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flh_bubba

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Greetings,
I am close to getting my 1975 XS650B back on the road, the next thing on the agenda are tires. I currently have a set of 40 year old Dunlop K81 TT100 (4.10 H 19 on front and 4.25/85 H 18 on the rear). I like the aggressive tread pattern and when I originally purchased these I went a size wider. These tires are still available from Dunlop, and I am thinking of going the same route with replacements. I was just wondering what tires and what size other folks are putting on their rides. What are your views about the over sized tires?
Thanks for your input.
 
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I’m running (edited) K70’s on my XS2, because I wanted a vintage tread design, stock sizes.
DA9ACA88-ECC2-4A29-97C1-95B887361E71.jpeg


On my ‘77D. I’m running Michelin Pilot Active , a modern tread design that handles really well. Stock sizes.
83D1890F-5E51-4243-BFBD-973F56DA79E4.jpeg
 
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Mailman, those are K70s on your XS2.

I'm not a fan of over-sized tires on these. They slow down the steering and handling. I like to stick to the original sizes. This is only about a 50HP bike. It doesn't need big fat tires on it. The stock sizes work fine. I use the modern metric equivalents to the original inch sizes, a 100 on the front and a 110 on the (18") rear.
 
flh_bubba said:
Greetings,
I am close to getting my 1975 XS650B back on the road, the next thing on the agenda are tires. I currently have a set of 40 year old Dunlop K81 TT100 (4.10 H 19 on front and 4.25/85 H 18 on the rear). I like the aggressive tread pattern and when I originally purchased these I went a size wider. These tires are still available from Dunlop, and I am thinking of going the same route with replacements. I was just wondering what tires and what size other folks are putting on their rides. What are your views about the over sized tires?
Thanks for your input.
Click to expand...

Hi bubba,
my view on oversize XS650 tires is that, depending on their make, they may not
clear the forks or the frame and a fatter than 130 rear tire will rub against the chain.
Why not a 130/90-18 rear if the Special's stock 130/90-16 rear works?
OK but add some links to the chain to allow pulling that larger OD tire back from
the swingarm's narrow frontal rubbing zone.
 
flh_bubba said:
I currently have a set of 40 year old Dunlop K81 TT100 (4.10 H 19 on front and 4.25/85 H 18 on the rear). I like the aggressive tread pattern
Click to expand...
Bubba, K81”tt100’s” were a long time favorite of mine. Having put two sets on these Standard XSs I hope to contribute to your tire decisions.
K81’s in the US are becoming difficult to even find. Sizes are limited to the 4.10-19 front and also a 4.10-18 rear.
(Norton style set)
That 4.25/85-18 rear was a descent choice however I wasn’t able to locate one recently. That and the fact that the old size 3.60-19 front has not been found by me for a long time. Bike shops/sites all try to push the K70 front with the K81 rear. Lack of convenience so I’ve thrown in the towel on K81’s
I as well discourage “oversize” tires now. I rode a 77 for awhile and experienced that.
The K81 tt100 tires, 4.10 front and 4.25 rear that are on your bike are not really very “oversized” because those tt100s tend to be smaller than other brands, especially the rear.
I have pondered tire sizes for a while now being that I am also swaying away from K81 tt100s .
I strongly encourage you to consider stock tire sizes as well.
100/90-19 or 3.25-19 front
110/90-18 or 4.00-18 rear
The Dennis Kirk tire web site has comparison “inflated dimensions” as well as weight for many tire choices and is a great site to gather info for your decision.
-RT
 

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One pitfall of going too wide is that it 'squeezes' the tire narrower. This changes the shape of the tire and causes the bike to 'fall over' in corners due to the ovalized shape.

That said, I am running shinko 705 110/90-19 front, 120/80-18 rear. And I love them.
 
I’m running a Dunlop D404 130/90-16 Rear Tire and a 110/90-19 Front Tire. I installed them a few months back and so far I really like them.

A6084B13-F691-4522-BE91-6CDBAFE38959.jpeg
 
:agree: stock or close metric equivelent size. Unless you change to wider rims. Old, 60's 70's tire specs for rim widths were REALLY too narrow, wobbly to start with, by any modern standard. Those old inch sized tires are very tall compared to their width. Going to even fatter tires is noticelably detrimental to handling. Though bad steering bearings and or swingarm bushings will be noticed more. Guys poo poo wider tires on these "low powered" bikes BUT low profile tires on wider rims do offer a better handling package, especially if you like to go round corners at a sporting pace. If you are straight line type of rider anything that doesn't rub will be "fine"
This gives an idea of more current rim tire width matching. shows both inch and metric tire sizes
You can see how narrow the stock rims are.
Dearly departed resto worked well onthe pilot activ's but was one size up on rim widths. front and rear. (1.85 to 2.15 and 2.15 to 2.50
Madness with a 110 70 front on a 3.50 rim and 120/70 rear on a 3.50 has noticably better cornering manners. Lots of other changes typically are made when changing tire rim changes so it is not ALL tire sizes.
Motorcycle-Rim-WidthTire-Size-Chart-by-MTSAC.edu-2.jpg
 
Machine said:
Bubba, K81”tt100’s” were a long time favorite of mine. Having put two sets on these Standard XSs I hope to contribute to your tire decisions.
K81’s in the US are becoming difficult to even find. Sizes are limited to the 4.10-19 front and also a 4.10-18 rear.
(Norton style set)

-RT
Click to expand...
I was going to reply that I had no problem getting a set, then I realized that they were for my Norton. :)
 
Wider tires are fine if you have the rims for it. I have a 120/70-17 on the front with a 3.5" wide rim and a 150/70-17 on a 4.25" rim in the back. 520 chain, no offset on the sprocket and the chain doesn't rub the tire. Like shotgunjoe I'm running the shinko 705s.
 
Clean looking “roadster” nice pics !
A small custom chain guard or oil sling guard might be cool on there too if you wanted to keep your chain oiled ?
Thx, Peter g
 
Thanks. Cleaning up the original chain guard and installing it is on my to do list. I hadn’t thought about keeping the chain oiled. Putting the guard back on is more to do with keeping my back not oiled!
 
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Thank you all for your replies, I think I have it narrowed my search down to three tires and would like to get your impressions of my choices and the sizes I have picked out. I am looking at the Michelin Pilot Activ (Front 100/90 - 19, Rear 4.00 - 18), Dunlop K70 (Front 3.50 - 19, Rear 4.00 - 18), and the Shimko 712 (front 100/90 - 19, Rear 110/90 - 18). Are the metric sizes correct for my bike? It originally came with 3.50 -19 front, 400 -18 rear. Since I am the original owner of this bike, by riding style has tamed down over the years.
Thanks again for your help.
 

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