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Thread: Car tires on rear

  1. #1
    Curmudgeon At Large Bobmws's Avatar
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    Car tires on rear

    New to this forum and newly returned to a hack after 30 years.
    I just put a Hannigan Conde Classic on my BMW K1200RS, and I'm sure tire wear will soon be a concern! Rear rim is 5.5 x 17 and I've seen some numbers for mounting a 205/50-17 (Bridgestone Potenza G 019) that is actually specced for a 5.5 rim width.

    My question is how thick of a spacer can I safely use to gain a bit of clearance on the swingarm?
    I'm assuming it would be best to find lugs bolts that are longer so the threaded depth in the hub is the same.

    Any help would be appreciated, thanks.
    Bob Weis
    '04 K12RS - Hannigan Hack
    www.earplugco.com

  2. #2
    "Running Out The Clock" grafikfeat's Avatar
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    Quote Originally Posted by Bobmws View Post
    ...I just put a Hannigan Conde Classic on my BMW K1200RS...
    What does Hannigan say?
    "Stupidity, if left untreated, is self-correcting."

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    I'm running a 2004 K12GT with Hannigan Astro Sport. The GT also uses the 5.5x17 rim, and I did a lot of research after having the rig built and quickly burning through a couple of expensive MC tires. Unfortunately, I didn't find anyone who had mounted anything wider than a 195 tire. Using the tire size calculator at http://www.tacomaworld.com/forum/tirecalc.php your 205 tire would be only about 1% difference in diameter, but I don't think you could safely mount a thick enough spacer to get that tire to clear the swingarm. If you prove otherwise, please let us know!

    In my own case I went with the adapter and car wheel from C Stanley Motorsports (http://freedomsidecars.com/) and am running a 155/80 R15 tire. This also works out to be very close to the OEM diameter, just a tad smaller which works out well on overall gearing. The adapter/wheel package is expensive but I'm putting on a $80 tire every 12-14k instead of a $180 tire every 4-5k, so over the life of the rig I'll come out OK. It's nice to be able to know the rig will be ready anytime for a weekend trip, no worrying about whether or not there's enough tire to go the distance.

    Good luck, and do let us know if you find a way to wedge in that 205 tire without over-spacing the wheel and getting some flex introduced.

    Good luck!

    GTRider
    Last edited by GTRider; 02-04-2012 at 03:13 AM. Reason: spelling
    DGerber
    1983 R80ST -- 1988 K100RS (r.i.p.) -- 1995 R1100RSL (gone, never forgotten) -- 2004 K1200GT w/Hannigan S/C -- 2010 K1300GT

  4. #4
    "Running Out The Clock" grafikfeat's Avatar
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    Quote Originally Posted by Bobmws View Post
    My question is how thick of a spacer can I safely use to gain a bit of clearance on the swingarm?
    Why not use washers to get the distance from the tire wall to shaft, get the measurement and then shop a spacer...

    They're sold everywhere!
    "Stupidity, if left untreated, is self-correcting."

  5. #5
    Curmudgeon At Large Bobmws's Avatar
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    GrafikFeat:
    Hannigan doesn't comment on car tires on a stock rim, the ones they use on their HP rigs have a widened rim.
    My stock MC tire measures 7 1/8" wide with 9/16" clearance at the swing arm.
    Tirerack lists the specs for each individual tire and which rim it was mounted on for measurement. The 205/50 has a widest section measurement of 8.3", mounted on a 6.5 wide rim. It is spec'ed for rim 5.5 to 7.5. Mounted on a 1" narrower rim the section width should be a bit less. I think 2 additional 2mm stock spacers will do the trick.
    Realoem lists 5mm longer lugs for one of the bikes so I should be good with retaining thread depth.
    The 195 tires list similar section widths also mounted on a 6.5 rim, but none of them are spec'ed top mount on a 5.5" rim.

