Sur Ron chain length information for various sprocket sizes: (does not apply to Luna’s final belt drive conversion kits)

Chains
420 CHAIN WITH 1/2″ PITCH (NO “O” RING) on the standard LightBee (LB)
420 GOLD CHAIN WITH 1/2″ PITCH “O” RING on the LightBee “X” (LBX)
WITH 48T RING YOU HAVE A 106 LINKS CHAIN
104 links 42T
106 links 48T
107 links 48T + pedal kit
108 links 52T
110 links 54T
112 links 58T
114 links for 60T
MASTER LINKS FOR A 420 CHAIN
O’Ring chains will require a O’Ring compatible master link
If you have the pedal kit installed, you need one extra link.
Belt drive model: Contitech HTD 560 8M, 15mm wide

I can verify that the RK 420 chain 110 link, fits the Sur Ron sprocket well. I purchased this chain to use with the Super Moto with pedal kit rather than the chain Luna Cycle provides with the SM kit.  The SM kit does NOT anticipate being used with the pedal kit option. Also the cost of the chain (because it is not an o ring chain) is very inexpensive. I plan to purchase another one to use with a chain breaker if I need additional links for other applications.

My change to an O ring chain

I also opted to change to an O Ring chain to keep chain maintenance to a minimum. I found that the noise of an O ring chain reduces chain noise by about 50% to my ear.

23 Comments

  1. Mark – have you considered the belt drive to reduce drivetrain noise further? I haven’t explored it, so I’m curious about the pros and cons that you’ve encountered.

    • I have not considered the belt drive regardless of the brand or noise. Based on where I ride I do not want to limit where I ride due to sand or mud. Everyone is different.

      • I’m confused the 110 link o chain would be good to use for the sur on lb x with pedal kit and 48t sprocket or should I size it down to an 107 link?

        • Eli 107 with the pedal kit. Since no one sells a chain in a 107 you simply cut the chain to the length you need. If you want your bike to handle a bit faster, you can move the rear axle forward which will then require removing a link(s) or moving the axle further back for a more planted feeling will require adding a link or two. It’s all about how/where you ride. Do what’s right for you.

        • You think I can use a non o ring chain on the LB-X it’ll just be noisy I guess right ?

          • Sure a non O ring chain works fine. Just a bit more noise and more maintenance needed.

  2. My sur ron should be coming in a couple weeks. I ordered the 54 tooth sprocket and pedal kit from luna. Do you know what length chain I will need for this configuration? If the chain is only a couple links too long, will it be okay by setting back in the adjustment range?

    I am new to the Bay Area (San Jose) and dirt biking and would like to get out and ride with you sometime and/or get some info on good spots to ride. Let me know.

    • Bradley I’m not sure how many links would be needed for a 54 tooth sprocket with the pedal kit. I’d ESTIMATE that it would be 3-4 more links than the 107 with the 48t sprocket, BUT I AM NOT CERTAIN. If the chain you’re using is a little long then yes, you can move the rear axle toward the most rearward part of the adjustment.

      In terms of riding it really depends on what/how you want to ride offroad. I find that my bike is just right for vacant lots or Bump City where I live. Although with COVID it’s a bit more difficult so I go out at night now. Investigate on Google Maps areas around where you live to find great spots. Welcome to the Bay, it’s a wonderful area.

  3. Hello Mark, sorry to bother you.
    I’m a new LBX owner located Vallejo. I just removed the stock pedal kit. (I should have heeded the warnings, but had hoped it would help me be an ebike)
    I have the 19″ stock wheels with the stock 48T sprocket.

    With 28mi on the new bike, it seemed the pedal kit was ready to self destruct and seize the rear wheel, obviously not a happy thing. The grinding noises and wobble of the crank arms indicated it was not suitable / unsafe at any speed …

    My confusion is about the small sprocket (label stamp reads WLJF 25-420) that came with the gold o-ring chain shipped with the bike from Luna. Am I supposed to mount it on the drive shaft in order to use the gold chain ?
    (I hope not, looks very difficult to do)
    If I just get a master link for the gold 420 chain, count 106 links and join, will that be roadworthy?
    Thanks in advance for any advise.
    I’ve learned a lot from the posts you’ve done for the sur Ron.
    Sincerely, GL

    • Hi Gary I’m sorry about your experience with the pedal kit. I have ideas why you had those wobbling experiences, but no need since you removed it. I am unfamiliar with the part number WLJF 25-420. If you are running the stock 19″ wheels and the 48t rear sprocket there would be no need to use that sprocket with the O ring chain. I have no idea what that part/sprocket is. 106 links for the 48t rear sprocket, no pedal kit. And yes be sure to use an O ring master link which includes rubber O rings for each side of the master link. Have a great time on your bike in the Bay Area and thanks for your kind words. I’m happy this site has helped you. It’s the only reason I built it.

