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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: pinhead on January 09, 2016, 03:09:02 AM
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I bought a 1985 bmw krt 100 just about a year ago. It had worn tires so I replaced both front and rear with Metzlers. Now I have enjoyed the heck of this bike traveling throughout Northern California, Oregon and Nevada this past year. I have been doing my winter service on this bike and when I checked the tires I was amazed that I have more than 50% wear on the rear. I don't think I have driven more than 7000 miles since the new ones were installed. Is that correct? What is the correct inflation pressure for this bike? I believe I inflated them to the manual (still have the original manual) specs. center tread is worn the worst.
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Pinhead I wish I would get that sort of mileage out of my tyres. I only got 10,000 Kilometres that's 6000 miles right down to the wear indicator, Bridgestone BT45s. I am now trying Michelin Pilot Activs. If you are doing a lot of highway mileage it is normal to wear down the centre of the tyre. I am currently running 36 PSI front 38 PSI rear. Some riders go by the maximum tyre pressure stamped into the side of the tyre should be about 40PSI. As far as tyres go Shinko 712 seems to be the new flavor, read a lot of good things about them really cheap and good grip.
Regards Martin
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I would say you are doing good.
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What type of Metzlers?
You're doing good though. Most all of my mileage is highway at 75-80 mph and a rear Shinko 712 lasts about 6k miles. I could run it a little longer but I ride in rain so I try to leave a little bit of tread on them
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I'm just past 17,000 km (10,500 miles) on a set of Sport Demons and into the wear bar.
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that is a little disheartening for me.
Now don't get me wrong, I like the bike.
But I have 3 RD 350s (old yamaha) that I run the heck out of too. and they have yet to wear out a set of tires.
I spent $300 for those tires and I thought I was getting automotive longevity in a tire. I guess not.
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What is the mileage on those RD tires, pinhead? Motorcycle tires don't give automotive mileage because the softer compounds in them made to provide traction wear much faster. My bike's Lasertecs get 6K–8K miles riding on gravel 30% of the time so it seems to me your results are typical for them.
I inflate them according to the K's manual specs. That's what Metzeler recommends. I'm not averse to trying Kendas or Shinkos to reduce cost significantly but I like how the Metzelers perform on wet roads for me.
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I have never seen motorcycle tires last like car tires.
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Although I haven't researched it I figure the weight of the bike/rider/luggage, wind resistance, speed, inflation pressure, and road surface all influence tire longevity
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They could make tyres that last as long as car tyres, but you wouldn't want to use them. Wear is inversely proportionate to grip, and riders want grip as well as mileage it is a balancing act .You can't have your cake and eat it to. More mileage equals less grip.
Regards Martin.
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My K75 when new in 1990 came with Perrelli tires. Man did it handle great in the curves mountain roads. But rear tire lasted as I recall 3,500 miles. Avons went on next to say get more mileage!
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They could make tyres that last as long as car tyres, but you wouldn't want to use them. Wear is inversely proportionate to grip, and riders want grip as well as mileage it is a balancing act .You can't have your cake and eat it to. More mileage equals less grip.
Regards Martin.
what martin said!
i am also lucky if i get 10k miles on my street car tires. i like grip, not concerned with how many 10's of thousands of miles they could last. i buy tires accordingly.
and then there are the tires on my race cars that may last 200 miles....
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ask Johnny on fitting a car tior
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im running car tiors off an early model convertable superbeatle right now...
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Car tiors!? Heck I'm looking for wheelbarrow tiors that will fit my bricks. I gots a wheelbarrow that's 35 years old, and that tior is still like new!!!
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that is a little disheartening for me.
Now don't get me wrong, I like the bike.
But I have 3 RD 350s (old yamaha) that I run the heck out of too. and they have yet to wear out a set of tires.
I spent $300 for those tires and I thought I was getting automotive longevity in a tire. I guess not.
I am getting up to 10,000 miles on the BT 45 but use the bike so much I use 2 sets a year. I am only 165 pounds/74 kg without bike gear and its an 84 K100RT. I found about 38 psi in front and about 42 in rear for solo riding works well.
The BT45 [110/90/18 and 140/80/17 rear] is a great tyre for our winter riding when its gets cold and wet [typically about 40-50F or 5-10C ] but I suspect wear rate increases considerably in hotter weather. However if you have tried wet weather riding after a dry spell in hot weather when roads are greasy they are still good. Its a trade off between grip and wear rate and as far as I am concerned the grip and wet riding confidence is second to none. In France in 35c I found both tyres were much hotter than usual due to the heat and that must increase wear. My friend who also has a K uses Pilot Road 3 and was getting much same mileage.
However going back many years when I had a Honda CB 500-4 and many of my friends were on the RD350 I could use a rear tyre in 3 weeks and the RD 350 my friends rode would eat them just as fast too. Might have been the spirited riding of the time but none of the tyres from that era compare with the modern ones or the BT45 I use. I had Lasertec on one K when it came to me and I couldn't get them off fast enough.
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I own a K1100 LT (< left) and I am now using a Michelin Pilot Road 4 in the rear. It is a 150/70/17. The OEM size is 140/80/17. I got 11,000 miles out of the rear Pilot Road 2 that was recently replaced. It still had another 1,000 miles remaining but it was replaced because of cupping...my fault, it was irritating rounding corners with the thumping. I was riding with 38 psi when it should have been 42 psi.
In the front I have a Michelin Pilot road 2 mounted in the stock size of 110/80/18. In a few weeks I will be replacing it with a Pilot Road 4 in size 120/70/18...in the GT version. The GT is the same except that it has a reinforced casing which is for heavier bikes. (The 110/80/18 size is not being made in the PR4.)
These are radial tires that handle well and are great in rain and cold too. They have a 2 part tread. A harder tread in the center for mileage and a stickier tread on the sides for, well, you know. They are slightly expensive but they get high mileage and offer up great handling. Well worth the price IMO.
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Here's what my Skinko 712 rear tire looked like after almost 11,000 miles of mostly highway (coast to coast and back again).
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Here is what they look like.
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I have those same Shinko 712 tires on my BMW R90/6. It looks like I will get between 5,000 and 6,000 out of the rear. Maybe a few k's more for the front. They are OK but I'll be trying something else next time. I used to put the Metzlers on it years ago. ME33 Lazer in front and ME88 Marathon in the rear - both dc'd.