    GTRider:

    I'm aware of the car tire adapter ($$$), I'l try this route first and will report back.
    What front tire are you running?
    Bob Weis
    '04 K12RS - Hannigan Hack
    www.earplugco.com

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    Quote Originally Posted by Bobmws View Post
    GrafikFeat:
    Realoem lists 5mm longer lugs for one of the bikes so I should be good with retaining thread depth.
    The 195 tires list similar section widths also mounted on a 6.5 rim, but none of them are spec'ed top mount on a 5.5" rim.
    Ahh, I had not seen the longer bolt availability--that was one of my concerns with stacking additional spacers on the wheel.

    Quote Originally Posted by Bobmws View Post
    GTRider:
    I'm aware of the car tire adapter ($$$), I'l try this route first and will report back.
    What front tire are you running?
    The only thing I've found that gives any kind of reasonable life is the 120/70VB17 Metzeler ME880--the bias belted version. And at that, I'm only getting about 6k from a front tire. If you have found something better please speak up!

    I can't find a car tire in a usable size for the front and don't see a reasonable way to fit a car rim up front on the stock front end. "Unit", from overseas, is not interested in building a LL front end for the telelever brick K bikes either--at least that was their response last time I contacted them.

    Now, if one were to replace the front shock with a strut and remove the OEM fork tubes, then replace them with an appropriately size and properly constructed pair of leading-link fork legs.... well, you get the idea. But that's a project that will have to wait until after I retire and that's a bit down the road yet...

    Best,

    GTRider
    DGerber
    1983 R80ST -- 1988 K100RS (r.i.p.) -- 1995 R1100RSL (gone, never forgotten) -- 2004 K1200GT w/Hannigan S/C -- 2010 K1300GT

  7. #7
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    On my rig I also went with an adapter from Claude Stanley



    Used a 195/50 x 16 tire, on a Mini Cooper rim

    Over on the HSidecar forum there has been topics on car tires on bike rims

    http://hpsidecars.com/


    I don't have the exact #'s in front of me but besides the rim profiles being completely different, bead seat diameters are also different on car and motorcycle wheels. In the case of 17", the motorcycle rim diameter is significantly smaller than a car rim. So a car tire slips easily on to a motorcycle rim but it's wrong because the rim can move around on the bead seat. Basically the tire has to be over inflated to secure it to the rim but there is always the possibility of catastrophic failure.

    Wheel size 15" ________ 16"_________ 17"_________ 18"

    car rim dia 14.968"______15.968"______17.189"______18.189"


    mc rim dia 15.08"______15.978"______17.08"______18.08"

    I know lots of people do it, but I'd be careful.
    Mike Currin
    93 K1100RS / EML Speed 2000 sidecar
    89 Honda GB 500
    67 Triumph 650 Chopper

  8. #8
    "Running Out The Clock" grafikfeat's Avatar
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    Quote Originally Posted by michaelcurrin View Post
    ...I know lots of people do it, but I'd be careful.
    30k plus on a 50k tire on a 15" BMW rim.
    No worries... Even while flying the chair.
    "Stupidity, if left untreated, is self-correcting."

  9. #9
    Curmudgeon At Large Bobmws's Avatar
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    Car tire mounted

    Mounted a Yokahama 195/45-17 S-Drive tire on the bike rim yesterday. Original plan was a 205/50-17 Bridgestone that i spec'ed to fit a 17" rim. The bridgestone measured 8" wide, side clearance required some more shims. Found 5mm longer wheel bolts from the R12C so I could maintain enough thread depth. Only problem was the height of the tire at 25.1" The radius cast into the monolever arm hit the edge of the tire. You can see the light spot in this pic.
    Attached Images Attached Images
    Last edited by Bobmws; 03-05-2012 at 04:28 AM. Reason: correction
    Bob Weis
    '04 K12RS - Hannigan Hack
    www.earplugco.com

  10. #10
    Curmudgeon At Large Bobmws's Avatar
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    The 195/45 S-Drive is 23.9" tall and measures 7 1/2" wide when mounted, similar to the Avon but .8" shorter. Still required the 2 additional shims (6mm total) and longer 60mm bolts. I'll check the speedo against the GPS for indicator difference. Shorter gearing won't hurt with the sidecar. Initial short ride feels a bit more stable, no indication of tire rub when warmed up. The difference in scuff on the left edge vs the right is from attempting to fly the car. A bit more difficult to come up with the flat profile tire, a good thing!
    Pic from behind;
    Attached Images Attached Images
    Last edited by Bobmws; 04-25-2012 at 02:26 PM. Reason: Correct typo's
    Bob Weis
    '04 K12RS - Hannigan Hack
    www.earplugco.com

