Opinions on Tires

[JohnPaul]

Ok, so I have a ton of questions about the best tire setup to go with. I have a few questions and I'm sure I'll get a load of info quick, so these are the basic questions:

1) Hoosier, Goodyears or Avons: best tire? best price?

2) Radials or bias ply? faster, better feel in turns and better wear?

3) Sizes: I know that the consensus is that the 6-8" is fastest but i've noticed in DSR's they
are going with 10's all around. I'm figuring that with the bodywork drag isn't a big issue plus they get better handling for the wider front tires. So my question is would I be defeating the purpose of going with a 6" front wheel if I try a 7" tire (for added front traction)? I know people do the 6-8" and the 7-9" combo but has anyone tried the 7-8" combo?

Please feel free to give personal experiences, data, opinions, advantages and disadvantages etc.

[Mike Devins]

Who is running 10's up front in DSR? We run 6's and 8's on our DSR.

[starkejt]

Ok, so I have a ton of questions about the best tire setup to go with. I have a few questions and I'm sure I'll get a load of info quick, so these are the basic questions:

1) Hoosier, Goodyears or Avons: best tire? best price?

2) Radials or bias ply? faster, better feel in turns and better wear?

3) Sizes: I know that the consensus is that the 6-8" is fastest but i've noticed in DSR's they
are going with 10's all around. I'm figuring that with the bodywork drag isn't a big issue plus they get better handling for the wider front tires. So my question is would I be defeating the purpose of going with a 6" front wheel if I try a 7" tire (for added front traction)? I know people do the 6-8" and the 7-9" combo but has anyone tried the 7-8" combo?

Please feel free to give personal experiences, data, opinions, advantages and disadvantages etc.

Schwietz and Dixon are both running 7" and 9" wheels. At the runoffs, both ended up on 7" and 8" tires (Hoosier). Schwietz sometimes run 9" rear tires, but he seems to prefer the 8".

[Wren]

Dixon ran the race and set the track record on 7" and 9" tires, but did run the 7"&8" tires earlier in the week. I think we stole them from you even. Thanks.

Who knows what the fast setup is going to end up being.

[starkejt]

Dixon ran the race and set the track record on 7" and 9" tires, but did run the 7"&8" tires earlier in the week. I think we stole them from you even. Thanks.

Who knows what the fast setup is going to end up being.

Oh yeah, I forgot the R25s he switched to were 9" rears.

[Richard Dziak]

Tires:

If you think your Mario Andretti, Al Unser Sr. or Michael Schumacher you can spend lots of bucks on tires from week to week. I feel that spending $600-$800 per set every race weekend or every two weekends, you best have some deep pockets or have lots of wealth. I have used Goodyear Eagle, Avon, Hoosier and lately Hankook. May be hard to believe but I use the Hankook 10's in the rear, and 8's in the front and love the tires and grip. I used to only buy new sets, but then determined for my racing it was not necessary or cost effective. Now after 7 years of racing Formula Ford, F2000 and now F1000, I only buy used tires with 90-95% rubber from John Berget, and find they are a great deal at $250.00 to $275.00 per set delivered to my door.

If your a National racer looking to win a championship, then the new tire sets may give you an advantage. If your just a regular racer who enjoys the sport and want to be cost effective, then I am convinced the used tires at 90-95% rubber are the only way to go unless you have a large budget for tires each season or you have a tire sponsor.

Try the Hankooks if your a regular racer out for some fun. They are great tires and with the weight of the F1000 cars, the tire wear is minimal. I have had great success with Hankook, otherwise; my choice is Goodyear Eagle 160's.

This is just one persons opinion.

[ghickman]

JP
Mechanical grip is the rule in F1000. Make your chassis have as much mechanical grip as it possibly can....then opt for the narrowest tire that doesn't compromise the grip.

I've tested several different tire width combos and in my opinion the 7 / 9 is the best. The car felt balanced but not over tired, and the MPH numbers and lap times proved it.

I know this is off subject a bit....if your car is over weight put it on a diet. Finishing races 30 lbs. over weight is a kin to being down several HP. The grippy tires and swoopy aero aren't going to make up that deficit.

[Ivinsea]

I know this is off subject a bit....if your car is over weight put it on a diet. Finishing races 30 lbs. over weight is a kin to being down several HP. The grippy tires and swoopy aero aren't going to make up that deficit.

Is there a rule of thumb for what each additional 10 lb or 25 lb over the 1000 lb minimun weight costs in lap time?

Obviously there are huge variables in track layout, but does 25 lb over cost a 10th or more?

I have weighed 1100 lb in my Stohr after a short race and overfull tank and have always wondered what that is costing me....

[Evl]

If you think your Mario Andretti, Al Unser Sr. or Michael Schumacher you can spend lots of bucks on tires from week to week. I feel that spending $600-$800 per set every race weekend or every two weekends, you best have some deep pockets or have lots of wealth.

Just to offer a counter-opinion: Don't chase bad tires. It's kinda like having a $4000 guitar and not keeping fresh strings on it. It will still sound like cr@p. Regardless of how much rubber is left, race tires only have so many heat cycles in them, and once you get past that, they are pretty much useless. You may not feel that going 1s/lap slower is too much of an issue, but unfortunately the fronts and rears may not die in sync with each other, in which case you can end up chasing car set up to cure over/under-steer when what is really needed are fresh tires. from someone who made that mistake.

[RobLav]

I've heard somewhere around .1 sec per lap slower due to 10 lbs. Depends on the track, but my experience seems to show somewhere near that figure.

