cubewheels

I bought a cheap Chinese knockoff of the Rinsten saddle spring tech just to see how it performs.

Quality of the Chinese knockoff is OK but the concept seems to have a major flaw that badly affected the bike's balance and handling during hard braking (Unless Rinsten have managed to solve the problem).

I was testing the contraption at very slow 5 kph to test handling during hard braking (maximum effort braking without locking). During max braking, the spring would quicky unload and exaggerate the transfer the rider's weight to the front. In most of the tests, the rear wheel lifted off! Things did not end there. As the rider's effort is to resist going OTB, the action would transfer the weight to the rear wheel, but excessively with the spring compressing more due to the transfer momentum. It then caused the front wheel to lift off!. And the rocking back and forth after hard braking did not stop until a few cycles later!

Maybe it's just the knock off product that's literally trying to knock me off the bike? I also noticed it's much more difficult to move around the saddle now to deliberately transfer the weight because the spring would uncompress if unladen and the saddle would just rub against you, unless you stand higher on the pedal. Without the spring, you only lift your butt a little to transfer weight.

Not sure how Rinsten would be able to solve such problem using nothing else but curved metal spring with seemingly no damping system whatsoever.

So I tried to solve the problem with the simplest means possible (see steps and picture below):

Step 1 . Sit on the saddle (which compresses the spring). Make sure to put most of your weight on it.

Step 2 . Have another person loop around a steel cable on the saddle spring - while you remain sitted on the saddle and the spring compressed. Make sure the cable is looped tightly and then secured

Step 3 . If you did this right, the saddle should only rise up a very little bit if you get off. If you can get more weight on the saddle (at Step 1 ) by wearing a heavy backpack for example, it will also "preload" the spring which is a really cool thing!

The steel cable mod completely solved the hard braking problems, handling/weight transfer issues, and also eliminated rocking after hard braking. It works like a rudimentary rebound damper and also eliminated most of the bouncing or bobbing during hard pedaling or going over consecutive bumps on the road (improving ride comfort too). Preloading would further improve handling and damping at the cost of harsher ride.

Not sure how good this will hold in the long run so try at your own risk!!

shelbyfv

Bizarre! Like non-pneumatic tires, this probably won't be a problem for many

cubewheels

There's quite a few curious folks here one time when the product first came out.

It actually works even with the $10 Chinese knockoff. Just unsafe and too bouncy without modifications to limit rebound.

Reynolds 

Looks like it would flex sideways too.

veganbikes

So you bought a cheap knockoff of a bad idea? I guess someone had to do it or they wouldn't sell these things!

If I want some sort of suspension or isolation from the bumps I will go with a Kinekt Seatpost it is a reasonable design. It has two actual springs that can be swapped for different weights and ability to adjust preload and it unlikely to have the same odd flexing. I could also go with the good ole' Cane Creek Thudbuster or better yet ride a more forgiving frame.

2cam16

WTH is that?

Troul 

Looks like a poorly manufactured bottle cage redirected to the "Seat Inventory" area.

Ross520

Anyone who has thinks it would be a good idea to not only purchase an extremely sketchy, whatever that heck that thing is, but, on top of that, buys the generic version, almost deserves whatever happens to them subsequently.

A better, safer idea would be to just purchase a bike with decent suspension, heck, my rigid gravel bike practically floats on her low-pressure 35s...

Why is this even a thing?

GrainBrain

You should wrap an old inner tube around it as well, would provide some dampening.

cubewheels

I'd be expecting that too but didn't notice sideways flex with or without the mod even during hard pedaling, and passing through a rough section of the road.

It's probably flexing sideways but too little to be noticeable.

cubewheels

That might work too!

The high tension steel cables already provides damping as it eliminated bouncing during road test in both hard pedaling and bumpy sections of the road. Most importantly, eliminated excessive rebound (uncompress) during hard braking.

