Author Topic: Dunlop K81 Tires.  (Read 1435 times)

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Offline BenelliSEI

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Dunlop K81 Tires.
« on: February 09, 2020, 04:55:38 PM »
My Rickman CR Hondacb750 project bike has 18” wheels, front and rear. Considering mounting a set of Dunlop K81’s. Anyone using them? Results?
« Last Edit: February 09, 2020, 05:03:46 PM by BenelliSEI »

Offline seanbarney41

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Re: Dunlop K81 Tires.
« Reply #1 on: February 09, 2020, 05:27:16 PM »
...such a good looking tire, and totally period correct.  Sticky rubber, but man they get scary when squared off, and they square off fassst. 

Has been many years since I used them, I am tempted to try again.
If it works good, it looks good...

Offline HondaMan

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Re: Dunlop K81 Tires.
« Reply #2 on: February 09, 2020, 06:05:55 PM »
Are they true trigonometrics, now, or just the ones with the trigo-looking tread on the normal round metric profile?
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Offline BenelliSEI

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Re: Dunlop K81 Tires.
« Reply #3 on: February 09, 2020, 07:35:44 PM »
Likely the latter, but they look so good/right, I probably will.

Offline Bodi

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Re: Dunlop K81 Tires.
« Reply #4 on: February 10, 2020, 08:33:37 AM »
I used them a lot in the 70s and 80s, the "real" ones. The trigonic profile gave more contact area in cornering but they were not good for mostly highway riding as the somewhat pointy profile would wear flat at the centre and then the transition to mild cornering would get strange.
Other than the period look they are no longer competitive, even from the limited selection of 18" tires now there are superior alternatives.

Offline ekpent

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Re: Dunlop K81 Tires.
« Reply #5 on: February 10, 2020, 08:39:32 AM »
 This is 19" front tires but it was not rare 'back in the day' I think for guys to put big Dunlop 4.10's on the front. I have bought two bikes in the past with those and when they are very old, like most tires, can be real fun to get off.

Offline bryanj

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Re: Dunlop K81 Tires.
« Reply #6 on: February 10, 2020, 08:58:56 AM »
Plus the rears dont last very long
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Offline BenelliSEI

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Re: Dunlop K81 Tires.
« Reply #7 on: February 10, 2020, 09:42:12 AM »
Thanks for all his, I may consider other options. I need a fairly narrow front (18”) to fit inside the fork legs and clear the ‘glass fender. Suggestions?

Offline PeWe

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Re: Dunlop K81 Tires.
« Reply #8 on: February 11, 2020, 10:05:01 AM »
Heidenau?
K44  front, size 90/90-18
https://www.heidenautires.com/product/k-44/

Also as race version
https://www.heidenautires.com/tires/motorcycle/race/

Both my CB750 have K44 in stock size, 3.25-19, Vintage model.
K36 rear 4.0-18.
https://www.heidenautires.com/product/k-36/

I have not raced them only street use.  Feels good. My previous tires have been  Dunlop StreetSmart, Metzeler Laser Tec.

Both tires have the old good old look as old Metzeler or Continental.

I'll continue with these in stock size.
Earlier as wide as possible making front wheel extra tricky to remove and back on again with 3.50- 19
Rear 120-18 that flattened out early and bad handling at around  35.000km. Remove chain guard with wider rear needed some extra brutal method, especially with 130-18.
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CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
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http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
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http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
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http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline BenelliSEI

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Re: Dunlop K81 Tires.
« Reply #9 on: February 11, 2020, 12:50:35 PM »
PeWe........ I like them! Having difficulty finding the K36 3.50 X 18 in Canada, but may order from the US. I need to keep the OA tire width under 4” for fender clearance at the front........ THANKS!

Offline HondaMan

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Re: Dunlop K81 Tires.
« Reply #10 on: February 11, 2020, 06:33:44 PM »
Yeah, the front in [true] K81/TT100 had to be the 4.10x19 (same size as the 3.25x19) and the rear had to be the 5.10x18 (slightly larger than the 4.00x18), and the tire pressure had to be almost 40 PSI front and rear. Most of the bikes I saw with these tires were trying to run the tire pressures for the standard tires, big mistake! That made them wear out, quick. I got over 40,000 miles from my front K81. My rear ones were bested by the [early] Roadrunner, back when it had a vee profile (1980-1997). After that the Roadrunner changed completely (to something I don't like) and the metric profiles took over.
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com