Hoosier QTP D.O.T. Drag Tires

[mikelv]

Proper Wheel Fitment for Drag Slicks

Okay, so I've searched and searched, doing some shopping for this season and I’m looking at traction today.

As I’ve mentioned before, suspension/handling and tires are not my strong point. I am looking for the best traction for this season, and looking to snap off some great 60’ times.

One thing I have done in the past is usually follow the best….Shep, Brent, Jake, ect….

Well I noticed some guys out there run Hoosier QTP D.O.T. Drag Tires: 26.0'' x 9.50'' - 16''LT.

I’m not big on tire sizes and I’m trying to get smart on this stuff. What does these sizes reference and what am I going to need to make these wheels fit?

Here is what I've been reading about tire sizes:

Tire code - Wikipedia, the free encyclopedia

I have a set of the 16” 2G turbo wheels, can I make this work, and if so what size spacer would I need? Hell, I'm not even sure of the width on those wheels.

I'm going to pull power in the 9 second time frame, so I'm assuming this tire is where I need to go. Always open to suggestions guys.

Thanks for the help guys, been searching this topic and I’m sure there’s a ton out there, but can’t really find these answers. Someone link me here?

 

[mikelv]

Man, I'm trying to figure out these tire sizes and I'm getting quite confused.

According to the wiki conversion chart:

1 meter = .3048 ft


26 inches = 2.16 ft

.3048 feet (1 meter) conversion to mm would be:

.3048 x 1000 = 304.8mm which would equal 1 foot.

To find out the lenght in mm for 2.16 feet (26 inches) the equation would be:

304.8mm x 2.16 = 658.368mm

Give your tire a nominal section width of 658.368?

Are the sizes of the drag tire expressed differently than a normal tire, please reference.

Reference:

Conversion of units - Wikipedia, the free encyclopedia

What am I doing wrong?

 

[daren_p]

I didn't go through all your calculations but what exactly are you trying to figure out? The tire your looking at would be 26" tall, so thats the diameter of the tire. A typical aftermarket "street" setup would usually put the tire around 25" tall. Stock is normally slightly less then this (depending on what model). 9.5" would be the width of the tire, 1" is equal to 25.4mm so a 9.5" tire would be equal to a 241.3mm wide tire, in the "normal" tire sizing your use too.

What kind of drop are you running on your car & are you looking for tires for the GSX or GST? I have seen guys run the QTP's on their stock rims, probably not the most ideal rim width (abit wider would be better) but it can/has been done. 26" is a fairly "tall" tire for us, so you want to be making some descent power, since it will change your gear ratio to make it seem longer. If its for your GSX & sounds like your goal is the 700hp range, this shouldn't be an issue & the QTP's would be a good choice.

I know for sure there are a couple threads about specific fitment of this tire on this board.

 

[mikelv]

Okay, now I think I'm answering my own questions as I go:

This tire code is different as a standard:

26" refers to the tire diameter, as 9.5" refers to the width, and 16" is the size rim it will fit.

So I guess if this is correct, my question stands. Where can I find the the stock rim size and would these work on it?

Wheel Size

I have look at this, are the 2G FWD Turbo 16" rims, 16" x 6"?

I guess I'm just going on answering my own questions, but some supporting comments would be great thanks guys, I think that's it!

 

[mikelv]

I didn't go through all your calculations but what exactly are you trying to figure out? The tire your looking at would be 26" tall, so thats the diameter of the tire. A typical aftermarket "street" setup would usually put the tire around 25" tall. Stock is normally slightly less then this (depending on what model). 9.5" would be the width of the tire, 1" is equal to 25.4mm so a 9.5" tire would be equal to a 241.3mm wide tire, in the "normal" tire sizing your use too.

What kind of drop are you running on your car & are you looking for tires for the GSX or GST? I have seen guys run the QTP's on their stock rims, probably not the most ideal rim width (abit wider would be better) but it can/has been done.

Ha ha, thanks man. I'm not a suspension guru, so my brain is going a mile a minute!

I guess I was at first looking at metric conversion vs. tire size (ex: 225/40ZR18 vs. 26" x 9.5" x 16"). I see now that this is two totally different tire code references.

