Discussion in 'Triumph (Classic)' started by Bernhard, Jun 28, 2018.
Are the Dunlop KR124 racing tyres not available anymore?
But, I haven't seen any recently on classic race bikes and I tried but couldn't get any (not easily, at least). Avons (AM26) are the tyre of choice for many now. I miss the low profile Dunlop front tyre which had a good contact patch and inspired confidence. For longer road races, you would often see riders use a Dunlop front and Avon rear.
How do Battlaxe tyres compare with Dunlop KR124 on a classic bike ?
It may vary from classic to classic. I found that the front Bridgestone is light but the sidewall is not as sturdy as the Avon Roadrider. I and several others I know who fitted Bridgestones had to raise the tyre pressures significantly to get stability. I fitted a front Bridgestone to my old R75 Beemer and I upped the pressure to 36 psi and then it was OK, but haven't tried them on anything else. One has a very limited selection of makes to choose from in 3.60/4.10 or equivalent for the road and none of them inspire the confidence of the race Avons. Avon Roadriders are a good compromise (and they suit Commandos). I'd be interested to hear from anyone who has fitted modern Dunlop TT100s to their classic, particularly if they are more sportingly inclined. I only rode on them back in the day, but they should be a lot better now.
I rode TT100 s back in the day, but the world has moved on, I would like to know just what rubber they are using on these tyres now, the same as the original, or a more modern griping race compound rubber?
Bernhard - it's my impression that modern classic road tyres have stronger carcass construction, better design of tread to avoid 'white lining' and to promote directional stability, and slightly softer rubber. Like you, I would like to know the details of how they make these tyres in comparison with old style tyres.
IMHO they have a MUCH stickier compound.
They grip much better and wear out much faster.
A trade off which is fine by me !
Although I never found out to confirm it rumour has it that when the TT100s were being raced by the factories, Dunlop used a race compound –a simple enough tweak.
I could EASILY believe that !
I used Metzeler Motorcycle Tyres when I last raced in the production class, it was a ME1 on the rear with a Comp.K compound and a matching ME33 on the front with Comp.K compound was available to order. Sadly they appear to be no longer available
While compounding would help, set beside modern tread configurations, the K81's tread pattern forecloses it's potential for track use. Too much light and air between tread blocks such that their edges lack support and, when heeled over, there is just too little total contact patch surface area.
In the 70's, I was production racing on K81s when the Michelins came along and they just swept the K81s aside. The K81s' semi-"Trigonic" shape looked faster but their open tread pattern gave up too much in surface area contact patch while the new French compounds coupled with their radiused rounder dumb shape somehow just stuck better. There was even a moment in time when we ordered K81s that were made in France and supposedly had French/Michelin"ish" compounding. While they were better, they still overheated as compared to those slow looking Michelins. I thought that it was mainly compound as the witness marks at the edge of the Michelins showed a narrower contact patch when heeled over. The Michelins' scrubbed contact patch had an entirely different look. It was big, a paradigm shift, the Michelins demanded more warm up, far different pressures, and a different kind of sensitivity; they lacked the Dunlop's signals and just "went," albeit at a higher point of traction loss, until you recalibrated and discovered their signals.
Looking at the K81s, I see an evolution from the K70. The K70 came from an era when there were still a lot of dirt roads, thus it harkens back to a time when many bikes were on trials type tires. Similarly, the K81, with those dentile edged strips and the air between its outside tread blocks, compared to modern roundish, interconnected tread block semi-slick patterns, still offers superior traction on a dirt/dirty road.
Getting back to the original post, don't know about KR124s but I love the non-DOT Avons.
I saw 125GP bikes in national events here in the 80s with K81 tyres that were a race compound, so they were potentially available for larger machinery/larger diameter wheels.
Xbacksideslider - I like your assessment of K81s for racing.