Rene Herse Crankset Chain lockup
 

Downshifting from my Renee Herse 46H to 30L using a Shimano Ultegra HGCN-6701 chain, I am getting locked up. Any suggestions to resolve?

https://cimg7.ibsrv.net/gimg/bikefor...1db3d4d221.jpg

New chain with older chainrings by chance?

Directional chain in proper direction?

Just to elaborate on that, one side of the chain has lettering on it. That should be the side facing outward from the bike.

@Youdelr
The photo isn't working (I tried the exposed URL as well). If you can try again with the picture, that could really help reduce speculation. I had this happen on my White Industries 46/30T crankset -- one of the pins that is there to aid in shifting managed to work itself outward a bit, and the chain was hanging up on that. Once I realized what was going on, it was just a quick squeeze with a vice grip.

Confirmed chain direction is correct and chain wear is .50 on Park Gauge

Classic example of chain suck. Pretty common with earlier MtBs. Due to the chain's inability to release off the large ring during a down shift. Worn rings/chain and shifting under power are the two big no nos.

Best solution is shifting technique improvement. Andy

Could also be that the chainrings were designed for 8 speed or lower chains and the 10 speed 6701 has a narrower inner width causing it to get hung up occasionally.

Suggest you review a good article Jan Heine wrote on the Rene Herse Chainrings (https://www.renehersecycles.com/chai...hifting-ramps/


Based on your photo it looks like the small ring is forcefully "pulling" the chain onto the front side of the large chainring teeth just where the chain is supposed to release from the chainring. This is one of the reasons many crankset manufactures only do matched chainrings, they precisely control the travel distance between the teeth on adjacent chainrings so that the chain, when engaged on both chainrings during a shift, is not loose nor tight between the engaging/disengaging teeth on the 2 chainrings. As Andy noted above, this can lead to "chain suck". To minimize this, ease off the pedals when shifting,

They're not narrower between the inside plates...3/32" is the width on all chains except 1/8" bmx/track/single speed chains.

I've had The Best Crank In The World on one bike for four years and many thousands of miles and can't say I've experienced this. On any crank ever, in fact. Except maybe in the work stand?

Are you pedaling really slowly or under a heavy load when trying to shift down? Unlike rear shifting, front shifting can take some rider finesse to avoid problems, regardless of the components used.

I stand corrected. cxwrench is right.

I’ve read that the inner dimension between chain plates are 11/128” on 9-12 speed. The dimension is 3/32” on 8 and less multi-speed chains.

Not really believing everything I’ve read, so maybe no one should believe this, I measured some excess pieces of 8 and 9 speed chains. Taking just an internal measurement, and also individual (plate thickness and overall), with digital calipers, a 9 speed chain is less than 3/32. It is running around .085”.

This isn’t to say that .008” will cause an issue as I’m running a 9 speed chain with a 7 speed Sachs Aris freewheel without problems. And I can’t imagine a similar width aluminum chainring would fair worse.

John