Avon ACB10 Tires

[Nath_01]

Hey to all,
Our team runs the Avon A45 compund slicks at comp and was wondering if any other teams have used the ACB10 compound that the Australian Formula Fords use?

I understand that they are a harder compound in comparison to the A45s but for any testing or even potentially wet running does anyone have any opinions on them?

I would think that the "control" tire would not heat to well on a much lighter car in the wet but as the team is running on a very low budget and cant afford new wets i am exploring this path as i (may) have accsess to some used sets.

Any thoughts would be greatly appreciated!
Cheers!

[StevenWebb]

I remember seeing UoMelbourne testing on them in 2009

I would advise against using them (especially used ones) in the wet- i assume theyd be too hard a compound. but for just testing and driver training theyd be better suited than a radial by far.

btw, do you guys run 6.2 or 7.2 inch wide A45s?

[Nath_01]

Currently we run the 6.2's but we have in the past ran the 7.2's because of availability I think.
I thought the same thing with regards to the compound being to hard.

However last year when I was ordering the a45's the guy from traction tire center commented that the ACB10's are a cut a45?
At the time he was concerned that we couldn't get the 4th for the set of 3 he had there because the last shipment for formula ford was coming for the end of the year.

Can anyone validate this comment?
I've done the good old "finger nail in the tread" compound test And the acb10 felt alot harder. They had a few heat cycles however.

Thanks for the response.
Cheers!

[Luniz]

How are your experiences with the A45 compound?
My team used to run them in 2008 and 2009 and after 2009 we decided that the compound is too soft for our purpose. We had some discussions with avon in the UK and they confirmed that the compound is designed to be used in hillclimbing applications, where the tyre has to work without any extra temperature (a hillclimbing run usually takes less than two minutes). As soon as the tyre gets some temperature into it, it starts to smear and literally disintegrate. This was also our impression, especially after the endurance run at Hockenheim that year, where asphalt temps were about 40°C. The car was almost undriveable after the fifth lap...

More information about Avon compounds can be found on their UK website:
w w w . avonracing . com / compounds_page . aspx

[Nath_01]

They have been perfectly fine for us.
Generally speaking they will last one comp weekend and some short driving after comp.

However ive never really driven them at elevated temps before and cant give any feedback on how they react.
Also our car is pretty light so tire wear isnt a huge concern for us.

The reason im looking at the ACB10's basically is because im working with a formula ford team and was hoping to scavange some throw away sets for testing and what not.

Cheers

[exFSAE]

By "perfectly fine," have you done back to back testing against other tires?

On an autocross course, those super soft treads can really make your car drive like crap, IMO.

It's all relative.

[Nath_01]

By "perfectly fine" i meant perfectly fine for our needs. Low cost, relatively good availability, bias ply for driver feedback, soft quickly heating compound that lasts the competition.

We have never had a problem with them but have never had the chance (read funding) to test other tire brands and compounds.

Why do you say they make your car drive like crap? What experiences have you had with soft compounds?

[Pete Marsh]

We have used the F Ford control front tyre for driver training on an older, and heavy, car with good results. They grip OK, like 1.3 or 1.4G, and last for a hundred Km or so even though they are stuffed for F Ford when we get them. The lower grip eases the load on the car too, so less wear and tear there.
They are priced well too, free from the rubbish bin at your local F Ford team!
The only use we've found for the rears is dyno tyres, due to their big diameter.

Pete

[Zac]

Originally posted by Nath_01:
Why do you say they make your car drive like crap? What experiences have you had with soft compounds?

There are two problems with a "soft" compound.

First, cornering stiffness is going to decrease as compound stiffness decreases. FSAE cars tend to spend a lot of time at high slip angles so that may not be a huge deal in terms of lap time, but it can result in reduced steering precision (you'll need a better driver to go fast) and increased tire drag (costing you fuel economy and lap time).

Second, the "soft" compounds that a lot of tire manufacturers will use for autocross, hillclimb, or rain tires are super hysteretic. They will come up to temp really fast, but they can also suffer from reversion and begin to grain during long stints in warm weather. This can result in large balance and driveability changes after a couple laps. My experience is that a lot of the "soft" tires are faster out of the gate but will fall off pretty hard at the end of endurance once the car becomes a handful to drive.