  4. Hi, your information is very helpful, I am going to putting a 48t sprocket with the pedal kit and you said it needs a 107 link chain but I have heard from many different people that chains can only have an even number of links, what are your thoughts on that? Thanks

    • Hi Adam thank you. The BEST way to do any chain is to place your rear axle where you want it in the swing arm mount, stretch your chain around the countershaft sprocket and your pedal kit sprocket. Mate the chain onto your rear sprocket and determine where you want to break the chain. It’s much better than counting links and cutting the chain only to find out it’s too short or too long.

  5. Have you happened to notice which gear sizes/chain lengths put the axle all the way back in the dropout? I am looking for the longest wheelbase I can get

    • Tyler, nope, see the recommendation I just left for Adam.

  6. Hi again Mark. I’ve heard about this chain for Sur Ron and was wondering what your thoughts on it were? D.I.D 420 NZ3 Super Non O-Ring Chain. I anticipate keeping the stock sprocket for this year but will have more power next week with 72v bac8000 kit. The noise isn’t a concern for me either way. I just want to be sure I have the right chain for my bike to ensure trouble free performance. If it means slightly lower performance, I’m not worried giving up some power. Unless I’m wrong, the BAC8000 72v setup should more than make up for it. Interested to hear your thoughts. Thanks.

    • Nick I have used DID brand chains on my race bike (On road) and they are of great quality. I prefer O ring chains since they retain lube and repel dirt better. The SR sprockets are 420 and since I have no idea just how much actual torque the new controller you’re purchasing produces, I cannot accurately state if a 420’s tensile strength will be enough. There is only a 700lbs. difference between the two. Just to be safe I’d make the change to a 428, BUT you will need to change both the front and rear sprockets to properly accommodate a 428.

      420 Pin Length 16.65mm, Roller Dia. 7.77mm, Plate thickness 1.8mm
      428 Pin length 18.90mm, Roller Dia. 8.50mm, Plate thickness 2.0mm
      Both chains have a pitch length of 1/2″ but are different size chains

      Hope this helps.

  7. Mark are you saying you use an O-Ring Chain with the pedal kit? I feel like I was under the impression you could only use a non-o-ring chain with the pedal kit?

    • Jason, I DO USE an O Ring chain with my pedal kit. Around 3500 miles so far. No clue where the concept of a non O Ring chain with the pedal kit is the only one that works. Maybe the same folks who told me a 21″ front rim was no good for the Sur Ron.

      • Thanks Mark!

  8. Good afternoon,
    Let me start by saying your photography is outstanding. The way you capture the Sur Ron truly conveys it’s beauty the way few others have. Your blog has helped me immensely in deciding whether or not to purchase the bike, as well as in which modifications I would be interested in. I have a set of the Shinko tires coming Monday!
    Now, onto the trouble in paradise. I ordered a gates belt drive system from Luna. At first I was in love, it was so quiet and stealthy. Then came the squeak. That damned squeak. It howled like a banshee as I crept slowly down trails. It warned other bikers for miles that I was coming. It made the bike unenjoyable. I tried tightening the belt, but it didn’t help. I tried dish soap, which quieted it for a time, only for the squeak to return with a vengeance. Paraffin wax, same deal. Until two days ago – when it went downhill. I was riding the same as always after tightening my belt, and it made an awful sound when I got onto it from a stop. Puzzled, I couldn’t tell what it was. But it kept happening. Every time I’d put any real throttle into it, BRAAAAP, like a loud clicking noise. I believe that the belt is slipping over the pulleys. My belts teeth are splitting in half. In your experience, just what the hell is going on?! I’m at a loss. I’ve ordered a new belt and wrote Luna, but I am beginning to wonder if the belt drive is even worth it. Luna kept my stock sprockets and chain, so I am stuck not able to ride. As you can imagine, it’s been hard! I was hoping maybe you could help guide a newbie. Thank you for your awesome blog, fuck Facebook, and ride on!

    • Hi Alec thank you. My day job (well before COVID19) is a commercial photographer. But the vast majority of the SR shots are just done with my phone. I want to say that I have NO experience with the Luna belt kit for the secondary drive, the one on the right side of the bike. Having said that I do have experience with timing and other belts on automobiles. In those cases the only adjustment is for tension, no alignment adjustments. With the SR bike because it was designed to use a chain, the rear axle can be aligned using the two screws in the rear of the swingarm. It’s a standard thing on all motorcycles which use a chain final drive. What you are experiencing sounds as of the belt is not aligned properly between the front and rear drive wheels.

      You may wish to rethink the use of a belt if you are riding a lot off road. Sand, mud and rocks can damage a belt which is why ICE dirt bikes never use them. Up to you, but just judging by your description misalignment caused your issue. I’d talk with Luna about helping you fix the issue.

      • Mark, thank you very much for the response. I have contacted Luna and so far they have been helpful. They had me video the issue, which they say they’ve never seen before. They’re looking into it at the moment. In the meantime, do you know where to order the stock chain components? Specifically the front sprocket. Can’t seem to find it anywhere. I want to have the option of switching between the belt and chain. Thanks again!

        • Glad Luna is taking care of you. I believe the only source in the States for the front countershaft sprocket is Luna. I would ask them to sell you the front sprocket. You can get different size rears anywhere but the OEM 48T is not too common. I run the O ring chain and have been pleased.


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