The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: KiwiGF on 19.02. 2017 00:07
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It's 6400 miles since I got my A10 GF on the road (with new k70 tyres), the first (standard) size k70 rear lasted about 2700 miles before getting below 1.5mm, the second is at the wear limit at 6400 miles, so I'm getting on average a bit over 3000 miles out if them. The tyres wears mostly in the centre and there is plenty of tread on the edges when the legal limit is reached (I obviously don't go scratching enough *smile* ).
The first rear was run at below 25 psi, which is why I thought the low life was my fault, the second has been run at 28/30 psi.
The front still has plenty of tread.
Is this sort of life normal for a rear K70 on kiwi type roads? (Kiwi roads have a reputation for being rough on tyres).
If so I'm think of changing brands or tyre type as it's pretty obvious Dunlop are making too much money out of me!
There's not much choice of brands in NZ so I would be particularly interested in hearing where other kiwis are buying tyres. I used cycletread.co.nz last time, but they only have the k81 listed at 179 nzd as of this morning. I need to get a new rear tyre quick, so I can get the bike tested in time for he national bsa rally this coming weekend *help*
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Hi KiwiGF you story is the same as mine only getting about 3000Ml out of the K70 on both my A7 & A10 so it is not just you, I have just fitted a Dunlop Roadmaster TT100 410 H 19 to my A7 and have another on it way for the A10 I hope these do a bit better! *doubt*
Peter
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Thanks Peter, I can remember the tt100 from my youth and way back then they had a reputation for only wearing in the middle of the the as they were "triangle" shaped for better grip when banked over so that's why I initially went for the k70, but as you have confirmed the life I'm getting from the k70 I won't get any more of those. They are cr_p.
I'm pretty sure the tt100 of today is not the same as 40 years ago, and anyway come to think of it, the k70 is only wearing in the middle......so a tt100 cannot be any worse I guess *doubt*
Cycletreads may have the Avon road runner H in 410 x 19 at 229nzd, so it may come down the tt100 or Avon, but the tt100 is cheaper!
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Thats just under 5000 klms so about normal for a rear tyre. Good on you for wearing out so many tyres! *smile*
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Thats just under 5000 klms so about normal for a rear tyre. Good on you for wearing out so many tyres! *smile*
*problem* I was getting over 10,000km from rears on my Triumph street triple and that had over 100hp! Having said that I can understand Dunlop won't be making as many k70's as modern tyres, and they are much narrower tyres of course, and lower tech, so I can only expect 5000km from other so called classic tyres? There's nothing better than a k70?
Edit: to put this in perspective, the fuel cost of doing 3000 miles is circa 500 nzd, so I'm spending half as much on tyres as I do on fuel per mile covered *problem* *help* *dunno* *doubt*
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TT100, Avon SM, Avon Roadrunner, Avon Roadrider and just about anything else you can find, all last longer than K70.
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Dunlop make tyres in different countries with different compounds to suit the local climate.
The Japanes Dunlops just never wore, black concrete.
The French or Irish Dunlops were used by Historic racers because they were a lot softer & sticker compounds.
Now days what ends up down here is pot luck
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Good on you for wearing out so many tyres!
My thoughts also, at the moment my tyres crack up before wearing out
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I have a Avon Road Runner that I fitted circa '79- but it only did <2k miles still plenty tread but also a bit cracked, Michelin something on the front- same story but they still hold air fairly good.
Happy to say though that the Metzler Enduro 1 & 2 I now have on have done circa 9k miles and getting down a bit- reckon I'll get anther thou or so. Useless info to most though as they're 18 R & 21 F
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Good on you for wearing out so many tyres!
My thoughts also, at the moment my tyres crack up before wearing out
Yeah, you guys must be riding like maniacs.
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I have been using Mitas tyres for a number of years now with no problems, I have just been out and checked the tread depth on my A65 the tread depth is 4.6mm this tyre has done 3,200 miles. I have just fitted a brand new Mitas tyre to my A7 the tread depth is 5.4 mm. both measurements taken in the middle of the tread. I should add that the A65 tyre is on a 18" rim while the A7 is a 19" rim. I can't help but think that a good proportion of the cost for Dunlop and Avon tyres is you are paying for the name, I also do not ride either bike hard gave that up 50 years ago only costs money. These are both rear tyres.
