KH Zero and reinforcement plate: the homemade wedding

Some words about the why…

If you are riding with a KH Zero, you are in one of the following case:

  1. you are suffering from no flex at all
  2. you are suffering from a bit of flex when pushing on your handlebar
  3. you are suffering from pulling on your handlebar or both push & pull

In case 1, congratulations ! You are a happy rider and you can skip this thread and plan your next ride.

In case 2, you can use a reinforcement plate by attaching only the four front bolts and it should provide some extra resistance when you are pushing (I have not tested myself but see the diagram below). In such case, this thread has already proven useful and you can skip the rest of it.

In case 3, you may have considered other alternatives (like the KH One that is designed to use the reinforcement plate or even installing the KH Zero on a Nimbus Shadow base). However, either of these solution may cost you if you don’t have a Shadow base already or you have not just bought a KH uni with a KH One on it. The trick suggested for case 2 will only solve half of your problem as the pulling is not covered:

This thread is about cheap solutions (having most if not all the parts home helps :stuck_out_tongue: ). I am sharing this idea before I was able to test ride it. But as any cheap solution, I does not risk much and there is maybe room for improvement :wink:



What are the constraints of this tutorial ?

  • it should not cost more than buying a KH One (otherwise it is easier to buy a KH One)
  • it should be as non-invasive as possible (KH Zero having a stappled cover and a lot of people - including me - do not own a stapple gun)

What did I use ?

  • a KH Zero
  • a KH reinforcement plate
  • a power drill
  • two long pop rivets
  • a rivet gun
  • a drill bit matching the pop rivets diameter
  • a handsaw/cutting instrument
  • pliers


First, I got everything our of the way to check how does how the KH Zero is designed and how does the reinforcement plate was sitting.

As you can see, the front bumper sits in a depression so having the reinforcement plate under the front bumper was not a solution. On the upside, the shape of the plate is a good enough fit when sitting on top of the bumper.
I did not like how tight the plate was when putting it in place so I decided to make some room for it.

I used a handsaw to make a vertical cut right after the bolt rounding and used the pliers to back-and-forth the piece into a cut (hence the white coloring). My goal was to have it as flat as possible. You can skip this step if you don’t want to damage your front bumper or if the fit is not tight in your case.

As you can see, the plate can rest well on the front bumper. Do not forget to carefully set aside the original KH Zero bolts and use longer ones that are provided with the plate (if I remember correctly). Otherwise, you can go to the local hardware store and buy 4.

With the handlebar, it looks like any other saddle installation (and people in case 2 can go and enjoy their reinforced saddle).

Now comes the part not for the faint of heart. You can notice that the rear of the plate is long enough to touch the pivotal interface. Fortunately, it should not interfere with the recommended settings. The pic is taken with the post in the 3 notches setup (muni recommendation) and it is easy to move it to 2 notches (road recommendation) without interference. Going to 1 or more may be more problematic but let’s hope it is not used (or seldom used).

From there, it is easy to drill by using the plate’s holes as guides. Be careful not to push too hard as you don’t want to damage the foam or even drill (through). I don’t have pics for this part. From there, I used a piece of metal to try and guess the depth of the plate. I used some 30mm pop rivets that are given for a 21 to 25mm thickness to secure. It felt like forever to install them so maybe sorter ones can work too (25mm? 20mm?) but I wanted to be on the safe side ordering more than the 12mm I had. Be sure you have a proper rivet gun and strong hands as the last bit before it breaks is tough (at least with the rivets I had).
Fortunately, once done, it looks as good as it can (despite one being secured sideways).

I will post updates after a ride or two to see if it rattles or not. All in all, it should do the trick. If bad comes to worse, I will break a rivet and have to replace it. However, they seems mean enough to stay here for a good while.

Adding Stiffener Plate to KH Zero - Saddle Surgery

The previous post (and noticeable handle flex) above inspired me to try a more invasive/comprehensive approach to adding reinforcement bolts and a stiffener plate to my KH Zero by removing the foam/cover and making an extra threaded mount (or two) like the KH One.