Also, I would highly recommend that you get it out of your head that there is a strong relationship between compound stiffness and grip.

[Thomas MuWe]

We ran the A45 compound until 2009 and we were pretty satisfied with it - or at least I was in the year I was involved.
IMO it is a reasonable priced tire which is easy to drive and with a low weight car you will not destroy the tires. On our 180 up to 190 kg car it worked out to last much more than one comp. Maybe that is not a "normal" formula s-car but just to let you know.

[ffrgtm]

Originally posted by Zac:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Nath_01:
Why do you say they make your car drive like crap? What experiences have you had with soft compounds?

There are two problems with a "soft" compound.

First, cornering stiffness is going to decrease as compound stiffness decreases. FSAE cars tend to spend a lot of time at high slip angles so that may not be a huge deal in terms of lap time, but it can result in reduced steering precision (you'll need a better driver to go fast) and increased tire drag (costing you fuel economy and lap time).

Second, the "soft" compounds that a lot of tire manufacturers will use for autocross, hillclimb, or rain tires are super hysteretic. They will come up to temp really fast, but they can also suffer from reversion and begin to grain during long stints in warm weather. This can result in large balance and driveability changes after a couple laps. My experience is that a lot of the "soft" tires are faster out of the gate but will fall off pretty hard at the end of endurance once the car becomes a handful to drive.

Also, I would highly recommend that you get it out of your head that there is a strong relationship between compound stiffness and grip. </div></BLOCKQUOTE>

The compound being "soft" or "hard" has nothing to do with the tire's "spring rate". It is a totally independent characteristic.

[Jersey Tom]

Originally posted by ffrgtm:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Zac:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Nath_01:
Why do you say they make your car drive like crap? What experiences have you had with soft compounds?

There are two problems with a "soft" compound.

First, cornering stiffness is going to decrease as compound stiffness decreases. FSAE cars tend to spend a lot of time at high slip angles so that may not be a huge deal in terms of lap time, but it can result in reduced steering precision (you'll need a better driver to go fast) and increased tire drag (costing you fuel economy and lap time).

Second, the "soft" compounds that a lot of tire manufacturers will use for autocross, hillclimb, or rain tires are super hysteretic. They will come up to temp really fast, but they can also suffer from reversion and begin to grain during long stints in warm weather. This can result in large balance and driveability changes after a couple laps. My experience is that a lot of the "soft" tires are faster out of the gate but will fall off pretty hard at the end of endurance once the car becomes a handful to drive.

Also, I would highly recommend that you get it out of your head that there is a strong relationship between compound stiffness and grip. </div></BLOCKQUOTE>

The compound being "soft" or "hard" has nothing to do with the tire's "spring rate". It is a totally independent characteristic. </div></BLOCKQUOTE>

Regarding the "spring rate" of cornering stiffness, I'm going to have to disagree with you big time on this one.

[Zac]

Originally posted by ffrgtm:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Zac:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Nath_01:
Why do you say they make your car drive like crap? What experiences have you had with soft compounds?

There are two problems with a "soft" compound.

First, cornering stiffness is going to decrease as compound stiffness decreases. FSAE cars tend to spend a lot of time at high slip angles so that may not be a huge deal in terms of lap time, but it can result in reduced steering precision (you'll need a better driver to go fast) and increased tire drag (costing you fuel economy and lap time).

Second, the "soft" compounds that a lot of tire manufacturers will use for autocross, hillclimb, or rain tires are super hysteretic. They will come up to temp really fast, but they can also suffer from reversion and begin to grain during long stints in warm weather. This can result in large balance and driveability changes after a couple laps. My experience is that a lot of the "soft" tires are faster out of the gate but will fall off pretty hard at the end of endurance once the car becomes a handful to drive.

