I’m running SRAM Red eTap with an 11-30 cassette (supposedly only supports 11-28, but got it to work). I’m planning to do a bunch of big climbing events and quite frankly I just don’t have the power to do multiple hour-long climbs near threshold. So I’m looking for options to get a bigger cassette.
Can I get a derailleur hanger and fit a 34 or 36 tooth cassette? I guess I would need a longer chain, but can I do this without replacing the derailleur?
Have you considered the WiFli RD?
Also, try a mid compact or full compact if you are running a 53/39.
This will help if you want to run a bigger cassette
Thanks… ya I’m already running a 50/34.
Quick question, with the new 9100/R800 series of rear D, there is a piece of linkage that resembles the RoadLink. I wonder if is possible to angle it so that the rear D is able to cover bigger gears?
You need a longer cage derailleur if you want to go w/a bigger cassette. And this will require a new chain.
50/34 chainrings w/an 11x30 cassette. How much do you weigh and/or what is your W/kg such that the aforementioned combination is insufficient? You plan on doing multiple hour-long 20% climbs??
Go Sub-Compact? The crankset might be a good place to achieve climbing gears for you. This is because it allows you to use cassettes with less of a jump between the cogs, and because you won’t need to hack and modify too many drivetrain parts.
I second the derailleur hanger idea. Shifting isn’t as crisp, but price is tiny & much much less than a new derailleur.
You may need a longer chain. Depends on amount of slack currently.
In mechanical derailleurs I’ve had luck reversing the B screw. Don’t know if you can do that with eTap.
It’s also possible to get a longer one
Is there something smaller? I couldn’t find a smaller chainring than 50/34 from SRAM. Or are you suggesting a whole new crankset that’s smaller?
I’m at about 3W/kg… with a 230 FTP. I’ve done this Fondo a few times, the climbs definitely aren’t 20% but even so, doing 3 hour long climbs plus 3 other significant climbs, I just can’t push out 190 watts. At 140 or so I’m having to grind at a really low cadence that after 60 miles I just don’t have the muscle to do.
HOPEFULLY, I can pull up my FTP to around 250+ by Sept and this won’t be an issue, but if I’m still sitting at 230, that’s just barely enough to get through this ride.
The latter, but I understand this can result in bb issues, so know what you need for your bike.
The roadlink is a mutch simpler solution, but if this is something you will do regularly (climbing events) then it might be something to look in to at least.
But that costs money. You only need a screwdriver to reverse the screw.
On my MTB i have one of these:
https://www.garbaruk.com/rear-derailleur-cage-for-sram-11-speed.html
But I might be over thinking this now 
I run 50-34 cranks, and an 11-40 cassette on my road bike for gravel riding. I use a wolftooth roadlink, and a medium cage shimano derailleur. Works great, but I cant cross chain big-big.
Which test derailleur are you using?
Ultegra 6800 medium cage. I should swap for a long cage and longer chain, but I’m too lazy.
My understanding is that I cannot change the cage on the SRAM eTap derailleur… that I would have to get the Wifli derailleur, but that’s $600 
Plenty of time between now and Sept to get the kilos down and watts up which should help tremendously. Even so, lighter gearing never hurts when climbing and climbing and climbing and climbing.