Singlespeed & Fixed Gear - IRO crankset + bottom bracket chainline problems

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benm
07-14-07, 03:27 PM
Hi all,

I have a 2005 Bianchi Pista. I use it every day as my main transportation so I like keeping it in tip top shape. My old cranks and bottom bracket were worn out (the cranks would slowly loosen over time and work out the bolt), and also the rear hub went bad, so I just bought a new IRO rear wheel, IRO 110mm bottom bracket, new IRO 165mm cranks, and a new KMC Z410 1/8" chain.. According to IRO's website, the 110mm BB + IRO crank combination gives a 42mm chainline.

I put the parts on my bike today and I measure a 47.5mm chainline on the front and 41.7 on the back. Why is my front chainline over half a centimeter off? The bottom bracket is installed the right direction, and everything is tightened down properly. The cranks came with a 46t chainring which I haven't touched.

I am not experienced dealing with chainline issues... what's my best course of action? Replace the bottom bracket? Contact IRO? (they do say the cranks + bottom bracket combo should give a 42mm chainline...)

Thanks
Ben

SSSasky
07-14-07, 03:58 PM
Move the chainring to the inside of the crankarms spider.



(Sounds like you've got them on the outside). I've had that crankset for a couple years, several BBs. Always 42mm chainline with 110BB, with chainring on the inside.
SSSasky
07-14-07, 03:58 PM
Oh yeah: if that doesn't work, take pictures and post them.

benm
07-14-07, 05:14 PM
I would do that but the chainring is already on the inside.

Here are some pics. I can ride the bike but the chain is really noisy.

http://web.mit.edu/~benm/www/images/bike/bike1.jpg

http://web.mit.edu/~benm/www/images/bike/bike2.jpg

http://web.mit.edu/~benm/www/images/bike/bike3.jpg

http://web.mit.edu/~benm/www/images/bike/bike4.jpg

http://web.mit.edu/~benm/www/images/bike/bike5.jpg

Thanks!
chase.
07-14-07, 05:28 PM
good lord, that's a lot of electrical tape.
ernok1923
08-26-07, 02:09 PM
any luck figuring it out yet?
Savic
08-26-07, 06:08 PM
good lord, that's a lot of electrical tape.

Why the tape?
exfreewheeler
08-26-07, 06:11 PM
I've seen people tell others to flip the chainring/cog.

I guess some manufacturers make the them with the teeth offset, or suh'm?
Landgolier
08-26-07, 08:39 PM
Very weird. Maybe pull the cranks and confirm that the BB is actually 110.

Also, I've said this 1,000,000 times, but when you have a problem with IRO stuff or a question about their products, CALL TONY. People act like this board is the IRO support forum.