Now I see what you are saying, and I’m sure I would have a difficult time running these tires on stock rims.

I am looking for traction control on the GSX this year and I’m just trying to get my facts correct to make an educated and well thought out decision.

Hell even the suspension is up in the air at this point. Still trying to do my research on the topic, so what suspension/spring setup would you suggest for this tire? I'm sure there is more factors that come into play on this subject!

Also, if you could reference me to some links on drag theory in relation to suspension/rebound ect…. That would be most appreciated!

 

[mikelv]

I am currently running Tokico Illumina five-way adjustable shocks with RSR springs.

RSR Spring rates are as follows:

319 pounds/inch front
179 pounds/inch rear

This effectively drops the car:

1.5" Front
1.3" Rear

I just pulled those specs, but I have no idea what that means or does! Again some reading material on the subject would be awesome! I always perfer to read, learn and practice by trial & error instead of bothering you guys! Thanks!

 

[daren_p]

Well with the QTP's your looking at, they do have a good amount of sidewall, so that allows them to be run on a smaller width rim vs the typical 225/40/18 etc, low profile street setup you'd see. So Hoosier does say they can be run on as small as 6" rim (6-8" preferred range), I believe the stockers are 6.5" so like I said may not be the very best rim choice but if thats what you have, they'll do.

Reason I ask about suspension, is because this is a taller tire then your typical "street" setup, so if your car is really dropped your going to have issues with the tires rubbing. I don't have specific info on what drops required but I would imagine something around 1" will probably be ideal & a coilover setup would defently help out, so you can set your ride height exactly where it needs to be.

Also is this going to be driven on a daily basis? While the QTP's are great for straight line traction, you have to remember they are a bias ply construction with a large sidewall which your probably not use to. They are not designed to turn corners, especially if you like to do "spirited" driving around corners.

Edit: Just see you posted up your suspension, more then likely that will be too much of a drop for the QTP's

 

[mikelv]

Thank you for the information. Yes, I see based upon your reply that I’m going to have to go with something else. I actually was planning on going to a coilover setup as you say because I love the results I’ve had with the Tein SS setup on my GS-T.
As for any daily driving, none at all; I would most likely trailer the car this year or at least make tire changes at the track. (I still have 3 sets of street tires right now). I have made a decision to build a complete straight-line car out of her, so we'll see what happens. I got my hopes set high.

Would you suggest upgrading to a Tein SS AWD coilover? I mean you are looking at 16 way adjustable dampening along with as you say full ride height adjustment.

I also have a set of 17” wheels that I believe measure 8”. They make a Hoosier in 17” correct?

Edit: Spacers? How would they come in play here? Not needed?

 

[slowgsr]

Are you going to run these things on the street? Or just at the track.. I was going to use these tires, I called up Hoosier and talked to I guess some tire pro there (they are local to me), and he basically told me these tires would be very dangerous to use on the street, if there is any moisture on the road if you have to do emergency braking, or turning etc..

I went with the MT ET street in a 235/60/15 which is a 26x9x15 tire (similar to the QTP's). Im running them on a 7.5" wide wheel with a +35 offset so I won't need spacers. However I do run very stiff suspension (especially in the rear), and my car isn't exactly 'slammed'.

Taller tires put added stress on the transfer case especially, you dont really need a 26" tall tire to get traction, Shep used a 24.5" slick, If you are ONLY going to run these at the track, I would suggest going with a full set of MT slicks in a 24.5x9x15.

Also what gears are you using in your transmission? Are you using the stock ratio? How fast are you turning the motor and what time of MPH you want to see in the quarter has a big role in tire sizes.

 

[daren_p]

Are you going to run these things on the street? Or just at the track.. I was going to use these tires, I called up Hoosier and talked to I guess some tire pro there (they are local to me), and he basically told me these tires would be very dangerous to use on the street, if there is any moisture on the road if you have to do emergency braking, or turning etc..

I went with the MT ET street in a 235/60/15 which is a 26x9x15 tire (similar to the QTP's). Im running them on a 7.5" wide wheel with a +35 offset so I won't need spacers. However I do run very stiff suspension (especially in the rear), and my car isn't exactly 'slammed'.

