about rapid-rise derailleurs

[kim young]

I have a question about the low-normals. I know riv loves the RR’s, but I hesitate. 

I know that if the cable breaks- they default to the low gear. And that is brilliant, because its still easy to get home. 

But if my chain snaps, then the cage and whole mechanism - like its gonna clam up without its chain and then the cage might go into the big gear and possibly over into the spokes (if that makes any sense.)

Is this a legit concern or am I just being paranoid? 

Thanks for reading :) 

(From kim in AZ)

[Jim M.]

On Saturday, August 15, 2020 at 6:50:22 PM UTC-7, Flowerfang wrote:

But if my chain snaps, then the cage and whole mechanism - like its gonna clam up without its chain and then the cage might go into the big gear and possibly over into the spokes 

If the derailer is properly adjusted, the limiting screw prevents it from moving into the spokes, whether you're shifting or snapping a chain.

My chain snagged a stick once that pushed the derailer into the spokes. The derailer hanger bent but the chain didn't snap. But it didn't matter whether the derailer was high or low normal (it was high normal).

Just curious, how many chains have you snapped? I'm 220 lbs and only have snapped two chains in 50 years of riding, including lots of single speed mountain biking. 

I like low normal and have switched most of my bikes, but I've certainly heard plenty of others who don't like it.

jim m

wc, ca

[Patrick Moore]

Kim: If the inner limit screw is properly adjusted, the derailleur won't go further than limited by that screw, so only to the inside cog.

OTOH, regular movement rds can be fudged if a cable breaks by screwing in the outer limit screw to hold the chain on the cog of your choice; or at least, on one of the bigger ones.

I recall the Cyclo Benelux rd that I accidentally stumbled on in my pure ignorance and naivete when I was overhauling a late '60s or very, very early '70s Varsity -- I fudged 2 cogs on the driver of an AW 3 speed hub and, thinking that the OEM Alvit was broken (the skipping was, in retrospect, probabably due simply to a bad chain), I looked around locally for a rd, these being rarae aves indeed, and somehow found this relic of the 1950s. It was a true low-normal, in that in place of a parallelogram, there was a push/pull rod holding the cage at the end, with a pull chain at the other end to which the shift cable attached. A helicoidal spring provided tension both to cage and rod. If you let it go -- say, if your cable snapped -- there was no limit screw and the thing would boink into the spokes. 

But for 2 cogs, 16 and 18 (the 18 t reversed on the driver, the 16 dished outward as per spec, left no room for the circlip, so I had a fundi tack weld the 16 in place (squatting on the porch of his single-car-garage workshop). Long-term replacement didn't figure in to my plans, as back in those salad days I thought chains and cogs and brake blocks were all part of the fundamental, permanent infrastructure of the bike, like the frame.

Come to think of it, even the AW was exotic at that time and place, and I found mine at a local flea market, so perhaps I found the Cyclo there too, flotsam cast overboard from the wreck of the British empire (Kenya had gained independence only 3 years before we arrived) by some long-departed representative of the Raj.

Riv content: I think Rivendell should re-make a Silver version of this rear derailleur, and reproduce straight-teeth 4 speed freewheels. Combine it with zip-tie fastenings and twine accents for the new "RetroRiv" grouppo.

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Patrick Moore

Alburquerque, Nuevo Mexico, Etats Unis d'Amerique, Orbis Terrarum

[kim young]

Jim- thank you 

 I can get up to 145 pounds come winter and I have broken a couple chains bc I thought I was too fat for my poor bike! Lol - But I am often messIng around with drive train combos.  I live in the mountains and it is so rocky with a lot of climbing.  I need low gears. I am gonna put fresh chains on my bikes. 

Patrick- the Benelux !! omg so cool. 

And a good story. 

(....And tip re: provisional outer limit screw/ emergency fix :)

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[Jim M.]

On Saturday, August 15, 2020 at 8:07:00 PM UTC-7, Flowerfang wrote:

 I thought I was too fat for my poor bike! Lol 

145? That's light for a bike. ;-)

I like rapid rise but I'm not a proselytizer for it. For simplicity, you might want to look at 10-speed 1x drivetrains for the mountains. 10-speed are pretty affordable these days because everyone wants 12-speed. If it's Shimano, a 10-sp cassette fits on a 9-sp hub, which made it cheap for me.

[kim young]

Lol -  thanks for saying.

Yes I’ve got 1xs on a couple bikes, but with that much chain-line or however you say it , I’ve had issues. They’ve been great when it’s dry, but in weather it has been fussy for me. 

Tho I am running an NX group on one bike, so that might be my problem. 

But thought I’d try out a 2X this time on the wolbis and see if it’s less trouble.

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[Jim M.]

I'm using Riv's wide low double: https://www.rivbike.com/collections/cranks-bbs/products/silver-crank-wide-low-double-38x24-with-guard, and 2 of Riv's MicroShift left shifters https://www.rivbike.com/collections/shifting/products/microshift-thumb-shifters-9-speed-sl-t09, and XT 9-sp derailers on my Bombadil. Very happy with the friction shifting from the setup.

On Saturday, August 15, 2020 at 8:37:52 PM UTC-7, Flowerfang wrote:

Lol -  thanks for saying.

Yes I’ve got 1xs on a couple bikes, but with that much chain-line or however you say it , I’ve had issues. They’ve been great when it’s dry, but in weather it has been fussy for me. 

Tho I am running an NX group on one bike, so that might be my problem. 

But thought I’d try out a 2X this time on the wolbis and see if it’s less trouble.

On Sat, Aug 15, 2020 at 8:25 PM Jim M. <math...@gmail.com> wrote:

On Saturday, August 15, 2020 at 8:07:00 PM UTC-7, Flowerfang wrote:

 I thought I was too fat for my poor bike! Lol 

145? That's light for a bike. ;-)

I like rapid rise but I'm not a proselytizer for it. For simplicity, you might want to look at 10-speed 1x drivetrains for the mountains. 10-speed are pretty affordable these days because everyone wants 12-speed. If it's Shimano, a 10-sp cassette fits on a 9-sp hub, which made it cheap for me.

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[kim young]

I love riv simplicity. (...and the versatility and the whole ‘just ride‘ ethos, etc etc. 

ha sry I get a little extra :)

Thanks for these links jim 

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