Also, I would highly recommend that you get it out of your head that there is a strong relationship between compound stiffness and grip. </div></BLOCKQUOTE>

The compound being "soft" or "hard" has nothing to do with the tire's "spring rate". It is a totally independent characteristic. </div></BLOCKQUOTE>

Who is talking about spring rate? I'm talking about cornering stiffness. The number one factor in controlling cornering stiffness is the stiffness of the tread band. Individual variables that a tire designer will use to tweak cornering stiffness include: compound stiffness, tread cavity shape, tread design, tread depth, and belt angle. If you don't follow, read either Pacejka (if you want a headache) or Purdy (if you want a migraine).

But now that you bring it up, both lateral and vertical spring rates will change with compound stiffness. It won't change as much as tweaks to either mold geometry or material lay-up, but it will have a measurable effect.

Another caveat about tires: never assume that you're dealing with a totally independent characteristic. Tires are highly non-linear composite structures.

[Rex Chan]

Well, to bring this thread back from the grave: I found some old 7" FFord Avon ACB10's in our "storage" area, which will fit our wheels (had a lot of 6" FFords too narrow for our rims). Most of them don't even look too bad, or worn.

Thus, we will be soon driving the 2011 Melbourne Uni car on said tyres. Photo below:

Melbourne Uni FSAE 2011 car with Avon ACB10 7.0" (http://www.facebook.com/photo.php?fbid=10150563719018036&set=a.10150481926443036.373793.559588035&type=3)

The reason we're running these is that we only have 50% tread left on some new Hoosiers, and the comp set of Goodyears, both of which we would like to save for practice closer to (2012) comp. We have new drivers to train (100% new guys on the team; 100% new drivers), so to save money, we're using the FFord Avons.

The main concern seems to be low grip, and not being able to get heat into the tyres. Well, the 2011 with the heavy wheels was 250kg, on Goodyears. The ACB10s are a LOT heavier, so add another 10kg to the whole car. Any opinions on how the car should handle? Low grip sounds fine to me (an engine guy), but not if it handles VERY different to how the good slicks will perform. And, the variation in OD (20.0" to 22.0" = 1" increase in ride height) means a rather big change in suspension stuff, I'm sure.

[Pete Marsh]

Rex, see my post above, we use the 6" fronts on 7" rims no worries.
They handle a bit differently, but nothing that would detract from driver training, and maybe even some car development.
The height of the fronts is ok to.

Pete

[dela]

.

[STRETCH]

I can only reiterate Luniz's comments, as we had the exact same problem in 2009, except we were running 6" all round, unlike Kiel's 7-8" beasts. I remember some jaws dropping at the state of our rubber when we pulled into the fuel station! This was the only time we'd had a major problem though, in a very high track-temp enduro. Other than that, the A45 is an awesome FS tyre as its superb right out of the box, and gave us P2 in skidpad and accel that year.

[Rex Chan]

Hello!

Just went for our first drive on Avon ACB10 (7" Formula Ford tyres all round). There was a lot less grip, understeer, and lots of tyre squeal. Our drivers liked to use the throttle to get the rear tyres to spin and get the car pointing faster. Use the same tyre pressure as normal Hoosiers/Goodyears (around 10-11psi). Got "warm" 40-50C on a nice sunny 24C day in Melbourne.

Bonus: you can lock up for 10m, and not flat spot the tyres. They get warm, but not sticky. We drove on smooth concrete though.

Photo album on fb: MUR 2012: Flat Sump First Drive/Avon ACB10 First Drive (FFord) (http://www.facebook.com/media/set/?set=a.10150684412833036.403180.559588035&type=3)

Overall: a really good way to get new drivers some seat time without the cost of using up valuable rubber. With Valvoline as oil sponsor, it's only costing us fuel money to buy Caltex E85.

And now for some videos: Driving on Avon ACB10 7" Formula Ford tyres in an FSAE car (http://www.facebook.com/video/video.php?v=10150684503468036&saved)

Another video uploaded (YouTube): MUR 2012: Formula Ford Avon ACB10's on an FSAE car (http://www.youtube.com/watch?v=K6kBxsO84yE)

Even more videos: MUR 2012: More Avon ACB10 drifting in an FSAE car with Hashan (http://www.youtube.com/watch?v=wLyPUaWSzcc)
MUR 2012: FSAE Flat Dry Sump testing at Essendon Airport (http://www.youtube.com/watch?v=o0ehHtnPckA)