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bikerbob, it is interesting to read your comments about Mitas tyres, because I have a brand new Mitas 19 x 3.50 sat in my garage that I bought because the tread appeared to be a rounder profile than the Avon SM MK 2 that I was using. I did not fit the Mitas tyre however, because it looked far to narrow to be a 3.50. In my opinion it looked to be more suited to Bantam or C11 than to its claimed suitability for an A10. In stead I opted to fit another SM MK2. Despite the derogatory remarks expressed by many people about SM's (skidmasters etc) I have never had any cause to worry about their grip or road holding abilities. Like you I no longer race about. I got that out of my system many years ago, but having said that I don't dawdle either, and the SM's in my experience feel perfectly safe and sure footed no matter how far over I lean.
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Hi a101960 Just been out into the garage to measure both tyres. The A65 is 3.50 X 18 but the A7 is 3.33 X 19 so is narrower but it looks OK but the tread patterns are different.
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is this now a tyre thread, like an oil thread but more rubbery?
because I like to pretend I'm still young and throw the bike around I'm very fond of my avon roadriders - nice round profile, sticky, predictable and track straight on the front, but the profile looks a little low on the front of the a10. a long life for me is more important than a long life for the tyre and i don't think they wear worse than any other comparable tyre. have them on the b33 too. i noted out at the classic racing meet recently that probably the majority of similar bikes had roadriders with melted sections on their sides from hard cornering. yum.
if i slowed down a bit or had to watch the $ i hear mitas do well on an a10, tho no personal experience.
interesting now i also have a modern how its wide profile tyres skip more when hitting cats-eyes and other road bumps, especially if leaned over. the a10 tracks much straighter under such circumstances.
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My mate (Paulo) finished building an A10 last year and fitted new K70's. He has done less than 3000 miles and the back tyre is nearly worn out. I use Avon SM's on my A10 and it handles fine and tyre wear is insignificant, though obviously I ride it quite conservatively. I've got TT100's on the RGS rep; I haven't used that bike for a while but I know that it is fine for grip and tyre wear.
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Thanks everyone, I've had to bite the bullet due to the need to get a tyre delivered in time for the bsa rally in a couple of days time *beer* *woo* , and I've bought a "Duro" HF308 in 3.5x19 (133 nzd).
Others experiencing a life of 3000 miles from the k70 made me rule out getting another one. The handling gets iffy well before that as the tyre squares off. It's not a "safe" option in my opinion.
In about 12 months I will be able to report on how the Duro wears (if I'm not beaten to it by another forum member), the Duro is very similar in look to the k70, at first I thought it was a copy.
If the Duro's grip is no good I will report sooner, hopefully not from a hospital bed *shh* *sick*
Just my 2 cents worth but I reckon every forum needs a "tyre thread" *smile* *fight* (as well as an oil thread), at the very least we should be able to get a consensus on tyres to be avoided *pull hair out*
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Kiwi I'll look out for you in 'the naki', and examine this new Duro you've bought. there's a bunch of us coming south from Auckland on Friday (safety in numbers - and more spare parts carried between many). the weather is looking good and should be a great rally *smile*
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Kiwi I'll look out for you in 'the naki', and examine this new Duro you've bought. there's a bunch of us coming south from Auckland on Friday (safety in numbers - and more spare parts carried between many). the weather is looking good and should be a great rally *smile*
I'll look out for you as well Mike, are you the clubs facebook group site? There are some details of where people are meeting up, but no meet up details for aucklanders yet. Try joining at https://www.facebook.com/groups/NZBSAMOC (sorry non kiwis, group is for nz club members only).
It's looking so good weather wise I'm thinking of travelling real light and not being prepared for poor weather, however last time I tried that I arrived at the kaiapoi rally site totally drenched and suffering from hypothermia.........darn those weather forecasters *bash*
Back to tyres, the Duro has 5/16" of thread versus the k70 1/4", so it's has a third more usable thread and costs almost 2/3 of the k70 (I actually paid more like 110nz for it). I'm pretty certain it should be cheaper than that looking at what they go for in the USA.
