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HenryJonesJr
Joined: 19 Oct 2012
Posts: 16
Location: Sierra Nevada Mountains, California
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 Posted: Sat Nov 17, 2012 11:08 pm Post subject: Rear Tire Diameter / Rolling Circumference |
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Hello folks,
I'm trying to allow for how much different my 14 inch auto tires are than the stock tires so that I can know how much my odometer is off.
I can get the rolling circumference of my tires from TireRack or similar but I don't own a K11 rear wheel/tire (  ).
Can one of you kind people measure the circumference of your rear tire and post the result here?
Cheers,
Hank
_________________
1993 K1100LT / 1996 EML GT2000 Sidecar
2001 R1150GS
Riddle me this:
Two motorcycles are being ridden down a two-lane road. They are followed by a long line of cars.
What brand are the motorcycles? |
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drikko
Flying Brick Rider
Joined: 20 Nov 2009
Posts: 1966
Location: Brisbane, OZ
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| Posted: Sat Nov 17, 2012 11:37 pm Post subject: |
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The best way to check this is to borrow a GPS and go for a ride, far more accurate than measuring rolling radius as that depends on tYre pressure, load weight etc etc.
_________________
K1100RS '97
Laverda RGS 1000 '84
Jim Young Trailer Sailer 5.7M WB
DISCLAIMER:- Anything I say may have been when I was drunk so please don't take it personally.
'Bigamy is having one wife/husband too many. Monogamy is the same.'
Oscar Wilde |
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HenryJonesJr
Joined: 19 Oct 2012
Posts: 16
Location: Sierra Nevada Mountains, California
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| Posted: Sun Nov 18, 2012 12:22 am Post subject: |
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Thanks drikko, but I can't measure my current odometer (via GPS or otherwise) against the stock setup as I don't own any K11 wheels / tires anymore (and I wasn't clever enough to make the measurement before the bike was converted to sidecar.
I just need to figure out a ratio between a (not every) K11 rear wheel and my 14" automobile tires.
Then I can apply that ratio to my maintenance records both past and future.
Can you help?
Cheers,
Hank
_________________
1993 K1100LT / 1996 EML GT2000 Sidecar
2001 R1150GS
Riddle me this:
Two motorcycles are being ridden down a two-lane road. They are followed by a long line of cars.
What brand are the motorcycles? |
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drikko
Flying Brick Rider
Joined: 20 Nov 2009
Posts: 1966
Location: Brisbane, OZ
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| Posted: Sun Nov 18, 2012 12:50 am Post subject: |
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Mines an RS so it had different tyre sizes than the LT. I guess we'll have to wait till one of the LT riders can help.
_________________
K1100RS '97
Laverda RGS 1000 '84
Jim Young Trailer Sailer 5.7M WB
DISCLAIMER:- Anything I say may have been when I was drunk so please don't take it personally.
'Bigamy is having one wife/husband too many. Monogamy is the same.'
Oscar Wilde |
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rbm
Mad Brick Rider
Joined: 02 Jun 2009
Posts: 115
Location: Toronto
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| Posted: Sun Nov 18, 2012 3:49 am Post subject: Re: Rear Tire Diameter / Rolling Circumference |
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| HenryJonesJr wrote: | | Can one of you kind people measure the circumference of your rear tire and post the result here? |
Hank, If you are using a PC, then download Karamba and run it. There is a library of various BMW K-bikes in that program and selecting a bike from the library will give you the wheel details you are after.
_________________
- Robert
1987 K75 @k75retro.blogspot.ca
2011 Moto Guzzi V7 Racer |
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HenryJonesJr
Joined: 19 Oct 2012
Posts: 16
Location: Sierra Nevada Mountains, California
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| Posted: Sun Nov 18, 2012 1:14 pm Post subject: Re: Rear Tire Diameter / Rolling Circumference |
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| rbm wrote: | | HenryJonesJr wrote: | | Can one of you kind people measure the circumference of your rear tire and post the result here? |
Hank, If you are using a PC, then download Karamba and run it. There is a library of various BMW K-bikes in that program and selecting a bike from the library will give you the wheel details you are after.
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Thanks Robert. That's going to do the trick. (soon as I translate some of the words, that is )
_________________
1993 K1100LT / 1996 EML GT2000 Sidecar
2001 R1150GS
Riddle me this:
Two motorcycles are being ridden down a two-lane road. They are followed by a long line of cars.
What brand are the motorcycles? |
|
| Back to top |
|
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rbm
Mad Brick Rider
Joined: 02 Jun 2009
Posts: 115
Location: Toronto
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| Posted: Sun Nov 18, 2012 1:24 pm Post subject: |
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Good to hear. When it comes time, you can use Karamba to recalibrate your speedometer to the new wheels. There is a tutorial I wrote on K100RTforum and an associated discussion thread. Good luck with your conversion.
