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Old 04-10-2006, 09:22 PM   #1
User Name OP
Dobeck Performance
 
Joined: Feb 2006
Location: Memphis Tn
Oddometer: 190
Please help me with my tire question on my f650

I have a new f650 Dakar with Sahara's on it. I took it today for the first time above 50 mph. Coming from street bikes with pure street rubber I was alittle shaken by the skidish feeling of the tires. I felt I was riding on a 1/2 inch contact patch. I went 60 mph and can't imagine doing 70mph which is a typical speed limit around here. Do all the dual sport tires handle similarly? I don't plan to "offroad" mostly fire roads and lite 4x4 roads. If I did I would'nt mind having a second set of wheels with 606's or such. Are there other tires out there that I might consider that give me a somewhat more secure feeling on the black top at speed?
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Old 04-10-2006, 11:28 PM   #2
Anorak
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Check tire pressure and rear shock preload. Make sure the preload is set high enough and that the tire are set to at least what BMW reccomends. I have ridden a couple of F650 Dakars with the Sahara's at 90ish miles per hour and they felt fine.
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Old 04-11-2006, 03:24 PM   #3
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I think I might have found out why. I checked the rear tire pressure it was 49 psi which is 11 psi over the tire spec. I was stupid I thought the dealer would have it set and on the maiden ride I did not bother to check.
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Old 04-11-2006, 06:26 PM   #4
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Quote:
Originally Posted by User Name
I think I might have found out why. I checked the rear tire pressure it was 49 psi which is 11 psi over the tire spec. I was stupid I thought the dealer would have it set and on the maiden ride I did not bother to check.
If there really is a high speed handling problem, I doubt that an over-inflated rear would be the real cause.

If you aren't used to riding 'at speed', take it in degrees and don't rush youself. More miles will usually equal more confidence.

That 650 is a rock solid bike.
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Old 04-11-2006, 06:43 PM   #5
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Funny i took it out today up to 70 mph and the back end was "wagging around" that is the only way I can describe it. I find it very unsettling. Is this just the cost of riding dual purpose tires? THere was also a stiff crosswind.
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Old 04-12-2006, 06:54 AM   #6
Bigger Al
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My guess is that stiff crosswind+49 psi in the rear will cause the exact condition that you've described. More air in a motorcycle tire will shrink the contact patch. I'd try setting the pressures to whatever book spec is and go from there. Find one of the many excellent articles online for setting rear sag and fork spring preload and do those, too. Sometimes these changes will transform the machine, especially if one is larger than the average rider.
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Old 04-12-2006, 09:27 AM   #7
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Quote:
Originally Posted by Lone Rider
If there really is a high speed handling problem, I doubt that an over-inflated rear would be the real cause.

If you aren't used to riding 'at speed', take it in degrees and don't rush youself. More miles will usually equal more confidence.

That 650 is a rock solid bike.
Second Lone Rider's remarks. The Saharas are really more like street tires, and the ones on my '01 Dakar were stable at 100 mph.
Be careful until the bike checks out and you have experience with it.

Check the front and rear sag.

Put the bike on a stand and see if the wheels have any play.

Also check rear wheel alignment - axle marks should be the same on both sides.
Even if they are, check to see if the wheel appears to be aligned straight.
If in doubt, have the dealer check it.
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Old 04-12-2006, 09:42 AM   #8
rossi
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Quote:
Originally Posted by User Name
Funny i took it out today up to 70 mph and the back end was "wagging around" that is the only way I can describe it. I find it very unsettling. Is this just the cost of riding dual purpose tires? THere was also a stiff crosswind.
The Sahara tires are not the greatest for tarmac.

A crosswind on an F650 is/can be problematic with regard to handling.

Mefo tires are my recommendation: www.f650.com

You will see great improvement. The Sahara on the back will only last 5K or so.

Give yourself time to learn the bike.

Best.
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Old 04-12-2006, 07:11 PM   #9
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With 32 up front 35 in the rear and the suspension set at low (I'm a light weight) I got up to 85 today with none of the jitters. I think it helped but like some have said I'm still learning the bike. I used to have a M900 Ducati and was spooked at the difference in handling. I put on some miles and really like the bike. I don't want for power just a six gear would be nice. Thanks for the help guys. I appreciate it.
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Old 04-12-2006, 07:14 PM   #10
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We have cross wind Rossi. About 30 miles east of me records the highest average wind speeds of any where in the US. We'll get sustained 45 now and then sometimes gusts at 100mph. Today was about 20 mph not to bad but I do find as well that the f650 does walk around alittle in the breeze. I suppose nothing to worry about if you are prepared and give yourself room.
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