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SRAM Etap with triple chainrings

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SRAM Etap with triple chainrings

Old 03-26-23, 11:33 AM
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jnbrown
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SRAM Etap with triple chainrings

Is it possible to run etap 12 speed on just the rear derailleur and keep mechanical shifting on front triple chainrings? Will a 12 speed chain work on my current chainrings?
I am looking for ways to get lower gears.
current gearing is 50/39/28 front and 12-32 rear.
with Etap it says I could use 36T cassette.
Another and much cheaper option is to change 28T chainring to 26T.
Not sure if the jump from 26 to 39 would be too much.
Thanks for any advice.
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Old 03-26-23, 01:42 PM
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My triple is 52/39/26 and shifts fine. I am pretty sure it would still work fine even if I changed the inner to 24, which I might do sometime soon.
What speed is your cassette? I’m using a 9 speed 11-34 which also works well with a road link extender, and I know even bigger range cassettes are available.
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Old 03-26-23, 02:21 PM
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Going to 24 or 26t chainring would be by far the cheapest thing to do. I think I'd do that first.

There's no generic reason why Etap rear shifting wouldn't work with a mechanical front derailleur. I did this with a bar end shifter for a while, but only with a double chainring set up. You might, however, run into issues with the rear derailleur being able to wrap enough chain to do it with a triple. In determining how much of your drivetrain you'd have to change, it would help to know more about exactly what is on the bike now. How is one supposed to tell if your current chainrings would work when you didn't say what your current chainrings are beyond the teeth count.
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Old 03-26-23, 02:23 PM
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Forgot to mention my cassette is 10 speed.
unfortunately cannot find 12-34 cassette, just 11-34 and 12-36.
I am not sure if a road link would allow 12-36 with my SRAM force RD which is rated at 32T.
changing to 12-36 would give a lower gear than dropping the front ring to 26.
If I did both it would be really low.
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Old 03-26-23, 03:34 PM
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I looked at my RD and there seems to be a good amount of clearance between the jockey wheel and 32T cog.
So I am thinking it might be possible to use 12-36 cassette if I adjust the B screw in. If not I can always try a road link.
I am debating whether to try the 26T ring first or the 12-36 casette.
Changing the cassette would give me 12% lower gear and changing the chain ring would give me only 7% lower gear.
With the cassette change I would loose the 14T cog, so the jump from 13T to 15T would be pretty big.
I am sure not we use those gears that much, we tend to use the upper half of the cassette more.
I looked for a 26T chainring and there are not a lot them. I found an old Salsa ring that I think is the same as the one I have on now but the color doesn't match which is not a big deal.
There is the TA Zelito that says it is 10 speed compatible but not sure it worth twice the price of the Salsa.
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Old 03-27-23, 12:49 PM
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In your quest to find lower gears, don't forget not to overshoot your derailleur wrap capacity. Here's a good article: Sheldon Brown's Bicycle Glossary Ca - Ce

In nutshell, be careful with just adding larger cassettes without considering whether your derailleur can handle the range. While a RoadLink will help the derailleur reach larger cogs, it doesn't help with chain wrap.

I have used a cassette with 42t cog (to climb Pikes Peak), but I had to lock out the big ring in the front to make sure that I didn't exceed chain wrap limits.

Last edited by TobyGadd; 03-27-23 at 05:59 PM.
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Old 03-27-23, 05:51 PM
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Originally Posted by TobyGadd
In your quest to find lower gears, don't forget not to overshoot your derailleur wrap capacity. Here's a good article: Sheldon Brown's Bicycle Glossary Ca - Ce

In nutshell, be careful with just adding larger cassettes without considering whether your derailleur can handle the range. While a RoadLink will help the derailleur reach larger cogs, it doesn't help with chain wrap.