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[quote author=KiwiGF
Just my 2 cents worth but I reckon every forum needs a "tyre thread" *smile* *fight*
Yes, good idea *smile*
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Getting off topic, but re this week end the northerners (from Drury to Whangarei at last check) have a starting place and time organised, anyone who missed the last clubnight and needs filling in send me a pm. *wink2*
I put tt100's on my super rocket but in hindsight don't think they suit the bike and would go for something else with a traditional pattern, but odds not a K70.
See you in Inglewood Friday arvo fellow kiwi riders
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A bit more info on this topic I started.
Well today I fiitted a “duro” brand tyre to my b31 (rigid) in preparation for a round trip of around 800 miles to the nz bsa National Rally next week. This replaced a worn k70.
The k70 was the (new) tyre I fitted during building the b31 basketcase up from parts, and registering the bike for the road not much more than a year ago. It was embarrassing that the WOF (MOT equivalent for you Brits) tester pointed the worn tyre to me before passing it as “marginal” but good enough, it had not even occurred to me to check the tread depth after so few miles. It looked ok but using a depth guage told a different story.
The Dunlop k70 has only lasted about 2000miles before being down to 1mm in the centre in some places, a bit under 2mm in others, and would have been bald by the time I got back home from this years rally. The tread on the edges is hardly worn so maybe I’m not the “scratcher” I thought I was eh.
About the only positive thing to come out of this was how easy it is to remove a tyre that is still soft and flexible which of course it should be, being not much more than a year old. Even the fitment lube was still there and not dried up. I only needed to use one tyre lever to get it off.
What a rubbish tyre life that is. I won’t be buying another Dunlop k70 *conf*
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Almost any tyre lasts longer than a rear K70.
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As with most things in engineering, there's a compromise to be made. Softer rubber will wear quicker that harder rubber, so one has to decide - do you want grip or long tyre life? I always used K70 for hillclimbing, as it outgripped the so-called racing tyres. Just another thought, if the centre is wearing badly, tyre pressures may need to be dropped, not raised. I run 18 - 20 on the back of my (rigid) M21 and 20 - 25 on my other (non lightweight) classics.
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I found K70's gave poor grip, wet or dry. I had some bum-nipping slides on dry roundabouts with them. My last one wore out in 1200 miles. Avon SM MkIIs are superior in every respect.
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Just replaced a K70 on a Notrun this afternoon - it did just on 3K miles on a 650SS and was well dead. TT100 on both ends now, and we'll see.
Avon Roadriders are nice but look a bit funny to me on oldies. Had them on a café-racer and they were pretty good on the bendy bits, but out of place maybe on most classics in more standard trim.
SMs on a couple of all-year workhorses have done pretty well, and I also find they handle OK with my fat backside holding things down. On the A I was getting about 5-6K miles on rears - a TT100 on there now is half worn at about 1800 miles though.
A tyre I do like is the Pirelli Scorpion for rims that will take one - that's not 19" wheels I think. A similar-ish 19 inch Pirelli MT-something is OK too - but short life is guaranteed on the bike I have these things on (P11 desert sled). And the look of them isn't exactly period either. I think Ducati fit them on their Scramblers, or did, and they're pretty OK on the road (how many of those bikes ever go off it, for that matter?)
I'm going to stick with TT100s for the time being on the A, the Notrun and one AMC twin, having bought a car-bootload last time I passed Vintage Tyres in the UK. Pirellis for the P, and SMs on 2 others for economy reasons. Haven't tried Mitas - but a lot of friends like them, price-wise they're good and they seem to last pretty well. I rode a pre-unit Triumph with them on and it seemed fine - but it was a bike I'd done the engine on for someone else, not mine, so didn't explore the limits.
No risk of tyres cracking up or going out of date before wearing out round here, so I suppose that's something! But if there is one job I just don't like these days, it's tyre fitting . . . Is it the compounds, or what? Used to be able to get new ones on without levers almost every time - but not nowadays. Feeble with age? Or they're made of less forgiving stuff maybe.
