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Old 06-24-2012, 07:12 AM   #31
hunter_greyghost
XS650 Allroads Traveller
 
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Joined: Sep 2008
Location: Yass, Australia
Oddometer: 8,060
I'm thinking of two sets of wheels for my XL500R;-
Roadwork - 19" front with K70 / 17" rear ME880
Dirtwork - 21" D606 front / 18" D606 rear
Still thinking of how to set up this bike, W/E dirtwork / work commuter?
Cheers
Baza
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Old 09-15-2012, 11:23 PM   #32
twasp
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Adventure wheels

I went with a 2.15" x19" front wheel on my DR650. I am currently using a Metzler Karoo 2 in a 110/80x19 front size. With one inch lowering links on the rear it had a reduced castor effect on steering and the street biased tread pattern combined to cause the front tire to oscillate from side to side when traveling on soft sand/gravel over hardpack.
I lowered the fork tubes in the tripple clamp approximatley 1/2", which helped straightline stability and left the flickability very quick on firm surfaces. Felt good in the corners on tarmac and stable on firm dirt roads. There was still some instability on looser dirt surfaces.
I then went to 1& 1/2" lowering links. It now is quite stable on sand, gravel and loose off road surfaces. On street it is not as flickable but has good straight line stability and is stable in corners. I can change line mid corner.
One thing I have noticed is that there is more stability with wider rims. A 2.5' is more stable than this 2.15 and a 3.5" rear rim is more stable than a 2.5" on the rear.
Recently purchased a new to us 110/80x19 Pirelli Scorpion Rally front tire. It is over 1" taller than the Karoo 2, although it also has the lower FIM size knobs. When it is installed l should be able to return the fork tubes to their normal position.
Would like to hear from anyone with more geometry knowledge on the effects of changing the fore/aft pitch of the bikes when changing sizes and the effect of tire width on traversing soft or mixed terrain.
Even the vintage motocross racers go to 21" front tires on their 500s and 650 sleds, while we are in effect going the opposite way with our wide 19s. I do notice on this bike that it may float on top to a degree but find it better than tlhe narrow 21s digging in. Alternate views? Thanks, Tom
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Old 09-15-2012, 11:38 PM   #33
mousitsas
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Location: Athens, Greece
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Quote:
Originally Posted by twasp View Post
I went with a 2.15" x19" front wheel on my DR650. I am currently using a Metzler Karoo 2 in a 110/80x19 front size. With one inch lowering links on the rear it had a reduced castor effect on steering and the street biased tread pattern combined to cause the front tire to oscillate from side to side when traveling on soft sand/gravel over hardpack.
I lowered the fork tubes in the tripple clamp approximatley 1/2", which helped straightline stability and left the flickability very quick on firm surfaces. Felt good in the corners on tarmac and stable on firm dirt roads. There was still some instability on looser dirt surfaces.
I then went to 1& 1/2" lowering links. It now is quite stable on sand, gravel and loose off road surfaces. On street it is not as flickable but has good straight line stability and is stable in corners. I can change line mid corner.
One thing I have noticed is that there is more stability with wider rims. A 2.5' is more stable than this 2.15 and a 3.5" rear rim is more stable than a 2.5" on the rear.
Recently purchased a new to us 110/80x19 Pirelli Scorpion Rally front tire. It is over 1" taller than the Karoo 2, although it also has the lower FIM size knobs. When it is installed l should be able to return the fork tubes to their normal position.
Would like to hear from anyone with more geometry knowledge on the effects of changing the fore/aft pitch of the bikes when changing sizes and the effect of tire width on traversing soft or mixed terrain.
Even the vintage motocross racers go to 21" front tires on their 500s and 650 sleds, while we are in effect going the opposite way with our wide 19s. I do notice on this bike that it may float on top to a degree but find it better than tlhe narrow 21s digging in. Alternate views? Thanks, Tom
By lacing a smaller wheel in diameter in front, you effectively reduce trail which affects stability. The more trail the more stable. Also the more the trail is, the more effortless countersteering becomes. Steering angle also changes (if you don't compensate on the back) but the main effect is on trail.
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Old 09-17-2012, 05:47 PM   #34
Bambi
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Joined: May 2009
Location: Linz upon Rhine, Germany
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Hi,
I'm approaching the 19-inch-question from the other direction. Iris, my lady, rides a Suzuki GN 400 since 1981 (from new). During the years we have aquired more than one more of these ...
Iris got a 1972 Triumph Bonneville, too. In the early 90's. It became obviously that the term 'basket-case' wasn't really describing it's state. We're still hunting for parts for it ...
Some weeks ago I planned a dual-sport-ride with a friend of our's with my Suzuki DR 750 Big. Because of a crankcase-bearing-failure of my Big, the whole affair didn't take place. But that's another story ...
While preparing for the ride (getting me an off-road-helmet with goggles, boots, trousers, shirt and armour) Iris dropped the note 'I'd like to join you on this ride ...' Something I never would have expected.
I ride one of these many GN 400 in our barn, too. Equipped with a broader and flatter super-bike-bar and a pair of old BMW-GS-footrests. I've always been thinking about converting it to a 17-inch rear-wheel to get me a proper, grippy rear-tire. Now I'm thinking about changing it's front-wheel to 19 inch to be able to get some mild off-road-rubber (Heidenau Scout) on the bike and thus transform it into a scrambler. Just to give Iris a chance to join us on dry days for some green-laning. Because I know, that she won't ride a bike that doesn't enable her to get at least one foot firmly to the ground. The GN does! And with a 90/90-19 up front and a 120 or 130/80-17 on the rear (3.60-18 and 4.60-16 original) the bike won't rise too much!
So I'm very interested in this discussion, especially concerning a front-rim that fits the original GN-hub (been thinking about the Freewind-rim myself). On the rear, the rim of a drum-braked Big will do - even with the Bigs original spokes as it seems! And, what's been new to me, that a wider off-road-tire up front would provide more grip on the road?
Kind regards, Bambi
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Old 12-28-2012, 07:53 PM   #35
pingvin
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Location: Kongsberg, Norway
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Got another thread (http://advrider.com/forums/showthread.php?t=850683) where got some input on tyre choice but not really wheel size.

