Goodyear 2703 and 2704 Tires

[BMH]

I was curious if anyone has tried the new tires by Goodyear yet? We are considering a switch from the Hoosiers to the new Goodyears....

Since it won't be until early next year until we have access to tire data, I was hoping to see what experiences other teams have had with it.

[Mbirt]

Stay tuned into Monash:
http://www.youtube.com/watch?v...mfu_in_order&list=UL (http://www.youtube.com/watch?v=DH09OBfxYQ0&feature=mfu_in_order&list=UL)

[MartyB]

We're actually still using an old set of 2696's in those videos.

We'll be jumping onto some fresh 2704s in about a week and then we'll get back to you.

Marty.

[wagemd]

We just got a set, but have yet to run them on any decent surface. We are driving at a new location this weekend (hopefully better surface quality), so I'll post back if/when we get anything useful.

[buggaero]

We had taken them to the event but unfortunately.... we turned out to ineligible to even appear in the scrutiny. Maybe in a few days, we may be able to share the data.

[mattd27]

We recently ran the 2704 at FSAE Japan coming from the 6inch wide Hoosier which we ran at the 2010 Australia Comp. Whist we didnt do back to back testing, for our car id say they are good for an instant 1-2 sec for an 800m lap.

The conditions in Japan were a lot different than aus (30+deg and a very smooth grippy track, compared to aus with 20deg temp and normal road surface), but to compare we went from 5.6 to 5.1 in skidpad with the 1st timed loop being the quickest of the lot. We drove the absolute pants off the car in the enduro and they didnt degrade at all.

From my opinion in the seat.
Avon - Grip like you would not believe for 1 lap then nothing
Hoosier 6inch - Good life but takes half the endro to really start working
Goodyear - Not as quick as the avon but lasts like the hoosier

[BMH]

Thanks for your input on the tires Matt. So basically it seems like the middle of the road tire between the Avon and the Hoosiers. What about tire weights? Has anyone been able to confirm the actual weight?

I'm looking forward to what some of the other teams think as well on here.

[Scott Wordley]

2704 Weight is less than 4kg (or 8.5 lb) per tire totally green.

We will be testing ours as soon as the car is back together after paint.

Scott

[wagemd]

We got 9.0 lbs on a pretty accurate scale.

I think the pre-production ones were slightly lighter (8.5 lbs-ish).

[BMH]

Yeah I know they were stating about 8.5 lbs for the prototypes in an older thread on here, so I was wanting to see what the actual production units weighed. So it looks like they are pretty close to the claims made in said older thread.

Even 9 lbs is pretty light. I think the Hoosiers were around 10.5-11 lbs or so if I am not mistaken.

[wagemd]

Originally posted by BMH:
Even 9 lbs is pretty light. I think the Hoosiers were around 10.5-11 lbs or so if I am not mistaken.

The Hoosiers are almost exactly 11. We bought a set of R25Bs to test with the 2704s back to back. 8 lbs!!

[nick roberts]

You guys want weights eh? Should probably be more specific when stating Hoosier weights since there are several to choose from.

Goodyear D2704
Brand New - Average 9.13lbs
Tire 1 = 4185.8g
Tire 2 = 4118.2g
Tire 3 = 4118.4g
Tire 4 = 4142.6g

~5% Life Left - Down to 6.625lbs
Tire 1 = 3005.1g(corded)
Tire 2 = 3075.9g
Tire 3 = 3274.4g
Tire 4 = 3288.5g

Compare to D2696
Brand New - Average = 10.58lbs

Hoosier 43162
Brand New - Average = 10.37lbs
Tire 1 = 4715.8g
Tire 2 = 4695.6g
Tire 3 = 4701.6g
Tire 4 = 4694.1g

~70% Life Left
Tire 1 = 4252.4g
Tire 2 = 4255.9g

-nick

[BMH]

^^ Awesome! Thanks for the comprehensive weight data!