[S Lathrop]

Bruce Foss of Hoosier Tires was approached years ago about tires for FB. He was the one who suggested that the Piper use FC tires on 7/9 inch wheels. That car and that setup was proof of the issue.

For many reasons FC rubber is the optimum tire design available for FB. Most importantly there are more options of construction and compounds available. Also the 1" wider rims gives the tire the extra structure necessary to deal with the higher performance of the FB.

The 8/10 tire options are from heavier cars and generally are from spec tire series where endurance is the issue. An FB just is not going to load F3 type rubber sufficiently to get optimum performance. If you are not sliding the tires around a lot, the bigger tires may give you very good tire ware. Also weight and aero dynamic drag of the tires is an issue.

[carnut169]

I think avons are great but they are never at the track and Hoosier is always there- for that they get my business.

I was faster on 6 & 8's everywhere but Barber where I could get the heat into the larger (8 & 10") tires.

Hoosier R25s on the front and R35s in the back worked best for me even on the hottest summer days.

[RobLav]

Agree with Sean - Hoosier is always at the track.
On 7 and 9 Hoosier 35 FC rubber, I was always faster on 6's and 8's. I tried 7 and 9 Hoosier 25 rubber on 8's and 10's and hated it. The tires felt rock hard and had no compliance in turning and no feedback. I believe there was not enough flex in the sidewalls.

[JohnPaul]

what are the main differences (pros and cons) between bias ply and radials?

[S Lathrop]

what are the main differences (pros and cons) between bias ply and radials?

Post that question to Dave Weitzenhof. He has actually done development testing on both types.

[Richard Dziak]

John Paul:

As I stated above I have been using the Hankook tires on my F1000. They are radial, so when mounting the tire it needs to be mounted for the correct rotation. The tires are clearly marked for mounting in the correct rotational direction. Also the tire lyes very evenly flat across the width of the tire. Since the tire lays flater, you get better traction and grip vs the bias which is more rounded out and requires higher air pressure.

Also, before anyone (not JP) knocks using 95% rubber tires from someone like John Berget, I suggest you order a set. For $250 to $260.00 per set, I think you might change your opinion on the tires. Berget gets many of his tires from racers who have deep pockets or tire sponsors that might run the tires for only 1 session then switch them out. I sincerely believe they are worth the experiment to see these tires and how they perform. He also has all of the major brands which would be Goodyear, Hoosier and Avon. He's been around for over 30 years and has a big list of racer clients.

If your a highly competitive National racer looking for the best, you can't beat a new set of rubber. But for the regional racer or guy out to enjoy their F1000 the 95% rubber really cuts costs to the driver/owner and probably won't make a difference in overall fun, excitement and end result of the final position. If you can afford the new sets each weekend or every other weekend then go for it. Most racers just don't have the deep, deep pockets to buy 5 or 6 sets of new tires each year. For myself the 95% rubber tires makes the most sense economically. I don't need to spend the big bucks to get quality.

Here is a neat link to a comparison of radial vs bias ply:

http://www.michelinag.com/agx/en-US/...ias_radial.jsp

[B_Alley]

That link does seem to be more about selling the Radial tire vs. actually comparing the two types. Traditionally radial tires have a narrower slip angle to achieve max grip with higher cornering force and thus less drag force. In theory it should be a better tire all around- however, because of the aforementioned reasons, they are much less forgiving. I'm not good enough to use radials, at least when I tried running them, so I stuck with bias ply's.

They also differ greatly in load sensitivity so if you have your ackermann dialed with one tire, then switch, you should probably do some adjusting before write off the new tire as being terrible. Same goes with everything!

I'm curious myself to see what people prefer!

[JohnPaul]

I'm having a hard time finding comparisons between the radials and bias ply online but the ones I am finding seems to lean in favor of the radials. F1 use radials so I'm assuming (although f1 is not really a comparison) its the faster tire but.... it seems like it's not as forgiving as the bias-ply (I guess meaning more difficult to use) and they don't last as long as bias ply. I'm really interested in hearing first person accounts about the differences from someone here on forum so we can compare apples to apples not F1 or street cars.
Also, I'm assuming that most of the drag would come from the front tires as opposed to the rear so is there even any advantage too going with an 8" rear instead of a 9" rear
tire? would you benefit more from the wider rear for traction or narrower for drag reduction?

[S Lathrop]

JP

I think you are going to have a problem getting a definitive answer to your question. Again Weitzenhof is the most knowledgable person I know on the subject.

The reason you will not get a simple answer has to do with the fact that no one makes pure radial or pure bias ply tires. There are distinct differences between the construction methods of the two types of tires. But radial ply tires have some bias to the side wall plys and bias ply tires do have belts.

I have engineered a lot of cars on many different radial tires. For my own cars, I frequently have to make different suspension components and modify the geometry to optimize my cars when we change from one type to the other. The changes for radial tires are more subatantial than between different bias tires.

The biggest feature in favor of radial tires is the consistancy of the tires. With bias ply there is a big variation between individual tires and we find that the car has to be scaled on each set. The bias ply tires also change a lot with the first heat cycle. In almost 10 years of engineering Indy Lights, I only remember having one or maybe 2 sets of tires that were any thing but an excellent match to the tires I removed from the car.

One thing that might help you decide between the 2 types is weight. If the radial tires are several pounds heavier or lighter than the optional bias ply tire, than that may be the deciding factor in which tire is faster. Cost is something elso to consider. I believe that radial tires are more expensive to produce.