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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: bizzaro on November 05, 2017, 09:21:04 AM
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As many of us know, recommended matched front and rear tire sizes for the K 11 are basically non existent. Especially in radial tires, which I prefer on my K11. I am curious to know opinions and facts on adjusting the tire size's to fit my bike.
Do you think I would get better performance out of a matched set as in: If I buy a 150/70/17 rear, (the recommended tire is a 140/80/17 rear and is not available in the tires I am looking at), would I get better performance by matching that with a 120/70/18 on the front, or getting the BMW recommended 110/80/18, which is available? I know this is splitting hairs. With my driving skills and conditions, in reality, it probably makes no difference at all. Just looking for some feedback and opinions etc. Even better if you have a working knowledge of the physics and dynamics of motorcycle tires in regards to my question?(Handling and dynamics)
And a side note, if you read this Scott, a while back you said you took your spacers on your center stand out because it was harder to get it up on the center stand with the slightly smaller diameter tire (150/70/17). While this would get your rear tire closer to the ground on the center stand, but the length of the lever of the center stand remains the same. IE: You are actually lifting the bike the same distance. Did it help make it easier? And did you modify anything to adjust for the spacers being removed? The reason I ask is it appears that a radial tire in 140/80/17 will never be available again? I guess it is old school and discontinued by manufacturers!
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Hey there Bizz,
I didn't change anything else other that moving the spacer.... I took it from between the stand mount and transmission, and moved it to the bottom side of the stand and bolt head so I could re-use the same length bolt. If you look at the parts fiche's you may notice that the RS's don't use these spacers, so they were added to the LT's for the taller profile tires.
I still have ground clearance under the tire when on the center stand. It also has not interfered with the side stand safety switch operation.
One issue I have encountered with the 150/70 is that I have to remove my Remus exhaust can to get the tire in/out from the back. I've not tried taking it down out the bottom(when on lift), or tried taking the brake caliper off.
I'll probably find out this coming spring as my '97 will be due for new tires.
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Thanks Scott. Good to know about the RS n LT.
And, I would try seating the bead on your tire, and then under inflating it to "squeeze" it between your exhaust and caliper, Then inflate it to your running pressure. That may work and save you a good bunch of time? Mine, inflated to running pressure, takes a bit of persuading to squeeze it in just at the right angle, but not to bad with my standard exhaust.
So what do you run on the front? 110/80/18, or 120/70/18?
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I'm still running the standard size on the front.
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The standard K1100LT size front, 110/80/18, will no longer be an option if you want to stick with the Michelin Pilot Road tires. The PR3s are all gone, as in sold out and not made anymore. The front PR4 closest fit size is the 120/70ZR18 59W.
Also, it is only available in the GT variant, which is good since the GT version is reinforced for heavier bikes. The down side is that they cost $180 (plus $200 for the front) online at Revzilla. The former PR3 front was somewhere around $130...
I have no problems with the centerstand with the shorter rear tire. It is also a better fit with the sidestand since the bike doesn't go so far over. My 2c.
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So Beemerdon,
Have you ever mounted a 120/70/18 to your front wheel?(180/80/18,as you stated for size, is a typo I assume?) Just wondering if you had any issues with it, if you have run the 120/70/18? There isn't a lot of "extra" room up there! I may go with the Battlax T30's just to give them another try. I am not sure what is available now, but last time I ran the Battlax T30's, they had the proper front 110/80/18. And the rear I went with the stouter 150/70/17. And to add a comment on the Michelin PR series, They may cost a bit more, but the mileage you get out of them, more than makes your money back! As in the Shinko Tourmaster...........good tire at a great price. But I get 3x the mileage of a Shinko with the Michelin's.............You do the math! :eek:
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"Have you ever mounted a 120/70/18 to your front wheel?" Not yet Bizz. But if I keep going through tires like I have been, then the Activs will be history by April. I'm getting from 9,000 to 11,000 miles out of a set of PRs, depending on how hot the asphalt is. I don't expect any more than that from the Activ tires.
The 110/80vs120/70 size difference is negligible. I've run the next size up front tire on my R90 a bunch of times and it was ok.
Anyway, not too much choice, really. There's not a lot out there for sport touring Radials in our size.
(Caution...Rant Ahead)...The big difference for me is the PRICE. From about $135 for the PR3 to about $180 for the PR4-GT. Ouch!
The rear is somewhere around $200.... plus installation fee$.
This seems to be the low end of what premium motorcycle tires are going for these days as most current M/C tires are larger so cost more. There really needs to be more competition.
But, to answer your question, there looks like there is more than enough room for the 120 on the front.
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(Caution...Rant Ahead)...The big difference for me is the PRICE. From about $135 for the PR3 to about $180 for the PR4-GT. Ouch!
The rear is somewhere around $200.... plus installation fee$.
This seems to be the low end of what premium motorcycle tires are going for these days as most current M/C tires are larger so cost more. There really needs to be more competition.
Shinko.
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Shinko.
mine are coming today, $130 for the set.
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TMG were you running Shinkos on Moby Brick as well as the K75s?
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Shinko's on the K75 bikes, radials on the K100RS. If I can find Shinko radials for the K100's wider wheels I'll use them. I have a lot of miles on the Shinkos now, and they are good tires at a great price.
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Thanks for the suggestion Griff. I have those shinkos on my R90. They are OK on that lighter, slower bike but I don't want them on my K 1100. Also, they are wearing faster than the Metzlers that I usually use on the R.
I am only going with radials from now on for my K. My negative experience with the bias ply Michelin Avtivs has confirmed that radials are the way to go. If I have to bite the bullet price-wise on the best tires, so be it. Not a lot of choices out there in the K 1100 sizes.
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Shinko.
How do those work in the rain? The only time I cheaped out and bought Oriental tires I put some Kenda copies of Dunlop K81s on my Trident. First time it rained I ended up on my side.
Seems as if I can still find the Metzeler Z6 which are on my K100rs. If I can ever figure out the wear bars to tell me when I need new ones....