I have a Terra, with 21/18" wheels and I'm replacing them with 17's. I was wondering if anyone knows how to change the wheel diameter on the speedo? Couldn't find how to do it in the manual. Thanks for any assistance!
I don't think you'll find a way to modify the speedo. You could use something like a Speedohealer. I have one on my DL1000. They are plug and play on many bikes, but because the speedo runs off the rear ABS ring, this might be a trickier solution for the Terra. Alternatively, you could try to trick the speedo by messing with the abs ring on the rear wheel. Changing a 140/80/18 for a 150/70/17 will reduce the circumference of the rear wheel by about 5.8%. Maybe by reducing the number of slots in the ring from 48 to 45 would theoretically reduce the speedo by 6.2%. I don't know how you would do that.
Or, you could put a speedometer app on your phone and you could mount a cheapy gps and use the speedometer function on it.
Nev is right , sadly there is no option to re-calibrate the speedo when you swap wheel sizes. Luckily the Terra speedo is more accurate than most so when you do run 17's its error is not that different than a lot of bikes I have owned. Hot Rod Welding made a re-calibrated ABS/speedo ring for the BMW G650X series, the speedo's on those bikes were WAY off. http://www.advrider.com/forums/showthread.php?t=458634 http://www.hotrodwelding.nl/product.php?id=10 The one for the G650X bikes wont work on ours, but you might try contacting them and see if they could make one for ours. The biggest issue I see though is our rings have bent flange mounting tabs that make recreation a lot harder than the true flat style that the G650X used.
Wunderlich has a wheel tone ring from a bmw 650 that fits our bike. The ring is for a 17" wheel. No adjustments needed.
Baddrapp, Do you have a link to that? All I find is the ABS ring for running a 17" on the front wheel. Not the one for the rear that the speedo works off of. http://www.wunderlich.de/shop/en/abs-ring.html This is what our rear tone rings look like.
Sorry. I can't remember where I saw the posts. It might be on adventure rider. I see if i can find it again.
The factory parts catalog indicates the Terra and the Strada use the same tone ring for both 17 and 18 rear rims.
Yes, same part as on the 17" BMW 650 GS rims as well. BTW there are no 18" Factory rims for the BMW 650 GS bikes, they are all 17" I believe the actual speedo units for the 17" ABS Strada/Terra and the 18" US/non ABS Terra are calibrated differently internally. Hence the need for a special made tone wheel to correct the 18" US/non ABS Terra speedo if using a 17" rim.
I wonder if that is something selectable in the MOSS tool. A quick google search found this,.. published in 2000. http://www.ibmwr.org/ktech/speedo-cal3.shtml Seems BMWs had some calibration adjustment inside the dash.
My Speedo is over by about 8%.... a bit annoying. Has anyone looked in the back of their dash and seen any pots as mentioned above? It seems our bikes are calibrated to run an 18"rear and with mine being a 17' ABS version it goes a long way towards my 8% over read.
ok guys I'm looking at getting some new rings made with 4 less slots to correct my error. How many of you are interested in this? I know getting one set done will cost but getting 10 sets done will not cost a lot more. I am hoping to get them made from ferro magnetic Stainless Steel. PM if your interested.
Pending cost, I would be interested. Its something that would be nice to get more accurate when running 17's, but not something that really bugs me enough to spend a lot to fix. Kiwiape, I am surprised to hear your bike is off assuming it is stock. I swear I had had seen the 17" Strada guys claim their speedos were fairly accurate, just like the 18" wheeled Terra guys experience.
Running my 18" wheels/stock tires I saw the speedo showing 2 mph higher than the GPS almost across the board, regardless of speed. I had not checked it with different tires as I have not run them long or on any trips where I amuse myself with such things.
I have not noticed any significant speed discrepancy on mine. Still running the factory 17" rear rim. I'll double check on my way home tonight.
Yes there is, if you have a quick look over at the BMW 650 and comments they started this with Sensor rings with 4 less slots and that almost perfect for mine which is over reading by 8%. Mine is an ABS version. If my rear wheel was an 18, it would be better by about 6%....which would be close enough....
The ring over on ADVrider thread is for the G650X bikes. (Xchallenge, Xcountry, Xmoto) As I noted above it does not fit our bikes nor the single cylinder 650GS bikes.