[df_fsmb]

Thank you for all the data. We have a plan of testing three tires in March: Hoosier 7.0, Hoosier 7.5 and the new Goodyear.

But we are really concerned about the price of the Goodyear - have you also been offered a price that is more than twice the price of the Hoosiers?

[JT A.]

We just steal them http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

[carbon_black]

Originally posted by df_fsmb:
But we are really concerned about the price of the Goodyear - have you also been offered a price that is more than twice the price of the Hoosiers?

That's quite different to what we have found. We've found the pricing for any set of tyres to be ~1000 AUD, regardless of supplier/compound.

[BMH]

We will be ordering a set soon. The pricing we have obtained from one supplier is as follows:

Rain tire 2703
price 220.00

Dry tire 2704
Price 198.00

[Jersey Tom]

Originally posted by df_fsmb:
But we are really concerned about the price of the Goodyear - have you also been offered a price that is more than twice the price of the Hoosiers?

Per the Hoosier tire website... smallest 13" slick is $156 "SAE Price" $195 retail. Carroll Shelby Enterprises lists the Goodyear D2704 at $193.

Now, your average Joe might think my opinions are a bit biased here - and perhaps they are. However, I've always encouraged teams to do back-to-back tire testing and find out what package works best for your car and your driver.

Let's say you do your own testing, or even just hear through the grapevine that the 2704 is the real deal. Personally I'd be surprised if it didn't crush any of the 13" competition - but again don't take my word for it.

So now you have a choice. You've busted your ass all year making this damn car, tuning it up, and are about to drive it across the country for competition. For those that are seniors ready to move on to bigger and better things, this is the capstone to probably several years of work. Maybe several years of domination, maybe several years of frustration.

You can go there as is, or if you can scrounge together an extra $200 you can drop 10, 15, 20 seconds off your endurance time. How big is your team? If everyone on it foregoes that last case of Keystone Lite and chips into the "Let's kick some serious ass at competition this year" fund, should be pretty easy to cover that extra cost.

Don't shortchange yourselves and all the other hard work you've done. I don't care what manufacturer makes it - find the best tires and bolt 'em on.

Just my 2 cents.

[sbrenaman]

If a team has time to test the Goodyear/Hoosiers back to back, they're likely going to utilize the performance increase of the GY tires.

If a team does not have time, there are two scenarios/answers to the 'which tire to use' quetsion:
1) They will find money. Assume Jersey Tom is right, buy the damn GY's and move on; they have bigger problems to deal with.
2) They will not find money. Buy whatever tire and move on; they have bigger problems to deal with.

[Tom Wettenhall]

We've done it. We've had 7" R25Bs, 2696s, and now 2704s on the same car. I can't tell you times as we change the track daily at the moment, but I'd agree that each is quicker than the last. We picked up 0.2g lateral from 25B to 96, and ~10deg (C) tyre temperature. There's a few things which are rather different about how the car handles on each type of tyre, but I won't clutter the thread up with the details unless someone wants to know.

[MalcolmG]

Originally posted by Tom Wettenhall:
We've done it. We've had 7" R25Bs, 2696s, and now 2704s on the same car. I can't tell you times as we change the track daily at the moment, but I'd agree that each is quicker than the last. We picked up 0.2g lateral from 25B to 96, and ~10deg (C) tyre temperature. There's a few things which are rather different about how the car handles on each type of tyre, but I won't clutter the thread up with the details unless someone wants to know.

I'm sure everyone would like to know http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Rex Chan]

Just to clarify: the Melbourne Uni 2011 FSAE car was designed around R25B Hoosiers, but we've run 3 types of tyres thus far:

1. Brand new 7" Hoosiers front and rear, as well as with 6" fronts
2. Ex-Monash FSAE (used on 2010 car post 2010 comp, and 2011 car pre 2011 comp), and ex-ex-Auckland Goodyear 2696
3. Brand new Goodyear D2704

I'll let the SS guys talk about performance, but this is what I've seen about tyre wear (being an engine guy):

1. The Hoosiers were run for many (about 10) test days, and still have tread left. Tracks run on were Silhouette Karts and Top Kart.
2. 2696 were received from Monash with a little bit of tread, and got down to the canvas after 2 track days. This may have been caused by very tyre wearing SS settings, or the abrasive surface at the AARC (Australian Automotive Research Centre) DHF (Dynamic Handling Facility).
3. D2704 were scrubbed in at Top Kart, and also showed significant wear after use at AARC.

