Q45 Rack Stabilization

[AronL]

Sharing this here in case it's of interest.

For me, any amount of weight on the proprietary Q45 rack generated annoying and potentially unsafe swaying and rebound at most speeds, and especially down inclines and around curves. With some time, effort, and not much expense -- just like my water bottle cage fix I could (or did ?) post -- I have fixed this.

Both issues were avoidable with better design.

 

[Ramnob42]

Doesn't that negate the function of the swing arm?

 

[AronL]

Doesn't that negate the function of the swing arm?

Uh, what/where is the swing arm ? Or will I find out first time I ride it ?

 

[Greg S]

Uh, what/where is the swing arm ? Or will I find out first time I ride it ?

The swing arm is the lower assembly that the wheel mounts on. By adding a rigid member between that and the rack it won't be able to move up and down to absorb bumps.

 

[AronL]

The swing arm is the lower assembly that the wheel mounts on. By adding a rigid member between that and the rack it won't be able to move up and down to absorb bumps.

Aha. Rendering the shock inoperable then ?

 

[Greg S]

Aha. Rendering the shock inoperable then ?

More or less. My guess is the flexing would break your "fix" reasonably quickly.

Edited to add: and worst case, a large enough bump could cause one or more of your aluminum struts to bend into the spokes - not good!

 

[AronL]

More or less. My guess is the flexing would break your "fix" reasonably quickly.

Edited to add: and worst case, a large enough bump could cause one or more of your aluminum struts to bend into the spokes - not good!

We shall see. There must be a way to improve the significant load/rack sway without unduly compromising shock absorption. Hard to believe former doesn't bother folks (or at least those who've ridden with a rock-solid load on a Blackburn, Old Man Mountain, or similar rack). Thanks

 

[kizarmynot]

I had added a stiffener for a fender and it eventually failed due to flex. You should know right away because those stiffeners will probably make noise as soon as you go over a bump. Here’s a short back and forth on rack wobble.

rear rack wobble

For those that have loaded the rear rack, have you experienced any wobble? I have two rear panniers (about 11 lbs each) and a rear trunk bar (about 7 lbs), bringing the total to just under 30 lbs. When I started my tour the side-to-side movement of the rear rack, even though not huge, was enough...

forum.cruzbike.com

 

[AronL]

I had added a stiffener for a fender and it eventually failed due to flex. You should know right away because those stiffeners will probably make noise as soon as you go over a bump. Here’s a short back and forth on rack wobble.

rear rack wobble

For those that have loaded the rear rack, have you experienced any wobble? I have two rear panniers (about 11 lbs each) and a rear trunk bar (about 7 lbs), bringing the total to just under 30 lbs. When I started my tour the side-to-side movement of the rear rack, even though not huge, was enough...

forum.cruzbike.com

Thanks !! I'm not sure what the pre-loading is but I will look for something to tighten on the shock. I had replaced the shock with something slightly stiffer but maybe if pre-loading/tightening doesn't do enough I will find/buy/install an even stiffer one.

 

[AronL]

Ok, so here's the shock. Is 1250 a reasonable shock or should I go higher ? If I want to improve this shock, which way do I turn (pre-load) the ring, which is currently at about 2/3 threads above the ring and 1/3 below ? Thanks (and yes, I'll clean it. )

 

[kizarmynot]

I think the max “size” is 2000 lbs, so you can always upgrade it. To increase pre-load, turn the knob clockwise as you are looking at it from the bottom - you should see the knob moving toward the other end of the shock and the spring being compressed. It’s not easy getting pliers onto it, so it will take many small adjustments to get it moving any distance.
A few of us also tried replacing the shock with a metal (or wood) bar. It works for me, but obviously removes any softening of the ride. You can search the Q forum for that discussion.
Good luck!

 

[Chef-boy-arri]

We shall see. There must be a way to improve the significant load/rack sway without unduly compromising shock absorption. Hard to believe former doesn't bother folks (or at least those who've ridden with a rock-solid load on a Blackburn, Old Man Mountain, or similar rack). Thanks

It bothered me as well. Having ridden a loaded Trek 520 for years there is ALWAYS gonna be some sway because the load changes the center of gravity but the amount of sway with a loaded Q45 made me uncomfortable. My solution was to lower the rack, and learn to pack a little lighter as well .

I detached the rack from it's stays, loosened the stays' connections to the frame and pushed everything down- being careful not to lower it far enough to get into the tire (or fender in my case) when the shock is fully compressed. Then I leveled the rack platform and cut a short piece of aluminum bar to bridge the gap from the stay to the connection point at the rear of the rack. Pics attached- the first shows the rack in it's lower position- I think I dropped it down about 4 inches in total; the second is a picture of the short length of aluminum bar required to connect the rack stay to the leveled platform; and the third pic is a bonus because the thread mention fender stability which I ALSO found to be an issue.

This was also a bit tricky but it works very well. The first photo shows a second fender stay I attached toward the front of the fender. It terminates on the same braze-on as the rear stay, which you can see in the third pic. This of course requires a longer screw and an additional stay clamp, both of which I had on hand as they came with my Velo Orange fenders. The other thing I did was cut about 4" of fender length off so when installed I had a reasonable amount of ground clearance at the back of the wheel. With a full coverage fender it drug frequently rolling off a curb.

Hope this helps- both these mods worked very well for me.

 

[AronL]

It bothered me as well. Having ridden a loaded Trek 520 for years there is ALWAYS gonna be some sway because the load changes the center of gravity but the amount of sway with a loaded Q45 made me uncomfortable. My solution was to lower the rack, and learn to pack a little lighter as well .

I detached the rack from it's stays, loosened the stays' connections to the frame and pushed everything down- being careful not to lower it far enough to get into the tire (or fender in my case) when the shock is fully compressed. Then I leveled the rack platform and cut a short piece of aluminum bar to bridge the gap from the stay to the connection point at the rear of the rack. Pics attached- the first shows the rack in it's lower position- I think I dropped it down about 4 inches in total; the second is a picture of the short length of aluminum bar required to connect the rack stay to the leveled platform; and the third pic is a bonus because the thread mention fender stability which I ALSO found to be an issue.

This was also a bit tricky but it works very well. The first photo shows a second fender stay I attached toward the front of the fender. It terminates on the same braze-on as the rear stay, which you can see in the third pic. This of course requires a longer screw and an additional stay clamp, both of which I had on hand as they came with my Velo Orange fenders. The other thing I did was cut about 4" of fender length off so when installed I had a reasonable amount of ground clearance at the back of the wheel. With a full coverage fender it drug frequently rolling off a curb.

Hope this helps- both these mods worked very well for me.

Thanks so much !! A lot of ingenuity on this forum. Not exactly sure what's happening here -- a bit obscured with the rack top bag ? -- but I will spend more time on it once my fix fails. On that front, interesting where the brace decided to crimp itself; see photos here. 20-25 miles on it today, albeit with little weight on the rack -- and no obvious issue yet. Ride is stiffer -- as if I had maybe really tightened this shock or got a stiffer one ? -- but not horrible.