Chain tension again

Jose and I went back to the wrench work today to loosen up the overtight chain. I had tightened it two days ago because it was getting a little too loose. I was afraid that as the tension got looser, speeding up would cause the chain to flip right off the rear sprocket. This used to happen during interval workouts in early December, before the most recent time that I tightened up the chain tension. I would get a good head of steam on, and then about when I got to 25 mph or so as I passed the dump entrance (my point of reference for the interval), I could hear a loud grinding sound as the chain slack from the take-up was pulled around the rear sprocket and the chain would be riding clatteringly on top of the gears, instead of nestled smoothly inside them.

The first time it happened (2 December), I thought I had achieved enough speed to take off into the air, like one of the jets on the parallel runway, and that the grinding was related to that. It was easier to believe at the time than it is now because I had my hands in the drops and was bent way over, so that I could barely see the road ahead and all I could see what the quickly moving pavement right underneath the front wheel.

After Tuesday’s episode at the workshop, I noticed that it was hard to turn the pedals in reverse (free-wheel) and that in general the bike made more noise than it ought. Overtensioning the chain could lead to destruction of the race and bearings in the freewheel, as well as deforming the chain, so I took yesterday off, staying out of the saddle instead of riding the bike hard and wearing out the parts for no reason.

Last night, the good news started to return, however. First I discovered my personal 15mm box wrench in my jacket pocket so I didn’t need to go back to the garage to borrow their wrench. Then this morning, with Jose again levering the wheel tight with the broomstick, I tightened the bolts finger-tight and made sure that the chain could turn freely on the freewheel in both directions (look out for those fingers when the wheel turns, kids!). Then with the broomstick keeping the nuts from sliding forward in the dropouts, I tightened them up with the box wrench.

The first time on the bike again, on the way to the refectory this afternoon for lunch, I turned left at 2nd Street and pounded up the slight hill, leaving Jose and his boat-anchor bike in the dust. With the tension right, I could feel the difference in the ride, as the power I applied to the pedal stroke was smoothly and instantly transferred to the top of the chain, pulling the freewheel cog around and driving the rear wheel.

It sounds a little technical (I was going to call this post “Chain-al re-tension” but didn’t dare), but I thought I could tell the difference in the action, especially going uphill, where I use the freewheel less and rely more on the direct pull from the pedals to turn the wheel. Hasn’t the pony been riding a little sluggish lately? I thought it was me, but maybe it’s been the bike. I’ll find out more this afternoon on the ride, which I am looking forward to now that the wind has died down after three days.