mcooley

Curious if anyone, here, knows through experience if the Sram Rival 1 MEDIUM length rear derailleur will handle the 11-42 cassette with a 42t front 1x chain ring? I heard the manufacturer specs can be conservative sometimes.

Thanks

RubeRad

I don't know the answer to your question, but the size of the 1x chainring should be irrelevant to the question.

Specs usually are conservative, what is the stated capacity of the RD? 42-11 = 31, so I'd guess practically speaking you'd need at least 27-28 or so stated.

You'd also need to get the RD far enough down so the upper pulley doesn't ride on the big cogs. Shimano uses a B-screw for this, which can be replaced with a longer standard screw if necessary, but IIRC B-screws might be a shimano-only thing, I don't know if SRAM has B-screws.

cyclintom

From memory - no. This is a HUGE cog measuring about 8" in diameter. I believe the "medium" only goes to 36 teeth.

fietsbob

I think the whole RD must be mounted lower .. there is a widget made to re mount the RD lower.
it screws into th RD hanger and the RD screws into that thing..

of course the dropout is even more vulnerable to Bending, that way..

RubeRad

This is the widget fietsbob is talking about -- or at least one company's version of it...

RoadLink ? wolftoothcomponents.com

KonaRider125

No go. Sell your medium cage and get the long cage which is designed for 42t cogs.

RoadLight

Hi mcooley,

The answer depends on the length of your rear derailleur hanger (the part of your frame that your rear derailleur attaches to). SRAM's spec assumes a fairly short hanger. If your frame happens to have a longer hanger, you might be able to make it work.

The problem is the top jockey wheel must be far enough below the largest cog on your cassette (in this case 42t). I don't remember the SRAM spec off the top of my head but I think it's between 4 and 6 mm.

There are adapters you can buy from companies like Wolf Tooth Components that can extend your hanger so a short-cage rear derailleur will work with a big cassette cog. But, if you read the reviews written by folks who use these devices, you'll see that most of them sacrifice shifting performance. I'm not willing to do that so I think these adapters are a bad idea.

Kind regards, RoadLight

markjenn

I'm mounting up a Rival 1x med now with a 11-36 and it is adequate for capacity, but not generous. I'd be very surprised if you could get another 6t out of it. The b-screw has a very wide adjustment, but I had it fiddle quite a bit with it to get it to reliably hop onto the 36 - the 42 would be even tougher. All in all, I'd want to stack the deck more in my favor with the long-cage version of the Rival 1x RD.

I have heard that the 42t cassettes require a different hub, but may be off on this.

- Mark

mcooley

Thanks, I will find out today but I am not sure if the hangar is considered long, however, below is the link to the dropout I used when I built the frame.

www.paragonmachineworks.com - DR2040SteelRearVerticalDropout58DegreewithWindow

mcooley

I do know I should be good with my hub compatibility.

https://www.sram.com/sram/road/produ...1-42t-cassette

I did see online that people are saying it works but it is not spec to work according to Sram. Those numbers may be conservative as others have noted. I may end up going with the longer cage anyhow but I will let everyone know the outcome later today.

Thanks for replying!

mcooley

So it seems the medium cage has enough length and allows for shifting into the 42t cog. I still need to add a link or two to the chain but so far it actually seems to work. I think the trick with the 1x in general is to keep the right tension so the chain doesn't come off. The long cage would probably do better when not in the 42t because it might help take up some slack but it doesn't seem like slack will be much of an issue anyway on the medium cage. I will get it all setup by Monday and do some test rides.

mcooley

FYI, so, even though the medium cage worked I am going to go with the long cage because the chain is quite loose on the small cog. This was after changing the length of the chain. The chain that is on it now should work fine with the long cage but with less slack on the small cog. I was impressed though that the medium SRAM cage worked on the 42t cog because the specs had made it look like it wouldn't work.

MR BIG STUFF

What are you working on that you are running 42t in the front?