It worked well - I now have a stiff solid mounts for my several KH zeros that use a t-handle. I have completed one saddle mod using a single extra bolt, and one with two bolts. Both saddles have been tested with an hour or so of Muni riding and have held up.

I imagine you would have no warranty after doing these mods, but my saddles were bought used anyway.


Part 0: Preparation

Equipment: Make sure you have all of the following items ahead of time:

Tools ( available from most local hardware stores):

  • Hex Key Set
  • Small Flathead Screwdriver
  • Small Vice Grip
  • Wire Cutters (or something that can clip plastic)
  • Drill with 3/16" (5mm), 5/16" (7mm) and 1/8" (3mm) bit
  • Heavy Duty Staple Gun
  • 1/4 (6mm) deep heavy duty staples with pointed edge (needed to penetrate hard KH Zero plastic and re-attach cover) - Arrow Brand T50 staples worked for me where others did not.


  • KF Zero Saddle and Stiffener Plate (Duh!)
  • Tee Nuts M6 minimum 1 ( or 2 for 2 bolt Option) but get a few (fits 6mm metric bolts that come with stiffener plate) ( I got these from Ace Hardware)

Planning - Decide how many mounts to add for Stiffer Plate - 1 or 2.

  • 1 Bolt: Easier / Less Sturdy(?) - Recommended for shorter handle and newer plate with extra hole.
    Easier to do, especially if you have a newer stiffener plate with the single hole (above the double holes) for the KH One. I think this results in a weaker build because you need to drill out and remove some of the plastic cross members near the new bolt mount. I have ridden this build with a short muni handle on some demanding trails and it has been solid and stiff - so maybe the decrease in saddle strength is negligible.

  • 2 Bolt: More Work / Better Build - Recommended for longer handle / older plate without extra hole.
    This build option required more holes and an extra t-nut and bolt, but it allows the saddle base to retain more of its strength because no cross-members are drilled out completely. If you have an older KH Stiffener, you will need to lengthen the existing 2 bolt holes to use them, but you will not need to drill a third hole.

(Part 1 and pics in next post)

Adding Stiffener Plate to KH Zero - Saddle Surgery p1

Part 1: Disassembly

  • Remove Bumpers and bolts ( seat bolt can remain - it is captive in the saddle anyway)

  • Remove Saddle Cover Staples:
    Use small flathead screwdriver to carefully pry off staples. Small vice grip helpful to pull out stuck fragments ( try to get them all out). Pull cover away from plastic saddle base. Leave the cover on the foam.

  • Test Your Stapler: (important)
    These saddles are made from some super hard space plastic that fell to earth in a UFO and was probably recovered by KH on a muni ride in some remote mtn range. This plastic is almost impervious to staples. I had to get the exact brand above for my staples to attach (even then 1 in 4 failed). Test your stapler now!!! - try to attach one of your staples in an area where you pulled one off. If your staple wont attach - STOP - you will be stuck without a way to re-attach the cover!

  • Remove Foam Top:
    Carefully pry foam from saddle edge with the flathead screwdriver or a dull knife. The foam is thin and glued on around the sides so carefully pry it loose so it doesn’t tear.

The foam attached to the top of the saddle has some light adhesive that can be overcome using your hands - carefully pull foam off by pushing grabbing the cover/foam at the nose of the saddle and slowly pulling it off of the plastic base. Work around saddle pulling the edge of the foam up and pulling down on the plastic base.

When you are done, the saddle cover/foam and plastic will separate. Note: The plastic base has a layer of paper glued to it.

Remove the paper form the base in the grid section in front of the seatpost bolt area - this is where your new bolt(s) will go.

Adding Stiffener Plate to KH Zero - Saddle Surgery p2

Part 2a: Drilling Holes for Stiffener Plate Bolts (1 Bolt option)

  • Mount Stiffener Plate using two bolts/holes at the nose of the saddle. This will line up the plate.

