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Thread: My eyes are bleeding!

  1. #1

    My eyes are bleeding!

    Have been doing research on tires for my 1975 R90/6. After so much reading, I am now confused! Can anyone give me basic tire information. I just want to use the standard tire sizes for the front and back. I would appreciate it if you all could give me a couple of options when it comes to tire choices. Brand and model, please. I just tool around in the country and small towns on my bike. No off-road, no racing. Usually don't ride in the rain. My biggest preference is comfort!!

    And what is the standard tire size I should go with.


    Thanks for your help. Not looking to turn this into a tire thread, just a couple of basic suggestions.

  2. #2
    JohnWC
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    You have my sympathy, as I know just what you're going though. With my R80 I spent I don't know how long trying to figure out the "exact right" tires for it. There are countless opinions, and the conversions to metric from the sticker on the old bikes just adds to the fun. I can't remember the sizes I finally used (sorry, but I don't have the bike anymore, and I don't want to give you the wrong info) but I would offer a few suggestions. Trust the people here rather than the dealers, and especially not tire companies. They have no clue about older bikes. Secondly, don't go cheap. Motorcycle tires are outrageously priced compared to car tires, but you only have two to trust your life to. I ending up going with Spitfires (because Snowbum recommended them). They were pretty cheap too. Even better, I thought. But as I rode, I often regretted not paying the money and getting a really good set. I think the Spitfires rode poorly, followed rain grooves, and were just generally second rate. But at that point you have to ride them for 5000 or so miles to wear them out to justify getting another, better set. It's a long 5000 miles of waiting. Get brand name, good quality. You will never regret it.

  3. #3
    Registered User m_stock10506's Avatar
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    The correct OEM tire size for your bike are 3.25x19H front and 4.00x18H rear. These would be bias-ply tires, not radials.

    There are still tires available in those sies. (The H is the speed rating)
    I used Michelin Macadam 50/50E for many years but they are discontinued. They've been replaced with Michelin Pilot Active. I haven't run a set yet, but have a couple of rear tires on order. The ContiGo is also available in correct sizes; this is a very nice modern tread design and soft (sticks well) tire. I've gone through one set, but found the rear tires to wear out very quickly - could just be me.

    The Conti-Twins were the OEM tires on bikes in that vintage. They have a block design and tend to track rain grooves and get squirmy. If you don't care about looking like it has original tires, I would select a tire with a modern tread design. Much more likely to give good handling and road feedback.
    Michael Stock, Trinity, NC
    R1100RT, R100, R60/6

  4. #4
    WI Airhead r90r100r's Avatar
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    On my 76 R90/6 I have on the front - 3.25 19 M/C 54V Metzler Lasertec
    and on the rear - 120 90 B 18 MC 71H Metzler ME 88 Marathon
    I also ride mostly county highways and back roads with this bike.

    Mike H
    76 R90/6
    93 R100R Legend

  5. #5
    Liaison 20774's Avatar
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    As Kent will say, there's no metric equivalent for what was specified for the /6. Inch-size tires are the way to go, are still available, and offered by good manufacturers. The inch tires are correct for the geometry and provide the best ground clearance and setup for things like the sidestand and centerstand.

    There's been lots of tire treads...errr...threads; try a search. Avon Roadriders fits the bill in all categories. Thread happening right now:

    http://forums.bmwmoa.org/showthread.php?t=59902
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  6. #6
    Registered User
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    Quote Originally Posted by r90r100r View Post
    On my 76 R90/6 I have on the front - 3.25 19 M/C 54V Metzler Lasertec that is the correct stock sizing and on the rear - 120 90 B 18 MC 71H Metzler ME 88 Marathon that one is incorrect metric sizing. stock is 4.00x 18.I also ride mostly county highways and back roads with this bike.

    Mike H
    76 R90/6
    93 R100R Legend
    he did ask for standard sizing, rather than "what are you running?"
    Ride Safe, Ride Lots

  7. #7
    Avon Road rider

    3.25 x 19

    4.00 x 18

    People have had problems with the metric equivalant for rear tire due to swingarm clearance.

    No matter what you get the inch sizes are available and correct.

    I answered this over on ADVrider also pleas see my link:

    http://vintagebmw.org/v7/node/8217
    1974 R75/6 W Sidecar
    1989 R100GS


  8. #8
    Registered User
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    I like Dunlop K70 for airheads through 1980
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  9. #9
    WI Airhead r90r100r's Avatar
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    Quote Originally Posted by bikerfish1100 View Post
    he did ask for standard sizing, rather than "what are you running?"
    Then I should have quoted the manual - duh my bad!

    Mike H
    Last edited by r90r100r; 04-19-2012 at 10:31 PM.

  10. #10
    Douglas Williams
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    Quote Originally Posted by 85K100LT View Post
    Avon Road rider

    3.25 x 19

    4.00 x 18

    People have had problems with the metric equivalant for rear tire due to swingarm clearance.

    No matter what you get the inch sizes are available and correct.

    I answered this over on ADVrider also pleas see my link:

    http://vintagebmw.org/v7/node/8217
    Same as on my 81R100RT and 84 R100RS. Great tires. Good mileage and great handling and appropriately sized.
    Sent from a Galaxy, far, far away

  11. #11
    Whatever you buy, make sure it doesn't have a center groove or you'll be in for unpleasant times when you come to the rain grooves.

  12. #12
    Thanks for all of your replies. I ended up going with the Bridgestone S11's...

  13. #13
    ABC,AMA(LIFE),MOA,RA,IBMW MANICMECHANIC's Avatar
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    I'm on my second set of S-11's on my /6. I run them at 40 psi front and rear. They handle well and I've gotten great wear from them. They also do well in the wet.
    F.O.G.Rider, Rounder #6,
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