how safe is a conversion???
 

i just got a 72 schwinn super sport,,its a one pice crank....so im going to convert it to a fixed gear(its my first fixed gear build/first build ever)
i wanna ride this bike hard like the tank it is,,,,my question: is any one aware of saftey issue's that are assocaited with using the conversion,,,i dont want **** to break on the road,,this is the one they have at my local shophttp://cgi.ebay.com/ws/eBayISAPI.dll...#ht_500wt_1182
help is greatly appreciated ,,heres my bike by the way
http://i8.photobucket.com/albums/a13...01/gtbike2.jpg

At least install a front brake and use it, especially if you're going to be running a suicide hub.

There really isn't any inherent reason a conversion is more or less likely to fail than a bike designed for fixed-gear use (barring the rear wheel falling out of the front of horizontal dropouts, which is easily avoided). The most important thing is that your bike is well maintained- bolts are tight, threads aren't stripped, chain tension is correct, drivetrain parts aren't worn, brake pads are functional. The reason conversions can be dangerous is that people pull bikes from the 1970s out of their damp garages, Loctite themselves a suicide hub, and then take off into traffic. Not long after, any number of simple things goes wrong (a loose crankarm falls off, they realize the brake pads are dry rotted and do not contribute to stopping the bike, a rusty or worn chain snaps, a rusty frame breaks in half, etc.). These are all also things that can happen with a brand new bike, they are just less likely because some of them take time to develop into a real issue.

If you are good with bikes, do an exhaustive once-over before you build it, checking and lubing threads, looking for rust, etc. If you don't feel qualified, bring it to a shop for a once-over by a mechanic (but make sure you have a good shop, because there are a lot of mechanics I wouldn't let touch my bikes).

The last thing is be smart. "Suicide hubs" are called that for a reason. A functioning fixed/free wheelset can be had for close to $100, and no matter how zen meditative voodoo you are in traffic, no amount of skidzzz will stop you if a chain snaps. If safe is a priority, use a front brake and learn to use it.


If you do these things, your conversion will be safer than most fixed gear bikes out there, whether brand new or from 1972. That looks like a sweet frame- looking at it makes me think polished silver should be added liberally.

thanks a ton for your info...helps alot!!!!!

Wheels won't fall out of horizontal dropouts unless they are totally unengaged. That will happen on the first pedal stroke and the drive side will pull and hit the left chainstay instantly anwyays.

+1 on the rest of the stuff though

Besides a "real" track hub and basic mechanical competency a conversion is more suited for the road than a pure track frame.

It looks like the fork is bent.

I noticed this as well.

Fixed wheels were commonly used on road bikes for 70 years and many of these bikes had horizontal, forward facing dropouts... it's only the kids who think a bike has to have track ends for a bike to be a proper fixed gear.

You can do better than this for a frame and with a nice frame and a decent fixed wheelset you will have most of what you need... that fork does look bent to me as well.

I'm not dead yet

4130 fillet brazed straight gauge tubing = not a bad frame. Think the fork is bent tho.

and the reason is that it sounds cool.

suicide hubs are perfectly safe to use provided you do your loctite job properly and use quality components. that means: make sure your hub threads are clean, clean, clean and degreased 'til they're squeaky, use lots of loctite, and chainwhip a good cog on securely... and wait for it to dry before riding.

do it right and 'suicide' hubs are perfectly safe.

Yeah until you go to backpedal and your cog spins off. Gee I wish there was a hub designed with a device that would resist the cog spinning off like that... I wonder what that's called.

do you really believe that you are able to "spin off" a properly loctited bond with your legs? because, let me tell you: you can't.

Yeah, you going to bet a lawsuit on that one? Red loctited cog, probably - blue or lower? No.

I've used a suicide hub setup for the last 5 years, with a brake, on my spare/errand bike. I'm a heavy guy and the cog has never spun off. When I had to replace a spoke, I had to heat the cog and lockring to soften the locktite.

Just make sure you use a wire brush, citrus degreaser, rubbing alcohol, red loctite, and a bottom bracket lockring. Rotafix doesn't hurt, also.

Just install brakes and use them. Then you don't have to worry about loctiting that suicide hub or using that completely useless bb lockring on it.

i have successfully used suicide hubs on my winter training conversions for years. I do run full brakes with hoods. Hell, I don't even use loctite, just rotafix the cog onto the hub with grease. This allows for easy gear changes as I get stronger and it gets closer to race season. If you are going to run brakeless or even just a front brake, I suggest picking a cheap fixed gear wheel for piece of mind alone.

If you guys had read the OP's post, you'd have noticed he was specifically asking about converting from a one piece crank to a three piece. He stated nothing at all about the hubs he plans on using.

For all the people fear mongering about "suicide" hubs: have you ever actually ridden one and have it spin off during normal riding conditions?

I ask becaue last night I threaded a track cog onto my freewheel hub and took the bike out, with no brakes, and I actually tried to spin it off and I couldn't. And I just threaded it on with a chainwhip... I can only imagine how secure it would be rotafixed with some loctite or jb weld.

Sure, if you thread an old cog onto a dirty hub and go riding downhill in the rain, it may fail you, but even so, just use your front brake to stop and then walk your bike home.

I honestly think that a decent rider with a "suicide" hub and a front brake stands a better chance (or at least no worse) than a person new to riding on a brakeless track bike.

I used red large diameter loctite and let it sit for a few days while it rained outside. rode it for 5 months with no brakes and it worked fine. When I went to take it off, that was almost impossible. I had to use a torch for a couple minutes while turning the wheel to get the thing off and it still took alot of effort. (used rotafix method puttiing it on and taking it off.)

I must note however that this was done in a controlled environment and was cleaned and applied in my clean room at work. You dont need to do this but I figured if I have one, might as well use it.

well, that's overkill: but the general idea is important... the only reason why suicide hubs fail is because the surfaces weren't clean or had a tonne of residual grease. if a 'suicide' hub is built correctly it is impossible to unthread without a heat gun.


oh, and that fork looks bent.

I have built up and logged some insane hard miles on a number of suicide hubs and never had a failure and still use one wheel that has seen over 10,000 km...

Biggest issue with suicide hubs is when they aren't built up properly and removing a worn cog is really difficult and can destroy the threads on the hub if one is not really cautious especially if it was one I put together.

You can get a decent rear fixed wheel for very little money and if you are a skidder this is the way to go as a suicide hub should only go on a braked bike.

Since I am always swapping cogs I only use my old rear wheel as part of a spare set for my coaster bike as it has the same size cog and wheel swaps are pretty easy.

a conversion is as safe as the competence of the mechanic building it. if you are comfortable with your mechanical abilities and have a very thorough work process you'll be just fine. but try and breeze through it for pennies on the dollar and you may end up knee deep down **** creek without a paddle.

on the other handle you could be very methodical and have a freak failure while the penny pincher on a scrap yard bike rides on for years. it is impossible to predict the safety of used components. however, better judgement can be used to build a cycle with the best probability of functioning as designed.

something else to consider. i built a fixie conversion last week and it snowed today. it may not be unsafe to build one, but it will screw with the weather. science proves it.

Convert is and enjoy it.

I rotafixed a cog and I couldn't get it off for the life of me with a chainwhip. I had to extend the lever a few inches past the rim to get that thing off. But still...