Classic race tyres

This is a more general question, not really Commando but I know there are a few racers at this forum so I hope it's OK to post it here.

I've been using Avon AM22 and AM23 race tyres for ages. While they give good grip, they do delaminate sometimes, and the last three pairs I've bought have come apart quite quickly. See photo.

I was thinking about using Continental's new Road Attack2 CR which they say is a race tyre, but I have heard varying reports from " race winner" to "useless, no grip"

I'm looking for input from racers who have tried the Conti or know someone who has. Are they any good?

Thanks
john


Latest Avon de lamination

I know a few lads who have used them on our classic racing scene , they say good things about them . Slightly longer to warm up on a cool day but i should think where you are that should be less of a problem . I can give you a few email addresses if you would like to contact a few of my mates. Alan

Speak to Avon directly they do many tyres in race compounds, they just don't advertise it. I also thought the Conti attack tyres are steel belted, but maybe wrong.

The amount of lean you need to get around corners sometimes depends on steering geometry. One thing I've noticed about the kids who race today, is that they are much more tyre-dependent. What it means for me is that, if it rains I am in with a big chance.

Ashphalt Al said:

I know a few lads who have used them on our classic racing scene , they say good things about them . Slightly longer to warm up on a cool day but i should think where you are that should be less of a problem . I can give you a few email addresses if you would like to contact a few of my mates. Alan

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Thanks Al, I'd be keen to get in touch with your friends who have used them. Whereabouts are you? Here in Brisbane the climate is sub tropical so it's unusual to be racing when it's less than 25C ( 77 f) so as you suggest, warm up may not be a big problem.

Having said that, the only guy I've met who used the Contis was here in Brisbane and he just couldn't get them to work. I was sharing a garage with him and the tyres clearly weren't getting up to temperature. After a race they looked like a road tyre after a Sunday ride.

I've not had the rear Avon delaminate on the BMW but the front 90/90/19 has.
The rear on mine started to show signs of cracking.
Saying that, there is not a lot of option here in 19" other than the Heidenaus K34R http://www.motorcycletire.com/product/HN-K34R35019.html
Was going to use it on the yet unfinshed R 500 but been on R100 for a year and despite looking a bit old skool does the job. However I'm not the fastest rider.

I'd send that pic to one of the tire gurus, and to Avon, and ask them what they think the cause is.
Couldn't hurt and they'd appreciate it.

In the photo, I can't see a lay up seam in a transverse line running across from where that "delamination" is.
Could it be a "cold tear?" Pressures and tire temperature, of course, are a complex.

I've run the non-DOT Avons both on the street and the track for many years, never had that problem.

I've seen that tear on many brands of tires and it never gets worse. I've seen it on 1000's on rears and the tire guys don't think twice about turning the tire around to wear out the other side and the tear just wears off. Nonissue.

edgefinder said:

I've seen that tear on many brands of tires and it never gets worse. I've seen it on 1000's on rears and the tire guys don't think twice about turning the tire around to wear out the other side and the tear just wears off. Nonissue.

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I could peel it further apart by hand. This is a race bike that does well over 140MPH and if anyone wants to:

a: Turn a tyre around and run it the wrong way according to manufacturer's spec, they're welcome to, but I'm not going to.

b: Trust your life to a tyre that is clearly peeling apart and getting worse lap by lap, again they're welcome to but I think they're foolish.

xbacksideslider said:

I'd send that pic to one of the tire gurus, and to Avon, and ask them what they think the cause is.
Couldn't hurt and they'd appreciate it.

In the photo, I can't see a lay up seam in a transverse line running across from where that "delamination" is.
Could it be a "cold tear?" Pressures and tire temperature, of course, are a complex.

I've run the non-DOT Avons both on the street and the track for many years, never had that problem.

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That first shot was one of several Avons that have de-laminated/torn/failed. From memory the last three pairs have all failed in a similar way. Most of them separate in the lay up seam as you mention. This one looked different but was a more dramatic tear.

This is the one that's on the bike now. It has done 2 race meetings. The rainbow colours suggest maybe it's getting too hot, but once again it's falling apart along the lay up line.

Hi John, I apologize for he dismissive sound of my response to your questions. I'm lucky to get to a couple races a year and not riding so the withdrawl symptems are horrible.

From what I read on the net it looks like the UK alone has many times more classic racers than the US. Here in the states theres only a couple far flung regions with enough riders to support more than 1 or 2 races at a club event. The average distance for me in the middle of the country to our AHRMA national races is about 1200 to 1400 miles. I clicked your post hoping to gather information but since your asking heres what I see. The Conti Classic Attack and also Heideau tires are a very welcome addition to our series. The availability of Dunlop and Avons is never a sure thing. Talking to riders I hear a lot of I prefer this tire to that but i'm happy to run either. Any time I hear I don't like those on this bike its because they are too big, too tall, too heavy. This is common on small bikes where they run a rear tire on the rear and fixed by running a front tire backwards on the rear. The fastest guys seem to pick tires whose height complements the geometry of the bike, is light weight, mix brands front rear. The low budget guys are always willing to run a take off to try size geometry as much as grip. I think you should try Conti but be sure to compare height and especially weight as some are boat anchor heavy.

If you do a google image search for motorcycle race tire delaminating you'll see some like yours but it never gets worse. I think the tread rubber is wrapped 5 or 10 times around before vulcanization and your seeing the end of the strip. Plenty of chunked tires from big bikes spinning up and overheating. If you pull the torn end with a vise grip i'll be surprised if it comes off or it will stop at the tread groove that's way deeper than the rubber strip is thick.

