V1, Frozen or locked headset shock

[hardtd17]

Hey, everyone,

Long-time V1 rider. I have two of them, with upgrades to wheels, tires, brakes, gearing, rear shocks, etc.

I just realized that one of them has a headset shock that works great, while the other one's front shock doesn't move at all. I've read through the old posts, even the one that suggests fixing it wouldn't make a difference. But I ride both the bikes and can feel a difference in the ride on the bike that has a working front shock. And I'm retired and at the moment have not much better to do that put some time into tinkering with it---provided I can get answers or advice on the following questions!

1. Is working on the headset and shock area of the V1 something a technically competent regular person can do? I am not a trained bike mechanic, but I have done the basic maintenance and repairs on my bikes in the past, and I can follow instructions.

2. Can this kind of tinkering be done without specialized or expensive tools?

3. What brand and/or kind of shock is on the V1, and are there service bulletins, manuals, or youtube videos to learn from?

Thanks to whomever can help with this!

David Hardt
Roxboro, NC

 

[Doug Burton]

Hi David, I'll take a shot at answering your questions.

The shock section of the Silvio 1.0 fork was made by a company called Kind Shock. The fork was built around that shock by a Chinese company, as I remember. Kind doesn't do retail, unless you can find them on Alibaba.

The shock itself is not replaceable or particularly serviceable, but it is also a pretty simple beast; basically a synthetic rubber bladder inside a sliding chamber.

This is how I would check it out:

#1: Is it "flat"? Is the shock fully-compressed or stuck at some intermediate extension?

#2: Do you have a shock pump? One was provided with every bike. A standard tire pump will not provide the required pressure. If you don't have one, let me know.

#3: The air shock is filled via a standard Schrader valve like the one used on tires. You can remove the valve from the stem with a standard Schrader valve removal tool (just about any auto parts store will have one). Remove the valve from the stem, and see if you can then push and pull the shock up and down (it might be difficult, but any movement is probably good news). That will tell you whether you just have a defective, stuck or clogged valve, or, if the fork still won't move, it is mechanically stuck.

#4: If it is mechanically stuck, there may be some corrosion at work. You can peel back the rubber "boot" between the fork and the head tube, which should reveal the sliding section of the fork. Use penetrating oil between the outer and inner slider, and let it soak really well, say overnight. You may have to have the bike upside-down for the penetrant to get where it needs to go. Then attempt to cycle the shock by hand.

Let me know if none of this works.

Best,

Doug

These air forks could be a pain in the old days, which is part of the reason Cruzbike doesn't use them anymore.

 

[Doug Burton]

Hi David, I'll take a shot at answering your questions.

The shock section of the Silvio 1.0 fork was made by a company called Kind Shock. The fork was built around that shock by a Chinese company, as I remember. Kind doesn't do retail, unless you can find them on Alibaba.

The shock itself is not replaceable or particularly serviceable, but it is also a pretty simple beast; basically a synthetic rubber bladder inside a sliding chamber.

This is how I would check it out:

#1: Is it "flat"? Is the shock fully-compressed or stuck at some intermediate extension?

#2: Do you have a shock pump? One was provided with every bike. A standard tire pump will not provide the required pressure. If you don't have one, let me know.

#3: The air shock is filled via a standard Schrader valve like the one used on tires. You can remove the valve from the stem with a standard Schrader valve removal tool (just about any auto parts store will have one). Remove the valve from the stem, and see if you can then push and pull the shock up and down (it might be difficult, but any movement is probably good news). That will tell you whether you just have a defective, stuck or clogged valve, or, if the fork still won't move, it is mechanically stuck.

#4: If it is mechanically stuck, there may be some corrosion at work. You can peel back the rubber "boot" between the fork and the head tube, which should reveal the sliding section of the fork. Use penetrating oil between the outer and inner slider, and let it soak really well, say overnight. You may have to have the bike upside-down for the penetrant to get where it needs to go. Then attempt to cycle the shock by hand.

Let me know if none of this works.

Best,

Doug

These air forks could be a pain in the old days, which is part of the reason Cruzbike doesn't use them anymore.

David,

Here are some photos of the shock section with the boot removed. We are looking at the fork from the back side. You can see the valve stem; the valve has been removed from the stem. You can also see the inner sliding section of the the fork; the diameter is smaller than the steerer section of the fork, and slides in and out of the steerer tube. The fit and the grease between the tubes provides the damping. The travel distance is very small. At the bottom of the sliding section is a dust seal; try not to damage it as there's no way to install a replacement, if you could find one.

Let me know if you have questions.

Best,

Doug

 

[Doug Burton]

David,

Here are some photos of the shock section with the boot removed. We are looking at the fork from the back side. You can see the valve stem; the valve has been removed from the stem. You can also see the inner sliding section of the the fork; the diameter is smaller than the steerer section of the fork, and slides in and out of the steerer tube. The fit and the grease between the tubes provides the damping. The travel distance is very small. At the bottom of the sliding section is a dust seal; try not to damage it as there's no way to install a replacement, if you could find one.

Let me know if you have questions.

Best,

Doug

Oops, now I see this post is in the Sofrider section, not the Silvio section. Sorry about that.

