Track Cycling - Chainline and Chainring Size on a Leader 735tr

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mitchnodland
11-15-07, 09:33 PM
Hey,
I posted a couple days ago asking about which tires to use and stuff like that, and now I have another problem.
I used the 53 tooth chainring that came with my dura ace cranks.
To get my chainline correct, I need to mount it to the inside (I'm using Dura-Ace cranks off of a 10 speed).
The Large chainring hits the chainstay. I went to my lbs which know almost nothing, and they said people might sell cogs, that lean over away from the wheel, so I could mount my chainring on the outside of the crank away from the chainstay.
I called Leader Bikes, and they said no body on the track uses over a 48 tooth chainring.
Is this correct??
If it is, then I'm going to have to go back to my lbs, and buy another cog and chainring since my setup is unable to work.
Mitch
With a road crankset it's not surprising that you are mounting the chainring on the inside. Track and road cranksets have different chainlines.
A 53 is indeed a really big chainring, but you can make it work with a big rear cog. The point is to get a gear you can ride reasonably. Most riders on the road don't use too much more than a 48 front with a 17 or 18 rear, possibly a 16 if you're strong or on the flats. So you'll need about a 20 on the rear. The better approach is to get something like a TA Alize, Sugino Zen Messenger, or similar 130 mm BCD chainring (130 mm fits road cranks) for around $50.
mitchnodland
11-15-07, 10:36 PM
Track and road cranksets have different chainlines.
Ya, but the chainring would still be in the same place, aligned with the cog, still hitting the chainstay.
I am using this for velodrome.
Pasqually
11-15-07, 11:07 PM
pretty sure you will find that, unless you are just a very lucky person, the track crank and bb width will most likely postion the chainring in or around the centre of the road set up (between the small or large, slightly towards the smaller if anything). Possible that a 53 won't fit at all without some fiddling?
You could try different width bb's, spacers, set ups etc and spend more time and money than getting a track set up.
a 53 is indeed a large chain ring. as suggested above maybe try to source a smaller chainring for the crankset you have.
The point is that a typical track crankset has a 42.5 mm offset while road has something like a 45 (to the center of the spider). Your inside is too far in, and the outside position is too far out. When you're too far in, you may be able to fit a small chainring and get away with it but a large chainring is definitely too close to the centerline and most frames aren't going to accommodate it. Just think of switching the chainrings around if they were on a road bike and you'd still have problems there; on a track bike you have 2.5 mm or more less room to play with and that's about all the road clearance for an outside chainring that you usually have. It just doesn't work. You can usually get away on the inside position with a road crankarm on a track frame with a smaller ring but that's it.
mitchnodland
11-19-07, 05:10 PM
ok thanks guys.
I got away with putting on a 43 chainring. Chainline looks perfect although it is probably 2.5mm off like he was saying.
Now it is time to go ride it =)
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