Originally Posted by victorthewombat .
PeterMC is correct...suicide hubs do work. Here is my time tested method:
1) and just about the most important. The freewheel threads need to be laboratory clean and dry. You need a least two hours before installation of the cog.
2) Insert track cog. thread on with blue locktite (hey you may need to change the sprocket later). Use a chain wip to get it on there nice and tight. Now go ride the bike w/o using back pressure.
3) Come home after about 1/2 hour and re tighten cog w/ chain wip and let sit over night.
4) The next day you can install the bottom bracket lockring if you want to. No locktite on the bottom bracket lockring. Just crank it on there and check it at least every week. By using this method I have had reasonable success keeping the cog on. Most of my problems were with my mechanical skills until I got the method down pat ie reread rule number 1.
Good luck
VTW
I went a few steps further over a year ago. Before i dedicated funds to a real flip flop wheel, i wanted to see if i would like riding fixed. (at least some of the time)
I had a decent alloy rim with a freewheel threaded hub i got with a frame i had upgraded wheels on. Nothing really into this wheel, but it was running smooth and had SS spoked and spun true.
Anyway, i wanted to do a "test run" on this wheel before i would stake my life on it, so like you i REALLY cleaned both the alloy hub threads and the dura ace 16T cog i would be using. I needed a small washer behind the cog to get the chainline "close". I really needed a little fatter washer to optimize chainline, but then i wouldn't have any threads left to use a bottom bracket lock ring for a bit more security.
Anyway, on my trial run i used rubbing alcohol and cleaned all the treads up on the hub, cog, and bb lock ring.
THEN, .......probably overkill but i decided to use the RED (permanant) thread locker. This stuff needs 400 degree heat applied to have any chance to get them separated!
I put it all together and tightened it all up with a longer handle chain whip. Even the outer BB lock ring got the RED threadlocker! About 24 hours later i went out and put the wheel through a really tough time! I tried everything to get the cog to break loose (a long time in a long and clear parking lot), but also rode the wheel for 3 days on some of my daily commutes.
Nothing EVER loosened, ........BUT, i wanted a clear indication of just how good a connection the cog was to the hub. The same long handled chainwhip was tried, of of course i couldn't budge the BB lockring, (and only about 2/3 of the lockring were catching threads)
Just so you know, i was a bench jewelry repairman for 35 years, and still have a workbench and oxy/propane torch set up in my basement. After thinking about it for quite awhile, i decided to see just how hard it would be to get this disassembled, yet protect the spokes and most of the alloy hub threading from the heat i was going to use.
So i took the hub apart to remove the axle, ball bearings, seals, and every remnant of grease. Next i folded up a stack of 6 paper towels and soaked them in water, and poked a hole in the center to fit over the hub end. The soaked paper towels covered the spokes and the back part of the hub thread area.
I used the largest torch head i had, and directed the HOT flame "sideways" and mostly onto the BB lock ring initially for about 15 seconds, then tried the chain whip,.....and NOTHING moved! Another 15 seconds and tried again,.....this time the BB locking ring JUST barely moved a few MM before it froze in place. Several heatings of about the same 15 seconds combined with use of the chain whip and the lock ring came off,.....but just a few mm's at a time!
I knew the Dura Ace cog would be much harder to remove, since it had a wider threaded area and it was all being used. The thicker steel makeup of the cog (compared to the BB lock ring), also tended to suck heat away much quicker. It took all of 1/2 hour of repeated short heatings of the cog to get it off,....and after each heating the cog could only be nudged a few mm's!
I did all of this to get a real feel as to the safety of running a "suicide hub" set up with the stronger "red" thread locker. I also wanted to see "if" i could then remove the cog and bb locking ring, as of course eventually a worn cog would need replacing.
I can say without hesitation,....there isn't ANY way a properly cleaned and prepped fixed cog will EVER tread off on it's own when using "red" threadlocker! I suspect the "blue" thread locker would be plenty secure also,.....but haven't run the same test with it.
Another reason i decided to remove the cog was to fit a fatter washer behing the cog to optimize my chainline. This would mean i had no usuable thread remaining for an outer bb lockring, but i had no problem with that considering all the work it took to get the cog off!
Considering that even "if" the cog loosened, it will not be quickly spinning off. Even after barely surpassing the 400 degrees of applied heat to specific areas the cog would only move a few mm's at a time, and then freeze in place. I suspect the rapidly lowering heat ( below 400 degrees as mentioned in the product directions) causes the red threadlocker to refreeze. I also suspect if you failed to properly prep the threaded parts, you will have warning that something has loosened, and the cog will NOT just spin quickly off.
After i finally removed the cog and thin washer, i went ahead and recleaned the hub, i fitted a "new" Dura Ace 16T cog just in case the hardness of the temper had been compromised. (after placing a thicker washer for optimum chainline) I will make use of the 1st cog in a standard fixed hub, and if it wears prematurely at least it is easy to change.
Using a "new" Dura Ace cog guarantees the steel hardness is there, as i didn't want to have to go through all this again for a LONG TIME. So far (over a year), this hub and wheel has remained servicable and runs true. I use it on a beater bike, so in truth it's not used every day. But had i only one bike instead of 15 i would not hesitate to do so.
Also, since i decided i do often like riding fixed (and SS also at times), that i went ahead and bought dedicated flip/flop wheels of good quality and fitted to some of my daily rides. This experiment served it's purpose, in that i would feel comfortable with riding a "suicide hub" set up carefully were that the only economic option a had available.........
......BUT,......everything MUST be well cleaned and free of any oil before assembly! (and of course YOU must accept the risk of running like this
