Dunlop tyres

Peter Mac · Post by **Peter Mac** » Sun Sep 16, 2012 2:20 pm

Does anybody know were i can buy a set of gold seal tyres for my 70 h1 ... Z power dont list them anymore

BIG H · Post by **BIG H** » Sun Sep 16, 2012 5:22 pm

Google & ebay search?

http://www.rgmmotors.co.uk/items.asp?ca ... er%20Tubes

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Peter Mac · Post by **Peter Mac** » Sun Sep 16, 2012 6:00 pm

Tried google but does'nt seem to find k87 or f11 are these tyres na & what are people using instead for the oe look ?

Peter Mac · Post by **Peter Mac** » Sun Sep 16, 2012 6:42 pm

Looks like k70's are the ones but they list them for lightweight bikes & i'd class the 500 as a middleweight...I guess the other option is tt100 's but the rear is a wider than stock.... Whats people's opinion on these ?

robh1f · Post by **robh1f** » Sun Sep 16, 2012 7:25 pm

Pete there are period looking tyres out there and there was a post about them some time back AND they were cheap to boot .......I'll do a bit of sniffin later

BIG H · Post by **BIG H** » Sun Sep 16, 2012 8:54 pm

`g6mow` is showing some classic style tyres on his site made by `KINGS`.

http://www.kawasakitripleparts.com/inde ... =55&page=1

.

g6mow · Post by **g6mow** » Sun Sep 16, 2012 9:02 pm

I can also supply TT100 and K70 and most other types, except the Gold Seals

Peter Mac · Post by **Peter Mac** » Sun Sep 16, 2012 9:08 pm

Cool simon, i'll call you in the week... Are gold seals no longer made ?

Cheers rob if you can find the thread

BIG H · Post by **BIG H** » Sun Sep 16, 2012 9:18 pm

Some vintage style tyres here.

http://www.heidenautires.com/vintage-motorcycle-tires

http://www.reifenwerk-heidenau.de/?lang=en

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robh1f · Post by **robh1f** » Sun Sep 16, 2012 10:04 pm

I've looked mate and came up with Cheng Shin aka Maxxis who do a period looking back tyre 4.00x18 @ £44.00 but not 3.25x19 for front ........they do a ribbed one for that............I want K87s for the 69

. Let us know what you go with ,the k70s look good and its not as if its gonna get ridden at 100mph + everywhere..............or is it

Eric · Post by **Eric** » Sun Sep 16, 2012 10:35 pm

I have TT100`s on mine now and they do the job OK and back in 71 that`s what I had on it then and you ain`t going to ride it as hard as I did back then.

g6mow · Post by **g6mow** » Mon Sep 17, 2012 12:11 am

Bargain

malc87 · Post by **malc87** » Mon Sep 17, 2012 7:16 am

Ive got a NOS one of those Dunlops (F6B) and a NOS matching rear

Clive · Post by **Clive** » Mon Sep 17, 2012 8:28 am

I'm sure Z Power sell a new K87 for the rear and here's a link for a good used front K77.

http://www.ebay.com/itm/Kawasaki-H1-Use ... 4607d6531a

BrynP · Post by **BrynP** » Mon Sep 17, 2012 8:59 am

Dunlop Europe, and therefore Dunlop UK doesn't import the OE-spec F11 and K87 in classic sizes. Any you see for sale in the UK are as a result of dealers importing them independently.
When I was at Dunlop I made enquiries about several sizes that dealers had requested, only to be told by Dunlop Japan that they were not E-marked so not available to us. (Tyres have to be E-marked to be legal for sale for road use over here). I'm not saying this is the case with these two sizes but it would always be worth asking the supplying dealer.
Dunlop would also argue that the demand for these sizes is limited and they already have the K81 TT100 and K70 in their range for the classic market.
By the way, the K70 range carries different speed ratings dependent on size. The 3.25-19 and 3.50-19 are P speed rated, i.e. up to 93mph. The 4.00-18 rear is S rated, which is 112mph.
Sorry to drone on but it's also worth pointing out that the 19 inch K70s are actually intended for rear wheel use only (common Brit bike sizes) but many people also fit them on front wheels and even Dunlop supplied them to Triumph in the 1970s for front wheel fitment on T120s and T140s.
K81 TT100s are H speed rated for speeds up to 130mph so are a better bet for the 500 and 750. They also qualify as being "period" because they were launched in 1969.
The only thing that confuses people with the K81 TT100 are the sizes. This is because they are 90% aspect ratio imperial-sized tyres; a form of sizing that was fairly short-lived. The equivalents of 3.25-19 and 4.00-18 are 3.60-19 and 4.25/85-18 respectively.
I won't go into how this came about because I'm sure you all have better things to do with your lives!

Neil the Don · Post by **Neil the Don** » Mon Sep 17, 2012 12:50 pm

No, we don`t............................................

SAM · Post by **SAM** » Mon Sep 17, 2012 4:15 pm

Yes i was just getting excited!

BrynP · Post by **BrynP** » Mon Sep 17, 2012 7:07 pm

Crikey, you guys must live sheltered lives. I thought I was the only one who found tyres gripping. Sorry

, I had to get that one in.

Okay, but don?t blame me if you get bored!

During the '60s the tyre manufacturers were searching for ways to improve grip levels without sacrificing mileage. Nothing changes, huh?

