The Rear Derailleur EXPLAINER 

These have been a brilliant series of videos mate. I really appreciate your attention to detail and diving into the $25 GRX cage update someone mentioned in your comments. I have both a SRAM Eagle mullet (42T 10-52) and a 1x 11spd GRX setup (42T 11-42) that I really miss the SRAM range on. I've installed a Classified Powershift on the GRX bike... but.. it adds a lot of complexity (2x batteries, firmwares, and even having to remember to switch 'modes'). I'll be doing the cage swap option when I can source the parts. Keep up the great work here on the channel, it's appreciated by a lot of people!

Great explanation! Covered all the important points and still challenged the haters in a polite tone in under 8min. Your channel is a well oiled machine.

Wow, such detailed vid Nolan. Lot of things I didn’t know. I have swapped the 11/34 casette for 11/40 and I use a Shimano RX clutched long cage derailleur and it works fairly well, but the back pedaling when on the 11 tooth cog and 50 in the front (2 bi) does have some issues. My mechanic suggested we change the shim spacer one cassette to 1 mm instead of the 2 mm it had originally. It sure helped. I may need to watch this vid a few time as you spit out so much useful info I can remember all at once. 👏🏼👏🏼

My bike’s 3x gearing technically needs a derailleur with a 55t capacity but don’t tell my bike that because it’s working fine. 😬

Thanks for this deep dive! I really want to see people experiment to extend the 2x to larger and large cassettes. Like, what size of cage would be needed to run a say 11-50 AND a 46-30 chain rings for massive range.

I choose to believe that my IG question about using the 810 instead of the 812 was the only inspiration needed for this video and reject any notion to the contrary. 😎 Thanks for nerding out on this! As a fellow nerd, I could watch just about an infinite number of these kinds of videos.

Very nice explanation, Nolan! This is the first time I understand the rear derailleur specs! 👍

Excellent video! One thing I wish you could discuss more is the difference between a cage with an offset upper pulley vs. a cage without an offset upper pulley. 1X RD uses an offset pulley, whereas a 2x RD uses a non-offset pulley. The offset pulley is used to maintain a constant B-gap across a wide range cassette. On a 2X RD the offset pulley can't be used, hence a 2X RD has limited max cog as compared to the 1X RD. We'll need a new invention to allow for both a large max cog AND high chainwrap capacity, something I was hoping to see with the new Shimano 12-speed GRX group. The 11-36 2x cassette just isn't wide enough. I was hoping to see a new 12-speed 11-40 2x cassette and matching RD.

Once again another outstanding video and explanation!…thanks for making this and sharing it with us!…😎

wow how awesome that you have just uploaded that video not one hour ago. i'm just getting into the topic of Derailleurs and your channel was recommended to me. thanks!

Great video thanks. Some exploration and explanation about pull ratios, and mixing & matching them would make a much appreciated addition.

I have a 3x10 speed Ultegra group set on my tandem where I installed a cassette that (according to Shimano) is beyond the recommended spec limit. The B screw was maxed out. I just simply installed a longer screw, and it works great! On most derailleurs, the B screw can be extended for more capacity. In my opinion, Shimano should install a longer B screws from the factory.

as a shimano fan boy i love this sort of content! always cool to learn about solutions/cross compatibility etc.

Great explanation of the differences in RD that is very helpful.

Awesome experiment / hack / advice 😎👍 The reason why I am subscribed to your channel 💯

What a wonderful explanation! Nice one. Cheers.

Actually 11s shimano RD & FD has about 15% plus more capacity than the spec on manual. Just screw it at the first, then buy a sgs plate, if they don't work, buy a longer hanger. The road bike FD can handle 18 teeth difference between large and small chainring. 52-34, 48-30, 44-26 or 42-24 works well. UT and grx has the same limited screws, they can work on the MTB none-boost 2x crankset.

Thanks for following up! Awesome vid

Because of this....i subscribed. Great info. Done 11 42t on grx810 10 speed with 4700 sti and a goatlink.

Loving the Spindatt shirt

Thanks! Great. I have to rewatch cause I'm slow.

My touring bike uses a tanpan with a shimano xt sgs derailleur. 11-46 cassette matched with 46/30 chainrings. Shifts flawless and very quiet.

i just subcribed, this channel is gold! thanks for the tips!

Takes me back this video to when I first came across the one up radr cage to mod my xtr rear mech to run a 42t cassette

Great video. This was helpful. Enjoy your day my friend. 🧡

Super helpful explanation!

Finally checked "your"channel great info on derailleur,very good explanation on different combos,fun stuff! Gotta thank Russ for your introduction!😉👍

Thanks for sharing the knowledge! Love your videos!!

