JRC Components 11T Ceramic Pulley Wheels | Compatible with Shimano Dura Ace R9250, 105 R7150 & Ultegra R8150 | Hybrid Ceramic Derailleur Pulley Wheels for Shimano 12 Speed Rear Derailleur

This was my second set of jockey wheels from this manufacturer. Not because they needed replacing, but because I got a new bike and drive train. I love these so much, it was a no brainer to get these to replace the factory jockey wheels for smoother operation and saving a few watts.

Bike upgrade for rear derailleur

EDIT: Was contacted by JRC via email a few days later - there was an issue with the listing and now you have the option to select the two different versions with the correct dust caps - I'll return the Dura Ace one and will reorder the 105 Di2 version. Understandable listing error and not reflective of the quality of the pulleys.Really well made pulley but way too narrow compared to the official Shimano pulley - 2mm difference causing chain to rub inside the derailleur cage. Used a couple of 1mm nylon washers on each side to match the original and it works great. Tried contacting manufacturer via Instagram and email with no response.

These pulleys are quite nice and the cost is reasonable.They spin smoothly and look very nice on my 105 Di2 rear derailleur.Thank you for the fast shipping too.

I have an all black bike and wanted to add some color. I bought the purple ones. I was hoping it would be a little darker color than what they are but they are fine. My biggest issue is when I put the upper one on my chain skips a little bit on it. So for now I only have the lower one replaced. I have an Ultegra Di2 drivetrain and you can’t really see the upper pulley anyways. The next time I change the chain I’ll try replacing the upper pulley again and see if that helps. So for now since I can only use one of them I’ll say they’re alright and rate as 4 stars

If you have the funds, there are companies out there selling pulley wheels for hundreds of dollars, even close to 1000! #crazy. They make lots of promises but the one thing they definitely do is make your bike look a bit more unique. If you're not in the uber rich camp and want to personalize your bike, these are awesome. They spin well, esp after replacing the bearing grease/oil, and are built solidly. Most importantly, they're easy to install (i installed on an 11/12sp shimano rear mech) and they have been guiding the chain as well as the original ones. For a fraction of other places, i get the look and the ceramic bearings. As far as performance, it feels exactly the same as the previous, so don't expect to all of a sudden join the TdF but who knows.... if you look faster, maybe you are faster.

These great looking, smooth spinning pulley sprockets are perfect for my bike with Shimano Ultegra. I did try first to install them on a Shimano XT derailleur, but the sprockets are different sizes (see photo). Once I put them on the Ultegra derailleur they fit perfectly. The shifting improved immediately, and the drivetrain was much quieter, and easier to pedal. I never realized how much ceramic pulleys would change the drivetrain.PROs:Fit what they are specified for.Look great. Add a bit of bling to any bike.The ceramic smoothness is amazing.CONs:NoneRECOMMENDATION - I love these and I am recommending them to my cycling friends.

I have a confession to make... When I ordered these, I wasn't paying close attention and didn't realize that the product listing says that these are for Shimano Ultegra R8150 and so I was really bummed when I received it and noticed that on the packaging. See, I have the prior generation, Ultegra R8050 (their 11-speed drive train, whereas the R8150 is Shimano's 12-speed drivetrain). I was bummed because these are pretty sweet derailleur pulleys. The machining on the pulleys is very nice, and the anodized finish also nice (my bike is blacked out, so I went with the black pulleys, even though I was tempted to get a nice bright color to make these the bling on my bike). They spin very smoothly and quietly. And while I would have a hard time justifying this upgrade in general, I was excited for it. Now you understand my disappointment.Well, I rode my bike today and it was a bit muddy, so I decided to wash it, and one thing led to another and I decided to try removing the OEM derailleur pulleys to just see if these would fit on the R8050 rear derailleur. Lo and behold, they do! They fit just fine. Maybe there's a reason that JRC doesn't have these listed for R8050, but I can't see anything thus far that would say that it won't work, and at least with my bike in the work stand, these work just fine.I will note that both of these JRC pulley wheels are identical, unlike the Shimano OEM R8050 pulley wheels which have a different tooth profile for the guide wheel (a taller tooth) vs. the tension wheel. I'm not well-versed enough to know if this is the case with the Shimano OEM R8150 pulley wheels, or why Shimano used different pulleys for the guide and tension wheels.I haven't had a chance to take my bike for a spin with these pulleys installed, but will do so next week and will update this review if for some reason they cause any issues. Of course, these are not a cheap upgrade, and who knows whether they do anything to make my bike faster, but they look cool!UPDATE: I took these for their maiden voyage today. I did about a 20 mile loop and, while it may be the placebo effect, the drivetrain felt a little smoother. Shifting was completely normal and unaffected relative previously using the OEM Shimano pulley wheels, which is what I would want to see. The only other thing I noticed is there was more drivetrain noise using these pulley wheels vs. the OEM Shimano pulley wheels. It's more noticeable when cross-chained, but even in an ideal chain alignment, there's more noise. I assume that's due to the fact that the chain is now metal on metal with these pulley wheels vs. metal (chain) on delrin (Shimano pulley wheels). I'll be interested to see if the noise quiets down as these pulley wheels break into the chain (which I assume will eventually happen given that these pulley wheels are aluminum and thus softer than the steel chain).