Results 1 to 13 of 13
  1. #1
    mtbr member
    Reputation:
    Join Date
    Jul 2007
    Posts
    221

    Interesting 20 Inch Kids Suspension Fork Potentially

    I picked up a few 20" suspension forks the other day. They are made for high end recumbent bikes, but I am going to give them a try on my kids' 20" bikes. (Hotrock and Scott Contessa Jr).

    Made by Mekkem who also makes White Brothers and several other forks.
    First Impressions:

    1835 Grams: but with the steel steerer I think a lot of weight will come off when cut to length.
    Hard anodized aluminum stantions.
    Internal sealed rebound cartridge. (supposedly adjustable rebound but acts more like a lockout)
    Steel spring + elastomer. The spring is WAY too stiff. The fork is not even a suspension fork at this point. (I will comment more on this with the photos)
    Disc or rim brake bosses.
    Carbon wrapped magnesium lowers looks pretty cool.
    Steel Steerer:
    Seems to have a high quality fit and finish. Doesn't look like a toy like the RST capa I am replacing. The anodized stantions are sharp. The thing is way over built and looks a little bulky though in my opinion.

    Here are some photos:Interesting 20 Inch  Kids Suspension Fork Potentially-fork3.jpgInteresting 20 Inch  Kids Suspension Fork Potentially-fork1.jpg

  2. #2
    Havok
    Reputation: Jordan300's Avatar
    Join Date
    Jul 2008
    Posts
    209

    Good job!

    wh0a !

  3. #3
    mtbr member
    Reputation:
    Join Date
    Jul 2007
    Posts
    221

    Disassembled Fork and Potential Modifications

    Like I mentioned in the original post, the spring is WAY too heavy.

    I disassembled the fork to see what the potential is for modification. It looks pretty promising in my opinion.

    The preload works pretty nicely and has quite a bit of adjustment.
    The main red spring is ridiculously heavy! I would guess it takes close to 100lbs to compress it. I put it against a wall and with all my force I could not get an inch of travel out of the spring.

    The elastomer is not compliant at all and really just a bumper or spacer.

    The good: I removed the entire spring assembly and just tried the rebound assembly. It actually has a pretty nice action. It has some spring action to it in addition to the slowed rebound.

    Travel: The fork has 50mm of travel, but with the spring assembly removed there is about 70mm travel. My plan is to try to find a much softer spring that will offer about 65mm travel. I will then shorten the elastomer a little bit to accommodate the longer spring. My goal is to actually have some sag like a normal fork.

    Axle to Crown: The axle to crown seems to be between 15mm and 20mm shorter than the RST Capa. I think that if I can put a spacer on the end of the damper cartridge assemble, I may be able to give the fork another 10 or 15mm of height, and potentially travel. I think I would also have to cut down the bumper on the lower rod of the spring side assembly. Looking at the position of the bushings in the lowers, I think this is possible without jeopardizing the stability of the fork. That was a fail. I re-measured and the bushing is too low chance the AC internally. The bottom of the stantion catches on the top of the bushing with any length spacer

    Let me know if you have any suggestions. Interesting 20 Inch  Kids Suspension Fork Potentially-photo-4.jpgInteresting 20 Inch  Kids Suspension Fork Potentially-photo-3.jpgInteresting 20 Inch  Kids Suspension Fork Potentially-photo-2.jpgInteresting 20 Inch  Kids Suspension Fork Potentially-photo-1.jpg

  4. #4
    mtbr member
    Reputation:
    Join Date
    Jul 2007
    Posts
    221
    Okay here is what I have discovered with my tinkering.
    A 24.8 lb spring from Home Depot, that is just about 1/2" longer, markedly improves the spring rate of the fork for a kid sized rider.

    The only problem was that the rebound seemed too slow even on the "fast" setting. I removed the rebound dampener and tried it with the spring only. Still slow...so it was friction in the seals and bushings that was "slowing" the fork down. I cleaned out the original grease and tried some Silkolene I had on hand. Assembled entire fork and it is much better!

    Now I want to try some Slick Honey. I think that if I used Slick Honey, and if the fork breaks in a bit, it may actually be a legitimately good kids fork. I will mount it up soon and give it a try.

  5. #5
    mtbr member
    Reputation:
    Join Date
    May 2011
    Posts
    823
    How much shaft travel does the dampening cartridge on these have? (when removed from the fork).

    What does it weight after removing dampener cartridge and changing spring?
    Might be an interesting weight savings project to press-out the steel steer tube, replace with a lightweight aluminum steer tube.

    I would imagine that the fork seals & bushings will break-in with a bit of use, move more freely.

    From my experience shortening old Tomac era Manitiou forks to 20" , there definitely are constraints on how much travel you can get out of such a short fork.

  6. #6
    mtbr member
    Reputation:
    Join Date
    Jul 2007
    Posts
    221
    Quote Originally Posted by GrayJay View Post
    How much shaft travel does the dampening cartridge on these have? (when removed from the fork).

