More as a general comment but ime, this has always been something of a Dunlop problem. I first encountered it back in the late 1970's after I bought my first T160; I worked for a shipping company and was often away for several months at a time; I had to replace the tyres pretty much at the beginning of every leave. Iirc, TT100's were still made in GB then.
I'd begun to think they'd solved the problem. When Dunlop brought out the K181 - still called 'TT100' but with different front and rear tread patterns - I swapped one T160 to them and certainly the front is still sitting around on a wheel without any cracks. And the T150 I bought about seven or eight years ago came with new K81 TT100's; they're still fine.
However, while it might not be a problem with Brien's tyres, Dunlop appears to have shifted production of certainly lower-quality/volume tyres to other, lower-wage, Far Eastern countries. Is Dunlop HQ in Japan keeping a close eye on quality? With all the other problems the country, and possibly the company face, do they care enough?
Originally Posted By: Brien Morrissey
donations accepted for a set of Avon's!
From late '79, I was working in London and running my work (Jap) bike on Avon Roadrunners; once Dunlop became Japanese, since I couldn't tell any quality difference between the two makes, jingoism seemed as valid a consideration as any other and, after fitting those K181's to one T160, I've always used Avon Roadrunners on everything until I bought that T150. I've never encountered cracking on any iteration of Roadrunner tyres.
One of the complaints voiced when BSA/Triumph was failing was that people weren't buying the bikes that Triumph (and BSA) were making. While I don't think anyone would argue today that one of the reasons for that was the-then gulf in quality between British and Japanese bikes. However, in the case of Avon Roadriders and something like the Dunlop D404's, is there any discernible difference in quality (ride/wear)? Especially on a British bike, I cannot see any reason not to use quality British tyres.
Have Dunlop K70's on my pre war speed twin. Less than 5,000k on the rear, very , very, dissapointed. At nz$160 notes each I might as well have fitted some elcheepo Mitas from the old Eastern Block or some Chin Shin from Taiwan (China).
66T100SR Cafe racer 59 T20 Cub 1938 - 53 5T Bitsa project, now a roller Duplex frame under the bench
I contacted Avon and I have to go through an official Avon dealer. They should be covered under warranty but Avon needs the tire in their possession before they issue a replacement. The build date on the tire is 2007. I have a matching rear that does not have any cracks. I just wanted to point out that it can happen with any brand. Who knows why it happens but I believe it is a manufacturing issue. The good thing with Avon tires in North America is that the warranty is based on tread depth not a set length of time.
New search for Dunlop shows as 'Vintage', available in K70 or K81 / TT100 series. Were these available back in '08?
K81 was developed in the mid- to late-1960's as a rear tyre for the Triumph and BSA triples, and twins like the Commando and tuned 650's from all the makers, which were ripping bits out of K70's on the rear. By how long the K70 predates the K81, I don't know.
The K70 and K81 remain available, when later tyres have come and gone, because Dunlop discerns a sufficiently-large world-wide market in those owners of decades-old Britbikes who take what they read in decades-old Britbike manuals as immutable gospel.
Originally Posted By: JBMorris
Old front: 325-19 = 100-90 Old rear : 400-18 = 110-90
Ye-ea-ah ... take yourself to the Avon Roadrider page and ask yourself why, if the above are really "equivalent", does a maker like Avon make four different tyres for those four sizes? Then look at the overall dimensions of each tyre size and ask yourself whether certain tyre makers have the same dictionary definition of "equivalent" as the Oxford English Dictionary? Then remember that tyre makers stay in business by selling the tyres they make, not by riding your bike. Finally, remember that certain tyre makers simply tell shocking porkies ...
The K81 comes in 3 sizes: 4.10H19, 4.25H18, and 4.10H18. Like Stuart said they have been available continuously since the late 60s. On the disk braked OIF bikes with the underslung caliper the 4.25H18 will rub the inside of the chainguard. The 4.10H18 is the way to go for the rear if you want K81s. They are really modern tires with old tread patterns. And yes the K81 rears will wear out first, probably before 5,000 miles. Tires Unlimited sells them pretty cheap. http://www.tiresunlimited.com/ALL%20TIRES/Dunlop/dunlop_vintage_k70.htm
Since I have both the Avon RoadRunner (original tread design AM9) and the K81 installed right now on bikes that get ridden, I can honestly say that they are both great tires. Neither tire has ever broken loose on me and aside from the sidewall cracking on the front Avon I am happy with both. Just to note the K81 front that I replaced on my T140E had sidewall cracks but it was made in England and probably the original tire.
Skidog- what size roadriders did you put on your 67 TR6R? Maybe I should try some.
I use K70s on my 67 because I like the look of them and they work fine for me (very rarely more than 80mph). I can lean the bike right over on fast bends and nothing bad happens. The back one wears out in about 4000 miles. I don't get any sidewall cracking but there was a bit between the treads on the last front one at the end of its life. The front lasts a lot longer than the back, of course, so has time to perish, I suppose.
I suspect that rubber compound has something to do with the sidewall cracking. My D404's had sidewall cracking long before the tread was worn out and I ride every day all year long. I rarely get two years out of a tire. Other tires I have had never had any cracking after years. My TT100's wore out so fast they didn't have a chance to crack. I've since started to try other brands. I have a Duro tire on my KZ but i'm using a tire prep by Armorall to test their claim that it prevents side wall cracking. Cracking between the treads is another thing altogether. Bill
Bikes 1974 Commando 1985 Honda Nighthawk 650 1957 Thunderbird/T110 "Flying Tiger" Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
Hiya Folks - newbie on here so please show patience !! When I used to have my tubeless (car) tyres repaired (punctures plugged). The tyre fitter I used to frequent refused to repair tyres over 5 years old (Original Scotts date of 2007 would put them in that time braket) !! I'm looking at fitting new tyres to my T140E (mongerel) and having been in Warehousing/stores as a trade for some years I know how long stuff can sit on shelves etc. What worries me is when ordering new tyres - How can you ensure you can get recent stock & not get old knackered tyres when ya parts with ya cash ?? - Smokey
There was an earlier post about the cracks and 'mblab' commented:
There should be a date somewhere on the tire. First 2 numbers denote the week the tire was made, last 2 the year. Some people won't use a tire more than a few years old, say its dangerous. Personally, I wouldn't use one that looks like yours. I order my tires from Tires Unlimited and always ask for a recent date code. Last ones I got were only 3 months out of the mold
Oh yeah, welcome aboard!, he was right and my tire showed a build date of '07, and they were bought in '08.
The tires on the bike when i bought it were Continentals, and after 15 years (in storage) were totally shot.
Did zero research, just noticed the 'Dunlop' sticker and assumed they were original.
Did not ask for a cheap set of tires, just Dunlop.
Finding out the hard way that 'Impulse' shopping may not be the best!
Good luck with yours and let us know how it goes.
Still think a tire sidewall should last a bit longer!
How dangerous is a tire with cracking down by the bead.
woodsie, Good question and to be honest , am still riding this time bomb (?), that is to say slowly(?)!
It does have a tube innit, so some semblance of safety?
Dunlop has responded to my problem, just recently, so we are negotiating a resolution?
The warranty covers cracking for four years ( from the date of manufacture ) or until the tire is worn out. Please contact the dealer of purchase for an evaluation of the tire in question The dealer has the ability to adjust when a warrantable condition exists.
. . . don't quite get this one but will wait and see . .