Shimano Alfine DI2 SG S7051 8 SPD Intertnal Centerlock Rear Hub
The Shimano Alfine Di2 SG-S7051-8 is the Alfine 8 with electronic shifting: eight gears with a 307% range, a centerlock disc mount, chain or belt compatibility and 135mm spacing, shifted by a motor in the hub driven by a Di2 shifter and battery. Shifts are exact every time with no cable to adjust, and the hub shifts at a standstill. It is the hub we build for premium commuter and city bikes that want electronic shifting without the cost of eleven gears. This page covers the Shimano Alfine DI2 SG S7051 8 SPD Intertnal Centerlock Rear Hub.
The Alfine Di2 8 is built to order here. Choose the rim, spokes and nipples in the configurator; the wheel leaves Georgia laced, tensioned and trued.
Design and construction
An internal-gear hub is a planetary gearbox inside the hub shell: a set of sun and planet gears that the shifter engages in different combinations to give eleven ratios from a single sprocket. The Alfine 11 runs its gears in an oil bath rather than grease, which makes it smoother and longer-lived than the 8-speed and needs an oil change every couple of years. Shifting is by a single cable through Shimano's Rapidfire trigger or a twist shifter, and the hub can shift at a standstill, which is a real advantage in traffic. It takes a single sprocket for chain or a Gates belt sprocket, has a centerlock disc mount, and is drilled for J-bend spokes in 32 and 36 hole.
How it rides
An Alfine Di2 8 bike shifts with a click and a whir, the same on the first day and the thousandth, with nothing to adjust. The 307% range covers city riding and moderate hills; for steep terrain the Di2 11 is the better choice. For a premium commuter, the Alfine Di2 8 is the Shimano hub we recommend.
Specifications
| Position | Rear |
|---|---|
| Axle options | Bolt On 10x135mm Rear |
| Driver bodies | Internal Single Speed Spline |
| Drillings | 32h, 36h |
| Spoke head | J-bend |
| Brake | centerlock disc |
| Left flange diameter | 92.6 mm |
| Right flange diameter | 92.6 mm |
| Left center-to-flange | 31.8 mm |
| Right center-to-flange | 25.5 mm |
| Spoke hole diameter | 2.6 mm |
| Weight | 1670g |
| Material | Aluminum |
| Finishes | black, silver |
Which version this is
Version notes. Centerlock rotor mount, Bolt On 10x135mm, 32h, 36h, about 1670g, in black, silver. If your frame or fork uses a different standard, the other versions of the Alfine Di2 8 on this site cover it.
Centerlock is the lighter, quicker rotor mount: a splined rotor drops onto the hub and a single lockring holds it, so a rotor swap takes a minute with a lockring tool and there are no six small bolts to torque or lose. Shimano and most current road and gravel rotors are centerlock; 6-bolt rotors fit with an adapter.
Sizes, fit and compatibility
The Shimano Alfine DI2 SG S7051 8 SPD Intertnal Centerlock Rear Hub comes in the drillings listed on this page in 135mm quick-release spacing with a centerlock rotor mount; it needs a frame that can tension the chain or belt and a Di2 shifter, battery and wiring, which we can supply. J-bend spokes in any gauge; we build most Alfine Di2 wheels with DT Champion or Competition or Sapim Race and Strong spokes and brass nipples.
It pairs naturally with the Velocity Dyad, Atlas and Cliffhanger, Mavic A319, HED Belgium G and Velo Orange Voyager rims. Pick commuter or touring as your bike type in the configurator and it recommends a spoke count and lacing pattern.
Build it into a wheel
This hub is live in our Custom Wheel Program for road rim brake, gravel and road disc, track and road single-speed, touring, tandem and e-bike, mountain bike, MTB single-speed and fat bike builds. Start a build with the Shimano Alfine Di2 Sg S7051 8 SPD Intertnal Centerlock Rear Hub and the configurator opens with this exact hub pinned at the top of the Shimano list — you choose the rest of the parts and it validates every combination as you go.
Shimano's testing and certifications
Shimano publishes no load, fatigue, or salt-spray figures for its hubs. Its US warranty states that most bicycle products are warranted free from defects in material and workmanship for two years from original purchase, and that DURA-ACE and XTR components and wheels are covered for three years, for the original owner with proof of purchase. Competition or commercial use, improper assembly or repair, finish deterioration, labor, and normal wear are excluded; bearings, corrosion, dust seals and spokes are listed as wear parts.
