Peculiar Instability Going Downhill
08-06-07, 10:58 AM
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Peculiar Instability Going Downhill
I did a 35 mile jaunt yesterday on my Marin. I've got the factory "dirt/street" Kenda, Krossplus 26"x 1.95" tires on it. I was a little heavier laden with gear than usual, and I noticed that coming down long hills once I got beyond about 25 MPH I started feeling an intense wobble, almost like the whole rear wheel was coming off. I stopped, checked it and everything was kosher. Nothing loose at all. Then I'd start again and get this death wobble. I did some experiments and noticed it only happens when I'm coming down the side of the road on light road sand and gravel. On good solid pavement I feel no wobble even at high speeds.
Given that roadside sand and gravel is ubiquitous in Alaska, I'm wondering if I should be eyeing a different tire. Speed is not important, but I don't want to wipe out! I've never been a fan of the dirt/street concept and actually don't mind light knobbies for what I do.
Given that roadside sand and gravel is ubiquitous in Alaska, I'm wondering if I should be eyeing a different tire. Speed is not important, but I don't want to wipe out! I've never been a fan of the dirt/street concept and actually don't mind light knobbies for what I do.
08-06-07, 12:19 PM
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I did a 35 mile jaunt yesterday on my Marin. I've got the factory "dirt/street" Kenda, Krossplus 26"x 1.95" tires on it. I was a little heavier laden with gear than usual, and I noticed that coming down long hills once I got beyond about 25 MPH I started feeling an intense wobble, almost like the whole rear wheel was coming off. I stopped, checked it and everything was kosher. Nothing loose at all. Then I'd start again and get this death wobble. I did some experiments and noticed it only happens when I'm coming down the side of the road on light road sand and gravel. On good solid pavement I feel no wobble even at high speeds.
Given that roadside sand and gravel is ubiquitous in Alaska, I'm wondering if I should be eyeing a different tire. Speed is not important, but I don't want to wipe out! I've never been a fan of the dirt/street concept and actually don't mind light knobbies for what I do.
Given that roadside sand and gravel is ubiquitous in Alaska, I'm wondering if I should be eyeing a different tire. Speed is not important, but I don't want to wipe out! I've never been a fan of the dirt/street concept and actually don't mind light knobbies for what I do.
The tire, by the way, has little to do with it.
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Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
08-06-07, 12:51 PM
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Interesting. Can the problem be reduced by keeping the gear lower to the center of gravity or something?
08-06-07, 04:06 PM
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I've had that problem when riding fully loaded during tour. Like Cyccommute said, pressing one leg to the top tube seems to help, particularly when cornering going downhill. This is where low-center of gravity front rack and panniers can help, it seems.
08-06-07, 04:47 PM
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__________________
Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