These are my options:

- 21"/18" wheels (OE KTM 690EnduroR)
- 17"/17" wheels (690SMC wheels)

Planning 5000km/3000mi trip this summer, probably a little bit more tarmac than gravel. But will be good gravel roads and mostly not that twisty. So no mud, sand or rocky stuff at all, hard packed gravel mostly.


So question is, will 17" front be OK? Must admit slightly nervous on tarmac on 17"/17" even though got SMC forks/shock so correct height. Nothing I mind and got steering damper anyway but maybe more of an issue on gravel?

Could of course buy a 19" front wheel but prefer avoiding the expense...
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Old 12-29-2012, 07:45 AM   #36
pingvin
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Location: Kongsberg, Norway
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Never mind, got a hub and found a 19" rim on internet so then I'll go for the adventure wheel conversion myself, thanks for the idea, never thought of that option before saw this thread!
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Old 01-08-2013, 02:40 AM   #37
n1tr0
Dual Sport rider
 
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Joined: Jun 2012
Location: Pacific Northwest
Oddometer: 117
I'm curious about which rim widths to go with and possible tire recommendations since I won't be tubeless. I'm thinking I'll probably go 150/70-17 in the rear and 110/80-19 in the front, some wet roads and gravel, but really, these'll be my street/touring/hooligan wheels/tires.

I got traded my SM wheels for some dirt wheels a couple years ago and then lowered the suspension via a lowering link and dropped the front as much as possible. I'd like to go to the 17/19 combo mostly so I can restore the suspension to how it ought to be while still being able to stop without falling over.
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