Author Topic: Tyres  (Read 2394 times)

Online Angus

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Re: Tyres
« Reply #60 on: 11.08. 2018 14:20 »
Hi Not sure I want to enter this as I am quite happy with my tyres pressures on both A’s and the Norton (28F 30) A7 Roadrunners, A10 K70s, Norton Mitas)
Anyway see pick below Dunlop Gold Seal K70 purchased October last year, date of manufacture (DOT code) week 14 of 2017
1961 A7 since 1976
1960 A10 Gold Flash Super Profile Bike
1958 Matchless G80 Project
1952 Norton Model 7 Plunger
1950 T100

Offline RogerSB

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Re: Tyres
« Reply #61 on: 11.08. 2018 15:17 »
Many thanks Ellis for that useful info. It seems mine are Sept 2013.

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Offline wortluck

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Re: Tyres
« Reply #62 on: 11.08. 2018 15:33 »
Perfect, cheers Bill. *smile*
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Online berger

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Re: Tyres
« Reply #63 on: 11.08. 2018 17:45 »
I am not in the pub and all this tyre thingy going on made me have a butchers at mine, Dunlop roadmaster made in france TT100 K81's 410-19 rear 360-19 front H rated , after seeing some posts about pressures I may up mine from 22 front and 28 back  and see how things feel especialy over those blasted speed mountains.

Offline wortluck

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Re: Tyres
« Reply #64 on: 11.08. 2018 18:48 »
Got the chain on Berger, cheers!  All is working.  Let us know about the tyres as my logic says having a bit more rubber on the rim will help it round corners.  I still have the 3.50/3.25 set up with low to mid budget traditional tyres and it is ok (apart from a bit of wander on the rougher roads as said earlier).  I do like to swing it about a bit so feeling a bit more assured it'll actually do what I'm asking of it may further enhance the riding experience (providing, of course, I don't bust something else!).
'62 Flash
'49 B31
'59 BMW R60
FS1-E, YB100, RS100, RD200DX,250DX,350B, XS750



"I may disagree with what you have to say, but I shall defend to the death your right to say it."
Evelyn Beatrice Hall

Online berger

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Re: Tyres
« Reply #65 on: 11.08. 2018 19:48 »
alls good then wortluck , I will find time to have a play inbetween pub and recovery time. I do know that too much air in the K81s wears the middle down faster than Mc fast and double white lines with a worn K81 take the bike on a fairground ride but when newish there good, my mate who was 20 stoneish only got  under 2000  miles out of a back one but I think mine are clocking up 3000 and back one getting near for replaceing *roll*

Online muskrat

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Re: Tyres
« Reply #66 on: 11.08. 2018 22:15 »
G'day all.
Strange then that there's no mention of the Gold Seal on the Dunlop site.
Made in 2013 is getting past their useby date.
When I re-commissioned the A10 Cafe I had my old race tyres (Dunlop Elite race compound) on that had only done a few laps of Eastern Creek. On my 2nd or 3rd test ride the front let go, lucky only a 2nd gear (40mph) corner. New tyres fitted next day!
I never think of cost when it comes to tyres. An extra $50 can save $1000 in damage if they let go.
Cheers
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Online Black Sheep

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Re: Tyres
« Reply #67 on: 12.08. 2018 06:16 »
One problem with TT100/K81 tyres in a damp climate is that as 99% of your riding is bolt upright, the centre of the tyre wears flat. That's OK until you ride round a wet roundabout where your necessarily modest angle of lean means that your tyre contact patch is a knife edge where the flat section meets the curved section. The result is horrid skittering and yes, the bike does that too.
Great tyres for racing though. I managed to wear the side tread away whilst leaving the centre section almost unworn.
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Offline wortluck

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Re: Tyres
« Reply #68 on: 12.08. 2018 09:49 »
I think Roger's tyre is dated Week 37, 1913 ;D  Seriously though, maybe it was manufactured somewhere else as a copy.  Can't find a reason why it's manufactured so recently.  If it's a limited edition, then it would be made to modern standards using modern materials, so would attract a higher pressure.  Anyhow, it is what it is. *????* *????*

