HMJ

Greetings,

I am interested in hearing from anyone with actual experience using a Shimano Sora RD-R3000-GS 9-speed "medium" cage RD with a 36T large sprocket. Shimano's maximum recommended large sprocket for this RD is 34T. I have a 48/32 chainrings (with Sora shifters and FD) and I *think* installing an 11-36 cassette will work OK but would like to hear success - or failure - stories from those who have done it.

I realize that:
- Shimano is widely thought to have slightly conservative stated limits
- I will need to replace the chain
- an Alivio MTB RD should work (same pull ratio, 36T max large cog)
- I may have to adjust the B-limit some

Many thanks in advance.

Camilo

I apologize for not actually answering your question. But - I've gone to 36t on two different derailleurs that were spec'd for 34t and they both worked just fine. In fact, I didn't even have to use a longer chain (I had sized the chain originally on the 34t so that it was as long as possible rather than as short as possible).

I hope and expect you'll get actual experience replies. But even so, i recommend you just try it. Because it can be that individual bikes may differ in how this might work. It will cost you nothing other than the cassette to try it, maybe a chain as a second potential cost (which you can just save for future use if it doesn't work).

70sSanO

The long and short of it is probably. But dropout length of the particular bike does impact whether it will “absolutely” work.

Some people need to use a longer B screw to squeeze out a larger max cog. Worst case is a RoadLink, but I doubt you will need it.

John

Bill Kapaun

It's always a bit of a crap shoot.
Shimano tends to be conservative because different bike Manfs. may have a slightly different/out of spec RDER hanger geometry and so Shimano gives "some" leeway.
You might be one of the unlucky ones.

EDIT-
How come nobody ever says SRAM.....

delbiker1 

Being that the big ring is 48 tooth, I think it will likely be fine. I am using a 6700 short cage RD with 6750 crank that has a 48-36 rings. I believe that derailleur's stated limit is 28. I have run 11-34 and 36 with no issues. When on the 46 tooth ring, I can still get the chain onto the 34 tooth cog, but it does not run well. If I added a link to the chain, it would probably run better, but no need to do that. As others stated, you have to try it to find out for sure.

Ron Damon

Oh, geez. 34T to 36T is mere 6% beyond spec. I've pushed 10% beyond spec (e.g. 42T to 46T) sans problems. I can't see why you haven't tried it already. Do it.

veganbikes

SRAM at least on the AXS level couldn't handle a 11-44 cassette on their GX AXS derailleur very frustrating and expensive. Apparently for that even taking out the B-Limit entirely wouldn't get it close enough to shift correctly and we tried everything we could and no luck. Put the 11-50 on there and it shifts perfectly (or well enough still need to replace the chain with something a tad longer but it goes into all the gears like it should.

HMJ

Posting for posterity in case someone else has the same question...

I installed the 36t cassette and a new properly-sized chain. The RD did accommodate cassette - although I did have to tighten the B-limit screw nearly all the way in.

The bike shifts very well on the stand. I have not had a chance to ride it yet but based on what I have seen so far I don't expect any problems.

Thanks all.

70sSanO

You can get a longer screw if you need to. I typically get a socket (allen) head cap screw, I think 4mm, at Ace Hardware. Take the old one out and match the thread.

Even if I don’t need a longer one, I sometimes replace it because I hate the having to use a screwdriver on them; especially after they have been gunked up.

John

HMJ

Yeah: I have an Ace Hardware location about 3 miles from my house. They have an entire aisle dedicated to loose hardware: screws, washers, bolts, etc. - and it has saved my bacon many times when working on bikes and other projects. Sure, you might pay $0.59 for one screw...but it is SO worth it