Spinner Grind Air fork disassembly issue – RESOLVED

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Spinner Grind Air fork disassembly issue – RESOLVED
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flag markusarulius
O+
Posted: Aug 17, 2015 at 10:03 Quote
I need help disassembling a Spinner Grind Air 20" fork off my son's Spawn Cycles Savage 2.0.

I've removed the top caps on both fork legs, the lower bolt on the oil side, and pulled out the rebound cartridge.

The problem is that the bolt on the bottom of the air side of the fork can not be loosened or removed.

When I try to loosen it – it just turns and turns. It is in fact rotating the air spring shaft inside the fork leg. I can see it turning through the top of the leg.

There is no way to grip the air spring shaft through the opening in the top so that the bolt can be undone.

I have tried pumping the fork up to max psi and loosening the bolt – still spins.

I have tried an impact wrench to see if I could jolt the bolt loose – did not work.

I can not compress the fork enough to reach the top of the shaft through the top of the fork leg in order to hold onto it – this would also probably damage the air seals on the top cap threads.

Any ideas on how to remove this lower bolt?
flag ryanme
Posted: Aug 17, 2015 at 10:42 Quote
markusarulius wrote:
I need help disassembling a Spinner Grind Air 20" fork off my son's Spawn Cycles Savage 2.0.

I've removed the top caps on both fork legs, the lower bolt on the oil side, and pulled out the rebound cartridge.

The problem is that the bolt on the bottom of the air side of the fork can not be loosened or removed.

When I try to loosen it – it just turns and turns. It is in fact rotating the air spring shaft inside the fork leg. I can see it turning through the top of the leg.

There is no way to grip the air spring shaft through the opening in the top so that the bolt can be undone.

I have tried pumping the fork up to max psi and loosening the bolt – still spins.

I have tried an impact wrench to see if I could jolt the bolt loose – did not work.

I can not compress the fork enough to reach the top of the shaft through the top of the fork leg in order to hold onto it – this would also probably damage the air seals on the top cap threads.

Any ideas on how to remove this lower bolt?

take it to a bike shop who know what they are doing
flag markusarulius
O+
Posted: Aug 17, 2015 at 12:17 Quote
ryanme wrote:
markusarulius wrote:
I need help disassembling a Spinner Grind Air 20" fork off my son's Spawn Cycles Savage 2.0.

I've removed the top caps on both fork legs, the lower bolt on the oil side, and pulled out the rebound cartridge.

The problem is that the bolt on the bottom of the air side of the fork can not be loosened or removed.

When I try to loosen it – it just turns and turns. It is in fact rotating the air spring shaft inside the fork leg. I can see it turning through the top of the leg.

There is no way to grip the air spring shaft through the opening in the top so that the bolt can be undone.

I have tried pumping the fork up to max psi and loosening the bolt – still spins.

I have tried an impact wrench to see if I could jolt the bolt loose – did not work.

I can not compress the fork enough to reach the top of the shaft through the top of the fork leg in order to hold onto it – this would also probably damage the air seals on the top cap threads.

Any ideas on how to remove this lower bolt?

take it to a bike shop who know what they are doing

Thanks ryanme, great advice.

There are no shops in my city that sell or have serviced this fork. Spinner does not provide any shop service manuals or instructional videos for this fork. I've serviced and re-build a numerous forks from Fox, Marzocchi and Rock Shox. I know what I'm doing. I'm looking for advice from a mechanic on how to handle a specific problem.
flag denchy1
Posted: Aug 19, 2015 at 2:34 Quote
[Quote="ryanme"

take it to a bike shop who know what they are doing[/Quote]

I hate this attitude. Its a bike not a jet fighter. There is very little on a bike that a home mechanic cant do, and you only learn by trying.

I would say be careful with using an impact on a bicycle.

I will try to offer my suggestions but without pictures its difficult. The bolt is seized into the airshaft would be my guess. I would try tighten the bolt slightly so there is some friction between the bolt and the lowers. Then shock the ratchet/hexkey to break the threads lose.

Also is there a hex on the top of the air piston, that you can get to with a socket and extension.
flag markusarulius
O+
Posted: Aug 19, 2015 at 10:38 Quote
denchy1 wrote:
[Quote="ryanme"

take it to a bike shop who know what they are doing

I hate this attitude. Its a bike not a jet fighter. There is very little on a bike that a home mechanic cant do, and you only learn by trying.

I would say be careful with using an impact on a bicycle.

I will try to offer my suggestions but without pictures its difficult. The bolt is seized into the airshaft would be my guess. I would try tighten the bolt slightly so there is some friction between the bolt and the lowers. Then shock the ratchet/hexkey to break the threads lose.

