Shimano 105 Di2 vs Ultegra Di2 (12-speed) Groupset

By : Mr Mamil
Updated :

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From the outside, both the Shimano 105 (R7100) and Ultegra groupsets (R8100) look very similar. They have the same shape, design, and technologies, but the price difference can be up to 3x for some components.

  • Shimano 105 Di2 groupset is designed for entry-level to mid-range road bikes. It offers a good balance of performance, reliability, and value. It has a wider range of gears for everyday cyclists.
  • Shimano Ultegra Di2 groupset is a high-performance groupset designed for top-end road bikes. It uses advanced technology, such as electronic shifting motors and a digital display, to provide precise, smooth, and consistent shifting performance. The Shimano Ultegra Di2 groupset includes lighter-weight components, making it a top choice for serious road cyclists and professional racers.

I’ll break down each component in this article and discuss their differences. This will help you to decide if 105 or Ultegra is for you, or a mixture of both to get the best value for your money.

Key takeaways

The 12-speed Shimano 105 Di2 groupset (R7100) is marketed as a mid-tiered groupset for everyday cyclists vs Shimano Ultegra Di2 (R8100) as a mid/high-tiered for serious cyclists.

The Shimano 105 Di2 inherits many of Ultegra’s features, such as semi-wireless shifting, a redesigned brake hood, an extra 10% brake pad clearance, Servo Wave technology, and 160mm crankarm length.

But unknown to many, there are many differences between the 105 and Ultegra beyond just the weight and price.

ComparisonShimano 105 Di2Shimano Ultegra Di2
SeriesR7100R8100
Speed1212
LaunchedJune 2022August 2021
Rim brakeNoYes
Disc brakeYesYes
Semi-wireless shiftingYesYes
Power meter cranksetNoYes
Price range (USD)$1,900 to $2,000$2,400 to $2500
Shimano 105 vs Ultegra Di2 groupsets comparison

Brake levers and shifters

Shimano 105 R7170 vs Ultegra R8170 Brake Levers
Shimano 105 R7170 vs Ultegra R8170 disc brake levers
ComparisonShimano 105 Di2Shimano Ultegra Di2
Disc brakeAvailableAvailable
Rim brakeNot availableAvailable
Model no.ST-R7170-R/LST-R8170-R/L
Servo WaveNoYes
Coin batteries2x 16321x 1632
Coin battery indicatorYesNo
Hood buttonNoYes
Di2 ports12
Weight442g400g
Price (USD)$570$910
Shimano 105 vs Ultegra 12-speed brake levers comparison

Both the 105 and Ultegra levers have the same ergonomic design and functionalities. They support wireless shifting and have 16.4mm of lever reach adjustment. That’s where the similarities end.

There are seven differences between the 105 and Ultegra brake levers.

Rim brake

The 12-speed Shimano 105 was launched as a disc brake-only groupset compared to the Ultegra, which still has a rim-brake option.

Servo Wave

Shimano Servo Wave Technology
Shimano Servo Wave Technology

The 105 does not have the Servo Wave, unlike the Ultegra and Dura-Ace brake levers.

Servo Wave is a Shimano’s mountain bike brake lever technology introduced to the 12-speed and GRX groupsets in recent years. Servo Wave increases the brake lever’s leverage by reducing the distance it needs to be pulled before the brake pads get into contact with the rotor.

More reading : How to Fix Sticky A Disc Brake Caliper

Batteries

Shimano 105 vs Ultegra Di2 Brake Lever Batteries
Shimano 105 vs Ultegra Di2 disc brake lever batteries

The 105 brake levers require 2x 1632 batteries each vs 1x 1632 battery each in the Ultegra levers.

Battery level indicator

Shimano 105 Brake Lever Battery Indicator
Shimano 105 brake lever battery indicator light

There is a LED on the levers to indicate the coin battery levels. Press two shift buttons for 0.5s, and the LED will light up.

More reading : How to Check Shimano Di2 Battery Levels

Hood (third) buttons

There is no button on top of the hood, unlike the Ultegra and Dura-Ace brake levers.

The button can be programmed via the E-Tube app to do various functions, such as shifting and changing the pages on a bike computer.

Di2 ports

The less obvious difference is the number of Di2 cable ports. The 105 brake levers have only one Di2 port vs two for Ultegra.

This means there is no option to connect the satellite shifters to the 105 brake levers.

Weight

Being a lower-tiered model, the 105 levers are 42g (~10%) heavier than the Ultegra.