_________________
- Robert
1987 K75 @k75retro.blogspot.ca
2011 Moto Guzzi V7 Racer |
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HenryJonesJr
Joined: 19 Oct 2012
Posts: 16
Location: Sierra Nevada Mountains, California
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| Posted: Sun Nov 18, 2012 3:50 pm Post subject: |
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OutSTANDing.  Now I can much more easily correct my speedo reading. It's about 10% off from my previous attempts to adjust it to match the sidecar tire size.
Cheers, (he says on his way to the garage to fabricate a cable and take the instrument cluster off and apart . . .)
Hank
_________________
1993 K1100LT / 1996 EML GT2000 Sidecar
2001 R1150GS
Riddle me this:
Two motorcycles are being ridden down a two-lane road. They are followed by a long line of cars.
What brand are the motorcycles? |
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| Back to top |
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Tyronewildman
Joined: 16 May 2012
Posts: 24
Location: Tyrone, Georgia USA
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| Posted: Sun Nov 18, 2012 4:46 pm Post subject: You Asked & Here It Is |
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It wasn’t a major PITA but for an old guy it wasn’t easy and here it is. My ’04 Kll00LT ABS has a Metzeler ME88 Marathon 130/90B17 rear tire that has maybe 5,000mi on it and its circumference is 83” plus or minus 1/8”. From the tread wear, I’ll probably get around 20,000mi on the rear tire. Using the “PIE THEOREM” this makes the diameter of the tyre about 26.42”. No wonder the seat is so stinking high! No Wait, the “PIE THEOREM” is; Pie R Round, Cake R Square. Dang, what was the question again? I spelled "tire" both ways to please most of the guys & gals.
Later, De
_________________
'13 FJR Yamaha
'09 Road King
'07 Buell P3 Blast
'02 Buell S3T
'94 K1100LT ABS BMW
'94 GL1500 Honda
'89 PC800 Honda
'77 T140V Triumph
'69 441 Victor Special BSA
'69 CT90 Honda
"It Doesn't Have To Make Sense" |
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drikko
Flying Brick Rider
Joined: 20 Nov 2009
Posts: 1966
Location: Brisbane, OZ
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| Posted: Sun Nov 18, 2012 5:03 pm Post subject: |
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I'm surprised you even considered using an 'i' in tyre considering you live in TYrone!
BTW too many uses of the pie theorum will reduce the rolling radius slightly if you don't increase tyre pressure slightly to compensate.....
_________________
K1100RS '97
Laverda RGS 1000 '84
Jim Young Trailer Sailer 5.7M WB
DISCLAIMER:- Anything I say may have been when I was drunk so please don't take it personally.
'Bigamy is having one wife/husband too many. Monogamy is the same.'
Oscar Wilde |
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HenryJonesJr
Joined: 19 Oct 2012
Posts: 16
Location: Sierra Nevada Mountains, California
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| Posted: Sun Nov 18, 2012 5:20 pm Post subject: Re: You Asked & Here It Is |
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| Tyronewildman wrote: | It wasn’t a major PITA but for an old guy it wasn’t easy and here it is. My ’04 Kll00LT ABS has a Metzeler ME88 Marathon 130/90B17 rear tire that has maybe 5,000mi on it and its circumference is 83” plus or minus 1/8”. From the tread wear, I’ll probably get around 20,000mi on the rear tire. Using the “PIE THEOREM” this makes the diameter of the tyre about 26.42”. No wonder the seat is so stinking high! No Wait, the “PIE THEOREM” is; Pie R Round, Cake R Square. Dang, what was the question again? I spelled "tire" both ways to please most of the guys & gals.
Later, De |
Thanks, De, for throwing yourself on that grenade. What you measured is pretty close to what I've decided to use as my "stock" rolling circumference number.
Cheers,
Hank
_________________
1993 K1100LT / 1996 EML GT2000 Sidecar
2001 R1150GS
Riddle me this:
Two motorcycles are being ridden down a two-lane road. They are followed by a long line of cars.
What brand are the motorcycles? |
|
| Back to top |
|
|
HenryJonesJr
Joined: 19 Oct 2012
Posts: 16
Location: Sierra Nevada Mountains, California
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| Posted: Tue Nov 27, 2012 2:19 pm Post subject: Re: Rear Tire Diameter / Rolling Circumference |
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| HenryJonesJr wrote: | | rbm wrote: | | HenryJonesJr wrote: | | Can one of you kind people measure the circumference of your rear tire and post the result here? |
Hank, If you are using a PC, then download Karamba and run it. There is a library of various BMW K-bikes in that program and selecting a bike from the library will give you the wheel details you are after.
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Thanks Robert. That's going to do the trick. (soon as I translate some of the words, that is ) |
So, now I've used Karamba to set my speedo to be spot-on from about 45mph to 80mph (it reads very slightly too low below 45 and too high above 80-90 - it's just how it works, I guess).
