Notices
Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

suicide hub

Old 10-28-08, 03:29 PM
  #1  
melon
Senior Member
Thread Starter
 
Join Date: Oct 2008
Posts: 187
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
suicide hub

so my mates just got this ratty old road bike he want to convert to fixed on the cheap.

its got a 7 gear cassette on the back and 2 chain rings up the front. he wants to use the bigger of the two rings at the front, which lines up with the 4th biggest gear on the cassette. theres about 2.5mm between the hub and this gear.

im guessing theres good reason why more people dont do this and it all seems a bit shonkey to me. even if he still uses a front brake. ive told him hed be better off with just building a new hub but hes adamant to not spend money on it.


how can a suicide hub be made safe and reliable, if at all?

theres going to be about 2.5mm between the hub and the correct chainline, this seems like a big gap for spacers to fill, is this going to be a problem? redishing isnt really possible due to the state of the spokes/nipples.

we have all the tools neccessary to mod stuff if neccessary.
melon is offline  
Old 10-28-08, 03:36 PM
  #2  
roadfix
hello
 
roadfix's Avatar
 
Join Date: May 2003
Location: Los Angeles
Posts: 18,602
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 162 Post(s)
Likes: 0
Liked 22 Times in 13 Posts
Originally Posted by melon View Post
how can a suicide hub be made safe and reliable, if at all?
First, by making sure the fixed cog is screwed on tight and secure, then by running at least a front brake and not relying too much on back pedalling when slowing down. Your suicide hub should be fine.
roadfix is offline  
Old 10-28-08, 03:38 PM
  #3  
melon
Senior Member
Thread Starter
 
Join Date: Oct 2008
Posts: 187
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
whats the deal with the big gap between the hub and sproket, is it ok to have that much spacer?
melon is offline  
Old 10-28-08, 03:41 PM
  #4  
roadfix
hello
 
roadfix's Avatar
 
Join Date: May 2003
Location: Los Angeles
Posts: 18,602
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 162 Post(s)
Likes: 0
Liked 22 Times in 13 Posts
Originally Posted by melon View Post
whats the deal with the big gap between the hub and sproket, is it ok to have that much spacer?
OK. Are you running a fixed cog or are you using the existing freewheel cassette and running it as a single speed?
roadfix is offline  
Old 10-28-08, 03:50 PM
  #5  
zzyzx_xyzzy
headtube.
 
zzyzx_xyzzy's Avatar
 
Join Date: Sep 2008
Posts: 803
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
Originally Posted by melon View Post
whats the deal with the big gap between the hub and sproket, is it ok to have that much spacer?
With a multispeed cassette all the cogs you aren't using are "spacer" whenever you aren't using them. So it'll be as reliable as the multispeed cassette was.

This is an excellent way to set up single speed on the cheap. I don't know about fixed, though - I've heard of people welding the freehub body to the hub but that seems pretty sketchy.
zzyzx_xyzzy is offline  
Old 10-28-08, 03:50 PM
  #6  
melon
Senior Member
Thread Starter
 
Join Date: Oct 2008
Posts: 187
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
i want to remove the freewheel cassette and replace is with a fixed cog. so basically putting a fixed cog on a non track hub.
melon is offline  
Old 10-28-08, 03:55 PM
  #7  
melon
Senior Member
Thread Starter
 
Join Date: Oct 2008
Posts: 187
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
just meausred it, massivly over estimated the gap, its actually 1.5mm.
melon is offline  
Old 10-28-08, 04:00 PM
  #8  
roadfix
hello
 
roadfix's Avatar
 
Join Date: May 2003
Location: Los Angeles
Posts: 18,602
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 162 Post(s)
Likes: 0
Liked 22 Times in 13 Posts
Originally Posted by melon View Post
just meausred it, massivly over estimated the gap, its actually 1.5mm.
Chain line difference of 1.5mm is no big deal. There's no problem running that.
roadfix is offline  
Old 10-28-08, 04:10 PM
  #9  
Seggybop
o.O
 
Seggybop's Avatar
 
Join Date: Dec 2004
Posts: 578
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by melon View Post
im guessing theres good reason why more people dont do this and it all seems a bit shonkey to me. even if he still uses a front brake. ive told him hed be better off with just building a new hub but hes adamant to not spend money on it.
The reason more people don't do this is that they care more about having "real track bike" components than getting a functional bike for a reasonable cost and use safety as an excuse (if you ride around with no brakes you're unsafe regardless of your hub), or they are misled by the aforementioned people.
Seggybop is offline  
Old 10-28-08, 04:18 PM
  #10  
benhenley
Senior Member
 
Join Date: Sep 2008
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by melon View Post
i want to remove the freewheel cassette and replace is with a fixed cog. so basically putting a fixed cog on a non track hub.
If its a cassette then you will be making a single speed by putting a cog on there.

