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View Full Version : Benefit of ramped and pinned chainrings?


NHAero
11-24-2018, 04:21 PM
I've bought a set of barely ridden SunXCD cranks that are coming with 44T-28T TA chainrings (which is the pair I want). TA doesn't include ramps and pins on the rings that fit this crank (50.4mm BCD, like the old TA Cyclotouriste cranks). I converted my Anderson to Ultegra 2x11 STI and my Bob Jackson to 3x10 STI this year - both previously has 9 speed DA barcon shifters - and I've never used STI with non-ramped and pinned chainrings. Barcons work fine on plain rings. What about STI - do the ramps and pins make a noticeable improvement in shifting quality?
As far as I can find, only SunXCD makes a 50.4mm BCD large ring with ramps and pins. In addition to SunXCD, VO makes a replica of the Cyclotouriste crank, and the rings are ramped and pinned, but only 46-30 is available from VO. I'll try the plain TA rings first when the cranks come, but curious what others experience has been.
The front derailleur is a Shimano CX70, and it shifts the current 44-33 ramped and pinned rings very nicely. But I'll be going to plain rings at the same time as jumping from a 11T difference between rings to 16T.
Thanks!

palincss
11-24-2018, 09:12 PM
If it's coming with the rings you want, perhaps you'd do well to just try it as it comes, and see how the shift quality is. No need to try to solve a problem if you find one doesn't exist.

oldpotatoe
11-25-2018, 06:11 AM
I've bought a set of barely ridden SunXCD cranks that are coming with 44T-28T TA chainrings (which is the pair I want). TA doesn't include ramps and pins on the rings that fit this crank (50.4mm BCD, like the old TA Cyclotouriste cranks). I converted my Anderson to Ultegra 2x11 STI and my Bob Jackson to 3x10 STI this year - both previously has 9 speed DA barcon shifters - and I've never used STI with non-ramped and pinned chainrings. Barcons work fine on plain rings. What about STI - do the ramps and pins make a noticeable improvement in shifting quality?
As far as I can find, only SunXCD makes a 50.4mm BCD large ring with ramps and pins. In addition to SunXCD, VO makes a replica of the Cyclotouriste crank, and the rings are ramped and pinned, but only 46-30 is available from VO. I'll try the plain TA rings first when the cranks come, but curious what others experience has been.
The front derailleur is a Shimano CX70, and it shifts the current 44-33 ramped and pinned rings very nicely. But I'll be going to plain rings at the same time as jumping from a 11T difference between rings to 16T.
Thanks!

STI depends on ramps, pins and such since the front der is positional..you can have it overshift a bit to get the chain up there, and it can be made to work but only with very minimal pedal pressure when you are shifting. Probably no go if you are under any kind of 'load'. Friction, either DT or barends is much less positional, so works better. Once upon a time, there were no pins and ramsp on chainrings. BUT all shifters were friction.

A 'modern' front der certainly helps but again, not as good as either pins and ramps or some sort of friction LH shifter.

NHAero
11-25-2018, 06:55 AM
Yes, definitely starting there, why not?
Thank you
If it's coming with the rings you want, perhaps you'd do well to just try it as it comes, and see how the shift quality is. No need to try to solve a problem if you find one doesn't exist.