Taller tires put added stress on the transfer case especially, you dont really need a 26" tall tire to get traction, Shep used a 24.5" slick, If you are ONLY going to run these at the track, I would suggest going with a full set of MT slicks in a 24.5x9x15.

Also what gears are you using in your transmission? Are you using the stock ratio? How fast are you turning the motor and what time of MPH you want to see in the quarter has a big role in tire sizes.

Sounds like he's not planning on running these on the streets, so thats not an issue. I know a few who do run these on the streets but as you mentioned most defently not an ideal street tire, for several reasons. It sounds like his goal is 700or so whp & 9 second slips, so a 26" tall tire should be a descent choice. But as mentioned can take a toll on other drivetrain related pieces as you normally have to launch them abit harder to prevent from bogging. But the soft sidewall of the QTP's will help & I'm sure he's going to pre-load the car before launching

A 24.5 slick would be a good option for a track only tire but when I looked through his gallery it looked like he was running some Wilwood big brakes? If so, 16" is probably the smaller rim diameter he can run, which removes all slicks as options (as only 15" & smaller are options).

No hoosier doesn't make any drag racing tires (either bias ply or radial) for a 17" rim.

 

[Got Grip]

The QTP's are actually a pain to fit on a 2G. The drop of the car isn't the main issue, it's the spindle arm. I installed them on my 2G on 16x7" rims with 40mm offset and they still required about 12-15mm of spacer in the rear (don't remember the exact amount). In the front I think I had about a 5mm spacer. After two passes, I pulled the tires and saw some (very minor) rub marks on the arm still. The tires weren't really sticking out of the fenders, they were more flush with the outside but you'd have to run some pretty wild offset numbers to get them to fit without spacers, or some huge spacers. 2G's weren't meant to have a tire that tall on them.

Just for reference, my car has JIC coil overs on it and I have no idea what the current drop is. The car hasn't been stock height in about 7 years so it's hard to remember how low it is now. If I had suspension as soft as yours, the definitely would have rubbed the fenders hard on the launch.

 

[mikelv]

Thanks for the information guys. I suppose I will clear a few details up since it can assist in the completion of my goals.

Right now I’m running a Shep Drivetrain with stock transfer case. I have stage II DSS axles and a DSS driveshaft. I would upgrade my transfer case, but at this point I’m not in a financial position to do so.

As is, I’m looking at about a $2000.00 excess budget this year, which will include a clutch. The left over $800.00 or so I would like to spend on traction. (7.25” PTT twin disc).

Let me add, that I'm not going to compete on any circuit this year, so I understand the financial piece, this is merely recreational. A few passes in and out of some test and tunes, just for bragging rights/ personal pride, ect….no one should plan to compete without excess cash.

If I continue to run this suspension setup as mentioned, there really is no possibility of running an actual drag slick tire, (along with bake size). My next look for my power range was into BF Goodrich G-Force series Drag Radials. Your opinion on this tire in reference to meeting my traction needs? If I could run this tire on a 17” rim that I have it would save me a great deal of trouble in relation to my current suspension and brake setup. Well, at least the brakes, but I do see myself upgrading to an adjustable coilover like Tein SS.


Current setup:
2.3L 6- Bolt Built Stroker
Wiesco/Eagle
Eagle Crank
Fully built head: ported & polished (272’s & the whole deal)

Shep Stage III (which runs stock ratios I believe just stronger parts, I do not have much transmission building experience, but plan on learning and building my own )
DSS Stage II
DSS Driveshaft
PTT Twin Disc

FP3065 w/ all FP supporting mods

Twin 255’s
1600 FIC’s
APFR

DSMLink….Big front mount, intercooler spray, All supporting mods, the whole deal.

Basically, without getting off topic anymore, the suspension and Drivetrain (minus T-case) should be able to handle the aforementioned BF Goodrich Drag Radials.

In your experiences, or opinions (well appreciated opinions), is a 650-700hp car going to grip ok with these radials.

I tell you one thing; I can’t get out of the 10’s on these street tires. Right now, my streets are Michelin Pilot SX 225/40ZR18’s and lose traction at 28 pounds of boost on a free-rev launch.