The Sofrider fork is a little different animal.

There are 2 suspension fork shock springs inside the steerer tube, one on top of the other with a separating spacer between them. I have a drawing around here somewhere that shows how the parts are arranged. Lemme see if I can dig it up.

Same potential issue concerning corrosion may be the issue, you can similarly roll back the boot to check the sliding section.

Sofrider forks are difficult to dis- and re-assemble successfully, but it can be done. Again, lemme see what I can come up with.

Thanks,

Doug

Edit: I found the drawing. This is for the early Quest, but in this section the Sofrider fork is the same.

Working from right to left in the drawing, there's the top cap, which isn't used on the Sofrider, then there is an inner cap, that has a 6mm hex hole in it. This anchors the whole assembly at the top, and stops the springs from coming out. The inside of the steere tube is threaded, so you can back the inner cap out by unscrewing it. Then the spacers and springs should be accessible. The bottom sliding section of the fork tube transmits its load through the center divider by way of the thinner section that passes through with the allen head screw holding the spring seat in place. There are two flat head screws that come in from each side of the steerer tube; these keep the upper and lower tubes from rotating separately, so avoid removing those if you can (they are hard to re-align if they get crossways.

If you take out the inner top cap, you can spray penetrant into the spring area and let the fork stand upright for a good while to loosen things up.

Lemme know if you have questions.

Best,

Doug

 

[hardtd17]

Hi, Doug,
Thanks for the reply and diagram regarding the Sofrider front suspension. I think I understand it's structure and functioning. Yes a question or so.

A. Where in the diagram would those two screws to avoid moving be?

B. Is access to the steer tube through the headset and extension tube? If so, is that part of the assembly easy to disassemble with regular tools? And are there instructions, diagrams, or videos on doing that?

Warm regards,
David

 

[Robert Holler]

These forks are old and are not technically designed to be user serviced - so proceed with caution on them if you embark on any disassembly. All suspension forks are wear items (also why we abandoned them over time) as they all eventually become problematic. There are two set screws in the steer tube as you can see in the diagram Doug posted. It is critical to check these (even on properly operating forks of this design wether they are on a Cruzbike or not) and ensure they are tight and thread locked into the tube.

One of the main reasons these forks go bad (and later the forks on the Silvio) is the reality that locking the lower part of the fork at the axle to the chainstay prohibits the fork from operating as designed, especially when the angle of the stay interacts with the axle at anything other than 90 degrees (which is never basically) - just enough to cause additional wear. The stay acts as additional leverage that causes impeded and irregular movement of the shock internals that it was not designed for.

 

[Doug Burton]

David,

I have to agree with everything Robert wrote here.

If you look very carefully at the drawing photo, at the extreme bottom, upside down, in pencil, is written "folding bike". That's what these forks were originally designed for. The wear stresses would be different from those applied by the Cruzbike front end design.

If you remove the fork from the bike, the set screws will be visible, screwed into the side of the steerer tube. They should be set with red Loctite or equivalent. They will be very hard to remove (they might bring the threads out with them), and should be re-installed with red (permanent) Loctite when re-installed.

These forks were replaced with non-suspension, solid forks, with no loss of functionality for the bikes, and a lot less hassle for Cruzbike. Overall you my well be in better shape if you just leave the fork stuck. There aren't many, if any, replacements available.

In general, for safety's sake, you have to be very very careful working on these forks.

Robert is correct, and reminds me with his post of things we went through a long time ago. In my zeal to help you out, I may not be helping you as intended. If you proceed, do so with surgical caution. You might go from having two bikes that are rideable to one that ends up being spare parts.

Best,

Doug

 

[hardtd17]

Cautions noted and heeded!

In that case, is it true then that this completely immovable fork will continue to operate as an unsuspended fork with safety for many many more years? I ride road only, or short grass areas on a campus.

Or at some point will it become a safety concern leading to me abandoning the bike and buying---my next cruzbike?

 

[Doug Burton]

Hi David,

It should be fine if it's stuck. Just like a non-suspended fork.

Now if you need an incentive to buy a new Cruzbike, far be it from me to take that away from you...

Just joking. I get out over my skis sometimes trying to help people with the old bikes, of which I have many, and fond memories that go with them.

The Sofrider, overall, was very trouble-free and served well, benefiting from its relative simplicity. While seemingly a tad heavy, at about 35 lbs. it was right in the middle for weight of available suspension bikes at the time. It was the superior climbing performance of my first conversion bike, which weighed 47 lbs., vs. my beloved Vision R40, which weighed 33 lbs., that sold me on the Cruzbike concept and got me involved in 2005.

But the new ones that have been improved in design and execution by Robert Holler and Johnathan Garcia are in a whole, new, different class for speed and reliability, and compatibility with popular (and available) bike parts.

The new bikes rock!

Best,

Doug

 

[hardtd17]

Hi, Doug,
Thanks again for the advice and insights. And the perspective on the new bikes. Indeed I have no need for a new bike. But maybe I'll look for where I could test ride those awesome looking latest incarnations.

warm regard,
David

 

[Doug Burton]

You appear to have good understanding of the bikes you have.

If you have any questions, feel free to contact me via DM .

Best,

Doug