Simplex prestige gearing
 

I have a stronglight 93 crank with a 52 outer chainring. I am trying to change the inner 45 to something smaller like a 40-42 or even smaller. I have a front simplex sj102a derailleur. 122bcd

I have a 1972 simplex prestige rear derailleur with either 13-24 or 14-24 6 speed freewheel (I can't remember). I am thinking of switching this to something with a lower low gear.

I'm hoping to make my gearing more conducive to the hills around here. What are limits on lowest gearing I can put on? 40/52 and a 13-26? Lower?

chainwheels for the 93 nominally go down to 38T in the mfr's literature. some enthusiasts report finding 37T's.

the prestige rear mech is rated at a large cog limit of 28T and a wrap of 28T.

hope this helps you a bit. ;)

Your post is cofusing because taller means higher gearing, not lower. The cog is bigger, but the gear ratio is lower.

Thank you. I'm trying to avoid chain droop and ensure that whatever chainring combo up front the gearing won't have issues with chain length.

28t chain wrap...

52-40 + 28-14 = 26t.

Ok, apparently I learned what chain wrap is.

Someone please correct me, but I believe those 38T 122mm BCD chainrings are exceedingly rare and very much in demand among Stronglight fans.

One other consideration: Assuming a 5-speed freewheel, 52-40/14-28 provides a superb 1.5-step gear ratio progression and was extremely popular in its day. 50-38 would take you down about as low as your rear derailleur can go, while still providing a great set of ratios, a reasonable top gear, and a very easy-to-find 5-speed freewheel.

xxcycle.com in France stocks them semi-regularly (they're not showing any right now). They don't quite have the same vintage look as the rings that came on a mod. 93 crankset, but they are 122bcd and 38t.

I need to figure out which derailleur it is. I thought prestige but perhaps it is criterium? It is identical to this one with the red plugs.

Those chain wrap and max cog sizes have to be wrong. 34T?
VeloBase.com - Component: Simplex Criterium

Yes, they are. But BF member jonwara has been making new 37T 122mm BCD rings now:



122 BCD Conventional Chainring, 37 Teeth - Red Clover Components

You can tell by a couple of things. The Criterium has chromed steel plates added to the body. And the pulley cage plates are solid rather than stamped and hollow-ish looking.

Yup. Took me a year plus to get mine.

I've got one mounted on here. 38/45. Didn't know they were rare.
http://i1227.photobucket.com/albums/.../Gitane108.jpg

You can use Model 57 Super Competition rings if you drill them out for 10 mm bolts and countersink.

I'm running a Simplex 410 short/medium? cage, on a triple with a 14-28 freewheel.
Works pretty good. But I do have a 410 long cage on the bench right now I intend
put on.

http://i48.photobucket.com/albums/f2...ps08p4m5y5.jpg

Speaking of chain wrap, check this out.
Small gear to small gear. 34-14, not recommend
http://i48.photobucket.com/albums/f2...pstbohorhf.jpg

Simplex 410 long cage on a hanger. as came from France.
14-28 freewheel 52/40 crank.

Narhay
This is an old photo but, there is the ring I'd like to send you.


http://i48.photobucket.com/albums/f2...pswalf6djs.jpg