    What does it weight after removing dampener cartridge and changing spring?
    Might be an interesting weight savings project to press-out the steel steer tube, replace with a lightweight aluminum steer tube.

    I would imagine that the fork seals & bushings will break-in with a bit of use, move more freely.

    From my experience shortening old Tomac era Manitiou forks to 20" , there definitely are constraints on how much travel you can get out of such a short fork.
    I didn't test the cartridge travel by itself, but it had 65 or 70mm when just the cartridge was in the fork. I think you almost have to have a bumper though, so 50 or 55mm is the most you can effectively get.

    The damper cartridge weighed 161 grams, with the cap still attached. The lighter spring was 15 grams lighter.

    I would think the fork would be in the 1500 gram range if used without damper, a light spring setup and the steerer cut. Maybe this weekend I will get the steerer cut to see what the potential is.

    This same company makes an airspring, alloy steerer version that supposedly weighs 1600 grams uncut. But it is like $400 if you can find one.

    With all the cheap spring options out there, I don't see any reason to go with air spring unless you can get them as cheap.

    Do you think the axle to crown length would affect the bike much?

  7. #7
    mtbr member
    Reputation:
    Join Date
    May 2011
    Posts
    823
    If you are OK with rim brakes instead of heavier disk and you are not using the dampener cartridge anyway, the early manitou forks can be re-built into 20" kid MTB forks that are much lighter than current ISO certified offerings (way overbuilt for kids).
    Tigworld managed to get one down to 1145gr weight, FAQLoad - 20" front fork build
    THe earlier version Manitou I fork I built into a 20" has steel stanchion tubes (instead of later aluminum) and I used a (heavier) coil spring rather than elastomers and it came out at 1330gr. Novara Pixie 20" project
    Daughter #2 just got this bike passed down, I am tempted to lighten it further with aluminum stanchions and an aluminum steer tube.

  8. #8
    mtbr member
    Reputation:
    Join Date
    May 2011
    Posts
    823
    Quote Originally Posted by Venturewest View Post
    Do you think the axle to crown length would affect the bike much?
    On a full size adult bike, rule of thumb is that 20mm of AC change causes a 1 change in the HTA and STA for the frame (and alters the bottom bracket height). Unless your frame is unusually steep, I dont think that the 1 degree change will be a big problem, lower BB height is probably a good thing to fit to a small kid, gets them closer to the ground.

  9. #9
    mtbr member
    Reputation:
    Join Date
    Jul 2008
    Posts
    790
    What recumbent site/dealer did you source it from? I looked into them a couple months back and all I could find was the $400+ ones. Don't remember the sites I visited, but would recognize them if I ever saw them again.

  10. #10
    mtbr member
    Reputation:
    Join Date
    Jul 2007
    Posts
    221
    The only one in the US I could find is hostel shop and those are $350 for air forks. I actually bought mine from a recumbent bike manufacturer going out of business. I bought all the rest that they had which is quite a few.

  11. #11
    mtbr member
    Reputation:
    Join Date
    Jul 2008
    Posts
    790
    That's place. Definitely the same Saso fork. https://www.hostelshoppe.com/cgi-bin...ory=1049573167

  12. #12
    mtbr member
    Reputation:
    Join Date
    Jul 2007
    Posts
    221
    Quote Originally Posted by bme107 View Post
    That's place. Definitely the same Saso fork. https://www.hostelshoppe.com/cgi-bin...ory=1049573167
    It looks like that is almost the same fork as the ones I have. That one has the 1" threaded steerer though. That one also says it has grease ports, but I don't have those on mine. I have a bunch of these forks so if you are still interested in one just PM me.

  13. #13
    mtbr member
    Reputation:
    Join Date
    Jul 2007
    Posts
    221

    Fork in Action on Youtube

    I think I pretty much got the fork dialed in. I replaced the stock grease with Slick Honey, and went with the 27.5 lb Home Depot spring. The action feels really nice to me. For my daughter, an even lighter spring might be appropriate.

    Here is the video:


Similar Threads

  1. When do you move your kids from 20 to 26 inch? what size?
    By surftime in forum General Discussion
    Replies: 19
    Last Post: 12-04-2013, 12:20 PM
  2. Spinner Air 20 inch suspension fork
    By BlairW in forum Families and Riding with Kids
    Replies: 1
    Last Post: 11-09-2013, 03:59 AM
  3. Ridgid or suspension fork for kids bike?
    By amheck in forum Beginner's Corner
    Replies: 26
    Last Post: 12-25-2012, 08:13 PM
  4. interesting court decision potentially of interest to mt bikers
    By NateHawk in forum General Discussion
    Replies: 25
    Last Post: 03-02-2012, 12:31 AM
  5. wanted: 20 inch kids bike
    By chollaball in forum Arizona
    Replies: 5
    Last Post: 08-30-2011, 11:28 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •