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⚡ Power your ride with invisible precision!
The Shimano Ultegra Di2 Internal Routing Junction Box (SM-JC41) is a lightweight, compact hub that connects all Di2 electronic shifting wires inside your bike frame. Compatible with Ultegra 6770, 6870, and Dura-Ace 9070 groupsets, it enables a clean, professional internal cable setup, enhancing both aesthetics and performance. With a mere 13.6g weight and a 2-year warranty, it’s the must-have upgrade for serious cyclists seeking flawless electronic shifting.
| ASIN | B005DTRW0E |
| Best Sellers Rank | #373,261 in Sports & Outdoors ( See Top 100 in Sports & Outdoors ) #218 in Bike Cables |
| Brand Name | SHIMANO |
| Color | One Color |
| Customer Reviews | 4.3 4.3 out of 5 stars (60) |
| Date First Available | July 21, 2011 |
| Item Dimensions LxWxH | 3 x 4 x 2 inches |
| Item Package Dimensions L x W x H | 4.4 x 2.2 x 1.3 inches |
| Manufacturer | Shimano |
| Material | Plastic |
| Model Year | 2012 |
| Number of Items | 1 |
| Package Weight | 13.61 g |
| Part Number | SH4255 |
| Size | Internal/SM-JC41 |
| Sport Type | Cycling |
S**S
Brand new.
A must.
H**X
Internal wiring junction box - picture is wrong
If you are going to run your Di2 cables inside the frame tues, this is the part you want. The picture is of the external mount box, but the internal box is the one I received. Just remove your crank, plug in your 4 wires, tuck this back into the frame tube, reinstall the protector sleeve and crank and you are all set. A very clean install of shifting perfection!!
C**S
expensive but functional
It is an expensive item for its size but essential to install Di2
D**.
Not sure
Not sure this isn't a fake. Came in no official packaging. Wrapped in a piece of paper with a sticker on it. It looks real, but still I have no assurance its new and not damaged internally
C**L
Works fine
I decided to build my new road bike with Di2 electronics. I didn't want to drop $1,500 at one time on the kit so I bought one component at a time. It all came together nicely and all components work fine. I highly recommend this product.
T**K
Genuine Shimano
Works great
R**O
Works good
Wow this thing is so light and tiny! It does it's job, nothing fancy. Good seller...
F**R
A necessary part for Di2
Not much to say about this junction box. It’s a necessary part for installs. This allows you to easily stuff it in the seat tube or down tube to conceal it. I added foam insulation around the ends to make it quieter inside the tubes.
Trustpilot
3 days ago
1 month ago