While I'm on, since having a blow-out on the A a couple of years ago on a dual carriageway, I now only fit Michelin 4mm thick inner tubes, for scrambles I believe, to everything in the shed. And I always replace them with each tyre change, plus new rim tape. Bloody difficult sometimes to get them into front tyres - but no more problems with sudden deflation and/or valves ripping out on some of the tubes I've had in recent years (from god knows where probably). Could have killed me when the rear SM went on the A - glanced off central armco barrier and then off a concrete near-side barrier while getting the thing under semi-control with the tyre blown clean off the rim and the back hanging out 45° from straight. The extra cost of the heavy-duty tubes is worth it - and a hell of a lot less than the new rim, spokes, tyre etc etc that I had to sort after that incident.
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Hi Bill and All,
Totally agree about using quality tubes
I had a big bang experience on a Morini
In 2001, *eek* that put some age on me *ex*
Do you or your friends have any experience of the "own brand" tyres sold by
"Chambier" over there in France?
Apparently made using the Michelin moulds ???
Prices arevery keen too *smile*
John
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Hi John,
Hmm . . . but No, I have no real knowledge. Tyres for 25 bucks don't seem too bad though.
Maybe just the ticket for machines that need something period, and aren't going to be hammered . . . dunno.
Chambrier 'père & fils' are well-known here, and travel the land with a posh articulated truck full of bits and pieces, selling at autojumbles all over the place.
To be honest, I think I'd tend to stick with known-brands for most things. I don't have any bikes that just 'need something to keep the rims off the tar' so they can be set in motion for, eg, exhibition purposes and gentle strolls.
Most of the road-going locals looking for 'best value' seem to go for the the Mitas. Quite a few SMs, TT100s etc etc too though- and Vintage Tyres have a French service. If you ring them from here, they answer the phone in French, and they will ship any order over £100 for free I discovered, having turn up in person to buy a year's worth!
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G'day Fellas.
I still love the RoadRiders. Their not cheap and don't last long and don't look period but I'd rather have skin on my butt than money in my wallet.
Why is it I can put 4 tyres on the ute for less $$$ than two on the bike?
Cheers
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Don't forget security bolts. If you get a blowout, they keep the tyre on the rim.
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roadriders for me too on the A and B. sticky, good on the twisties and last a lot longer than your K70. the profile is a bit low tho.
A similar-ish 19 inch Pirelli MT-something...
that's the MT60 on ducati scramblers. i took them off the scrambler i had as they were squishy at the front under heavy braking and could slip at rear when applying wrist out of a bend. they are also very wide so i'd be surprised if they fit our rims
Kiwi I think the real problem is the amount of wrist you use and the awesome power of the B31 ;)
And Musky the tyres on your ute are probably made of wood, and not made in europe
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Thanks Mike, MT60 yup.
Heavy braking potential just isn't something you get with a sls Matchless-wheeled P11, so no worries there! But the tyres fit easily on the rims and between forks and s/arm (with the correct guards), no worries there either - and I have found them better than what I had before.
Not a rational choice for an A though I don't think, except maybe on the Spitfire Scrambler types.
(With security bolts in this case!) But most rims aren't drilled for them are they? Maybe they all should be . . . .?
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You have to be careful with Dunlop tyres.
They are made in several different countries using the same tread pattern but different compounds.
The ones from Japan fitted as new bike tyres are fairly hard & give excellent wear.
The ones made in France or Ireland got used by the classic racers cause they stick to the track but are scrubbed bald after a single meeting.
When Scott's had the tyre shop in Goulburn St I used to get them to put aside the Dunlops that new owners wanted changed & we bought all of them for the courier fleet.
The trouble now days is most bike shops have no idea what tyres they are fitting apart from what is written on the side walls.
It pays yo go to a specialist motorcycle tyre shop and not your local parts supermarket.
The story with Bridgestone battle axe was the same.The ones fitted as OEm wore really well & gripped OK.
The ones bought as tyres wore the center tread down to the legal limit in a couple of months if you were lucky and just below if you were not.
It would not move from this for a full 6 months of courier riding and when pulled over for a safety check usually you could bluff your way out of it.