Rear derailleurs

Shimano 105 vs Ultegra Di2 Rear Derailleurs
Shimano 105 vs Ultegra Di2 rear derailleurs
ComparisonShimano 105 Di2Shimano Ultegra Di2
Model no.RD-R7150RD-R8150
Shadow TechnologyYesYes
Weight300g262g
Price (USD)$280$410
Shimano 105 vs Ultegra 12-speed rear derailleurs comparison

Both the 105 and Ultegra rear derailleurs use the Shimano Shadow Technology, which was first introduced in the 11-speed groupsets (Ultegra R8000 and 105 R7000). With the Shadow Technology, the rear derailleur has a low profile design at the top gear position (smallest cog) for a quieter drivetrain.

There are two differences between the 105 and Ultegra rear derailleurs.

Minimum and maximum cog sizes

The 105 rear derailleur has a longer cage design to accommodate up to a 36T cassette compared to 34T on the Ultegra.

The table below shows the difference between the minimum and maximum cog sizes for each rear derailleur.

ComparisonShimano 105 Di2Shimano Ultegra Di2
Min. small cog11T11T
Max. small cog11T14T
Min. big cog34T30T
Max. big cog36T34T
Minimum and maximum cog sizes for Shimano 105 and Ultegra rear derailleurs comparison

The B-gap settings for these cassettes are also different. An incorrectly set B-gap will lead to degraded shifting performance.

Weight

The 105 rear derailleur is 38g heavier than the Ultegra due to the heavier materials used in some rear derailleur parts.

More reading : Shimano 105 vs Ultegra vs Dura-Ace (12-speed) Cassettes Compared

Front derailleurs

Shimano 105 vs Ultegra Di2 Front Derailleurs
Shimano 105 vs Ultegra Di2 front derailleurs
ComparisonShimano 105 Di2Shimano Ultegra Di2
Model no.FD-R7150FD-R8150
Weight138g112g
Price (USD)$153$260
Shimano 105 vs Ultegra 12-speed front derailleurs comparison

The 105 and Ultegra front derailleurs have the same functionalities but differ in shape and weight.

The 105 front derailleur body is bigger, similar to the 11-speed Ultegra. The 12-speed Ultegra front derailleur has a slimmer design, smaller frontal area (33% less than its predecessor), and lower weight.

The 105 front derailleur is 26g heavier with the different materials used for the screws and plates.

Cranksets

Shimano 105 vs Ultegra Cranksets
Shimano 105 vs Ultegra cranksets

Shimano introduced the 160mm crankarm length for the 105 cranksets, a similar move when it launched the Dura-Ace and Ultegra groupsets earlier. The 105 cranksets are available in five crankarm lengths;

  • 160mm
  • 165mm
  • 170mm
  • 172.5mm
  • 175mm

Shimano no longer offers the standard chainring size (53/39T) for all 12-speed groupsets. There are two chainring options for 105 and Ultegra.

The crankarms have a four-arm attachment, similar to the previous generations. However, the 11 and 12-speed chainrings are not cross-compatible due to the arms’ location.

There is a dual-sided power meter option crankset (FC-8100-P) for Ultegra.

More reading : Which Power Meter Fits A Shimano Crankset?

Chains

The 12-speed 105 and Ultegra chains are the same Shimano 12-speed mountain bike chains. The XT is renamed Ultegra, and SLX is renamed 105.

Both 105 and Ultegra chains are the same. They’re made from steel with gray outer plates coating and a hollow design.

The main difference is the coating on the inner plates and pins.

  • Sil-Tec coating on 105 inner chain plates.
  • Chrome coating on Ultegra’s pins.
ComparisonShimano 105 Di2Shimano Ultegra Di2
ModelCN-M7100CN-M8100
Links116, 126116, 126
Weight (116)254g254g
MaterialSteelSteel
Outer plates coatingGrayGray
Inner plates coatingSil-TecChrome
Rollers coatingNoneNone
Pins coatingNoneChrome
Pin designSolidSolid
Price (USD)$43$46
Shimano 105 vs Ultegra 12-speed chains comparison
More reading : How to Wax A Bicycle Chain

Cassettes

Shimano 105 vs Ultegra 12-speed Cassettes
Shimano 105 vs Ultegra 12-speed cassettes

With all its 12-speed groupsets, Shimano has streamlined the cassette sizes. There are three differences between the 105 and Ultegra cassettes.

Cassette sizes

Cassette sizeShimano 105 Di2Shimano Ultegra Di2
11-30Tnot availableYes (CS-R8100-12)
11-34TYes (CS-R7101-12)Yes (CS-R8100-12)
11-36TYes (CS-HG710-12)not available
Shimano 105 vs Ultegra 12-speed cassettes availability

105 cassette sizes start from 11-34T and Ultegra from 11-30T. The 11-36T cassette is a non-7100 series cassette.

