Freewheel, just a little bit too free!

[vekter303]

Thought someone may have an idea to help this situation...

I have a freewheel Shimano SF-1200 on my daily driver. Not the first time this has happened, but over the past week it has been cold enough to happen a few times. Basically, my thinking is that it gets so cold that the pawls don't re-engage and the cranks then spin out...even anticipating it, it's pretty scary.

I will likely give it a service and regrease, just eliminate the possibility that needing a clean, fresh grease is at fault. Otherwise, what do you guys think? Are there better systems for freewheel single speed sprockets to avoid this?

 

[Sharky]

If you mean single speed sprockets. I used "dicta" sprockets. They work fine and never let me down and cheap.

On a flip flop wheel, have a fixed sprocket on the other side, just in case.

Get mine from Velosolo.

 

[raleighnut]

3 in 1 is your friend, it will reinvigorate stale grease

 

[Big John]

My freehub decided to spin both ways this morning so I feel your pain. I changed it for a spare out of my 'stock' box before I went out for a ride but it wasn't a five minute job. With your problem just be careful with what you grease. Pawls appreciate light oil as grease can make them actually stick. As a quick fix spray it to within an inch of it's life with GT85 and spin it umpteen times to see if it's worked. The cold weather nowadays highlights any freewheel/freehub that's got a potential issue. If I'm honest my freehub was showing signs of sticking for a few weeks. I should have sorted it before it went completely.

 

[vekter303]

Nice one. I did wonder if something higher viscosity might help.

Any of these bits with factory grease tends to be really tacky and I'm sure that's not helping.

The spring return on the Shimano freewheel seems pretty light, but I am not that familiar with these system or alternatives. I will go with the suggested careful clean. Cheers!

 

[fossyant]

Moving to fixed gear is the answer !

 

[Big John]

When you actually see the innards of these wonders of engineering you'd be surprised at how flimsy they are and how they work at all. But they do. And they keep working. A bit of oil sometimes is all it needs. Pawls are often held in place by the flimsiest piece of sprung wire you can imagine.
Edit: fixed gear a good suggestion 👍

 

[vekter303]

Yes, that had made me think there might be an alternative - your description sounds like exactly what is in there - I wasn't sure all freewheels had the same system.

I tried fixed, scared the bejeesus out of me. Had gotten my head around peddling to a stop at lights. Completely underestimated how often you actually coast, bumping up a kerb, cornering etc. Bucked out the seat a few times. Was also running 50/15 (have 50/16 on single speed and part of the idea trying fixed was getting a bit more speed out the gearing) so staying on top of the gear was too much too. Never again

 

[silva]

I had the same story, a downpour started, all of sudden freewheeling forward, water in it makes grease stickier and the springs unable to push them back > walk further to work.
Or, frost. Once riding back home late in the afternoon, it started to freeze and ... a walk further home.

The springs are just too weak. Alike the ones in my Magura brake levers.
The dealer said it was probably bad sealing (water in), but another one so called with better sealing was just a same story.

One can identify weak by the sound, strong springs make the freewheel alot louder.
Also the number of springs has an impact. If only a few a sticking one = end operation.

I solved it by dumping the freewheel altogether, moved to fixed gear in 2017 and gone was the crap situation of having to walk further due to a stupid freewheel that suddenly fails to then work again when it has dried out...

 

[overmind]

I tend to spray small amounts of Gt85 which I find dilutes the gloopiness of the oil; but not much. Similar idea to 3in1 I suppose.

 

[Marchrider]

heat it up with a hot air gun, not stupidly hot, just maybe too hot to hold, keep it like that for 10 or 15 minutes and the water will evaporate off. Its not a long term fix but you nay get a few hundred mile out of it. It will need rebuilt or replaced at somepoint, but as a quick fix to get back on the road the following day, it has worked for me

 

[vekter303]

Food for thought, thanks guys.

The strength of the spring wire is likely a culprit too. Makes sense with feedback from the pawls, it runs silent. Something that had previously been a good thing to my mind...made me feel like I was in that Mitsubishi from The Cannonball Run

Strip it out, give it a clean and regrease this weekend. 3 in 1 on stand by too.