The 46/812 combo works flawlessly. I just bought an 822 based on your video so I can run a 51 on my 11 speed.

Well articulated. Would be great if you can teach tuning derailleur and brakes!

super informative, thanks! I ride a Marin DSX 1 and love the 'one-by' and the Shimano Deore 11-51 rear. I am almost 60, and the more upright position on the flat bar gravel has given me such a great feeling for riding more technical routes when I do. btw....came across you via your livestream with Russ at @PathLessPedaled yesterday. Good, fun video that.

Thank you for the follow up.

Excellent video! Very informative! 👍

Great job. This goes in the reference section.

Great work across this series. I tried the XT cage mod with Di2 GRX 1x on a 46-11t and it worked much better than the unmodded attempt. Looking forward to trying the 51-11 with a Shimano chain and a larger front chainring than the current 38t now thanks to your follow up. 👍

I see that Spindatt shirt 👀

My personal experience with backpedaling is that wear on the big cog combined with short chainstays are the biggest factors. My gravel bike has two wheelsets, with the second using a leftover 10-51t 7100 cassette off my fat-cargobike. The aluminum 51t cog was showing some decent wear and was replaced with an all steel M6100 cassette. I put that cassette on the gravel bike's road wheelset where I expected very little big cog usage. Sure enough it will fail the back-pedal test, while the fresh M7100 10-51t cassette on the gravel wheelset using an identical hub can backpedal with impunity. So long chainstays on the fat-cargobike was fine with a worn cog, short chainstays with a fresh cog was fine, but worn cog with short chainstays is not.

Good stuff Nolan!

I run the RoadLink on two of my bikes. Love it.

Nice! I'm running GRX 812 RD with an 11T-40T cassette but I have a few doubt if there will be enough for bikepacking, so if necessary I have the info to modify correctly my setup 👍

Best bike tech channel…for sure some stuff goes over my head but I still get a lot of knowledge. And the things that do go over, I can then ask my LBS. Got the uniche pump and multi tool cos of the review. But most of all the OUTBACK. Which I’m picking up in bangkok at the end of the month (I’m from KL Malaysia) then heading off to Koh samui (Thailand still) for a month of easy riding. Wanted something comfy

Thanks for the video. I've been tryng to see what mods are possible when its time to replace parts and this video answered a bunch of questions i had.

Many thanks for this! I've been needing something lower than the 11-42t for my 1x gravel bike for ages. So I bought the Deore cassette and XT SGS derailleur parts you recommended. Also put on a new chain with 118 links. Seems to work well with a quick test ride. I'll try an off-road session next weekend. Thanks again. 😊

Love the nerding out! Love the content!

Nice explanation

Awesome video,the modern rear dérailleurs design hasn't really changed much in the past 50 years and probably won't for the future.💯👌🏻🚴‍♀️

Why are cages on Sram derailleur so much shorter? Even shorter on the new Transmission AXS? I like Shimano groupsets, but the cages are humongous in comparison. EDIT: when googling i see Shimano Cues have a quiet similar Cage to SRAM Thanks for your Videos!

two surprising setups i was dealing with. first: 2by, very short cage shimano 6400 rear mech that somehow worked fine with 11-34 cassette. second: 50/34 2by, sunrace m9 rear mech, 11-34 cassette, and there's no way i could make that work, even though the capacity should be fine.

Love the video man. Learn something knew every day, even when I was starting to thi k how much more could I possibly know about bikes

Great explanation. A shop once Sold me a cassette that was beyond my derailleur capacity on a 3x system & it was a DISASTER! This was a great review of what I learned through that experience about what had went wrong.

For personal beliefs, I prefer using a no more than 10 speed cassette. I have had my fair share of chinese brand 10 speed 11-50 cassettes and I'm fine with how they perform but wanted a beefier Shimano derailleur. According to some info about pull ratios, a 10 speed SRAM shifter and a Shimano RD-M5100-SGS have the same pull ratio of 1.1, but I am not sure of the veracity of this. Would these components be compatible?

< psst Nolan... your 'Educator' is showing > Haha Thanks a lot + always Enjoy your Insights !!

Positive comment here! Woohoo! thanks for the explanation!

me:adding a hanger extender so i can get even larger casette installed. :D

Interesting as I’m debating how high I can go with the GRX400/10sp in a 1x setup. It’s on the 11/36 right now but I think I would be okay with an off-brand 11/40 with my 44T crank. I could also keep the existing 11/36 and go to a 42T or 40T chain ring. It’s fun to play with all of this but the $ aren’t as much fun. P.S it’s a bodged bike with no front derailleur mounts or guides but I guess that is another option to get a wider range with smaller steps between the gears. Won’t be used for bike packing or anything like that.

