Pedal Kit Maintenance or Repair

For those of you who prefer a video over reading there is an online video by “fuzzyfriendlydoggy” which illustrates how to accomplish this task.

The Sur Ron Pedal Kit is basically like the simple bottom bracket on a child’s bike. There are two reasons for disassembling your pedal kit:

  • Pedal kits should be serviced regularly depending on how much you ride your bike and in what conditions. There is a small hole on the top of the tube which holds the bearings and the spindle. I believe this hole was meant to face DOWNWARD to allow any moisture to escape, but because it faces upward on the Sur Ron’s application it would only allow moisture and debris to enter, NOT escape.
  • Some of you may find that your pedal cranks have an undo amount of play in them. This will cause wobble of the pedal kit sprocket as well as a loose feeling as you ‘pretend pedal.’ This is almost always caused by the removable bearing race having loosened because the threaded collar ring has loosened from being tightened securely against the shell tube.
This is the hole in the pedal kit’s shell. I will be looking for a rubber plug to insert into this hole and will add it to this post once that’s done.
This is the correct orientation of the pedal kit as it is installed on the bike’s swingarm. The wider mounting flange is toward the front of the bike. As you can see the hole is forward and upward facing. In my view there is no reason for the hole at all. I may decide to drill a second hold on the bottom of the pedal kit shell to allow moisture to escape and plug the existing hole.

BTW the pedal kit with the OEM cranks and metal Luna pedals weighs 5.6 lbs.

NOTE: Two weeks ago I was contacted by a fellow Sur Ron owner who lives here in the Bay Area. He had taken his two Sur Rons down to Luna to have pedal kits installed onto both of them. One week after he returned one of the pedal kit sprockets separated from the shell tube and caused the bike to become inoperable. The chain was binding so much that the bike would not move. He went to three motorcycle shops and two bicycle shops to have it repaired. All five of those shops said that they could not work on something they were not familiar with. Bike shops said, “That’s a motorcycle, we don’t work on motorcycles.” Motorcycle shops said, “That’s a bicycle, we don’t work on bicycles.” So for ten months he could not use one of his bikes! Holy shit man! I ended up fixing it for him….for a fee of course. And the reality? EVEN IF either of those types of shops would work on his bike they would NOT have been able to repair it. The fix required a new pedal kit assembly. I had a back up (Boy Scout shit never dies!) which I ended up selling to him. They would never have had one!

Then just today (7-8-19) he sent me the following photos of his other bike which now has the very same problem:

Bearing race has separated from the pedal kit’s shell tube.

The reason it has separated is because the locking collar ring was not sufficiently tightened down on the bearing race. I use blue Loctite btw on the ring. This allowed the race to back out from the shell tube. But the most concerning thing here is the bearing race has now threaded onto the pedal kit sprocket. You can see that the locking collar ring is now pressed up against the sprocket housing. And if it’s locked on so tight that it cannot be removed (like it was with the one I fixed for him), he will need to purchase another pedal kit. Ugh! The rotation as you pedal your bike will naturally TIGHTEN the sprocket against the bearing race IF the locking collar ring is loose enough to allow the race to rotate out. That’s what made it impossible for me to separate the bearing race from the sprocket.

The reason I posted this is to illustrated that if you purchased your bike with the pedal kit already installed, it would be a great idea to inspect the locking collar ring to ensure it is tight. Otherwise you may find yourself in the very same predicament as this poor fella. Enough said, let’s move on….

The Sur Ron pedal kit itself is very simple to maintain. It basically consists of the following parts:

  • The ratcheting sprocket assembly
  • The housing shell which holds the pedal spindle
  • Two thrust ball bearing cages
  • One spindle
  • Two removable ball bearing races. One that is REVERSE threaded. That is the one opposite the race with the threaded locking collar ring
  • One threaded locking collar ring
You should note that BOTH SIDES of the pedal kit’s shell tube assembly can be detached. The side that does not have the locking collar ring is a REVERSE THREAD, meaning to loosen that race you would rotate it CLOCKWISE which is the exact opposite of normally threaded items. I recommend removing both since it’s much easier to clean and grease the races when they are removed from the shell tube. And you will definitely want to clean out the shell tube itself as well.

You should note that the spindle side where the ratcheting sprocket is attached has ground flat spots which securely hold the locking bolts onto the spindle. Make note of its position when you reassemble your pedal kit sprocket onto your bike.

In this image you can see the thrust ball bearing cages, the removable ball bearing race and the threaded collar ring. NOTE that the thrust ball bearing cages have the ball bearings facing OUTWARD. Be sure to do the same when reassembling the pedal kit.