My launches, which are pretty sick anyway are around 4600rpm. This year I want to 2-step Link at 5,000 w/ 35 lbs of boost, and I always limit the stroker to 8000 (7750). Chances are I’ll need a transfer case real soon but at this race weight, I would be extremely happy with high 9 second passes & traps in the 140-150 range.

I guess bottom line, will a drag radial that’ll fit my rims & suspension (G-force??) get me out of the hole like I need & rip off that great 60’?

Thanks for the help guys.

 

[Got Grip]

On my car, I've run 17" all season radials, 16" all season radials, 17" BFG drag radials, 15" MT Drag radials, 15" MT slicks and 16" Hoosier QTP's. All of these tires have been run while the car was trapping in the 140-144 MPH range.

I honestly think DSM's work well with street tires (all season radials) or bias ply style slicks. Drag radials flat out would not work on my car. I have all poly bushings, solid motor mounts, DSS stage 5 axles, DSS driveshaft, DSS t-case and a shep dog box. I've managed to break driveline components on almost every single drag radial pass on my car. On street tires I managed 10.0 at 144 with minimal wheel hop. The reduced grip allows the car to spin and hop a little without breaking as bad. The drag radials have the same hop but with the better grip of the soft tread compound, the hop gets magnified until something snaps.

The bias ply slicks and QTP's I have far fewer runs on but I can see them providing a smoother and cleaner launch, hopefully with less breakage.

This is all just my opinion from my experiences. I've used quite a few tires over the last few years and I have quite a few runs on my car at these power levels.

 

[JWoodley]

Per Twicks69 with my paraphrasing.....

Slicks:

You want to use a 40mm offset with the Rota Slipstreams. Then use a 3mm spacer to clear the upper section of the spindle where it bolts up to the upper control arm on the rear.

Use a 3mm spacer on the rears with a set of 16x7" 5x114.3mm 40mm offset slipstreams.

Use Mach III for your wheels. They should be $500 shipped.

spacers --> http://supercar-engineering.com/sc2/...9455c494307722

slicks: 26x9.5x16 Hoosier QTPs

 

[talont3t4]

Has anyone managed to fit a 15" rim on a 2G with willwood front brake kit?

 

[99gst_racer]

Has anyone managed to fit a 15" rim on a 2G with willwood front brake kit?

Better late than never. For reference, a 15" wheel will definitely not fit over the Wilwood big brake kit. Some 15" wheels would fit if there were 1/2" more clearance around the caliper, but most 15" wheels won't even be close. It all depends on the inside diameter of the wheel, which will vary from model to model.

 

[Todd TCE]

The Wilwood factory kit may clear some 15s actually. Depends upon the barrel size of the wheel and the flange offset etc. etc. I've got a 12.25" radial mount DP set up for the rear of a Charger SRT that fits 15" Bogarts with oodles to spare.

The next option would be a 11.75 version of that particular kit which is also doable but at a higher cost do to the radial brackets.

 

[99gst_racer]

The Wilwood factory kit may clear some 15s actually. Depends upon the barrel size of the wheel and the flange offset etc. etc. I've got a 12.25" radial mount DP set up for the rear of a Charger SRT that fits 15" Bogarts with oodles to spare.

The next option would be a 11.75 version of that particular kit which is also doable but at a higher cost do to the radial brackets.

Alot of that probably had to do with the large diameter drum that Bogart used.

My Wilwood big brake kit almost fits inside of these 15" Motegi Trak-lites. It's about a 1/4" shy. So, I'm now considering swapping some 11.75" rotors onto my hats and shortening up the caliper bracket in a mill. As long as it nets me enough clearance, it's definitely the cheapest solution.

You must be logged in to view this image or video.

 

[Todd TCE]

Before you go off the deep end let me mention that you can't shorten the bracket you have now. You won't have enough barrel for the stud and meat left on the bone you might say. It's really only doable with new brackets. Figured I might toss that out before you damage one you have now trying!

 

[99gst_racer]

Ohh don't worry, I'm just thinking out loud right now. I haven't even begun measuring yet. If making a bracket from scratch is the worst-case senerio, that would still be the cheapest and easiest way to do it for me.