Both days at AARC (first day on used 2696, then on very fresh D2704), we did skidpad & acceleration event practice (~5 drivers with 6 skidpads and 4 launches each) first. Used 2696 were then used for enduro practice, and were showing canvass after maybe 20 laps. New D2704 did about maybe 4-5 half enduros when we noticed the significant tyre wear.

Apparently, the DHF was designed to test ESP on, so has a high mu surface.

More info: the reason to switch from Hoosiers to Goodyears was unavailability of enough 7" Hoosiers for the upcoming FSAE-A comp.

[Rex Chan]

And some more info: the 7" Hoosiers seem to be significantly wider than the 7" Goodyears: I used a ruler across the tyre and the 7" Hoosiers seemed to be ~7.5" wide. The Goodyears are very close to 7" wide. I know nothing about tyre construction, so maybe the contact patch for both are the same, or maybe there's some other suspension magic going on...

The Goodyears (2696 and D2704) have very noticeable tyre sidewall movement/deflection under lateral loads. Kind of looks like the tyre wants to come off the rim. I never noticed this with the Hoosiers.

[Mbirt]

Originally posted by Rex Chan:
The Goodyears (2696 and D2704) have very noticeable tyre sidewall movement/deflection under lateral loads. Kind of looks like the tyre wants to come off the rim. I never noticed this with the Hoosiers. I'm another engine guy that knows just enough about this to be dangerous, but the above sounds like a very good thing. Anyone who has been to Optimum G can recall the pictures of F1 sidewall deflection during cornering and "no slip, no grip". You see FSAE cars shod with LC0's have sidewall deflection like this. Hopefully this means there is now a comparably sticky 13" tire for the masses.

[Zac]

I would be hesitant to make any judgement about tire wear from testing on different surfaces, on different days, and potentially using a different course layout, or even drivers.

In tread wear fleet testing, it really isn't unusual to see a 10% variation in wear mileage. Please keep in mind that this with trying to remove as many variables as possible on a test with the sole purpose of wearing out tires. The route is fixed, vehicle alignment is checked on regular basis, drivers rotate through vehicles, a stable reference tire is used, vehicles are run in a convoy, etc. If you take some of that control away, you'll see results all over the place.

[Tom Wettenhall]

Zac: I'd agree with that. AARC I think is a pretty fresh surface, still new enough to be really destructive but not old enough to have good grip.
I'm happy enough to put it down to our car being fat, (~240kg) running a locked diff and also a reasonably healthy four cylinder engine, all of which will contribute to accelerated tyre wear. I wouldn't say it's a Goodyear issue, especially given Monash's and Auckland's experience with the selfsame set of tyres which we later wore out. We were much slower on the days we had Hoosiers, so their comparative longevity on our car is likely false. We'll just have to turn the wick down a bit when team 2012 want to use it for driver training, otherwise it's going to be pretty expensive for them...

Malcolm: Okay, trade secrets forthcoming. Subjective of course, and partially specific to our own car. I'll try and keep the bullshit meter low.
The main difference between the three is in the sidewalls. Hoosiers are pretty stiff, 2696s are somewhat softer, and 2704s are really soft. This means that your instantaneous turn-in is affected, as you can't turn the wheel faster than you can deform the sidewall. That wasn't too hard to fix though.
As I mentioned above, lateral grip is improved with Goodyears. The local grapevine story about Goodyears being worth 2-3s a lap probably isn't too far off, although that's purely speculation as I have no data to compare the two on the same track.
Goodyears run ten degrees hotter by our gauge.
Lastly, the terminal grip of Goodyears is very, very good. If you spin up Hoosiers, all your grip will go away and you'll end up facing the way you came. Goodyears appear to keep providing traction through wheelspin, which means that you can safely drift a lot more. In general, this helps your drivers push harder as the car will forgive them a few more mistakes. I reckon that this trait is almost as valuable as the outright speed increase, as we hit less cones and had less risk of a spin after the change. You probably won't pick this from the TTC data though, so you may have difficulty using that as a justification in the design event.

