Author Topic: Tyre question  (Read 2464 times)

Online Black Sheep

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Re: Tyre question
« Reply #15 on: 18.09. 2017 17:58 »
I don't rate Dunlop K70s. Prone to sliding, even in the dry and wear quickly. The last one I tried lasted 1,000 miles and couldn't be trusted on roundabouts. Had a few nasty slides. I corner to the limits and my BSAs were all fitted with Avon Speedmasters on the front and SM MkII on the back. Absolutely fine even when footrests are scraping the tarmac. Much better than their reputation in my opinion and reasonably long lasting. Pretty good wet grip too.
However, I am going the way of Avon Roadriders. Excellent tyres in my experience and as tyre changes become necessary, they have become the replacements of choice.
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Online Greybeard

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Re: Tyre question
« Reply #16 on: 18.09. 2017 18:20 »
I don't rate Dunlop K70s. Prone to sliding, even in the dry and wear quickly. The last one I tried lasted 1,000 miles and couldn't be trusted on roundabouts. Had a few nasty slides. I corner to the limits and my BSAs were all fitted with Avon Speedmasters on the front and SM MkII on the back. Absolutely fine even when footrests are scraping the tarmac. Much better than their reputation in my opinion and reasonably long lasting. Pretty good wet grip too.
However, I am going the way of Avon Roadriders. Excellent tyres in my experience and as tyre changes become necessary, they have become the replacements of choice.
Interesting points of view. Thanks.

Online KiwiGF

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Re: Tyre question
« Reply #17 on: 18.09. 2017 21:30 »
Im no Barry Sheen but so far the Duro brand seems a better version of the k70 to me.

See https://www.a7a10.net/forum/index.php?topic=11470.msg87192#msg87192
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Online Black Sheep

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Re: Tyre question
« Reply #18 on: 18.09. 2017 22:27 »
Duro tyres are new ones to me. Presumably available in the UK if you know where to look. Another tyre I don't rate is the TT100. I used them OK when racing, wearing the sides off the tread before the middle but in road use the centre of the tread wears quickly leaving a step which is frankly 'orrid on wet roundabouts. You need a well tucked in bike to use the edge of the tread and it's not often you can corner safely quite so hard on normal public roads.   
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Offline wortluck

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Re: Tyre question
« Reply #19 on: 19.09. 2017 18:28 »
This may be a daft question, but I can't really tell if my rear tyre is supposed to be illegal or not.  It's a Cheng Shin which came with a very shallow central groove - this has now pretty much worn away.  However, the treadwear indicators seem to taper up toward the central point of the tyre, making one end of the indicators look flush with the other end well within the tyre groove.  Interweb says stuff about 1mm in a continuous band around 75% of the tyre (or something like that), but I can't believe it could be worn out on the small amount of wear on the centre of the tyre (even though the shallow pattern has disappeared).  The tyre still has loads of tread and has only done 3000m.  What do you reckon (can't do pics at present as jpeg files seem too large??)
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Online JulianS

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Re: Tyre question
« Reply #20 on: 19.09. 2017 19:19 »
That tyre has had it. Reduced grip. I see it as a question of safety for all road users.

3000 miles is about the mileage I get from Roadrider rear on A10.

Offline wortluck

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Re: Tyre question
« Reply #21 on: 19.09. 2017 21:35 »
Picture of tyre attached - what do you think?
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Online bsa-bill

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Re: Tyre question
« Reply #22 on: 19.09. 2017 21:49 »
looks like it's been run over inflated
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Offline wortluck

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Re: Tyre question
« Reply #23 on: 19.09. 2017 21:55 »
Always run on 30 pounds rear and 28 front.
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Online Black Sheep

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Re: Tyre question
« Reply #24 on: 20.09. 2017 06:47 »
Despite strong advice to the contrary, I run closer to the original recommended pressures (18 psi front, 20psi rear) using 22 psi front and 25 psi rear. I'm still not sure why pressures of 30+ psi are now recommended - except perhaps to wear out the centre of the tread quicker and hence increase the need for replacement tyres?
Higher pressures came in with radial tyres with very flexible sidewalls - but our old beasts still run on crossplies and are in fact generally lighter than modern machines.
As for the tyre in the picture... It's a pretty chunky tread and has seen a fair bit of use without a lot of hard cornering. Were it on my bike, I would replace it but then it's not my bike. 
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Offline Tomcat

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Re: Tyre question
« Reply #25 on: 20.09. 2017 08:34 »
Love the Cheng Shins Wortluck, K70 and ribbed pattern, soft compound and half the price of the rest. I put a Dunlop K70 next to a Cheng Shin tyre once and am confident they come from the same mould. Pity these tyres aren't available Down Under anymore.
I ran Dunlop TT100's on the A65 and was also happy with these, possibly even better due to the more rounded shape. The thing to remember is that they are all made with modern compounds now.
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Offline Topdad

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Re: Tyre question
« Reply #26 on: 20.09. 2017 11:06 »
shows all our bikes are different, mine handles like a completely different bike on roadriders but only with 'em set at 30psi ,if lower not nice at all .
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Offline wortluck

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Re: Tyre question
« Reply #27 on: 20.09. 2017 21:02 »
Cheers all.  The Cheng Shin has been a great tyre and has seen hard cornering action around the Derbyshire/Yorks Dales and Yorks Moors!
I am a bit handy with the throttle so this may account for the middle wear a bit. *dunno*  Bike passed its MoT six weeks ago and no concerns were raised about the tyre??  As for pressures, anything beyond 30 psi at the rear and it squirms a bit on white lines and heavy braking.  However, I wouldn't go lower than 28 r and 26 f.  I'm going to nip over to another tyre place for their opinion.  In the meantime, I'm going to order a Mitas to see how they perform.  To be honest, I do expect a bit of weave and squirm from the bike, especially as I do like to chuck it around a bit.  My main issue (as you would imagine) is whether it all stays on the road!! *eek*  By the way, I did put the original recommended pressures in the bike at first only to be told by a white faced fitter this wasn't a good idea. :o  The reason, all motorcycle tyres differ from those produced 60 years ago and require the pressures recommended by the manufacturer of the day.  60 years ago, the tyres needed lower pressures, now they need higher pressures due to the changes in the way they are constructed - just a thought.
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Online Black Sheep

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Re: Tyre question
« Reply #28 on: 20.09. 2017 21:57 »
I don't think crossply tyres are constructed differently from they way they were previously - an Avon SM is constructed the way Avon SMs always were. What has changed is the carcase material - a bit more flexible than it was and the actual rubber compound which, as previously mentioned, is up to date. With our old bikes having short travel suspension, the tyres actually do a bit of the work. You will certainly discover that on rigid-framed machines where, if you use higher than recommended pressures, the back and hops to the outside of a bend when cornering on anything other than a dead smooth road. A bit disconcerting. If you want to sample real excitement, try riding a trials bike on the road with 2 psi in the back. Not recommended!
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Offline wortluck

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Re: Tyre question
« Reply #29 on: 21.09. 2017 17:11 »
I guess it's down to what works with your bike.
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