I deliberately went for steel cables as rubber or nylon rope (another alternative I considered) may stretch over time

cubewheels

I actually ended up not using it. The mod could not fully solve one of the problems - the saddle nosing up a bit whenever the spring is compressed like when pedaling hard or going over long stretches of rough surface.

The mod did considerably reduced saddle nosing up but not enough for me. I have very extremely sensitive perineum. I ended up making my own thickly padded saddle instead. It resembles a triathlon saddle but with very thick padding. Roads are really bad where I live, even worse than a freshly-rolled gravel. Really robs you of performance if you have to lift your butt half of the time. Full suspension bikes not an option. Gangs would rob it off you while you're riding. Just have to own a bike worse than what others have to avoid getting robbed!

Anyway, I'm definitely NOT recommending the knock off. Get at least the Rinsten brand version. I simply tried if the concept works.

And I found the concept is fairly problematic without some form of preload and rebound damping. Without a preload, it's especially difficult to mount and move back on the saddle and without any damping, handling becomes dangerous (exagerrates weight transfer), unless you totally avoid situations where you'll have to brake hard which means riding slow.

Ironfish653

I don’t think the Rinsten spring has any performance benefits, and it’s major comfort benefit seems to be low cost, compared to something like a Thudbuster.

I also think that the spring can amplify the effects of poor technique: Under braking, you should be putting your weight on your feet, and moving your butt back on the saddle. If you’ve ever had to handle an MTB down a technical trail, you often end up behind the saddle altogether, which is the whole point of ‘dropper’ seatposts.

cubewheels

Yes, the saddle height would rise up and also move you forward if you do nothing while braking. The action would move CoG up and forward - greatly increasing risk of going OTB under hard braking.

The unmodified spring also makes it harder to move you butt behind the saddle (for roadies using optimal seatpost height) because the spring would uncompress and raise the saddle up if you raise your butt (getting in the way so you need to lift your butt even higher to move back)

The hi-ten steel wire preload / rebound limiting mod made it safe enough for a road test (I have morbid fear of OTB and didn't test it in the road until I found a quick fix to the design problem) and also solved the problem of moving your butt behind the saddle and solved excessive weight transfer as well.

Not sure if the Thudbuster also has preloader / rebound limiter because the design is also susceptible to excessive weight transfer during hard braking. It could certainly use one if not yet equipped.

You're right, Rinsten spring doesn't seem to offer performance benefit. In reality, it feels a bit harder to pedal, worse with the unmodded spring (even with saddle height corrected).

Ironfish653

Like any other suspension system, it needs to be set up properly.

Designs like the Thud and the Kinect have adjustable springs, so that you can dial in the spring rate. Ideally you want to only be using 10-15% of the springs’ travel when you are at rest, with your full weight on it.

These designs also also have linkages to control the travel, unlike the Rinsten, which also doesn’t have a preload, so you might be sitting at like 50% of travel, which is why it gives you the feeling of trying to push you off the bike.

cubewheels

Not just a feeling, it's actually trying to throw you off the bike!

I set the hi-ten steel cable preloader to 0% travel when sitting on it at rest and all the problems went away.

Handling did not really improve compared to no-spring saddle. On the otherhand, thickly padded, no spring saddle did improve handling (rear wheel grip in bumpy roads) compared to either no spring or sprung saddle.

Anyway, I will never be hitting any trails. Simply using my bike for exercise, improving my pedaling strength and endurance riding around the city. And we we have terrible quality of roads, thus, the need for some sort of shock absorption. But don't want full suspension due to rampant bike robbing.

cubewheels

I decided to have another go at the spring + mod and reinstalled them since I now have a much more comfortable saddle with a deep groove in the center. One that remains comfortable even if it noses up!

...And this time I followed precisely your advice 10-15% compression at rest and it made a world of difference!