The Pedal Kit is just an early version of a tapered square bicycle bottom bracket.

Pedal Kit Measurements. The housing uses English style threaded bearing races. Note that the side which is opposite from where the sprocket is located uses reverse threads. If you’re wondering about the reason I’ve posted this graphic I created of the measurements it’s because I am considering converting the thrust ball bearings into sealed bearings. So I need to know the shell dimensions to look for an English style of bottom bracket in that length.

To remove the pedal kit assembly from your bike you will need to remove the chain from the rear sprocket and also remove the rear wheel. Although it’s possible to remove the pedal assembly without doing these things, it makes the job much easier.

Remove your pedal cranks from the pedal kit spindle. I use a very inexpensive crank arm puller to remove the cranks from the pedal kit. You can find it in my section “Gear I Use.” Or you can do it the gorilla way and use a claw hammer to pry the crank from the spindle. Up to you.

Four hex head bolts fasten the pedal kit to the swing arm. Some pedal kits have captured nuts on the underside of the pedal kit bracket. Some utilize loose nuts. In addition there are spacers on the side of the pedal kit that provide distance between the underside of swing arm. Some are not captured on the pedal kit, some are. These allow clearance for the ratcheting sprocket to spin.

Since mine is an older version it has both captured nuts and spacers.

Captured nuts

If yours are not captured I would suggest replacing your bolts with ones long enough to use nylock nuts rather than the loose ones supplied with your kit. Nylocks are available at most hardware stores or online. If not, use blue Loctite to secure the nuts well to the bolts. Just a suggestion…..

Captured spacers

Loosen the threaded collar ring with a set of Channel Lock pliers. You can also use a screwdriver and hammer.

Once the threaded collar ring is removed you can unscrew the bearing race with a set of needle nose pliers. Or you can use a screwdriver and hammer to loosen the bearing race until it’s easy to unthread by hand.

Completely clean the inside and outside of the pedal kit tube. I use kerosene to do so as it cuts grease and dirt well. I also soak the bearings and bearing race in it as well. Once those are completely dry I use Park Tool Grease on the bearings and bearing races. Be sure not to forget to grease the race that you don’t remove which is on the opposite side of the open pedal tube!

An optional step I follow is to sand off any rust that has accumulated on the pedal kit tube. After doing so and completely cleaning off any residue I paint the pedal kit to prevent future rusting.

Don’t forget that the bearings should face OUTWARD toward the bearing races. Be sure this happens on both sides, the one that you don’t remove and the one you do. Otherwise you will feel major bind in the spindle!

Assembly is the opposite of disassembly (DUH!) Check how much play you have in the spindle by putting the whole assembly in a vice or something similar. Then try to rock the spindle back and forth to determine if you have too much play. If so tighten down the bearing race, BY HAND until there is little to no play, but the spindle spins freely. I place blue Loctite on the threads before installing the threaded collar ring. There’s no need to hold the removable ball bearing race when tightening down the collar ring. It won’t move. Secure the locking collar ring down against the shell tube tightly!

I use blue Loctite for the collar locking ring.

Reattach the pedal kit sprocket onto the spindle and just hand tighten the locking bolts. Be very careful to leave space between the threads on the sprocket and the threaded bearing race! I had to repair another owner’s pedal kit because he had threaded the sprocket onto the bearing race. It was ruined.

Once the pedal kit is remounted onto your bike, align the pedal kit sprocket with your chain. Then tighten down the locking bolts being sure to align them with the flat notches on the pedal kit spindle. Reinstall your pedal cranks and you’re all done!

  • One thing to keep in mind as well is since the pedal kit is attached to the swing arm YOU become unsprung weight. Yep depending on how much weight you are placing on the pedals determines how much unsprung weight you are adding. I am always standing as I bomb down hills, so I’m adding 180 lbs. to the unsprung weight. As I’m riding I am placing varying amounts of unsprung weight depending on what I’m doing.
  • Perhaps one of its saving graces is that the pedal kit is located very close to the center pivot point of the swing arm rather than further out. I believe this may be one of the factors contributing to why I don’t notice it except in specific situations.
  • Now if I was racing I’d be damn upset and would only ride with pegs. But I’m NOT racing and truth be told the only time I definitely notice that I’m attached to the swingarm is when I land off of medium to high jumps. Even over rutted or chattered terrain I don’t notice. Just something to keep in mind that I never hear mentioned….