I see your in Australia, g'day mate!

I was talking to a guy using the Contis on a Triumph 750 triple at the weekend, he likes them better thann the Avons he was using and he likes the price. When I was looking they were still holding good heat from a practice session on a cool track, with beautifully even wear. Pretty sure you wont see the delaminate. I have seen othes use them again even wear, no cracking.

Personally I moved from AM22/AM23 to Heidenau K44/K64, smaller size front, same size rear. So 110/80 to 90/90 with 130/70 rear. I like them a lot and prefer the steering of the smaller front. Also cheaper than Avons.

some of the Avon AM22s I had cracked at the sidewall, which also seems common.

edgefinder said:

I see your in Australia, g'day mate!

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Yeah, we also have substantial distances between races. Phillip Island ( the best track in the country ) is 2000 kms give or take. I haven't been for several years but our club hires a truck to take the bikes and we fly down.

I think I'll give the Contis a go. I have just bought a set of Sportsvalve fork valves so I'll leave the Avons on for the next practice day to do a back to back comparison, and then try the Contis.

Cheers
John

SteveA said:

I was talking to a guy using the Contis on a Triumph 750 triple at the weekend, he likes them better thann the Avons he was using and he likes the price. When I was looking they were still holding good heat from a practice session on a cool track, with beautifully even wear. Pretty sure you wont see the delaminate. I have seen othes use them again even wear, no cracking.

Personally I moved from AM22/AM23 to Heidenau K44/K64, smaller size front, same size rear. So 110/80 to 90/90 with 130/70 rear. I like them a lot and prefer the steering of the smaller front. Also cheaper than Avons.

some of the Avon AM22s I had cracked at the sidewall, which also seems common.

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Thanks for the info.

I'll come back when I've tried the Contis and give a report on them.

pommie john said:

edgefinder said:

I see your in Australia, g'day mate!

Click to expand...

Yeah, we also have substantial distances between races. Phillip Island ( the best track in the country ) is 2000 kms give or take. I haven't been for several years but our club hires a truck to take the bikes and we fly down.

I think I'll give the Contis a go. I have just bought a set of Sportsvalve fork valves so I'll leave the Avons on for the next practice day to do a back to back comparison, and then try the Contis.

Cheers
John

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I put a set of Sportsvalves in my R90s and a set of .66kg/mm Sonic springs . Sportsvalve is so much easier to set up than Racetech emulators.
Does Glynn now make a BMW 'Kit" as he was talking about it when I got my ones off him?

72Combat said:

I put a set of Sportsvalves in my R90s and a set of .66kg/mm Sonic springs . Sportsvalve is so much easier to set up than Racetech emulators.
Does Glynn now make a BMW 'Kit" as he was talking about it when I got my ones off him?

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I have Marzocchi forks on mine. He does a kit for them.

I have ran Dunlops for years and they went away. I have the Conti's now on my XS based F750 bike. The tires are good so far , 100/90-18 front and 130/18 rear. Took some time to adjust bike to these new tires , but so far they work great. Have not been in the wet yet!! I have seen these Avons have these tears often. I think the Avon is okay at medium use , but pushed , they do not hold up.

John Ellis
AHRMA 5X
F750

Junk yard Dawg said:

I think the Avon is okay at medium use , but pushed , they do not hold up.

John Ellis
AHRMA 5X
F750

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Jihn, the comment doesn't really hold up either, I was at Cadwell Park last weekend, a demanding circuit, the majority of races were won by hard riding, on Avons!

some very quick laps also put in on a range of other tyres, but I don't think it is the hard use that killes these tyres, some have no problem, some delaminate, others crack sidewalls, some are perfectly fine, I would suggest manufacturing issues.

The first post's picture shows a smooth texture similar to beach sand just after a wave recedes. The second picture is not as smooth and it shows those little worms of rubber. As I learned it, the former is preferred, the latter not. Not so much because of less traction but mainly because the tire is wearing too fast.

I once hired a guy, Dave Moss, who was offering tire reading/suspension set up services at the track. I haven't been to the track in four or five years now so I've lost track of him. At that time, I was skeptical but his fees - compared to the price of tires - were right and I let him adjust my suspension based on what the tires were telling him. He could read spring, rebound and compression damping from the appearance of the tires, both in terms of the texture of the tire's surface and in terms of how the edges of the sipes were wearing. He schooled me, and he shared his reasoning from his observations. My skepticism quickly went away and thereafter, I paid him for his services whenever I was setting up a new bike. I found this, just now.

https://www.facebook.com/davemosstuning ... 6410429518

Do you use tire warmers? They take some of the doubt out of the analysis since you can't "cold tear" them if they are already up to temperature. Edit - assuming pressure is correct; and, I should add that tears and delaminationare associated with excess heat differential between the carcass and the tread.



For what they are worth, and regarding just tears, here are some very basic notes that I found on the subject of hot tears/cold tears. There is a lot of information in the link above. I don't recall if these ideas came from Dave Moss or not. Basic stuff really, and not exactly on point since what we are talking about appears to be a layup or joint tear, not a tread tear.

When it is a hot tear:
There is too little pressure.
The tire has a larger contact patch due to the lower pressure (deforms more)
The "rough" area you see in the pictures is fairly wide
The tears themselves are very shallow.

When it is a cold tear:
There is too much pressure.
The tire has a smaller contact patch during to higher pressure (deforms less)
The "rough" area is narrower
The tears are fairly deep. (You can get a fingernail under the tears)