Page 1 of 2 1 2 LastLast
Results 1 to 15 of 24

Thread: not sure what to do

  1. #1
    Registered User
    Join Date
    Apr 2010
    Posts
    98

    not sure what to do

    I'm in a bit of a quandry. I have a 76 r90 that I bought thinking this would be the bike I could crisscross America on while making yearly reliability and comfort improvements. Sort of like the Breakfast 101 story in the current ON-I love that story!

    After a 1700 mile trip last summer, it became obvious that future trips will not be happening until/unless I am able to resolve the bike's handling issues pertaining to grooved roads. I can't be calling every state's DOT and ask whether my planned route has grooved roads on it. I know the various techniques for riding on such surfaces, but I'm telling you it is downright frightening and I grew up riding dirt bikes in snow, gravel, etc, so I'm hardly a novice when it comes to handling bikes on various terrains.

    What don't want to do is sink a bunch of money into the bike only to find to find the issue is only slightly improved. I know there are fork braces, swing arm braces, suspension changes and tire changes available, but am real reluctant to go down that road without hearing from others that such expenses are well worthwhile.
    If I didn't have this problem, I'd be looking to get a custom seat and some different handlebars this year.

    Right now I'm running year-old Michelins and the front tire has a groove right down the middle.. I'd be willing to sacrifice that tire for another if others can attest to such a move and recommend a specific tire.

    Should I just accept the bike for what it is and get something else or there reasonable changes that could make a world of difference.

    Thanks

  2. #2
    Administrator 20774's Avatar
    Join Date
    Sep 2005
    Location
    San Antonio, TX
    Posts
    13,375
    Well, obviously you need to ensure that the bike is set up mechanically correctly and that you're running the proper pressure. I think the first thing to do is to address the front tire. A groove down the middle strongly contributes this problem. As this past post indicates, the narrow front tire only makes it worse.

    http://www.bmwmoa.org/forum/showpost...9&postcount=11

    More info here:

    http://www.bmwmoa.org/forum/showpost...06&postcount=9

    I think that's the easiest first thing to do.
    Kurt -- Forum Administrator ---> 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!

  3. #3
    Registered User
    Join Date
    Aug 2006
    Location
    Lawrence, KS
    Posts
    19
    I've had good luck with Dunlop 491 and 404's. Neither tire has a continuous groove running around the tire. That seems to make a lot of difference. The worst rain grooves always seem to occur in multi-lane congested traffic. I hate that, "I'm not really steering this bike feeling"
    John Kuhn MOA#83073

    R1100S, R100S, Honda VFR

  4. #4
    Benchwrenching PGlaves's Avatar
    Join Date
    Oct 2003
    Location
    "Big Bend" TX
    Posts
    8,780
    Assuming the bike is in OK mechanical condition the root cause is the flex in the small diameter forks, when the grooves in the tire try to follow the ridges/grooves in the pavement.

    The two direct attacks to minimize the problem are a fork brace and a front tire without circumferential grooves. My candidate would be a bias ply Metzeler 880 front tire if the 100/90-18 will fit instead of the original 90/90-18. There are others.

    You might still notice some steering oscillation but it should be less than frightening.

    This of course assumes:

    Sound swingarm bearings and adjustment.
    Decent rear shocks.
    Sound and properly adjusted steering head bearings.
    Good wheel bearings.
    Good forks, not worn, (with oil preferred. )

    By the way, if milled pavement is exciting don't try steel grate bridges, especially those with a diamond grate pattern.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://www.bigbend.net/users/glaves

  5. #5
    Registered User lmo1131's Avatar
    Join Date
    Jan 2010
    Location
    Pismo Beach, CA
    Posts
    3,074
    The two direct attacks to minimize the problem are a fork brace and a front tire without circumferential grooves.
    +1 on the front tire replacement.

    I had all kinds of low speed wobble issues and after much tweeking of fork stem bearings, aligning of sliders, etc. it came down to the front tire being OLD... it was a low mileage Continental RB2, but it was old... and no longer compliant. I replaced both of mine with Bridgestone S11 Spitfires... completely new bike, no wobbles, no "hunting" on rain grooves, etc.

    You could do a search of past "tire" discussions and totally overload your head on which ones would work the best; like this one for example... But I would bet a Pfennig that just about any brand new tire(s) would solve your initial problem. Cheapest route right now; replace the front tire.

    That said... perform the requisite mechanical checks; steering head tightness, or is there any "notchy" feel when you turn the forks? Have you checked/drained/refilled the front forks?

    These are still great bikes. But they're old and need to be regularly maintained, and maybe more importantly, understood.
    "It is what you discover, after you know it all, that counts." _ John Wooden

    Lew Morris
    1973 R75/5 - original owner

  6. #6
    --Tony AnnapolisAirhead's Avatar
    Join Date
    May 2007
    Location
    Watkinsville, Georgia/Annapolis, Maryland
    Posts
    1,783
    +1 on the Bridgestone S11 Spitfires (and a great value).

    Another option is Avon RoadRiders, that come in proper sizes for Airheads. The folks I know that have them swear by them and the tread design doesn't have said grooves down the middle. That would concern me too.
    '83 R100RT'd
    '71 R75/5 SWB
    '06 KLR 650

  7. #7
    ONE LESS HARLEY 04r1150rs's Avatar
    Join Date
    Jul 2005
    Location
    Bowling Green,KY
    Posts
    335
    Big windshields and a large heavy load on the back can cause problems too. Check rear sag, might help some. Not saying it is, but it's free to check. Weak fork springs also.

    My R80 G/S was terrible with groves and bumps mid curve. Little thin fork tubes!!! Even with upper and lower bracing it wobbled though they helped some!!! A R100GS front end cured the problem, but it was an expensive fix.