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I imagine I’ll probably be sent straight to Coventry for this but I have Dunlop Gold Seal K70s front and back on my 1960 Golden Flash and (as yet) I can’t complain. The tyres were on the bike when purchased over 2 years ago and looked reasonably new and unworn. I’ve covered 1,400 on them and I can’t see signs of excessive wear on either front or rear (see photo taken recently).
Maybe it’s down to style of riding but since having them on my A10 the important thing I have learned is that they do not tolerate either under or over inflation. We know that excessive over inflation will cause the centre to wear more than the edges and excessive under inflation will cause the edges to wear more than the centre and that under inflation also results in cupping.
The other important aspects are: Over inflation will produce a smaller contact patch with the road surface with the resulting less grip and a harsher ride. On the other hand under inflation will increase the contact patch but will cause the tyre to flex too much producing skittishness and too much heat, which will likely damage the tyre’s structure.
Also very important and sometimes overlooked is that tyre pressures need to be worked out according to the individual load being carried and within the limits of the maximum load and psi stated on the tyre wall and the way to do that accurately.
This is what Dunlop replied to one of my email to them last year when querying my K70 pressures:-
The K70s manufactured today uses modern materials e.g. compound etc. but the internal casing remains a crossply construction and as they are designed for older classic bikes their design takes into account the pressures used at the time.
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In fairness, the one I wore out in 1200 miles was on a Highland tour with my modern-mounted sons, not hanging about. I still wouldn't have another K70 though.
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This is what Dunlop replied to one of my email to them last year when querying my K70 pressures:-
The K70s manufactured today uses modern materials e.g. compound etc. but the internal casing remains a crossply construction and as they are designed for older classic bikes their design takes into account the pressures used at the time
They hardly ever say suchlike as “We’re selling quick-wear tyres for a laugh!”
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My SR came with new Avons front and back but when they are worn out I'll put Mitas tyres on. Loved them on my B44. They are a soft compound so stick well to the road and are cheap enough that I can replace them without a mortgage. The only pity is they make a lovely 18" front tyre with a beaded tread but at 19 you have only a block tread version.
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My SR came with new Avons front and back but when they are worn out I'll put Mitas tyres on. Loved them on my B44. They are a soft compound so stick well to the road and are cheap enough that I can replace them without a mortgage. The only pity is they make a lovely 18" front tyre with a beaded tread but at 19 you have only a block tread version.
Where do you get your Mitas tyres and how much? I’ve only got a requirement for 19” so far, but have got a 21” front rim for my b31 when I finally get around to spoking it. In a search for something better than k70s i bought rears of “Duro” brand from classic tyres of Tauranga, but they are not the easiest to deal with.
Note: re other posts on tyres, we don’t have much choice or availability of the “main” brands in nz eg Avon etc.
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Dold Industries in Te Rapa are the agents so a look at their website might give you a local provider.
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I recently fitted a set of avon SM mk2's to my vincent (as pretty much all thats available in a 20" front), I've been really impressed with them both , they are made in modern compounds and grip very well and did some good hard work for me without showing any evident wear. Speeds greater than my B33 is even capable of under its own steam... I'll be looking to fit equivalent rubber to my road rocket and the B33 in due course.
just my 10c worth
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G'day RR.
Not much lean angle on them. Your too used to riding bolt upright LOL.
Cheers
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So you may think. You can get plenty of lean on these Avons. You need a fistful of throttle when scraping a footrest to make them drift.
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You need a fistful of throttle when scraping a footrest to make them drift.
What kind of tread have you got on the footrest then *smile*
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Slicks of course! *smile*
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With my B33 and A65 I typically find the mufflers and pegs are the limiting factor, not the tyres. On a race pegged bike a different story, but on the vin we did some real twisty roads and fast sweepers and the tyres tread pattern wasnt the limiting factor.
Yes appreciate I normally ride with a training wheel on my race a10 but I do enjoy spirited road riding and think you'll find if you lean the bike until its run out of ground clearance (laden with a rider) there is still tread on the deck. Nothing wrong with predictable slides...
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I do enjoy spirited road riding
yes i can attest to that RR - recalling one ride where the only way to keep following you on your B33 was to follow the oil smoke behind you, and you were two up *eek*