Here are a few observations about using Karamba, specifically with the speedo on the bench.
Cabling for Bench Tuning:
In order for the speedo to work on the bench, it needs only a few connections: 12v power and corresponding ground and the two speedo signals from Karamba. The power first... All of the other instructions I found by searching online mentioned the needed connections, but not as explicitly as a dummy like myself needed. Figured it out, though... Here are the specific connections needed:
Pin# - Signal
------------------------------------------------
6 - 12v
18 - Ground (* from the same source as the 12v - gotta have a circuit !)
22 - Speedo signal (yellow, see RBM's tutorial for the wiring details)
23 - Speedo "ground" (brown, ditto RBM's tutorial)
I made a cable with a BMW accessory plug at one end and the speedo connectors at the other and used my 1150GS as the power source (as it's parked closest to the workbench ).
At the speedo end of the power cable, I used pins intended for a MOLEX connector. MOLEX connectors come in (at least) two sizes: .062" and .093" diameter and are available from electronics-stocking stores (Fry's Electronics and similar, or from Amazon (or similar ).
For example:
.093": http://www.amazon.com/Molex-14-20-Gauge-Pins-0-093/dp/B005VG6CT6/ref=sr_1_1?ie=UTF8&qid=1354038480&sr=8-1&keywords=molex+pins
.062": http://www.amazon.com/Female-Molex-Pin-062-Pinball/dp/B00907UFWC/ref=sr_1_cc_1?s=aps&ie=UTF8&qid=1354038661&sr=1-1-catcorr&keywords=molex+pins+.062
Female pins of the larger size work well to plug into the speedo sensor connector on the bike (under the right side cover) as the speedo side of the connector has male pins that, er, plug right in.
The (female) .062" size is a somewhat tight fit on the pins at the back of the instrument cluster but the MOLEX pins can be expanded slightly as they are not full-circle but have a slot or gap down one side. They can be pried open slightly with a fine screwdriver or similar. A bit of solder and shrink tube and the connections will be safe and reliable.
I ended up making the cable from the PC (again, RBM's tutorial shows how) with the .093" female MOLEX pins. I also made two short adapter cables (.093" male MOLEX to female .062" MOLEX) so that I can in future connect easily at either under the side cover or directly to the instrument cluster.
Other Tire Size Setting:
At first, Karamba was making me crazy as I couldn't figure out how to get it to represent my sidecar's 175/65-14 tire size. Yes, I could put that value in, but I'd get the same speedo readings as when I used the stock K11LT tire sizes.
After beating my head against it for a while (and plainly not paying close enough attention ), a beer brought enlightenment. If you look just below the speedometer in the Karamba image above, you'll see a pair of "radio buttons" (as they're called in user interface circles) with the upper one labeled "Originalbereifung" (Original Tires) and the lower labeled with my weirdo sidecar tire size. In order to use Karamba for other-sized tires, the "Freie Reifeneingabe" (Free Tire Input) needs to be filled in. When it is, the lower radio button will show the size "Free Tire" size chosen. Clicking on that radio button will cause Karamba to spit out a signal corresponding to the "Free Tire" size chosen. (with both sizes entered - and so both buttons enabled - clicking from one to the other button brings an audible difference in tone through the PC's speakers - at least at higher set speeds)
From there on, RBM's tutorial got me safely home (had to put the beer aside, though) and my speedo is as accurate enough to quit bugging me.
I hope this helps someone,
Hank
p.s. RBM: you are welcome to copy / re-post this on the site where your tutorial is if you like, I just wanted to close the loop on this topic here at K11og.org. hjj
_________________
1993 K1100LT / 1996 EML GT2000 Sidecar
2001 R1150GS
Riddle me this:
Two motorcycles are being ridden down a two-lane road. They are followed by a long line of cars.
What brand are the motorcycles? |
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| Back to top |
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michaelcurrin
Flying Brick Rider
Joined: 01 Jun 2003
Posts: 329
Location: eastern NC
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| Posted: Wed Nov 28, 2012 9:44 am Post subject: |
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Good to see another EML rider, there's not a lot of us around.
For what its worth I've been using a speedohealer to adjust my speedometer
http://www.healtech-electronics.com/
_________________
Mike Currin
20 BMW R1250RS
93 BMW K1100RS / EML Speed 2000
06 Ducati ST3
67 Triumph 650 chopper |
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rbm
Mad Brick Rider
Joined: 02 Jun 2009
Posts: 115
Location: Toronto
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| Posted: Sat Dec 01, 2012 9:38 am Post subject: |
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Hank,
Very good input regarding your experiences with Karamba. I will take this input and try to update the manual I wrote. Others will benefit from your experiences, I'm sure.
Also, congrats on getting your speedo adjusted.
_________________
- Robert
1987 K75 @k75retro.blogspot.ca
2011 Moto Guzzi V7 Racer |
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