Shimano's higher-end hubs, including the Dura-Ace R9270 wheel hubs, use cup-and-cone loose-ball bearings, which Shimano says “effectively displace lateral and vertical loads for smooth rotation and excellent durability — [and are] easier to adjust and service”. For the 2026 Dura-Ace WH-R9370 wheels Shimano states the system offers 30% lower rotational torque than typical cartridge bearings, that durability is enhanced with improved waterproof seals, and that balls, cups and cones are all replaceable. Dealer manuals instruct that only Shimano-specified lubricants be used, internal parts not be oiled, and the hub be inspected if the wheel becomes stiff. In 2023 Shimano introduced the TC600, TC500/QC500, QC400 and QC300 cartridge-bearing hubs with “Labyrinth & Contact” seals, described as double-sealed. A 2007 Bicycle Retailer report described Shimano's Malaysian hub and wheel factory as ISO 9001 and 14001 compliant, 89,000 square meters with 2,087 employees.
Certifications
- Warranty: 2 years / 3 years — Most bicycle products two years from original purchase; DURA-ACE and XTR components and wheels three years; original owner, proof of purchase; wear parts excluded (bearings, dust seals, free hubs, driver bodies, pawls, spokes) (source)
- ISO 9001 and ISO 14001 (Malaysian wheel/hub factory) — Reported by Bicycle Retailer, 19 Dec 2007: factory producing wheels incl. Dura-Ace, hubs, cranks, pedals is “ISO 9001 and 14001” compliant; 89,000 sq m, 2,087 employees (source)
Sources on Shimano's site:
- SHIMANO Warranty Policy | Ride Shimano US
- Is Shimano abandoning cup and cone hubs? - road.cc
- Shimano says RIP to cup-and-cone bearings with new hubs - BikeRadar
- Shimano's new Dura-Ace wheels double down on cup-and-cone hubs - BikeRadar
- Shimano Dura-Ace WH-R9370 C50 first look - BikeRadar
The figures, certificates and media above are Shimano's own. ProWheelBuilder does not run these tests; our part is the wheel we build on the hub.
Building it at ProWheelBuilder
Shimano makes the Alfine Di2 8; ProWheelBuilder is an independent custom wheel builder in Georgia and not the manufacturer. The build is the same every time: measured ERD, spokes cut to the half millimeter, staged tensioning with a gauge, stress relief, a final true, and tubeless tape and a valve on request.
The configurator shows only rims and spokes that fit the Alfine Di2 8 drilling, strikes through combinations that are not made, and prices the wheel live.
Warranty
Shimano's warranty. Shimano covers its bicycle components for two years from original purchase, with three years on DURA-ACE and XTR and one year on wheels, footwear and soft goods. Shimano's obligation is to repair or replace at its option, against the original dated receipt.
ProWheelBuilder. Any wheel we build on this part carries ProWheelBuilder's one-year warranty in addition to the manufacturer's. Broken spokes are replaced for a year whatever the cause, and all wheel-side labor is included - truing, re-tensioning, rebuilding. Where the maker covers a failed rim or hub we handle that claim for you; where they decline, an eligible replacement comes at 25% off current retail. The customer covers shipping in both directions. Components supplied by the customer are not covered.
Full terms are on our Policies & Warranty page.
Alfine DI2 SG S7051 8 SPD Intertnal Centerlock Rear Hub questions
Will my rotors fit this hub?
This is the centerlock version, so a splined centerlock rotor drops on and a lockring holds it - one tool, no six bolts to torque or lose. If your rotors are 6-bolt they will fit with a centerlock adapter, or take the 6-bolt version of the same hub, which is a separate listing.
Which spokes and nipples suit the Alfine Di2 8?
For most riders a double-butted spoke such as Sapim Race or DT Competition with brass nipples; lighter riders can go to Sapim Laser or CX-Ray. The configurator recommends a gauge and count for the Alfine Di2 8 from your bike type and weight.
What does the Alfine Di2 need besides the hub?
A Di2 shifter, a battery, the wiring and a junction box; we can supply and fit them.
Does the Alfine Di2 work with a belt drive?
Yes. It takes a Gates belt sprocket like the cable version.
How long does the Di2 battery last?
Weeks to months of commuting on a charge, depending on how much you shift; it charges from USB.
Alfine Di2 11 or cable Alfine 11?
Di2 for exact, adjustment-free shifting and shifting at a standstill with a button; cable for a lower price and no battery.
Is ProWheelBuilder the manufacturer of the Shimano Alfine DI2 SG S7051 8 SPD Intertnal Centerlock Rear Hub?
No. Shimano makes the hub. ProWheelBuilder is an independent custom wheel builder in Georgia that builds it into a finished wheel to your spec.
Not sure? Text or leave a voicemail on 470-253-0929 or email info@prowheelbuilder.com — you will be talking to the people who build the wheels.