  11. #11
    Curmudgeon At Large Bobmws's Avatar
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    Mounting the car tire I could have used an extra set of hands. Toughest thing was to keep the bead down in the center of the rim due to the width and the short sidewall. I actually used the bead breaker to hold it down while I spooned it onto the rim.
    FYI, I mounted a ME880 Bias ply on the front, spec'ed for a K12LT.
    And a side view:
    Attached Images Attached Images
    Last edited by Bobmws; 03-04-2012 at 01:51 PM. Reason: more words.....
    Bob Weis
    '04 K12RS - Hannigan Hack
    www.earplugco.com

  12. #12
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    That's a nice looking tire and it's nice to be able to keep matching wheels on the rig. According to
    from the online tire size calculator

    your new tire is close to an inch smaller diameter so you'll be geared down a bit, that's not a bad thing. I find with the 155/80R15s I run that I spend a lot of time cruising in 5th gear if there are grades or headwinds present--you shouldn't have to do that with the smaller tire.

    With 6mm of side spacer in there, are you going to need to re-check toe-in? Moving the rear wheel to the left should effectively increase to-in, I'd think.

    Best,

    GTRider
    Last edited by GTRider; 03-05-2012 at 03:30 AM. Reason: Fix hyperlink
    DGerber
    1983 R80ST -- 1988 K100RS (r.i.p.) -- 1995 R1100RSL (gone, never forgotten) -- 2004 K1200GT w/Hannigan S/C -- 2010 K1300GT

  13. #13
    "Running Out The Clock" grafikfeat's Avatar
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    Quote Originally Posted by GTRider View Post
    ...your new tire is close to an inch smaller diameter so you'll be geared down a bit, that's not a bad thing.
    Check your "new" speeds against a GPS to see what your speedo and odometer will be indicating.
    "Stupidity, if left untreated, is self-correcting."

  14. #14
    Curmudgeon At Large Bobmws's Avatar
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    Quote Originally Posted by GTRider View Post
    That's a nice looking tire and it's nice to be able to keep matching wheels on the rig. According to
    from the online tire size calculator

    your new tire is close to an inch smaller diameter so you'll be geared down a bit, that's not a bad thing. I find with the 155/80R15s I run that I spend a lot of time cruising in 5th gear if there are grades or headwinds present--you shouldn't have to do that with the smaller tire.

    With 6mm of side spacer in there, are you going to need to re-check toe-in? Moving the rear wheel to the left should effectively increase to-in, I'd think

    Best,

    GTRider
    Toe-in should be the same. When they set the bike up at Hannigan's they use 8' fluorescent tubes as they are perfectly straight. One tube bungied to the rear wheel, one to the hack wheel. The rear wheel line is parallel with the bike. The front wheel does not come into play as it is inside the rear wheel line with the stock wheel position or my spaced out wheel. The spaced out wheel just moves the line over, still parallel to the bike. The angle of the sidecar wheel (toe-in) remains the same.

    I appreciate the concern. We did a 60 mile loop this morning and the ride feels the same, no issues with pulling to either side on a straight road. A bit more stable and less tippy on right handers. I do have shocks and springs ordered for all three wheels,the stockers are way to weak. I know I will have to adjust lean out after they are installed.
    Bob Weis
    '04 K12RS - Hannigan Hack
    www.earplugco.com

  15. #15
    Curmudgeon At Large Bobmws's Avatar
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    Quote Originally Posted by GrafikFeat View Post
    Check your "new" speeds against a GPS to see what your speedo and odometer will be indicating.
    LOL, I remembered the GPS about 15 minutes into our ride this morning.
    I'll get it this week.
    Bob Weis
    '04 K12RS - Hannigan Hack
    www.earplugco.com

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