I have used a cassette with 42t cog (to climb Pikes Peak), but I had to lock out the big ring in the front to make sure that I didn't exceeding chain wrap limits.
Yep that could be problem. The current derailleur is Force Wifli and its chain wrap capacity is 37 teeth and I am calculating 46.
With my current 12-32 cassette it is still exceeding it but works well. We only use maybe the top 4 cogs when on the 28T chainring, so the chain being too loose beyond that is not an issue.
If it doesn't work I may have to swap out the RD for a long cage.
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Old 03-28-23, 05:01 PM
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So running a Sram 2x12 with a 10-36 rear cog and a 46-33 would give you pretty much the same low end and nicely spaced gearing.
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Old 03-29-23, 08:59 AM
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I went ahead and got the 12-36 cassette and put it on.
I added one link to the chain.
I adjusted the B-screw in a good ways and it does shift into the 36T cog.
There is just enough room between the jockey wheel and 36T cog for the chain and it does not make any extra noise.
The chain wrap seems ok but is at its limit. I only need to use the top 3 or 4 cogs when I am in the 28T chainring after that i can shift into the 39T chainring.
I think it is ridable as is but I am going to install a Roadlink to get the RD into a better position than it is, figured it was worth the $22 to do that.
I think this is really going to help ease going uphill albeit slower.
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Old 03-29-23, 11:49 AM
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Originally Posted by jnbrown
I went ahead and got the 12-36 cassette and put it on.
I added one link to the chain.
I adjusted the B-screw in a good ways and it does shift into the 36T cog.
There is just enough room between the jockey wheel and 36T cog for the chain and it does not make any extra noise.
The chain wrap seems ok but is at its limit. I only need to use the top 3 or 4 cogs when I am in the 28T chainring after that i can shift into the 39T chainring.
I think it is ridable as is but I am going to install a Roadlink to get the RD into a better position than it is, figured it was worth the $22 to do that.
I think this is really going to help ease going uphill albeit slower.
Thanks for posting an update.

If the jockey wheel clears the biggest cog without contact or noise, I don't think that you need a RoadLink. The downside to them is that they make shifting on the smaller cogs somewhat less precise, since the derailleur is farther away. It's not likely to be terrible or anything, but why do it unless it's necessary?

Last edited by TobyGadd; 03-29-23 at 12:59 PM.
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Old 03-30-23, 09:05 AM
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Originally Posted by TobyGadd
Thanks for posting an update.

If the jockey wheel clears the biggest cog without contact or noise, I don't think that you need a RoadLink. The downside to them is that they make shifting on the smaller cogs somewhat less precise, since the derailleur is farther away. It's not likely to be terrible or anything, but why do it unless it's necessary?
I feel a little uncomfortable with the RD being angled back away from the cassette. Whether this makes a difference or not, I don't know.
Adding the Roadlink will get the RD more under the cassette where it normally would be.
If it makes things worse I simply will not use it, not really an issue for me.

Thanks
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Old 03-30-23, 02:57 PM
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Originally Posted by jnbrown
I feel a little uncomfortable with the RD being angled back away from the cassette. Whether this makes a difference or not, I don't know.
Adding the Roadlink will get the RD more under the cassette where it normally would be.
If it makes things worse I simply will not use it, not really an issue for me.

Thanks
Sounds good. Please let us know how it goes.
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Old 03-31-23, 02:24 PM
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I installed the Roadlink. Had to back out the B screw a lot from its previous position.
Now the RD is in front of the rear wheel instead of behind it.
Did a short test ride and shifting seems to be good, won't know for sure until we do a real ride.
But I think it is going to work well.

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Old 03-31-23, 09:37 PM
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Looks like OP has found a good solution.

When we spec'd a new tandem a few years back, we knew we would be slowing more rapidly over the coming years and also knew we would sometimes ride in much hillier terrain. So, we ordered a conventional drive train - Shimano Di2 with 50-34 and an 11-34 (11 speed) cassette. That suits us fine around here where most hills are less than 5% and only a couple of the bigger ones are more than 9%. This base configuration shifts very nicely.

But, we got a second cassette with an 11-42 and a RoadLink. Its been a good solution, requiring a cassette change + Roadlink +swap to the second chain + a quick tune on the RD when we are headed for some time in the hills. It doesn't shift quite as crisply as the smaller cassette, but still far better than any old mechanical drivetrain I had. I expect there will come a day when we just leave the 11-42 on for good.

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Old 04-03-23, 04:59 PM
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^ a SRAM 12 speed setup with a 43/10 crank and 10-36 cassette is going to give you almos the same range and shifting within factory spec without any aftermarket hacks.
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Old 04-06-23, 02:51 PM
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Originally Posted by merlinextraligh
^ a SRAM 12 speed setup with a 43/10 crank and 10-36 cassette is going to give you almos the same range and shifting within factory spec without any aftermarket hacks.
Did you mean 43/30 crankset? How do you put that crankset on a tandem?
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Old 04-06-23, 04:02 PM
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Originally Posted by jnbrown
Did you mean 43/30 crankset? How do you put that crankset on a tandem?
yes 43/30 in the front 10/36 in the back.

its,a standard size fro SRAM; there shouldn’t be a problem putting it on a tandem.
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Old 04-06-23, 05:55 PM
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SRAM does not make a tandem crankset so it is not possible.
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Old 04-06-23, 06:18 PM
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Valid point so you’re probably limited to a 34 tooth small chain ring on a 110 bolt circle crank
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