  • Use the central hole in the bottom of the plate for the KH One ( or mark an “X” in the middle of the plate underneath the grid section in front of the seatpost bolt area (the are where you removed the paper at the end of last step).

  • Drill all-the-way up through the stiffener plate and the saddle base using a 5/16 inch bit (7mm). the drill should exit the plastic base near where the two plastic cross-pieces intersect in the grid section in front of the seatpost bolt area.

Part 2b: Drilling Holes for Stiffener Plate Bolts (2 Bolt option)

  • Elongate the two mounting holes at the bottom of the stifferner plate. The holes should be elongated into the plate going toward the far end. You can also drill two new holes just above (to the inside of the plate) the current ones and then connect the 2 holes together.

  • Flatten back one of the 4 metal spikes that are bending down from each of the 2 Tee-nuts you will be using. If possible, clip off the flattened spike.

  • Arrange the tee-nuts side-by-side in the holes between the cross-pieces on the saddle base so the flattened/removed spikes are next to each other or overlapping slightly.

  • Drill all-the-way down through the tee-nuts and the saddle base with the 1/8 (3mm) bit, being carefull not to scrape the insides of the tee-nuts as you are drilling. The drill should go through the bottom of the saddle just to the outside of two shallow crosspieces.

  • Remove the tee-nuts, re-attach the stiffener plate and see if the holes you drilled in the base line up with the the holes in the plate. If not, dril out the plate so the holes line up.

  • When the holes in the stiffern plate line up with the ones you drilled, Drill back up through the plate and the previous holes in the saddle base using a larger 3/16(5mm) drill bit.

Adding Stiffener Plate to KH Zero - Saddle Surgery p3

Part 3a: Attaching Tee-nuts and Stiffener Bolts (1 Bolt option)

  • Using a wire clipper, remove the plastic cross piece that were pierced by the drill - giving you a hollow box in the grid section in front of the seatpost bolt area.

  • Fit the Tee-nut down into the box-section and line it up with the hole. Try to arrange the Tee-nut so that the metal spikes hold it in place.

  • Put a long bolt from your stifferner/handle kit up through the bottom of the plate, and the new hole in the saddle base. Thread the bolt into the Tee-nut tightly. If the hole does not line up well, use the drill to widen the hole in the plate and plastic base until the bolt fits.

  • Once the Tee-nut is threaded into the bolt, use strong tape or glue (I used Gorilla Glue - messy!) to fix the Tee-nuts in place. Wait for glue to dry.

  • Cut a piece of styrofoam/wood/ metal and insert it into the box over the Tee-nut to maintain even pressure beteewn the Tee-nut and saddle foam.

Part 3b: Attaching Tee-nuts and Stiffener Bolts (2 Bolt option)

  • Place the 2 Tee-nuts back into the top of the saddle base and line them up with the holes that were drilled.

  • Put 2 long bolts from your stiffener/handle kit up through the bottom of the plate, and the new holes in the saddle base. Thread the bolts into the Tee-nuts tightly. If the holes do not line up well, use the drill to widen the holes in the plate and plastic base until they fit.

  • Once the Tee-nuts are threaded into the bolts, use strong tape or glue (I used Gorilla Glue - messy!) to fix the Tee-nuts in place. Wait for glue to dry.

Adding Stiffener Plate to KH Zero - Saddle Surgery p4

Part 4: Reassembly

  • Remove the stiffener plate and bolts.

  • Place the foam/cover back on top of the modified base and push/ stretch it down evenly so the cover folds over the lip of the plastice base just like it did before you removed it.

  • Stapling: Staple 4 spots 1st to keep the cover aligned - the tip of the nose, the middle of the back, and 1/2-way along each side. Work your way around the saddle stapling. I like to make sure I staple over any seams in the cover. I noticed that maybe 25% of my staples did not attach properly ( I also noticed the same thing for the factory staples - these saddles are made from hard plastic). Eventually, you will get staples to attach around the saddle and the cover will stay on firmly.

