Wednesday, February 07, 2007
VIIIH Chainrings: Turning the outside in
After giving a bit of theory in post 960, I will give you some actual applications. When I got the new VIII H SA8 out of the box, I noticed the bottom bracket was so tight it would hardly turn. I pulled off the cranks to adjust that and while I had them off I figured I might as well experiment a bit.
I dug around in my junk parts cache and found an old Shamano STX triple crankset from a mid 90s Kona MTB. The STX is kind of an odd ball deal that has the middle chainring and the granny gear attached to the small 5 bolt circle. [Most triples have the middle and big chainring on the larger bolt circle and the granny on a smaller bolt circle.] Since I was just chasing gear and chainline combos, I just turned the granny (24) and the middle (32) around and put it on (the granny is just a weird looking washer in this configuration. (I guess I could cover the teeth with reflective tape :-)
Next I shortened the chain and used a connector link (good hint, pine cone) to put it back together. It is sweet, but let’s just say you aren’t going to see this in LBS. I am not so sure I want to go with it either, but it promises to give the gear heads whiplash and it does ride like a dream. No, this is not trick photography.
It gives me, and you, an idea of the kind possibilities there are when you are looking for used parts. I would still recommend going with the 110 (preferred) or 130 BCD with the 74 (see post 960) granny for chainline position, gear tooth flexibility and wider availability, but who knows what you might have to do in a pinch?
The Sheldon Brown "Touring Triple Crank" section lists two Sugino Cranksets for less than a $100 twhich I'm guess would be about for the DownTube VIII. It also provides a benchmark when shopping for used parts.
I also disassembled the stock crank/chainwheel and in can be seen in the picture below.
Click on the pic to see full size.
According to Sheldon Brown, it is possible to get a 130 BCD 5 bolt 38 tooth chainring ($20)that would get closer to a reasonable gear but merely replacing the chainring would not solve the chainline issue,o'wtf,how about washers and longer bolts ???.
Like I said before, "Change the cranks. You will be glad you did." And don't forget the new sealed bottom bracket!
by WrencherWOAC
I dug around in my junk parts cache and found an old Shamano STX triple crankset from a mid 90s Kona MTB. The STX is kind of an odd ball deal that has the middle chainring and the granny gear attached to the small 5 bolt circle. [Most triples have the middle and big chainring on the larger bolt circle and the granny on a smaller bolt circle.] Since I was just chasing gear and chainline combos, I just turned the granny (24) and the middle (32) around and put it on (the granny is just a weird looking washer in this configuration. (I guess I could cover the teeth with reflective tape :-)
Next I shortened the chain and used a connector link (good hint, pine cone) to put it back together. It is sweet, but let’s just say you aren’t going to see this in LBS. I am not so sure I want to go with it either, but it promises to give the gear heads whiplash and it does ride like a dream. No, this is not trick photography.
It gives me, and you, an idea of the kind possibilities there are when you are looking for used parts. I would still recommend going with the 110 (preferred) or 130 BCD with the 74 (see post 960) granny for chainline position, gear tooth flexibility and wider availability, but who knows what you might have to do in a pinch?
The Sheldon Brown "Touring Triple Crank" section lists two Sugino Cranksets for less than a $100 twhich I'm guess would be about for the DownTube VIII. It also provides a benchmark when shopping for used parts.
I also disassembled the stock crank/chainwheel and in can be seen in the picture below.
Click on the pic to see full size.
According to Sheldon Brown, it is possible to get a 130 BCD 5 bolt 38 tooth chainring ($20)that would get closer to a reasonable gear but merely replacing the chainring would not solve the chainline issue,o'wtf,how about washers and longer bolts ???.
Like I said before, "Change the cranks. You will be glad you did." And don't forget the new sealed bottom bracket!
by WrencherWOAC
Labels: chainrings, cranks, VIII H SA8