[JWard]

Originally posted by Rex Chan:
And some more info: the 7" Hoosiers seem to be significantly wider than the 7" Goodyears: I used a ruler across the tyre and the 7" Hoosiers seemed to be ~7.5" wide. The Goodyears are very close to 7" wide. I know nothing about tyre construction, so maybe the contact patch for both are the same, or maybe there's some other suspension magic going on...

The Goodyears (2696 and D2704) have very noticeable tyre sidewall movement/deflection under lateral loads. Kind of looks like the tyre wants to come off the rim. I never noticed this with the Hoosiers.

Check out the terps racing, rear tyre view video. It's centered on some 13" hoosiers. Their sidewall deflection is SCARY. (can't post from work)

[MalcolmG]

Thanks for the info, Tom. I think some of what you've said can be seen in the TTC data - when we went to Goodyears in 2009, we essentially did it based on the TTC data (which, IIRC, was from round 3 with the D2692s?). I don't want to go into it too much, since the tyre data is supposed to be kept out of the public domain, but the slower drop off in lateral force either side of the FY vs SA plots for the Goodyears suggested they would be more forgiving at the limit. Unfortunately in '09 we didn't get much opportunity to do any really good testing, especially no comparative stuff between the Hoosiers and Goodyears, and since the new car was completely different to the '08 I never got the chance to really see how the two tyres compared - so it's nice to know the tyres basically behave as expected.

The increased sidewall compliance was very evident with the 2696s, despite the '09 being about 40kg lighter than the '08, and in fact it seemed to add considerably to our total roll angle and caused some ground clearance issues for us with our heavier drivers (Paul http://fsae.com/groupee_common/emoticons/icon_razz.gif ). You could tell just by deforming the tyres by hand that the Hoosiers were much stiffer in the sidewalls.

I had worried that the transient response of the tyres would be worse (again due to the shape of the FY vs SA plots), but our '09 car was so much better in transients than the '08 that it was never obvious, so again it's interesting to hear that the Goodyears are in fact slower to respond - not necessarily a bad thing with amateur/useless drivers http://fsae.com/groupee_common/emoticons/icon_smile.gif

[exFSAE]

Visual sidewall deformation ? slow response.

[Tom Wettenhall]

Certainly, by no means. However, a relative increase in deformation, for a comparable rate of deformation, must correspond to an increase in the time required for deformation, which to my mind is proportional to the rate of lateral force generation; response, or yaw acceleration. Is that reasonable?

[Zac]

No. Even if your relaxation length is shorter (ie. faster responding) the transient lateral force generated might still be lower than another tire if that other tire offers superior steady-state performance.

One thing that might be interesting to do would be to post-process out an estimation of relaxation length from TTC data.

[Zac]

Also, tying relaxation length to a physical deformation might not be 100% accurate. It's the footprint that develops force, not the sidewall.

[exFSAE]

Yep. Cornering stiffness (a "steady state" parameter) is going to be the primary driver of your car's yaw response, along with inertial properties.

Literal time lag of the tire (relaxation length) is secondary.

As an aside, in my experience when drivers talk about tires having "soft" or "compliant" sidewalls, majority of the time they aren't describing the sidewall effect at all. This includes former F1 world champions.

[M. Nader]

Originally posted by Tom Wettenhall:
We've done it. We've had 7" R25Bs, 2696s, and now 2704s on the same car. I can't tell you times as we change the track daily at the moment, but I'd agree that each is quicker than the last. We picked up 0.2g lateral from 25B to 96, and ~10deg (C) tyre temperature. There's a few things which are rather different about how the car handles on each type of tyre, but I won't clutter the thread up with the details unless someone wants to know.