Hyperglide+ vs Hyperglide

The 105 cassette uses the older Hyperglide (HG) technology vs the newer Hyperglide+ (HG+) on the Ultegra.

  • Hyperglide+ (HG+) is a specific cog tooth profile to match the chain for faster shifting, both up and down the cassette, especially under load.
  • Hyperglide (HG) is similar, but only for shifting up to a larger cog.

Spider arm design

Shimano 105 vs Ultegra 12-speed Cassette Sprocket Patterns
Shimano 105 vs Ultegra 12-speed cassette sprocket patterns

The 105 and Ultegra cassettes use an aluminum spider arm.

  • 105 cassette has one spider arm, connecting the largest five cogs for 11-34T (21, 24, 37, 30, 34) and 11-36T (21, 24, 28, 32, 36).
  • Ultegra cassette has two spider arms for the largest six and seven cogs for 11-30T and 11-34T, respectively.

Note : For the 11-34T cassette, the Ultegra is only 16g lighter but costs twice as much.

More reading : How to Shift Gears Correctly

Brake calipers

Shimano 105 vs Ultegra 12-speed Brake Calipers
Shimano 105 vs Ultegra 12-speed brake calipers
ComparisonShimano 105 Di2Shimano Ultegra Di2
Model no.BR-R7170-F/RBR-R8170-F/R
Weight (front)157g120g
Weight (rear)141g104g
Price – front (USD)$82$88
Price – rear (USD)$76$83
Shimano 105 vs Ultegra 12-speed brake calipers comparison

Both 105 and Ultegra brake calipers have the same design with a 10% wider brake pad clearance and easier access to the bleed port

The only difference between the Shimano 105 and Ultegra disc brake calipers is the weight. The 105 calipers are 37g/pair heavier.

More reading : How to Fix Sticky A Disc Brake Caliper

Brake rotors

Shimano 105 vs Ultegra Rotors
Shimano 105 vs Ultegra disc brake rotors
ComparisonShimano 105 Di2Shimano Ultegra Di2
Model no.SM-RT70RT-CL800
Weight (140mm)121g95g
Weight (160mm)133g113g
Price – 140mm (USD)$46$61
Price – 160mm (USD)$46$61
ICE TechnologiesYesYes
ICE Freeza TechnologiesNoYes
Shimano 105 vs Ultegra 12-speed rotors comparison

Shimano used the same brake rotors from their mountain bike lineup, the RT-CL800 (Ultegra) and SM-RT70 (105). Both rotors are available in 140mm and 160mm sizes. 

The difference between the 105 and Ultegra rotors lies in their design and cooling technologies. 

Rotor design

Both rotors are Centerlock, with the 105 rotors having six arms vs four for Ultegra.

Cooling technologies

Shimano ICE Freeza Technology
Shimano ICE Freeza Technology

One of the common problems with disc brakes is excessive heat during long and/or hard braking. To overcome this, Shimano deploys two methods;

  • ICE Technologies. Both 105 and Ultegra rotors have the same 3-layer rotor design (stainless steel/aluminum/stainless steel), which Shimano refers to as the ICE Technologies.
  • Freeza. Only the Ultegra rotors have cooling fins for better heat dissipation, which Shimano refers to as the Freeza technology.
More reading : Shimano Dura-Ace vs XTR Rotors Comparison

Brake pads

Shimano BP L05A-RF Resin Brake Pads
Shimano L05A-RF Brake Padsd

The 105 and Ultegra brake calipers come with the new L05A-RF resin brake pads with cooling fins. It’s Shimano’s fifth-generation resin brake pad that has 50% better wear resistance than its predecessor, L03A.

The L05A and L03A are cross-compatible as they have the same shape and design. The difference lies in the resin materials.

More reading : Resin vs Metal Disc Brake Pads Comparison

Brake hoses

Both the 105 and Ultegra disc brake calipers use the same brake hoses (SM-BH90-JK-SSR).

The brake hoses are available in two lengths, 1000mm (for front) and 1700mm (for rear).

Shimano Di2 battery

Shimano BT-DN300 Battery
Shimano BT-DN300 Battery

Shimano introduced a new battery (BT-DN300) for the 12-speed wireless groupsets.

There are three ports on the battery, with only two needed for a wireless setup. The third port will be used for a wired setup to connect the shifters via a junction box.

More reading : How to Charge Shimano Di2 Battery

Shimano Di2 cables

Only two cables are needed for a semi-wireless setup of 12-speed Shimano groupsets,

  • Battery to front derailleur
  • Battery to rear derailleur

The cables are available from 150mm to 1000mm in 50mm increments and 200mm from 1000mm to 1600mm.