Also is there a hex on the top of the air piston, that you can get to with a socket and extension.[/Quote]

denchy1 I will post some pictures tonight.

I was super careful with the impact wrench... Its an electric one and I just gave it one pop/impact by holding the socket to try to free the bolt. I'm sure blasting it with the wrench would do some damage.

You can't tighten or loosen the bolt. It spins the airshaft both ways. There is no hex on the top of the shaft either – it is perfectly flat aluminium that looks rather thin.

Stay tuned for pictures...
flag markusarulius
O+
Posted: Aug 19, 2015 at 13:34 Quote
Here you can see the air shaft spinning when the lower bolt is rotated:

Unsecure image, only https images allowed: http://s17.postimg.org/9atjwbzkd/fork1.gif
Unsecure image, only https images allowed: http://s8.postimg.org/ixrvaesf7/fork2.gif
flag markusarulius
O+
Posted: Aug 19, 2015 at 13:43 Quote
It is supposed to look like this when disassembled (photos from Demo9 on mtbr – Yes he was asked. But, he has not responded to questions from other people with this same issue).

Separated from lowers:
photo

Air shaft removed:
photo
flag feldybikes
Posted: Apr 18, 2016 at 14:05 Quote
Did you ever figure this out out? I've got the same issue.
flag rustyplanks
Posted: Apr 19, 2016 at 9:54 Quote
I would stick a towel inside the top and try and push down lightly to counteract the spining. Maybe even use somesort of rubber, like an eraser, maybe it would grip even better than a towel. I don't have this fork nor have I serviced this fork, but with little servicing info found on the web this is my best guess.

There is a diagram of the shock online and it looks as if the top part is just a cap, I could be wrong.

Let me know if this helps.
flag feldybikes
Posted: May 1, 2016 at 11:39 Quote
Thanks for the ideas Rusty. I'll give it a shot.
flag scottyf
Posted: May 24, 2016 at 6:18 Quote
feldybikes wrote:
Thanks for the ideas Rusty. I'll give it a shot.
I had the same issue with my son's Spinner Grind. I used a high speed drill with an Allen key attachment and it came loose, and then retightened after servicing very quickly. The idea is that the drill spins the bolt faster than the internals can spin, so it will tighten (or loosen in your case). I would suggest an impact drill, which in your case will add a bit of vibration to the bolt. But maybe not for tightening the bolt back up. A bit of grease on the threads when reassembling is a good idea.
flag wishfulthinking
O+
Posted: Jun 11, 2016 at 0:00 Quote
I guess I got lucky and got one that didn't spin. Did you guys disassemble to give it more travel?

I was about to do it but realized by giving it more travel, the fork will be extended further to give it that extra 22 mm, as opposed to the fork staying the same and just being able to travel an extra 22 mm. This will yield a more slack headtube angle.

And if you extended the travel, there seems to be two different ways to do it - did you cut the spring or move the pin up?
flag JCK1
Posted: Jun 11, 2016 at 7:29 Quote
If the cap screw is available from local sources , carefully drill or cut off the head. Remove assembly and work on remaining screw extraction on the bench. as long as it was not cross threaded to begin with it should spin right out. It may have lock tight used and if suspected carefully heat threaded area of shaft with heat gun or controlled flame. If you have a left hand drill bit of correct size it may spin out on its own while prepping for extractor...

For future service I would consider ...

Stud mounting the shaft with nut holding it to lowers, lock tight stud to shaft , allow a small amount stud exposed over nut (fully mocked up) and cut flats on it to hold in case shaft/stud/nut assembly spins , or for extra points find a stud with a head of some version to hold . It may be difficult to find correct thread pitch /size, some automotive exhaust studs are done this way, may have better luck with motorcycle fasteners.... or

Slot the upper portion of the shaft piston/ disk so it could be held , may not be robust enough...... or

Index/ key lower portion of the shaft to the lowers so that it cant spin and use identical cap screw.... may not be possible to index /key.

That's all I can think of , Good luck tup
flag markusarulius
O+
Posted: Jun 11, 2016 at 8:06 Quote
I've successfully serviced my 20" Spinner Grind Air fork and I thought I should follow up as some of you may find it helpful.

The fork came off of a Spawn Cycles Savage 2.0. It has worked ok, but as others have posted it did not get full travel, suffered from terrible stiction, and had a loose bolt on the air side that could not be tightened or removed.

I tried to follow Demo9's breakdown instructions, but could not remove the bold on the air side. Turning the bolt in any direction just spun the air piston.