NOTE: One of the things I noticed on my pedal kit is the sprocket ‘seemed to be out of round.’ I noticed that my chain would tighten and then loosen as I spun the wheel. It is not ‘too’ bad, but I don’t like any variance in tension. So today I was examining my disassembled kit and noticed that if I don’t tighten the two M8 bolts that hold the sprocket onto the spindle evenly I get an uneven rotation on the sprocket. Allowing the sprocket to go as far as it can onto the spindle to completely seat against it allows the sprocket to spin in a completely normal and uniform way.

Because the sprocket is properly placed in line with the chain as it is aligned to the rear and countershaft sprocket, it is not completely seated against the spindle. So a small amount of space exists between the spindle and the inner surface of the sprocket’s housing. Tightening the two bolts unevenly then causes the sprocket to be uncentered which then causes the uneven tension on the chain.

I’m very happy to have discovered this. Just be really careful as you tighten your pedal kit sprocket bolts evenly and you will not have varying chain tension as your wheel spins. If you do notice varying tension on your chain, just adjust the sprocket bolts until it’s even. Or perhaps you’ve never noticed…..

Mystery solved!

Update: AT SOME POINT if you are well versed in bearing maintenance both the bearings AND races in the pedal kit will need to be replaced. If you’re not the kind to check on those sort of things, keep moving along….

But for those who do keep up with maintenance I found a kit to replace both the bearings and races: Sunlite Bottom Bracket Cup Set for 3-Piece Cranksets, 68/73mm for a whopping $6.77 USD! Much cheaper than having to purchase a whole new pedal kit eh?

Reverse thread just like the OEM bearing race. And the wrench size is much more convenient than the OEM version.
Everything matches up just right with this kit.

Update: July 17 2019

In my seemingly never ending quest to improve the pedal kit I sourced silicon rings to use as seals on each end of the pedal kit. Besides the silly hole (which I’ve plugged) in the housing shell I found that the openings between the spindle and the bearing races lets in debris and moisture. So after measuring the size, the ID is 16mm and the OD is 19mm. I found some great O rings on Amazon and installed them into my pedal kit.

Before pushing the ring down into the recess of the bearing race.
Pushed all the way in. I also grease the O ring just to add a little more of a barrier from dirt and moisture. I do the same thing on the other side as well.

Time will tell me if this process keeps more crud out of the shell housing than before. Stay tuned….

15 Comments

  1. I really appreciate the work that has gone into your site. I am a retired pro motorcycle pilot & have just picked up a X model from Luna. My usages May mirror a lot of yours. Feel free to email me we can talk about the good old days on a racetrack. Age gets us all…

    Thanks again I appreciate your site & documentation of the changes made. Kinda curious as Öhlins makes a ttx22 10.5 “ travel shock. Seems like a lot of work to fit the 9.5” yo save a few hundred dollars vs new. I still have an Öhlins contact if your ever interested in changing.

    Flip side

    • Hey Rick thanks SO MUCH for your appreciation! Means a lot to me. Yeah age is not for sissies that’s for sure. I bought the 9.5 Ohlins because the 10.5 TTX was around 900.00 with a spring. I could not locate one used when I was looking. I got the 9.5 on eBay for less than half that amount. As you well know when you’re ACTUALLY competing it’s really easy to ‘justify’ spending oodles of cash on your race bike! LOL But for a fun bike like this I just could not bring myself to spend nine hundred bucks. Thanks for the offer too! Happy riding, you’ve entered an awesome Twilight Zone universe!

  2. Wow okay. Thanks so much for this. Got my bike Friday and now 4 days later my bottom bracket fell out like your pictures show. So now im going to have to get this fixed. Im going to see if Luna will fix it for me since I live down the street from them. Thanks for everything you did here. Ill need this if Luna doesnt come through.

    • Aristotle, you’re very welcome. If they don’t fix it for you it’s an easy fix. Just be sure to TIGHTEN down the locking collar ring WELL and use some blue Locktite too. I may be the only person on the planet that uses the pedal kit! LOL. BTW what a COOL first name you have! Wow.

  3. So Im crazy Curious how torque/speed differ with that TINY rear Sprocket ?

    • Dave if you are referring to that very small 25t sprocket in the Chinese pedal kit video I don’t run that one. I am using the OEM 48t sprocket. I have also run the Luna 60t sprocket with my pedal kit. I believe Sur Ron manufactured the 25t sprocket for the pedal kit so that you ‘could‘ move the bike by pedaling. I would NEVER use a sprocket like the 25t. This bike was never actually meant to be pedaled.

