;)

Adam
 

1MTNCAT

Registered User
Mike

I would suggest going to a 27" X 9". On an 8 inch rim you should be close to a 9" wide tread on track (dependant on tire spec) and will give you a little more leverage(Rollout) with just a slight reduction of gear with the height. You may be able to get by without having to drop tires pressures as low and therefore less rolling resistance. Also give you a little taller sidewall to help absorb some of the shock to the tires from the manual shift.
 

XR7 Dave

Registered User
In my case 9" tires are not wide enough. I was badly feathering the 9" hoosiers I had. Same thing is now happening with the ET drags. But the ET drags do hook very well. My cars have been a bit heavier than yours though so that is a factor. It also depends on how hard you are on them. Phil likes to launch @ over 4500rpm.
 

r429460

Registered User
If your tires are too narrow for the rims they are installed on
you have to run the air pressure too low.
With the too low air pressure that r creats more drag and uneven
tire contact.
Also there is waisted foward motion with low air pressures, from too much sidewall flex.

With an 8" rim, go with no more than 9" tire.
 

1MTNCAT

Registered User
In my case 9" tires are not wide enough. I was badly feathering the 9" hoosiers I had. Same thing is now happening with the ET drags. But the ET drags do hook very well. My cars have been a bit heavier than yours though so that is a factor. It also depends on how hard you are on them. Phil likes to launch @ over 4500rpm.

Dave, what height tire were you running-26" or 27"??

A 9" wide, 27" tall slick tire on a lightened car should work well, even with a stick. I run 28" X 10.50's on mine on 8" wheels but its an auto 4.6 and on the spray pulls 1.57 60 ft's. It would pull 1.62's on the 27 X 9 tires.

Also Mike, I didn't ask but what gear are you running? I'm interested in what your gear multiplication is in 1st and second gear and actual weight of the car with driver. Depending you may actually want to go to a 28" 9 or 10".
 
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Mike Puckett

SCCoA Member
I've got 27x10.5x16 ET Streets now. When I put them on 3 years ago I was suddenly running about .2 sec slower in the 1/4 mi as compared to the 26x10.5x16's I had previously run. One of the local racers told me I actually took some gear out of it by going to the taller tire. I'd really like to go back to the 26" tire size. I could have gone to a 28" slick and stuck with the 16" rims but that's too tall a tire and I'd lose even more in the 1/4mi. I want to check with Hoosier and see if there's any problem running the 10" tire on an 8" rim even if the spec says it's Ok. I know some really quick cars run 9" slicks but if it'll benefit me to run the 10" I'll get those. So far it's about 50/50 here on which one to get. I'm tending toward the 10" myself.
 

BLOWN38

SCCoA Member
HRTBird on here works for Hoosier. Wonder what HRT stands for?;)

Not sure how much he is on here tho.
 

JT's03

Registered User
Racemaster 28x9 will get you down the track. I'm going to do the mh next time I buy tires.
 

XR7 Dave

Registered User
Dave, what height tire were you running-26" or 27"??

A 9" wide, 27" tall slick tire on a lightened car should work well, even with a stick. I run 28" X 10.50's on mine on 8" wheels but its an auto 4.6 and on the spray pulls 1.57 60 ft's. It would pull 1.62's on the 27 X 9 tires.

Also Mike, I didn't ask but what gear are you running? I'm interested in what your gear multiplication is in 1st and second gear and actual weight of the car with driver. Depending you may actually want to go to a 28" 9 or 10".
In both cases the tires were 26". It's not that the car doesn't hook, it's just that the tires are being overwhelmed by the torque and weight of the car. I had discussions with Hoosier about this and they confirmed that the feathering I was seeing is a result of too much load on the surface of the tire. Once they start to feather then traction just goes away. I had it real bad on the Hoosiers but the ET Drags are doing it now too.

ET Streets are awful for actual racing. They are good for the weekend warrior or occasional track guy who isn't experienced running on actual slicks, but for a race car I would never run the ET Streets. It makes a huge difference.

As I said, don't get me wrong the ET Drags hook, I have several broken axles to prove it, but they are feathering so I know that it's not enough tire.

Mike, I agree about the gear ratio. I didn't think I'd ever say this, but thinking about going to a 3.73 in the 5spd. We currently have 3.55's.
 

Mike Puckett

SCCoA Member
Yes, I'm running 3.73's in the rear and the car weighs 3400 lbs right now. I'm really inclined to go with the 10"ers. After I put the 27's on and I didn't run as I quick I wished I had stuck with the 26" diameter so I definitely going to 26". A lot of the guys here run Hoosiers and love them but there are lots of M/T guys, too. I believe that M/T is recommending a 10" rim with the 10" tire and Hoosiers will fit on an 8" according to the spec. I'll call them tomorrow and check.
 

Mike Puckett

SCCoA Member
I just got off the phone with the Hoosier tech rep and he is advising that I go with the 9" tread. Considering the weight of the car with an 8" rim the 9" tread will sit flatter on the track and have a "better profile" giving a better launch. Apparently he feels that the 10" will turn up too much on the edges and not give any better contact patch.
 

nickleman60

SCCoA Member
I run Hoosier bias ply slicks, 28/10.5/15's, on an 8" rim and they hook great. I consistantly pull 1.52-3 60' times.
 

nickleman60

SCCoA Member
I run the E/T Street 28/10.5/16 on stock rims and they spin more often than they hook.

Ira

Sounds like you need to get some Hoosiers..................:D

I also run tubes and rim screws. I set the tire pressure at 12 psi. For the record I have 4.10 gears
 
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