If it is actually a freewheel then you will be making it a fixed gear by putting a cog on there.

Your using both words so its hard to tell which type you have. If its a cassette then you will have to get a new hub for a fixed. If its a freewheel then you can use the suicide hub method or buy a new hub.
benhenley is offline  
Old 10-28-08, 04:26 PM
  #11  
melon
Senior Member
Thread Starter
 
Join Date: Oct 2008
Posts: 187
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
whoops ive made some mistakes. ive been meaning to say freewheel.

also i meant to write 15mm, not 1.5mm.

so a suicide hub installed well should hold up well to everyday use, including skidding?
melon is offline  
Old 10-28-08, 04:50 PM
  #12  
roadfix
hello
 
roadfix's Avatar
 
Join Date: May 2003
Location: Los Angeles
Posts: 18,602
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 162 Post(s)
Likes: 0
Liked 22 Times in 13 Posts
Originally Posted by melon View Post
so a suicide hub installed well should hold up well to everyday use, including skidding?
In most instances, no. Install a front brake and use it.

You also need to respace the axle and dish the wheel to correct the chain line.
roadfix is offline  
Old 10-28-08, 05:11 PM
  #13  
melon
Senior Member
Thread Starter
 
Join Date: Oct 2008
Posts: 187
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
well this is what ive been asking about.

i want to do a ghetto conversion. no respacing, no redishing.

here was the plan:
i remove the freeweel, add spacers to get correct chainline, screw the cog on, affix with loctite+lockring- job done.

now what i want to know is if this is going to work. the spacers are going to have the fill a void of 1.5mm. is this going to work?

is a suicide hub capable of being used daily with skidding, i.e. is going to work?

what can i do to improve my chances?
melon is offline  
Old 10-28-08, 05:16 PM
  #14  
frankenmike 
mechanically sound
 
frankenmike's Avatar
 
Join Date: Jan 2007
Location: Dover, NH
Posts: 1,571

Bikes: Indy Fab steel deluxe, Aventon cordoba, S-works stumpy fsr, Masi vincere, Dahon mu uno, Outcast 29 commuter

Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 73 Post(s)
Liked 41 Times in 31 Posts
Some people claim to have used suicide hubs daily for skidding and braking with no problems. I personally wouldn't use suicide hub set-up for anything but forward pedaling.
frankenmike is offline  
Old 10-28-08, 05:18 PM
  #15  
Steev
Senior Member
 
Steev's Avatar
 
Join Date: Jul 2005
Location: Backwoods of Ontario
Posts: 2,152
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Judging by your mention of spacers, 15mm gaps and 7 speeds, I have to think that is a freehub and cassette that you're trying to convert.
Check this link.
https://sheldonbrown.com/fixed-conversion.html#hub
How are you locking the pawls?
I tried a locked up freehub to see if I liked fixed gear and found a problem in that the interface between the freehub body and the hub moves fractionally back and forth between forward pedalling and resisting, the movement was enough to work the retaining bolt out over time. Make sure your friend uses a brake. I doubt it will prove durable, especially if he plans to do lots of skidding.
Most people use "suicide hub to mean a track cog screwed onto a freewheel hub with no lock ring
Steev is offline  
Old 10-28-08, 05:20 PM
  #16  
roadfix
hello
 
roadfix's Avatar
 
Join Date: May 2003
Location: Los Angeles
Posts: 18,602
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 162 Post(s)
Likes: 0
Liked 22 Times in 13 Posts
Originally Posted by melon View Post
here was the plan:
i remove the freeweel, add spacers to get correct chainline, screw the cog on, affix with loctite+lockring- job done.
Not quite. There's not enough threading on the hub to add spacers to correct chain line. Remove the freewheel and you'll see what I'm talking about. There's not much threading holding the freewheel.

Are you sure you have a threaded hub???

Last edited by roadfix; 10-28-08 at 05:24 PM.
roadfix is offline  
Old 10-28-08, 05:26 PM
  #17  
melon
Senior Member
Thread Starter
 
Join Date: Oct 2008
Posts: 187
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
im pretty sure it is alough i cant really check it now im at home. how can i tell without removing it?
melon is offline  
Old 10-28-08, 05:48 PM
  #18  
fuzz2050
Real Men Ride Ordinaries
 
fuzz2050's Avatar
 
Join Date: Sep 2008
Posts: 3,723
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 16 Post(s)
Likes: 0
Liked 3 Times in 3 Posts
Suicide hubs work fine, provided you rotafix them (search can be your friend)

It will work fine for forward pedaling, but the second you try to skid, it'll come undone. No kidding, the first instant. You will go down in a blaze of fixxter glory.