  • re-attach the rear bumper and handle using supplied bolts.

  • go ride a solid, stiff handle !!

Of course, I offer the above posts as a “hey - this worked for me!” example only. I do not guarantee you will get the same results. I take no responsibility if my posts above cause your saddle to break, fall apart, fly off of your unicycle and kill a passing motorist, spontaneously combust while riding, etc. You follow this saddle hack at your own risk.

So there! Enjoy!

The 1 bolt modification took about 1.5 hrs to complete and the 2 bolt took about 2.5 hrs to complete (not including getting supplies).

There was a lot time trying to line up and expand the plate and saddle holes with the 2 bolt method (also a lot of time trying to get glue off of my fingers).

follow-up: Adding Stiffener Plate to KH Zero - Saddle Surgery

A few stapling tips:

Your best chance of getting staples to stay attached when putting the cover back on is to use this technique:

Make sure the stapler is pressed firm and flat against the lip of the saddle - this usually means you cannot staple deep into the lip and you will have more trouble in areas where the lip curves. Have the saddle secured in a position where it is comfortable to use the stapler and where the saddle wont slip.

I also posted some pics I missed earlier of the 2 bolt option with the cover re-assembled and the plate bolted on.

Forgot about bolt length:

You will need fairly long bolts to mount into the new holes for the two-bolt option. The bolts should have ~ 30mm of thread for a strong connection.

2 Week Follow-up - Durability / Reliability:

1 bolt option - did a couple short muni rides with a short handle

  • all good / no issues

2 Bolt Option - Using the long touring t-handle - did several muni rides a couple of which were with a 25lb pack on my back and a small bag of a couple lbs on the handle ( extra stress / weight on the handle)
-all good / no issues

I will try to post other follow-ups after a month, then a few months if I remember.

Siddhartha Valmont -

How is the pop rivet stiffener plate mount working?

That way definitely looks easier (if one has a rivet gun) - I’m curious how its lasting.

I have not ridden it recently but as far as I remember it was not showing any push-down flex when pushing from the tip of the horns in road mode (no heavy load or other crazy stress).

I will report more after next few rides now that I am back home and the sun is shining.

Seeing how big the rivets were and how hard it was to install them, I am confident that it will last for my use :stuck_out_tongue: Maybe I will reinstall my longer “horns” on the handle to benefit from the added strength.

The other advantage is: if it were to fail, I am partially ready for your approach (just need to open and put the T-nut right where the holes are :smiley:

6 Month Follow - Up: Good So Far

Both the 1 and 2 bolt setups have been holding up fine under a lot of muni riding. I had one of the screws on the 2 bolt work itself loose, but lock-tite fixed it. Its possible that the bolt angle is to blame for loosening - the bolts are not totally perpendicular to the stiffener plate where they press into it.

1 Year follow-up: No Issues

Both the 1 and 2 bolt setups have been holding up fine under a lot of (mostly XC) muni riding with some high speed falls on the G26.

I decided to see how much weight I could drop by drilling out the reinforcement plate for my 1-bolt setup, and if it would noticeably reduce stiffness of the handle setup. I used a hole saw to drill 2 overlapping holes near the 4 bolt mounting area. This was where stress seemed minimal - I could draw a straight line between the lower plate mounting holes on the nose and the centered hole near the seatpost without intersecting my drilled area.

Result: Saved 12g and no noticeable reduction in stiffness. I did achieve a 100% reduction in my ability to ever warranty or return my stiffener plate though. This project is only worth the effort (30 minutes) if you are a compulsive tinkerer like me and just need to experiment on your gear now and then.

12gm is 1/1000 of 12 kg, 1/10 000 of 120 kg.
The saved weight is between 1/10 000 and 1/5 000 of your body weight and it’s not rotational weight.
I’m not sure it is even worth a second of work, but it sounds like you are 100% aware of that. :wink:

Ha! Yes - I sometimes post projects that didn’t work or were not worth the effort so other people can learn from my mistakes.