Great video. This and the two other inspirer to buy the longer arm from the XT series. I have a GRX 817 di2 derailleur. It currently running a 46t wolftooth chain ring with a 11-36 casette. After a couple of races, I rolige I really need some lover gears. So I have been looking into a lager casette for my 11 speed bike. Either 11-46, 11-50 or looking at the Helix e-tirteen with 9-46. But struggelug in figuring out what casette to choos. I have already both thefront and back part of the derailleur. I would love to hear some feedback Cheers Peter

Excellent!👍

Where I noticed the crank spinning backwards being an issue with chain tension is in the highest gear (smallest cog). Didn't you make a video about this once?

Would the Wolftooth Components' Road link DM help improve your modified GRX812 RD with XT plates? Would it make it so the b-limit screw doesn't need to be maxed out?

GRX RD812 with XT cage is like XT RD with OneUp Shark haha

Great video. I lesrned something new. ❤

Excelent!!! And for the grx 10 speed, do you have any recommendations for using an 11-48 cassette? Can I use the 12-speed Grx transmission?

Nice T-shirt. :)

I've had very good success with the Shimano Deore off Amazon 1x11 setup. Low budget.

😊 thanks.

Great video - thank you! I am considering a 2x12-speed GRX groupset (GRX RD820 rear derailleur) for my bike, but I would like to use a 12-speed 11-30 Ultegra road cassette, rather than the 11-34 or 11-36 that normally comes with the GRX 2x12-speed groupset. The Shimano GRX 820 rear derailleur specifications state: Low sprocket: Max. 36T/Min. 34T. In the video, you explained why the max sprocket specification exists (36T, in this case) , but can you please comment on the minimum (34T, in this case) - why does that exist? Will I be able to use the GRX 820 rear derailleur with the 12-speed Ultegra 11-30 cassette?

good stuff - thx

i have an interesting question. I am switching from a long cage SLX derailleur to a short cage shadow + derailleur, at the same time I'm going from an 11-42T cassette to an 11-45T cassette. Should I shorten my existing chain, leave it the same length or do you think I'll need a longer chain? I have no idea. I'm thinking leave it the same length since i figure the shorter cage but larger rear cog even themselves out.

Thanks!

Nice

For 30 yrs I've run Shimano gs cages. Even getting the old dura ace super shorts. Worked for everything 😜 but also haven't run a 3x setup in also as long haha.. if you ran a 3x with the newer huge cassettes? Maaaaybe an sgs? But noooo hahaha.. keep it small and tucked.

👏👏👍

Is the min sprocket size real?? Ive been running an ethirteen cassettes with a 9 tooth cog on my grx 1x drivetrain for months with no issues.

Great series of videos on this topic of gearing, thanks! I am especially interested b/c I have a confounding gearing situation: gravel bike with Shimano 105 brifters (circa 2017), GRX 810 RD, 11-36 cassette, and GRX cranks with 44/28 chainrings. No matter what I try with b-screw, limit screws, cable tension, I cannot get the RD to shift into the smallest cog if there is enough cable tension to shift into the biggest cog, and if I slacken the cable so it shifts into the 11T cog, it won't shift up into the 36T (gets stuck in the second largest cog). Anyone have suggestions? There seems to be plenty of clearance at the largest cog/pulley (the b-screw is not maxed out). And I have double checked that the limit screws are not inhibiting the upshift or downshift. TIA! P.S. I did align the RD hanger using an alignment tool as well. It was a bit out of alignment but even after aligning the shifting still has the same issue.

Can I use M5100 cage?

The Shimano GRX 812 (1x11) uses the same cassette as a MTB and that have to mean it has the same pull as a MTB? So just switching the deraileur to a Deore 1x11 would mean a 11-51 capacity, right?

How would those mods work for a sram one buy setup?

I need to know if Wolftoth works and it do its job, i have shimano sora 3 per 9 50-39-30 11-34 I wont rear 11-42 With wolftoth is it possible? Heard about things like that are a mess But they are Not using wolfthof Thanks

Could I ask, would a GRX 812 RD work with the GRX 400 shifters so I can increase the Max Sprocket? Or are the pull ratios too different… and I’ll end up needing to use a wolf tooth link.

The spec manual only count the most conservative build from shimano, which they try to sale in 'group'. Its really annoyed to explain the trick secret which they are keeping for years.For example, RX812 only listed about 31t capacity, but it has the same cages as the m8000 gs, and if it changes the plate it can climb over 53 capacity, over 47t they listed on m8000. And m8000 can work on 2 or 3 by cranks, but they only list rx812 for 1x only. Shimano spec booklet is really funny.

What is it with the jump cuts? Out at sixty seconds. Not all of us are Americans. We do have attention spans exceeding 500 milliseconds.