Bicycle Mechanics - 38 tooth 130mm BCD chainring drags chain?

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Lambo
09-05-07, 01:29 PM
I read on lickbike.com that with a 38t 130mm BCD chainring, the chain may drag on the crank spider.
Is this really the case? I haven't seen it mentioned anywhere else.

Thanks y'all,

Lambo

Zouf
09-05-07, 02:31 PM
Depends on the spider design. In theory 39T is the limit, in practice there are a number of 38T 130mm BCD rings out there, and they work on at least *some* cranks. Measure the distance from BB axis to the chain on the 39T (this should be the same number on any 39T), take off 2.6% of that (38/39), and check that there is nothing on your crank spider that intrudes in this area.
Kommisar89
09-06-07, 11:40 PM
I've run a 38t chainring on a TruVative Elita and an old late '80's vintage Shimano crank without any problems.