The obvious way is to increase a tyre's width in order to increase contact patch size, after all, without changing the compound a bigger contact patch will give more grip.

The problem was that at the time all motorcycle tyres were imperial sized, e.g. 4.00-18, and tyres of this type are just as tall (from base of bead to top of crown) as they are wide.

So if you then make a 4.50-18 tyre it's going to be 4.50 inches tall. This has obvious implications for tyre clearance on full suspension compression. Sure, bike manufacturers can design bikes around ever taller tyres but there comes a point when a bike's performance would be compromised.

The other problem is that a 4.50-18 tyre would consist of a larger amount of material, which would increase cost and weight, adversely affecting handling and suspension response.

So the solution that Dunlop came up with was to design a tyre that was 90% as high as it was wide. This allowed them to increase a tyre?s width, and hence contact patch size, without increasing the tyre?s height. It also meant they could keep the cost and weight of extra materials down to a minimum.

To illustrate this let?s look at the common 3.50-18 size: the new-for-the-late-?60s ?90% Imperial? equivalent of 3.50-18 became 4.10-18, i.e. 4.10 inches wide with a height that is 90% of this width, or in other words 3.69 inches high. Okay, so a tyre that?s 3.69 inches tall isn?t exactly 3.50 inches but it?s so close that no one would notice.

These new sizes became what was commonly called ?low profile?. Although the word ?profile? actually refers to the curvature of the tread surface. The term ?lower aspect ratio? would be more correct. (More on aspect ratios in a moment).

So in the case of the 4.10-18 they now had a tyre that had roughly the same contact patch size as a 4.00-18 but the ride height of a 3.50-18. S2/S3 and KH250/400 riders in the 1970s rejoiced!

Other common sizes at the time were 3.10 (roughly the same as 2.75 inches), 3.60 (roughly 3.25) and 4.60 (roughly 4.00). So H1/H2 riders had cause for celebration as well.

The 4.25/85-18 Dunlop TT100 is a bit of a size anomaly in that it doesn?t really fit into traditional Imperial sizes or 90% Imperial sizes. It?s equivalent to a 4.00-18 and it?s in a size category of its own.

At this point I need to explain what an aspect ratio is. For those that already know, please excuse me but it?s worth explaining what it means for those that have never really been interested in tyres.

A tyre?s aspect ratio is the tyre?s height (from bead to crown) expressed as a percentage of its width. This is not something that we need to worry about with the ?90% Imperial? sizes talked about above. In those cases we just have to accept that they have a 90% aspect ratio. But aspect ratios play an important role in the way tyres sizes started to be expressed in the late ?70s.

What happened as the ?70s came to and end was the arrival in motorcycling of the Metric system of tyre sizing.

Let?s use 120/90-18 as an example. Expressing a tyre?s width inches became sooo last year.

120 referred to the tyre?s width being 120mm. And the tyre?s height was now included in the size; the number 90 meaning that the tyre was 90% as high as it was wide, or in this tyre?s case 108mm.

Of course, the metric take-over only went so far. Because imperial rim diameters were so well established they?re still expressed in inches.

This sexy new metric size system stopped the fledgling ?90% Imperial? system before it really got started and these days only one of the sizes, 4.10-18 is still in use on new small trail bikes and even that?s dying off slowly.

Sure, you can still buy tyres in these sizes, but they?re mostly tyres aimed at the classic bike and trail bike markets.

I?ve never managed to get to the bottom of why the tyre?s lower aspect ratio wasn?t included in the tyre?s size, even after research with some of the original designers of the TT100. I guess that at the time they were playing with something so new and didn?t think about where things would go next. You also have to wonder how they would have expressed the sizes of the lower aspect ratio tyres that came along in the early ?80s. It?s a good job that metric sizing arrived on the scene when it did.

Peter Mac · Post by **Peter Mac** » Mon Sep 17, 2012 7:10 pm

Thanks for that bryn, thats interesting about the E mark did'nt know about that ! I'm very tempted by the tt100's as they are period & this bike is a restoration so i want to get it as close to original spec as possible . Anybody know what tyre came on the euro h1's if it was'nt k87/ f11 combo ?

robh1f · Post by **robh1f** » Mon Sep 17, 2012 9:22 pm

After reading Bryns "very"

informative reply I did a bit of sniffin and reckon 69 bikes had k77s both ends and 70-72 (h1b) had k87s both ends . H1d and up had 87 on back and the ribbed f6? on the front............Bryn $64000 question , do you know of a dealer stocking k87s over here?? Johnny Bova in the US has rear ones at around £170

each plus shipping

If not I'll go the TT 100 route

BIG H · Post by **BIG H** » Mon Sep 17, 2012 9:50 pm

I see DOREMI in japan do the tyres you want.
I estimate a pair will cost about £370 including shipping & import tax.

http://server44.joeswebhosting.net/~do2 ... ts_id=1046

http://server44.joeswebhosting.net/~do2 ... ts_id=1049

On ebay usa.

http://www.ebay.com/itm/Dunlop-Gold-Sea ... 4f&vxp=mtr

Peter Mac · Post by **Peter Mac** » Mon Sep 17, 2012 10:18 pm

Some great info guys & thanks for all the replys....i think the tt100's are gonna be the ones as they are period/performance correct & sensible price to boot ! thanks bryn for the sizing info......