I am extremely interested in your times and conclusions using the R25Bs and 2704s. as we are in the market for either of these now, and we cant test them due to us being in the other side of the world and these things need time.

[M. Nader]

Originally posted by Tom Wettenhall:

As I mentioned above, lateral grip is improved with Goodyears. The local grapevine story about Goodyears being worth 2-3s a lap probably isn't too far off, although that's purely speculation as I have no data to compare the two on the same track.


So would you say that the 2704s have better grip than the Hosiers?
How much faster were they in comparison? ( i realize they weren't tested on the same time but with similar setup you can draw some conclusions)

[RyMan]

Here is an example of Sidewall Delfection (http://www.youtube.com/watch?v=vMfBG6SdXok&feature=plcp&context=C48bbe6aVDvjVQa1PpcFM97a4VzfX8wNvCNTgcKMUb JCIdPW7k6Gw%3D) of 7" Hoosier R25b's (The big hairy sweeper at 35s is money). I can't remember exactly what they were inflated to but it was super low, like 8-9 psi. I'm surprised to hear that someone said the 2696 Goodyears had more sidewall deflection than R25b's. I seem to remember the Goodyear carcass being a lot stiffer that the Hoosier.

[Tom Wettenhall]

Zac, exFSAE, I can follow that. Thanks for correcting me.

M. Nader, I'm sorry, I really don't have times for each tyre, we never used the same track layout twice.

Anything I say is just going to be speculation anyway until the new TTC data is released, and my experience is going to be biased towards the MUR car. (240kg, spool, spaceframe, ~55kW. Eats tyres. Homicidal tendencies.)

[df_fsmb]

Originally posted by Jersey Tom:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by df_fsmb:
But we are really concerned about the price of the Goodyear - have you also been offered a price that is more than twice the price of the Hoosiers?

Per the Hoosier tire website... smallest 13" slick is $156 "SAE Price" $195 retail. Carroll Shelby Enterprises lists the Goodyear D2704 at $193.

Now, your average Joe might think my opinions are a bit biased here - and perhaps they are. However, I've always encouraged teams to do back-to-back tire testing and find out what package works best for your car and your driver.

Let's say you do your own testing, or even just hear through the grapevine that the 2704 is the real deal. Personally I'd be surprised if it didn't crush any of the 13" competition - but again don't take my word for it.

So now you have a choice. You've busted your ass all year making this damn car, tuning it up, and are about to drive it across the country for competition. For those that are seniors ready to move on to bigger and better things, this is the capstone to probably several years of work. Maybe several years of domination, maybe several years of frustration.

You can go there as is, or if you can scrounge together an extra $200 you can drop 10, 15, 20 seconds off your endurance time. How big is your team? If everyone on it foregoes that last case of Keystone Lite and chips into the "Let's kick some serious ass at competition this year" fund, should be pretty easy to cover that extra cost.

Don't shortchange yourselves and all the other hard work you've done. I don't care what manufacturer makes it - find the best tires and bolt 'em on.

Just my 2 cents. </div></BLOCKQUOTE>

I haven't checked this thread for a long time. So to report: we bought the tires and compared them on the same short track of 15s with all FSAE elements, on the same day, with the same driver, back-to-back; and also in skid-pad. It was back in June.

We are very happy we did the test. The points we gained at the competitions due to the test are hard to quantify, but when we finished the test, we knew which tire we want to be on and that had not been the case before. It also helps the design direction for the next car.

We only compared 7.0 Hoosier and D2704. There was no time to try 7.5 and we just sold them.

Teams that are considering doing the test: you will not find a holy grail because there is no such thing in FSAE, but you will have one unanswered question less.

About the price: we got some wild numbers from Goodyear dealers in EU, but then contacted the Americans and also Hoosier went up so in the end they are similar in price.