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Sliping single speed
I decided to go the way of the single speed only to be met with more challenges than I first anticipated. It's a single speed how hard can it be to get a chain to go around a couple of sprockets? Really?
The first attempt, I bought a single speed conversion kit complete with a 16 tooth sproket, an unsprung tensioner and some spacers. As a result I ended up running a nine speed chain, 16 tooth sprocket and a very worn 32 tooth 9speed chain ring.The first attempt worked untill I started riding off road. The result was a chain that kept falling off.
The second attempt involved a new 32 tooth chain ring, new 9 speed chain, the oringinal single speed 16 tooth sprocket which had about 100km on it and a new sprung tensioner. I also put an old XT derailleur on the front to stop the chain from falling off.
This worked really well untill a well known and respectable BMORC member said "lets sprint to the gate at the top of Bennets". The result now is a chain that slips everytime I peddle with some force (Full on power).
What have I done wrong? Why doesn't single speed equal simple reliable speed? I really do enjoy riding with no gears. Any ideas? That last part was not meant to ryme.
Cheers
Steve
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I've never ridden single speed but I believe a lot get the tensioner thing wrong. It needs to push the chain up not down. Maybe I'm just talking out my a$$ but the two pics below show right then wrong
Right
Wrong
I had the same idea, maybe I have set the tensioner up the wrong way. However, the tensioner will only push down. If I run the chain above the tensioner it just springs backwards away from the chain. Then I had thought about changing the tensoner to the other side of the hanger but there is not enough room. My next idea was to pull apart the tensioner and reverse the spring. I have not tried that one yet.
I did put more tensioner on the chain by taking another link out but it put to much tension on the chain and made it to hard to peddle
What is important for setting up the single speed is a perfectly straight chainline. The 16t cog needs to be correctly positioned to the front ring with no angle at all. This prevents the chain shifting off the side of the front ring.
Tension is important... get the chain as tight as possible without the tensioner so it doesn't need to take up much slack. It will probably still be sloppy. Then with a springy tensioner push it down or up till you have enough tension. The DMR set and fix type tensioner I have found to not work well under an offroad type of load and they don't work as well with rattling down stuff... they slip, loosen and then lose tension.
I use a sping tensioner that is a combination of a Surly singulator for the roller and guide and another cheap ebay one for the spring arm that adds lots of tension. Never jumps.
Also I would not use a 9-speed chain... they tend to be too weak and unreliable for the forces you may be putting into a Single Speed off road. Go buy a good BMX chain. The advantage of a bmx chain as well is you can buy a half link to get your length really close so the tensioner doesn't have to do much. The extra weight of a BMX chain really is offset by the knoweldge that you aren't going to snap it and fly over the bars on some steep uphill.
He must be talking about you Tim. "a well known and respectable BMORC member".
Looking at Mog's last comment, I'm sure you and I are both glad I didn't ride your bike last night.
I shortened the chain and made a few other changes. I took off the connex quick link and put on a sram style quick link becasue the connex link did not seem to line up on either side of the link. I also took off the single speed 16 tooth and put on a 16 tooth from a sram pg 990.
I will get a single speed chain next week. I then put the bike on my fluid trainer and lined everything up again. Finally, I pulled the spacers off the back wheel and replaced them with stiffer spacers I had collected from old sram pg 990 casstte's. The original spaces were really soft and had a lot of flex in them which may have caused the 16 tooth on the back to flex a little.
Time for more testing after lunch.
Chuck you would have made a great guinea pig. I did use my wife to test the whole thing while it was on the trainer. Both of us could not make it slip.
Hi Steve, the Surly tensioner you get a spring for each pushing the chain down or up, not sure which tensioner you ended up with. The SRAM 8 speed chains are the go as you will have 3/32 chainring and cog.
I got the tensioner that pushes down. It all seems to be working ok at the moment, but time will tell. As long as I can get it running well for the fling all will be good. All the advice and experimentation has worked so far.
Cheers
Steve
When you get your SS setup working nicely its something you can completely forget about... also means you can just crunch through sticks and other stuff thrown up into your drivetrain and laugh!
Ahhhh so no more $300 XTR derailleurs getting smashed by a rock that happened to jump up from know where sweet! Going to go for another test session after lunch.
For me it was hangers, I was going through them one after another.
There is a lot of affectation around a lot of single speeding, but a lot of it comes down to just being able to ride and forget about all these other issues, of which gears and their smooth running is more often than not, the primary distraction. And really on an average ride you don't need them.
The SS bike often gets neglected as little goes wrong with it unless something breaks... no tweaking needed.
I run an old 9 speed chain off my geared bike and a "half-link". This gets me a chain length that happens to be just right for my frame with no need for a tensioner. I've found there is a small amount of adjustment in the dropouts (vertical style) too which helps.
Enjoy the peace and quiet of an SS off-road
All went well on friday with just one small slip when I took off at the lights in Emu Plains going up to Mitchel's Pass. I am starting to outgrow the 16tooth it might be time to try a 15 or a 14. The only challenge will be trying to get back out of glenbrook.
Have you checked your freewheel pawls and springs? a broken spring or sticking pawls will make it slip occasionally. They also work best with very light lube.
I have tried several wheel combinations from DT swiss, XT to XTR. They all originally produced the same results. It has settled down now so I will see how it wears in.