Cheers musky - would lay off the auto translate though *smile*

Berger, mate, I'd stay at the pub and go home for visits *countdown* *good3*  I've had way too much beer over this summer but, hey, last time we had a run of good weather like this I was too young to drink (officially) *whistle* *grins* *good3*

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'49 B31
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"I may disagree with what you have to say, but I shall defend to the death your right to say it."
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Offline RogerSB

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Re: Tyres
« Reply #69 on: 12.08. 2018 20:15 »
Hi all, Not wishing to extend this topic about my tyres but I thought I should (humbly  *red*) come on again to admit, after doing some extensive research today, that I now think Mr Dunlop was, in fact, playing it safe in his email to me (as some of you rightly suggested), and perhaps I shouldn't be setting my pressures to the 1960s BSA instruction book specification.

Trying to find out exactly what I should be setting them to wasn't easy as there are so many confilcting opinions on lots of other biking forums about K70s (mainly for Triumphs & Nortons).

I did find a tyre fitting chart on the Dunlop site but BSA isn't listed but Royal Enfields are and the 500cc bullet takes K70s with 3.25 x 19 front and 3.50 x 19 rear and the max load pressures are given as 32 psi for both front and rear. That ties up pretty well with the 33 psi that's on my Gold Seal K70s,

On the Dunlop chart the recommended pressures for the 500cc Royal Enfield Bullet is 24 psi for front and 32 psi for rear.  So I think I'll be safe to settled for that as a starting point.  After a ride I'll measure them again to see if the pressures are about 2 psi higher when warm, as I think that should be a reasonable indicator that those pressures are ok.

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Offline wortluck

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Re: Tyres
« Reply #70 on: 12.08. 2018 20:42 »
I think you're wise to do that Roger.  Ultimately, it's whatever suits yourself.

It does seem the Gold Seals are still available as Angus has one from late last year.  I'm going to do a quick Google to see who's selling them.
'62 Flash
'49 B31
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"I may disagree with what you have to say, but I shall defend to the death your right to say it."
Evelyn Beatrice Hall

Offline wortluck

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Re: Tyres
« Reply #71 on: 12.08. 2018 20:51 »
Found one here for sale in the UK

https://www.classicsuperbikes.co.uk/catalogue/Memorabilia/Dunlop-Gold-Seal-K70-Tyre.html

Don't know the year of manufacture.

Also found a NOS on Ebay manufactured in 2003!!

Definitely some still around.
'62 Flash
'49 B31
'59 BMW R60
FS1-E, YB100, RS100, RD200DX,250DX,350B, XS750



"I may disagree with what you have to say, but I shall defend to the death your right to say it."
Evelyn Beatrice Hall

Offline RogerSB

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Re: Tyres
« Reply #72 on: 12.08. 2018 21:09 »
Max load 507 lbs and max 33 psi on my 3.50 x 19.
Max load 505 lbs and max 32 psi on the 3.50 x 19 in the advert  *conf*.
Virtually nothing in it - but does seem a bit strange.

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Offline wortluck

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Re: Tyres
« Reply #73 on: 12.08. 2018 21:32 »
Er, should I ask, how many pounds are you and your wife together *eek*  I'd start with about 30lbs in the back and 26-ish front and see how you go.
'62 Flash
'49 B31
'59 BMW R60
FS1-E, YB100, RS100, RD200DX,250DX,350B, XS750



"I may disagree with what you have to say, but I shall defend to the death your right to say it."
Evelyn Beatrice Hall

Online Black Sheep

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Re: Tyres
« Reply #74 on: 13.08. 2018 05:48 »
One thing to consider is that our steam-age suspension systems did rely on a bit of tyre flex to maintain decent roadholding. If you have considerably higher tyre pressures, you lose that tyre flex and reduce the contact patch. Fine under most conditions but there are occasions on poor surfaces when cornering you may find the bike drifting (or rather bouncing) out on bends. With a rigid framed bike, the old recommended pressures are best otherwise on any bumpy bend it will skip happily towards the outside of the bend with potentially interesting consequences. 
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