Wobbly rear end

[marshall2389]

Image an axis that runs threw the hub of the rear wheel and is parallel to the bike's straight direction of travel. The rear end of my Quest 1.0 is very torsionally flexible. I can stand to the left of the bike, grab the left handlebar with my left hand and the top of the rear tire with my right hand and easily push/pull the top of the rear tire 1-2 inches out of plane. I've tried tightening the bearings on the rear wheel and tightening the pivot between the front and rear frame sections. This slightly improved the floppiness. Anyone else experience this?

 

[John Tolhurst]

In what riding situation does

In what riding situation does this manifest, and what are the symptoms?

 

[marshall2389]

it is noticable/detrimental

it is noticable/detrimental in two ways. The first is taking sharp turns. While taking sharp turns it feels like the back end slides out of the turn. The second is riding with weight on the rear rack. With a couple pounds of cargo on the rack, the back of the back wobbles back and forth during appropriate pedaling cadences and turning maneuvers.

 

[John Tolhurst]

I cannot concur, although I

I cannot concur, although I often ride with 20 kg of three (and a half) year old girl on the back, with tight low speed turns etc. I suspect the sensation you describe originates from your rack system moving with respect to the main frame. That I have felt before.

 

[MrSteve]

Troubleshooting, "101"

First, to answer you question, "...Anyone else experience this?"

No, not me.

But, Elliot, you say that you've tightened both the rear wheel bearings and the swingarm bushings, right?
Right.

What's left....
I think it's your rear wheel.
Have you checked the spoke tension in your wheels?
A set of loose spokes will allow a lot of movement to happen...
of the sort that you describe.

While you're at it, are you sure that your wheel bearings are properly adjusted?
If there is no, "play" (barely detectable slop), then the wheel bearings are too tight.
Also, check your swingarm bushings and your shock-mount pivot points.
Make sure that the bearings in your rear suspension are greased.

Anyway, please check the spoke tension in your wheels?

Good luck,

-Steve

 

[marshall2389]

i will check the spoke

i will check the spoke tension tomorrow. A fix that I have been using the past two days with great results is actually a riding style adjustment! I got to thinking that if the contact force between the back tire and the ground is causing a moment and twisting the frame, then the contact force is not in line with the wheel-plane/frame-plane. I noticed that I naturally lean my body into turns, causing the bike to be more upright that it would otherwise. Since the wheel is upright the contact force applies a moment and the wheel twists. By keeping my upper body in line with the frame, or even leaning out of the turn slightly, the rear wheel is now leaned more into the turn and it does not twist away! This is working great for now but I will definitely check spoke tension.

 

[marshall2389]

I just bought and installed

I just bought and installed new bearings for the rear wheel and this also stiffened the rear end. After 5500 miles the rear bearings were very choppy and loose.

 

[John Zabriskie]

I've experienced this; but it was due to loosening of the swing arm pivot retaining bolt. I added some blue Loctite (low to mid strength thread locker) & retorqued. The wobbly was gone.

 

[Mark B]

I used to have a wobbly rear

I used to have a wobbly rear end. That's the reason I started riding.

Seriously... When I first started riding, I got that sensation a lot. I figured out pretty quickly it was body english, or the wrong amount at the wrong times and it usually manifested in turns when I would move my hips incorrectly. Riding a Cruzbike successfully is all about the hips.

Mark

 

[marshall2389]

I found another source of the

I found another source of the wobbly feeling. It was my seat back. My seat back had cracked on both sides at the bottom around the bolts that connect the seat back to the seat pan. Now that I've got a new seat back the whole back feels stiffer. However, I have found that the most significant source of the wobbly feeling was unsecured luggage on the rear rack. I put my stuff in a bag mounted on the top of my rack. If I don't tighten everything down then the rear feels very wobbly (because it is wobbly when my cargo is free to jostle back and forth).

 

[Shakey]

Had the same thing.

Back end felt "loose" & the brake would rub on hard corners.
Turned out that the swing-arm bolt was loose AND the bolts holding the shock as well.
Tightened everything, much better now.

 

[Andrew 1973]

This reminds me of a female friend I ride with...

I was drafting her and when the pace slowed, I pulled up next to her and told her that her rear end tends to shimmy a bit during out-of-saddle efforts. It took her a few moments and my wry smile until she realized what I meant. ;-)

Sorry. Go about your business.