What brand and model is your bike?

..is the geometry the same and are your fit coordinates the same?

It's a Trek Emonda SL6 56cm. The other bikes are an old Trek 5000 and a Felt Z95. The other bikes are 58s Bike shop measures put me between the 56 and 58. I am afraid I can't really provide much more info on the geometry as that is beyond my knowledge base.

Is this speed wobble? https://cyclingtips.com/...nd-how-to-stop-them/

Or just handling that is more responsive than you are used to?

Do a quick check to see if the wheels are unbalanced. With the bike in a stand (or otherwise supported off the wheels), spin one of the wheels up to speed and see if the bike starts to shake. You can also swap wheels between bikes (assuming compatibility) to check things.


Examples:
https://www.youtube.com/...l=ShaneMiller-GPLama


https://www.youtube.com/...heSwiftWheelBalancer

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ECMGN Therapy Silicon Valley:
Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)

I have experienced quite a bit of speed wobble, which as you will now know is pant-shittingly scary. I also did a tonne of internet research to which I concluded that there is no one answer to your problem. It seems like it is a geometry equation to which no one answer works as the variables are too many. Now if I am even close between bike sizes I will always go for the bigger bike, which in theory should be more stable. In the interim;
If you go full wobble, grip the top tube with your knees and try not to brake (easier said than done when your life is flashing before your eyes)
Try to relax your hands on the bars
Look for somewhere safe to 'bin it'

Years ago, I took my Trek 520 touring bike to the Blue Ridge Parkway and experienced a problem with steering instability above a certain speed when going downhill. I subsequently changed the tires to thinner ones, and the problem did not recur the next time I rode that same road on the same bike. For both rides, the bike was not loaded with touring gear. I don't remember what the original tire width was. It might have been 32 mm, or it might have been 28 mm. The replacement tires were 25 mm. I wondered about this when I recently bought a new Emonda, which came with 28 mm tires.

I did some snooping around the web and found that the Trek 5000 and a Felt Z95 typically came with 25 mm tires. The Emonda SL6 comes with 28 mm tires. Based on my experience, I'd try putting thinner tires on the Emonda.

Thanks for all the help/ideas. Unfortunately my Emonda came with 25X700s, same as my other bikes. So much for an easy fix. I have thought it was just a question of getting used to it, but it's been a couple of years off and on (no outdoor riding last year for some unknown reason). I really don't have any motivation to ride a squirrely bike, I am slow enough in group rides now. The wheels seem to spin OK, I don't own or have access to a truing stand. I am open to any other ideas, I guess it is off to the LBS to see if it is me or the bike. Could become a dedicated trainer bike and I get to buy something new (n+1)

Swap the front wheels as previously suggested and see what happens. At least you’d either find the problem or knock one possibility out. Super easy to do.

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Not a coach. Not a FOP Tri/swimmer/biker/runner. Barely a MOP AGer.
But I'm learning and making progress.

You don't need a trueing stand to know if your rims are true.

Will wider tires fit your frame and fork?

Since it's off and on that it occurs, I'll add my n=1 for you:

A few years ago I fell in the driveway into my car and separated then broke my shoulder. Long story. When I finally got healed enough to get back on the bike - an older aluminum Trek 2100 - my first ride was up north over Dixville Notch. I've ridden it a bunch, should have been a pretty ho-hum ride.

Coming down the back side, I got to just about 40 mph and a speed wobble occurred. Thankfully, I was able to bring it out of it, but it was scary as hell.

So for a while after that, I was pretty hard on the brakes instead of just letting it fly, like before my injury - I'd routinely hit 50 on one ride that I do.

It took me a bit but I finally figured my issue out: it was my brain, I was scared of the decent. Because I was so nervous as I began to descend, but determined to 'ride through it,' I'd get in the drops and weight the pedals pretty heavy... bad idea.

My nervousness - and subsequently I've found, if there was a really hard effort on the climb that taxed the legs - I would start to get a little leg shake, and that was where the wobble originated from.

When I notice my legs feeling like this, I make sure I'm not supporting my weight on my pedals, but sitting my ass on the saddle. It has worked for me, at least enough to get over things and be able to ride.

Just my n=1, but hopefully it helps you. Good luck!
- Jeff

I have an Emonda SLR6 size 56. I don't experience any speed wobbles but I don't have much of the stock components.
One thing that I changed was the stem. I went to 110 instead of the 100. I felt that with the 100 the bike was too responsive and a little twitchy. But I also have 40 cm bars.
I like how it rides with the longer stem.

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Tiago
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Sponsors: : Blueseventy :

Similar to other posters in this thread, I once had a road bike that became really erractic on fast decents. Turned out to just be worn tires. Your tires would of course be new, but still a good place to investigate. Maybe swap out for a different brand, and maybe a different size. Also, some tires are directional, so must be mounted accordingly. Not sure it really makes any difference in actual performance, but only takes a second to check how they're mounted.