    #1 on what Paul said!!!make sure all the head set and swingarm bearings are good!!! Check the headset for looseness and notchyness.
    Richard
    2004 R1150RS
    1984 R80 G/S
    2003 Suzuki DRZ 400S

  8. #8
    Polarbear Polarbear's Avatar
    Join Date
    Jan 2006
    Location
    Clovis,CA
    Posts
    4,214

    Dunlop:)

    My '78 R100/7 has run Dunlops for so very long now, I cannot remember when I first changed over, as the original owner of this bike! Its certainly one of the finest tires and a great price you can get for that bike. I am currently using the 404s. About 75$ for a front. I'm sure others exist too, but I found my tire a very long time ago in Dunlop on the old airhead. Randy

  9. #9
    Registered User
    Join Date
    Apr 2010
    Posts
    98

    dealer recommendation

    Went to our local dealer to get his thoughts-he recommended Metzlers-I forget which model. When the weather improves, I'll spring for some tires. He assured me it will make a big difference-said in fact that even some modern bikes have that same problem.
    If that doesn't work, I guess I'll get something else.
    Thanks to all that have replied.
    Chuck

  10. #10
    --Tony AnnapolisAirhead's Avatar
    Join Date
    May 2007
    Location
    Watkinsville, Georgia/Annapolis, Maryland
    Posts
    1,783
    As others have said, there are a lot of things the add up to the sum of a good suspension. Its great to have multiple minds on it--nobody is as smart as all of us.

    I do think that any tire with a groove up the middle can't help in the situation like you describe. While I do like the S11 Spitfires, they too have said groove...as do the Metzlers (Lasertecs, not Marathons). Prior to my S11 switch, I had Metzler Marathons and they did not have a groove in the center. They last a loooong time as least in my case but lack in the grip department compared to the S11 and from what I've heard about the Avon RoadRiders.

    I think the S11 Spitfires are very similar to the Lasertec's, but a far better price point. They have a good rep for wet road handling, longevity and are plenty sticky on dry pavement. Snowbum had a good write-up on them as one of his favs. You can pick them up for $55-75. Lasertecs, not so much. The Avon RoadRiders are a bit more perf oriented and priced accordingly.
    '83 R100RT'd
    '71 R75/5 SWB
    '06 KLR 650

  11. #11
    lowkey
    Guest
    I have had a similar problem with other bikes (front end following rain groves), the fix is to change tires and raise air pressure. I always run the pressure in my tires right at the limit recommended by the tire manufacturer.

    Good advise about the amount of weight on the rear of the bike too. The farther forward (and lower to the ground) the load is the better the bike will track.

    My 78 R100S had ancient, hard Conti's on it when I bought it and handled like a turd. I wanted a vintage look so I put Dunlop K70's on and I really like the way it handles now. Tracks like it is on rails on the freeway and seems to stick real well on the curves.

  12. #12
    Registered User
    Join Date
    Jun 2003
    Location
    Northern Front Range, CO
    Posts
    6,440
    Quote Originally Posted by lowkey View Post
    I always run the pressure in my tires right at the limit recommended by the tire manufacturer.
    If you are talking about that "max pressure cold" label on the side, that is NOT the pressure you should be running at on a regular basis. That is "2 up, carrying all but the kitchen sink" pressure. you actually get slightly poorer tire life, and you definitely compromise handling.

    however; your bike, your choice.
    Ride Safe, Ride Lots

  13. #13
    Administrator 20774's Avatar
    Join Date
    Sep 2005
    Location
    San Antonio, TX
    Posts
    13,375
    Quote Originally Posted by bikerfish1100 View Post
    you actually get slightly poorer tire life
    That's right. By increasing the pressure, you reduce the tire-road contact patch. All the power now has to go through this smaller patch, thus wearing it out faster. Not to mention less surface area for heat transfer. Stiffer sidewall due to higher pressures and smaller contact patch...also contribute to compromised handling.
    Kurt -- Forum Administrator ---> 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!

  14. #14
    lowkey
    Guest
    Quote Originally Posted by bikerfish1100 View Post
    If you are talking about that "max pressure cold" label on the side, that is NOT the pressure you should be running at on a regular basis. That is "2 up, carrying all but the kitchen sink" pressure. you actually get slightly poorer tire life, and you definitely compromise handling.

    however; your bike, your choice.
    Well, I am not exactly a light guy. I really don't care if I get a few extra miles out of a tire, although I seem to be getting about what others seem to get out of similar tires.

    While I don't claim to be an expert I DO have some experience (21 years in the motorcycle business and riding for 44 years). What I have found over time is that generally speaking, the closer to max tire pressure (within 5% or less) I keep my tires the better my bikes seem to handle.

    Of course YMMV.

    P.S Most of the bikes that I have dealt with that had handling issues or odd tire wear problems almost always had low tire pressure when I checked. Some of them were as close as within 15% (40 PSI recommended max but down to 32), when I raised the pressure the wobble went away. Some of this is obviously the individual tire characteristics, but generally I'll stick with my statement. check tire pressure and go for a test ride before you start disassembling your bike.

    And one more thing........wasn't the OP talking about being on a trip, which would imply that the bike was loaded down?
    Last edited by lowkey; 03-06-2011 at 03:25 PM.

  15. #15
    Registered User donbmw's Avatar
    Join Date
    Feb 2004
    Location
    Monroe La.
    Posts
    456
    I will have to go with the higher tire pressures. When I first started running Metz. in the 80's the bike handling was not the same as the Conti. Talked to my dealer who call the tire dealer and said to increase the tire press. Increase to 42 on rear and handling problems went away.

    Don

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •