Speaking of smallest chainrings, I just received, bought from UK eBay, several modern Stronglight 130 BCD 38T rings. I'd usually seen 39T listed as the smallest ring for 130 BCD. I do note however that Sheldon's web site lists 38T as the smallest for 130 BCD.
This makes me wonder about the smallest ring listed for other circles. With 1/2" pitch chain, you should have to reduce the chainring circumference by 12.7 mm to reduce the smallest ring by one tooth. If you divide this by PI, you get a 4.04 mm reduction in BCD for a 1 tooth reduction. So, assuming 38T is indeed the absolute minimum for 130 BCD, then the 128 BCD old Nervar circle is still limited to 38T, as Sheldon lists it, 2 mm reduction in BCD being insufficient to reduce the teeth by one.
But Sheldon's list and every other list I have ever seen, including one on the modern Stronglight ring packaging, shows 38T as the minimum for the 122 BCD old Stronglight circle. This would seem to defy geometry. If a 130 BCD will handle 38T, then an 8 mm reduction to 122 BCD should certainly allow 37T and probably 36T.
Anyone ever seen a 36T or 37T Stronglight ring? Stronglight definitely made rings with odd numbers of teeth, so why not 37T? Also, even though 38T is shown as the smallest for 128 BCD Nervar, I've never seen one smaller than 40T. Has anyone else?
Regards,
Jerry Moos Big Spring, TX
Bob Freitas <freitas1@pacbell.net> wrote:
Having just bought my second Campagnolo 36t chainring in less than a
week ($10 no less!) we seem to have skipped over the fact that Campy did
do a tripple with a small inner ring that was not attached to the 144
bcd holes but to a set of drilled 100 bcd holes on the spider itself.
other alternatives would be to drill to one of the current bcds for a
more complete range of rings.
more alternatives would be a tripplizer ring which attaches a second
ring to the inner 144bcd (I have a Merz version which does TA
cyclotourist down to what 26T)
BOB FREITAS
Thinking this cat is skinned in MILL VALLEY,CA