  4. Mark
    Great write up on the pedal kit!
    I really want the belt drive AND the pedal kit for super stealth operation and lower maintenance. Was thinking it might be feasible to replace the sprocket with one from a belt drive kit if the spindle can tolerate an additional (1/2”thicknesses of the belt) and somehow attach it to the clutch. What do you think?
    Lonnie

    • Lonnie…oooooh I need to noodle that a bit. Because I don’t know much about drive belts I cannot speak to how critical the tension is or how to best adjust them to the proper tension. In my limited knowledge I ‘think’ the main issue will be finding a belt pulley/clutch mechanism that will work for the pedal assembly. As you have read I found that the pedal sprocket is very finicky in terms of where it resides on the spindle. If it’s off just a tad by the two opposing bolts that cinch the sprocket to the spindle the chain tightens and loosens the chain as it rotates through its run. In terms of the thickness of the belt that would depend on the belt tooth sprocket you find for the pedal kit spindle. I think it would be a fantastic idea for you to try though!

  5. Great site. Is it at all possible to use a planetary geared crankset in the Sur-Ron’s bottom bracket? I’ve heard that actually pedaling the bike if/when needed is pretty slow. As is when say the battery is drained before your able to get it charged.

    • Hi Richard, and thanks. All things are possible but the SR pedal kit is unlike normal bottom brackets on regular bicycles. Normally the cranks are connected to the chain ring and as far as I know this is where the planetary gearing is housed. In theory it is possible to use a crank connected to the chain ring, but it would have to be fabricated since the sprocket is further inset than normal bicycles. The diameter of the chain ring would also be limited by its location which would be fouled by the swingarm. One could use a wider spacer to lower the pedal kit spindle to allow for a larger sprocket.

      On normal full suspension bicycles the spindle, crank and chainrings are located ahead of the swingarm pivot point. The SR’s pedal kit is located behind the pivot point. I’m not sure how it would be accomplished to actually be able to pedal the bike. If you figure it out please let me know.

  6. Mark,
    Got my pedal kit and the first thing I did was take it apart and noticed mine was clean and BONE DRY! Zero lubricant was used. I soaked the bearings and races in water-based solvent, then compressed air, then isopropyl alcohol to remove any traces of water, more compressed air, then Park lube and reassembled. I ordered a second kit and will attempt disassembly of the gear ratchet using a pin spanner, I’m betting it has zero lubricant inside as well. If that binds up, bad things will happen. Also tolerances are poor and i also see some deflection in the lateral plane that i doubt I can correct with the 2 screw mounting design.
    I noticed SR includes a rubber plug (found it after i already found one in my parts bin) otherwise i would have welded the extra hole closed.
    Lonnie

    • Wow ZERO lubricant?! That’s horrible. Moisture can collect in the housing after riding in rain, mud, etc due to the hole in the housing. Glad they now supply a rubber plug. Of the four pedal kits I’ve seen the holes are not consistent in shape. Some have welds which makes them irregular in shape. I use Instamorph to plug mine. IF you can disassemble the ratcheting gear I would be very glad to include how that is done if you are so inclined to share your process.

  7. Peddle power a tiny generator – then both chain & belt drives might use? No chain line to worry about?
    Or just a small load/friction so clown peddling looks more natural? just a thought
    Sadly, I lack the knowledge nor skill to build such a contraption. Consider me a serious potential buyer.
    Riding to trail heads a big advantage. As you well appreciate, Mark.

    Thanks for all your great info, experience and thoughts on the Sur-Ron. I hope many more women give it a try.

    Just got my Sur-Ron with carbon belt drive and 17″ SuperMoto wheels – Love the quiet.
    This Spring I’ll put standard 19″ on the front and thinking 3×17″ Shinko 244 on the rear. Hilly Kitsap, BI, WA

    I don’t expect you to publish my random thoughts. Just dreaming.

  8. Hi,
    My ratcheting sprocket assembly seized up on me today and no longer free-wheels. Now the pedals turn all the time which makes the bike un-rideable. Have you heard of this happening before? Any idea what could’ve caused it?
    More importantly…where can I buy a replacement ratcheting sprocket assembly? I’ve been looking all over the internet and cannot seem to find a 28t single-speed freewheel for the Sur-Ron chain size to save my life!
    Any help is greatly appreciated! Thanks!

    • Oh Oh Bruno….
      Without examining your pedal kit it ‘sounds‘ like the ratcheting assembly locked into the threaded bearing race on the right side of the spindle. I show that in the post at the beginning. I cannot tell you where to find one of the ratcheting sprocket assemblies other than purchasing an entire pedal kit assembly. If it’s what I think the threaded locking collar ring backed out which caused the ratcheting sprocket to mate to the threaded bearing race. You can try to disassemble the unit to separate them. Good luck.


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