Unsecure image, only https images allowed: http://s17.postimg.org/9atjwbzkd/fork1.gif
I reached out to Spinner a year ago regarding the issues and for service instructions. Eventually they posted a service guide on their facebook page.

Spinner Grind Air OS 20" Service

This motivated me to give it another go. Here is what I did to finally successfully break it down and improve its performance (I did not follow all steps outlined in the Spinner service guide). Sorry I did not stop to take photos.

Step 1: Remove the fork from the bike, let the air out, and remove the air chamber cap.

Step 2: Remove the hex bolt from the bottom of the damper side.

Step 3: Use rubbing alcohol and a paper towel to clean out the top of the air chamber, making sure to clean the top of the air piston.

Step 4: Compress the fork so the top of the air piston is just below the top cap threads.

Step 5: Take an old inner-tube and cut it in half, clean about 6" of the cut end with rubbing alcohol, roll it up a bit and stuff it into the top of the air chamber. Stuff it in as tight as possible and try to pile it up out of the top of the fork leg.

Step 6: Hold the fork parallel to the ground and press the stuffed inner-tube that is sticking out of the air chamber against the edge of a solid workbench. The idea is to stop the air piston from rotating using the grip of the rubber. Now hold the fork lower in one hand and the hex key in the other and push as hard as you can against the work bench while undoing the bolt. Mine loosened rather easily.

Step 7: Now with both lower bolts removed remove the inner-tube and separate the lowers from the stanchions.

Step 8: Pour a little fork oil into the top of the air chamber and slowly press the air piston rod from the bottom up past the threads and out the top (the fork oil is to protect the piston seal from being damaged by the air cap threads as it passes through).

Step 9: Remove the lower rubber washer, plastic collar and top out spring from the air piston rod and clean with alcohol.

***Top-out spring position and holes in the piston rod*** The piston rod in my fork did not have as many holes as shown in Demo9's photos. It only had one additional hole about 4" up from where the top plastic collar was already secured. The fork featured in the Spinner facebook service guide is the 80mm version and shows the top plastic collar in the upper position. I'm not sure if moving the plastic collar to the upper position on my fork would increase the travel to 80mm. I don't know if the damper cartridge is long enough or if the stanchions are log enough, so I decided not to use the upper position. In addition I do not have a drill press so I was not about to try to drill an additional hole in the air piston rod as Demo9 did (1/4" up from the original lower hole). I decided to go another route as described below...

Step 10: Make an elastomer top-out bumper to replace the spring. I salvaged an elastomer spring from an old RockShox Quadra fork. I cleaned it, cut it to be 1/2 the length of the original top out spring and drilled out a hole down the middle so that I could slide it onto a drill driver bit. I then put the bit with the bumper on it into a drill and used it as a lathe to sand down the diameter of the elastomer bumper to match the diameter of the spring. Finally I drilled out the centre of the bumper to match the diameter of the air piston rod. I'm sure most any rubber bumper you can make will work. Before I found the old fork I was going to use soft skateboard truck bushings. Just don't use rubber that will breakdown in oil or crumble to bits.

Step 11: Lightly coat the air piston, new elastomer bumper, plastic collars with fork oil (I used fox float oil on the air seal).

Step 12: Place the new bumper, bottom plastic collar and rubber washer onto the bottom of the air piston rod.

Step 13: Lightly coat the inside of the air chamber with fork oil especially the threads at the top.

Step 14: Place the air piston rod back into the top of the air chamber stanchion, carefully pressing the air seal past the threads.

Step 15: Clean out the fork lowers/seals with alcohol and paper towels, then coat the inside with a thin layer of fork oil.

Step 16: Place the fork lowers back onto the stanchions.

Step 17: Replace the lower hex bolt on the damper side.

Step: 18: Press the air piston down far enough to loosely thread in the bottom hex bolt on the air side.

Step 19: Now to tighten the air side lower hex bolt you will have to follow the procedure in steps 3-6 (clean, stuff inner-tube, press on bench, tighten bolt).

Step 20: Replace air chamber top cap and inflate to 50psi. Finally re-install on bike.

We now have full, almost stiction-free travel. I've tried to test out the top-out bumper by compressing the fork and pulling up quickly. It does feel different from the original spring, but is not harsh or noisy. I would be reluctant to run this set-up at higher air pressures as the rebound could have significantly more force.

My 7yo son has been riding his bike for a few weeks since we completed this service. We reduced the air pressure to 48psi and the fork is performing awesome. Before the fork would not extend all the way after being compressed. Now even at the lower pressure it consistently returns to full length.

photo
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