I think I'll keep using it. Feels like a proper suspension now and feels great and safe even at high speed over bad roads! Quite interesting to note, even hard braking performance improved! Sadly couldn't take videos showing things like hard braking from high speed, going fast over bumps and pedaling hard with zero bouncing (just to show how vastly improved it is over stock Rinsten spring). I got nobody to tail me and take videos!

Anyway, here's the updated looks, not much has changed, except having more loops with the same steel cable which increases the preload value (to achieve 10-15% spring compression at rest, increased stiffness, and more rebound damping)

Miele Man

I can imagine t he consequences when that spring fatigues at the bend and snaps. It won't be pleasant for whomever is on the bike at the time.

Why anyone would buy and use a Chinese knockoff of such an important component is beyond me. Most of us have heard horror stories of the quality, or should I say lack of quality, on many other Chinese knockoffs. And that's not to mention that buying Chinese knockoffs is rewarding them for doing so.

Cheers

Wileyrat

There was a guy here a while back that had a sad story about an original, much less a knock off.

FiftySix

Weird spring. It is adjustable in the sense that if the saddle and seatpost are both mounted closer to the bend the stiffness should increase and the travel up and down should decrease to the point of near zero.

This saddle spring is of course mounted on that 20" BMX bike, but you're adult sized, so you have the saddle at max rearward (1st photo) which decreases stiffness but increases up and down travel. And your unsprung travel limiter is that cable, plus you moved the seat forward quite a bit in the 2nd photo.

Of course, this makes me think what's wrong in getting a traditional coil spring saddle and why are people that use those saddles not having issues? But, it looks like this Rinsten design allows the mounting of narrow saddles, which aren't typically built with coil spring support.

cubewheels

I am hoping the cables which vastly reduces spring travel will help prevent fatigue failures. Thanks for the concern though. Your concerns are valid and I'm keeping a close watch for any signs of problem

cubewheels

Yes, that is true. But I would advice against such adjustment (both saddle and post close to the bend) due to much higher fatique stress and higher change in saddle angle during bumps.

I really think, they need a heavier spring for heavier riders or for riders who wants stiffer settings because you really don't want to have things close to the bend.

The adjustment is a bit stiffer for my 132 lbs weight than is actually possible. Stiffer is better for pedaling efficiency.

The rest of the adjustments is to have the right fit, weight distribution, and least amount of saddle angle change as possible.

Many of the coil spring saddles look better design than Rinsten. Some seem to have travel limiter built into the spring. The 3-coil spring designs don't tilt when loaded or unloaded. They could be better in doing their job

But you're right, the major advantage of Rinsten is you can choose the saddle to put on it and kinda looks good compared to coil springs. Just don't bet on it for any serious riding, unless you put a travel limiter which can also serve as preloader and rebound damper.

cubewheels

This the guy?

Rinsten saddle spring

I'm definitely doing some precautions like inspecting for cracks before riding and avoid lifting the bike by the saddle to avoid unecessary tensioning of the spring unless I'm riding.

I'm also hoping the steel cable which vastly reduces spring travel could also eliminate spring fatigue. And I'm only 132 lbs, hoping my chances will be better

I guess I'll have to keep everyone posted if the thing fails (if I managed to survive it or at least able to type or think!) or the first 1000 miles if it's still OK.

FiftySix

Interesting read.

FiftySix

I've never had a 3-coil spring saddle. Currently I have a nose pivot 2-spring saddle on one bike. I just set the angle for what fits me best at my 185 pounds dressed weight. The tilt angle of that seat from unladen to laden to heavily compressed isn't that noticeable to me.

My most recent memory of that coil spring saddle smacking me in the back side was this past Friday when my curb "ascending" technique got out of hand. Normally, I lift the front wheel just enough to clear the curb, then shift my weight to the front wheel and the rear wheel follows up the curb with ease.

Except, this past Friday I was still sleepy and hoisted an honest wheelie with the front wheel which kept my weight back and then the rear wheel slammed into the curb. The seat smacked into me good and I thought I damaged the wheel . . . but so far so good.