Page 2 of 2 FirstFirst 1 2
Results 16 to 22 of 22

Thread: What rear tire should I have for my R90/6?

  1. #16
    Registered User
    Join Date
    Dec 2012
    Posts
    939
    Quote Originally Posted by nrpetersen View Post
    OP report (so far):

    The rear shocks (sorry they are original) were set to different heights. Fixed.

    The tire pressure has been raised to 36 psi. Tonight we are supposed to get 4 " of snow so I may not have an answer until next spring, dang it. THX guys!
    Don't let a little snow hold you back!

  2. #17
    Administrator 20774's Avatar
    Join Date
    Sep 2005
    Location
    San Antonio, TX
    Posts
    12,890
    Quote Originally Posted by 44006 View Post
    I am looking for a source for this tread style in 3.50x18 size for the front of the /2 bikes and for both wheels on /2 bikes with the higher rear end (25x8) rear ends. If anyone knows of a source please let me know - I used to be able to get this tread style in Pirelli and Cheng Shin and both now seem to be no longer available
    I don't know about all your requirements, but I run the IRC GS-11 tires on my R69S. They seem to give me reasonable distance for road use...I don't typically go off-road or ride gravel.
    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. #18
    Curmudgeon nrpetersen's Avatar
    Join Date
    Sep 2004
    Location
    minnetonka mn
    Posts
    603
    Update 2
    I see that a Michelin 400 H - 18 tire is wider, larger dia, and heavier. I decided to order a new tire from Dennis Kirk to replace the one I have. There will be a nearly new Avon 100/90-18 tire free at my house if anyone locally is interested. I'll also run the Michelin with the higher pressure. This marginally stable weave thing really has me spooked.
    Retired w 2005 K1200LT, 2000 R1100RT, & 1975 R90/6

  4. #19
    Registered User
    Join Date
    Jan 2006
    Location
    Wisconsin and Florida
    Posts
    375
    "OP report (so far):

    The rear shocks (sorry they are original) were set to different heights. Fixed. "
    -------------------------------------------------------------------------------------------------------------------
    "This marginally stable weave thing really has me spooked."

    -------------------------------------------------------------------------------------

    Are you saying that even after you reset the shocks which had been at different load setting each side the bike still weaves at speed? Mismatched rear shock load settings would have applied forces trying to twist the swingarm assembly when going over humps and bumps which could have easily made the bike behave strangely.

  5. #20
    P Monk
    Join Date
    May 2005
    Location
    Port Neches, Texas
    Posts
    636

    tight steering head bearings

    When I bought my 90/6 a few years ago, It was a scary ride especially in side winds. The bike just wouldn't track straight. I loosened the bearings so the wheel would fall to the side if not pointed straight ahead, with bike on center stand of course, and that solved the weaving problem.

    Later had the bearings replaced and it got even better.
    P. Monk
    My prized possessions. 74 R90/6 Mine! (also know by bride as the Black Hole). 09 R1200 GS. My wife, 1953 model who has survived aplastic anemia and a bone marrow transplant. My most prized possession is my relationship with Jesus!

  6. #21
    Curmudgeon nrpetersen's Avatar
    Join Date
    Sep 2004
    Location
    minnetonka mn
    Posts
    603
    Quote Originally Posted by 44006 View Post
    "OP report (so far):

    The rear shocks (sorry they are original) were set to different heights. Fixed. "
    -------------------------------------------------------------------------------------------------------------------
    "This marginally stable weave thing really has me spooked."

    -------------------------------------------------------------------------------------

    Are you saying that even after you reset the shocks which had been at different load setting each side the bike still weaves at speed? Mismatched rear shock load settings would have applied forces trying to twist the swingarm assembly when going over humps and bumps which could have easily made the bike behave strangely.
    I realize there could be a coupling from vertical input to steer yaw when the rear shocks forces are not similar, but I experienced a very heightened (i. e. peaked) yaw response to handlebar inputs at ~ 4 Hz with no vertical (jounce) input, very much like I have seen in videos of race accidents. I have never felt that before on this bike. Something is definitely wrong.

    Maybe the snow will melt (yeah....) enough for me to try if the new tire works. Will post.
    Retired w 2005 K1200LT, 2000 R1100RT, & 1975 R90/6

  7. #22
    lubbent
    Join Date
    Sep 2005
    Location
    Madison, WI
    Posts
    18

    R90/6 tires and stability

    1-Get the steering, swingarm and wheel bearings absolutely right and replace them if at all questionable. Steering bearings too tight will give spooky weaving at moderate speeds, but at high speeds it seems to be OK- I think the input energies are higher so the friction is overcome.
    Too loose and the best you can hope for is to fill your shorts, the worst is to fill your coffin.
    2-Also, check the front springs for sag. They do sag, and that steepens the steering angle. I have found up to a 2" sag, and that bike handled really scary. Rebuild the front forks is necessary, and
    3- MOST IMPORTANTLY, be sure the forks are aligned. See w6rec.com (Duane's site). Misaligned forks can fill your shorts as quickly as can steering bearings.
    4- Once that is done:
    I run Spitfire S11 tires front and rear and really, really like the handling. They are on an R90/6, am R60/6 and a SWB R75/5. I run 90/90-19 or 100/90-19 on the front (I have tried both and both feel OK- but the 90/90 is on the SWB R75/5 so a direct comparison is not possible.), and 110/90-18 on the rear. I don't know who said that was too small, but it is not- it is a bit bigger than original but is the smallest easily-obtained S11 rear. Any bigger and you will have clearance issues. The 100/90-19 on the front just misses the fender brace, but not by much, on the /6. Pressure is about 34-36 solo, maybe 38 rear. I weigh 200.
    5- As for shocks, please get rid of the originals. IKONs work, I have seen some OEM look-alikes (Bob's?), but don't know how well they work. I have Konis on the /6 bikes, and YSS on the /5. The YSS shocks were the best handling and comfort mod I ever made to that machine, and I have owned it since Feb of 1976. Ted Porter sold them to me. They weren't set up just right- the eye to eye length was a bit long (it should be 13'' exactly- at least that was what my OEMs and the Konis were) and the damping was too hard for me, but that was so easy that it did not matter. It took almost no time to set it right, he walked me through it, and the damping can be adjusted on the bike.

    With a decent set of shocks, your bearings absolutely correct, S11s front and rear, it should put a really big smile on your face. Not a pucker you know where.

Posting Permissions

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