Ride it, but don't rely on it for braking. Leave on both the front and back brakes and keep them well adjusted.
fuzz2050 is offline  
Old 10-28-08, 07:29 PM
  #19  
Philatio
we are 138
 
Philatio's Avatar
 
Join Date: Jul 2005
Location: Knoxville, TN
Posts: 678
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
If you degrease everything first, rotafix the cog on, add a BB lockring, and use lots of red lock tite you won't have any problems.

I've been running mine for about 4 months/500 miles with no sign of trouble. I run only a front brake and do a reasonable amount of skipping/backpressure. From everything I've read, the people that have problems don't put it on right.
Philatio is offline  
Old 10-28-08, 07:52 PM
  #20  
DannoXYZ 
Senior Member
 
DannoXYZ's Avatar
 
Join Date: Jul 2005
Location: Saratoga, CA
Posts: 11,736
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 108 Post(s)
Liked 5 Times in 4 Posts
Helps if you spin the cog on as tight as you can with a chain-whip. Then use a punch and hammer to really lock down the lockring.

A lot of the problems with cogs coming loose is people don't cinch down the cog tightly first. Even with the lockring tightened on it, chain-torque will still spin the cog away from the lockring and then everything's loose.
DannoXYZ is offline  
Old 10-28-08, 09:07 PM
  #21  
Philatio
we are 138
 
Philatio's Avatar
 
Join Date: Jul 2005
Location: Knoxville, TN
Posts: 678
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
yeah. I think it's worth it to crank it on as tight as you possibly can. I rotafixed (supposed to be more force than a chainwhip? guess it depends) rode up several hills and then rotafixed again.
Philatio is offline  
Old 10-28-08, 10:36 PM
  #22  
Seggybop
o.O
 
Seggybop's Avatar
 
Join Date: Dec 2004
Posts: 578
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by melon View Post
whoops ive made some mistakes. ive been meaning to say freewheel.

also i meant to write 15mm, not 1.5mm.

so a suicide hub installed well should hold up well to everyday use, including skidding?
Yes.

Anyone who's tried it and had a problem probably did it wrong.

You need to totally degrease all of the threads, and then put threadlocker compound on the threading like you'd normally use on brake bolts. Use rotafix method to tighten the cog with force beyond that what you can impart to it by pedaling. You need to be careful with this, because you can overtighten it and strip the threads. Then, screw on a bottom bracket lockring with a lockring wrench or a hammer and punch.
If after riding you find that there's any play on the lockring, the cog wasn't tightened enough. Tighten cog and lockring more.

If you do this properly, it would be necessary to exert enough force on the hub to destroy the threads before you managed to unscrew the cog.

A standard track hub set up without sufficient attention will certainly be more likely to fail than a carefully set up freewheel hub.

As for chainline, if you are using a road double crank with the chainring on the inside and the chainline is off, flipping the BB axle should align it.
Seggybop is offline  
Old 10-28-08, 10:57 PM
  #23  
patrick.decker@
snupontgeam
 
Join Date: Feb 2008
Location: boulder
Posts: 141

Bikes: Vitus, kilo tt

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
It will work. I've tried skidding my cogs loose (before I made a 1/8" chainwhip) - after having put them on with liberal amounts of grease - to no avail. But I'd still never do it without a front brake.... well I wouldn't even ride a regular fixed without a brake.
patrick.decker@ is offline  
Old 10-29-08, 12:04 PM
  #24  
bluenote157
Senior Member
 
bluenote157's Avatar
 
Join Date: Apr 2006
Location: Orange County CA
Posts: 963

Bikes: Surly CC, Raleigh Team Pro, Specialized Rockhopper with an xtracycle

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
ok.. so if it is a freewheel and not a cassette body, it can be done. I was running a fixed like this and accidentally skidded a few times... although i dont recommend it. Run a front brake.

So this is what you do...
Look up rotafix.. it is a way to tighten down a cog with more leverage than a chainwhip. Don't over do it or you might strip the hub.
Use red-loctite...then thread on a bb ring.

I've heard of others welding on the cog??

I actually did this rotafix with no loctite and no bb ring and it worked fine. However, again.. use this technique at your own risk.
bluenote157 is offline  
Old 10-29-08, 01:58 PM
  #25  
melon
Senior Member
Thread Starter
 
Join Date: Oct 2008
Posts: 187
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
well, im going to give it a go, just to see how well it works. im not going to loose out on anything. good call on flipping the bb axle, i hadnt thought of doing that.

id like to know how many people have had success with this with skidding.


the bike isnt mine, but i can call the owner (not bike literate) and ask him simple questions.
how can i tell just by observation whever it is freewheel or freehub?



im now more concerned about the chainline.
melon is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.