Hands-on with SRAM Red AXS | Real weights vs Shimano Dura-Ace Di2

SRAM claims its 2024 Red AXS groupset is 154g lighter than the previous version, making it the lightest electronic groupset available today.

At a claimed weight of 2,496g for a complete groupset, it undercuts our actual weights for Shimano’s flagship Dura-Ace Di2 R9200 groupset by 67g.

The question is, though, does SRAM’s claimed weight stand up to scrutiny?

We’ve had our hands on a full groupset, so read on for an in-depth look at all the actual weights for SRAM’s Red AXS 2024 groupset compared to Shimano Dura-Ace Di2 R9200, plus some highlights of the groupset’s new features.

For a full breakdown of the features, pricing and specifications of SRAM’s latest road bike groupset, check out our SRAM RED AXS 2024 news story.

SRAM Red XG-1290 cassette weight

• 226g

The new improved X-Dome construction of the cassette is a marvel of machining – and at 226g for our 10-36 tooth cassette, it’s impressively light.

That’s significantly more than SRAM’s claimed 180g, though this is explained by SRAM quoting the claimed weight for its tightest, 10-28t cassette.

Nevertheless, SRAM’s latest Red cassette is lighter than a 11-34t Shimano Dura-Ace CS-R9200-12 cassette, which weighed 256g.

SRAM DUB BSA bottom bracket weight

• 73g

SRAM’s bottom brackets are unchanged for this latest generation groupset, sticking with its DUB (‘Durable Unified Bottom Bracket’) bottom bracket design.

Our BSA threaded SRAM DUB bottom bracket weighs 73g – spot on SRAM’s claimed weight.

The bike we used to test Dura-Ace Di2 R9200 was fitted with a Shimano SM-BB92-41B press-fit bottom bracket, so we can't make a direct comparison, but Shimano claims its BB-R9100 BSA threaded bottom bracket weighs 65g.

SRAM Red AXS 2024 brakes, rotors and shift-brake controls weight

• 708g total weight

SRAM’s new shift-brake controls and brakes have received the most significant overhaul.

The brake calipers have received the skeleton treatment to reduce weight.

On the scales, the front and rear brake calipers weigh 314g. This weight includes hoses, brake fluid and pads but excludes mounting adaptors and bolts.

The updated Red AXS shifters add 202g per side, for a total weight of 708g – 19g more than SRAM’s claimed weight of 689g.

The equivalent for Shimano Dura-Ace Di2 R9200 was 665g, including pads, mounting hardware and hoses.

SRAM Paceline X brake rotors weight

• 132g

SRAM’s new Paceline X brake rotors have lightened carriers and a new brake surface profile that is claimed to dissipate heat better.

SRAM says the new rotors are 8g lighter compared to its previous Centreline XR rotors, with a claimed weight of 280g for a 160mm pair.

Our test set beat this, with an actual weight of 264g for a pair of 160mm Paceline X brake rotors.

The set of Shimano’s RT-MT900 rotors we had in for our Dura-Ace review weighed 196g, though this was for a 160mm front and a smaller 140mm rear.

An individual 160mm RT-MT900 rotor weighs 106g, though, so we can double that to get an actual weight of 212g for an equivalent set.

A pair of Shimano SM-RT81 rotor lockrings adds another 16g.

SRAM Red AXS 2024 rear derailleur weight

• 285g

The new Red AXS rear derailleur has also received the weight weenie treatment, with a hollow outer plate on the parallelogram.

It also gets a set of oversized pulley wheels with ceramic bearings. The derailleur can accommodate cassette cogs as large as 36t.

It comes with a claimed weight of 262g. our test unit snuck just under this, at 260g. That weight excludes a 25g SRAM AXS battery, which you’ll need if you want to be able to shift...

Shimano’s Dura-Ace Di2 RD-R9250 rear derailleur weighed 217g, though that excludes the wiring and Shimano BT-DN300 battery required to operate it and the front derailleur.

SRAM Red AXS 2024 front derailleur weight

• 144g

Though little has changed visually, the new Red AXS front derailleur brings an auto-trim function aimed at reducing chain rub. Revised cage geometry to improves shifting accuracy and speed.

SRAM quotes a claimed weight of 145g, with our sample weighing 144g – close enough.

Shimano’s equivalent weighed in at 96g, excluding wiring and Di2 battery.

SRAM Red AXS 2024 crankset with integrated power meter spider weight

• 574g total weight

As with the front derailleur, the new SRAM Red AXS crankset receives only a minor aesthetic update, retaining the integrated chainring design.

SRAM is also sticking with its carbon crank arms and oversized, 28.9mm aluminium DUB spindle.

Our crankset also includes SRAM’s power meter spider, which measures the total power produced by both legs (though with only an estimated left/right split).

As on the previous generation SRAM Red crankset, the power meter spider is integrated into the chainrings and can’t be detached.

While it’s slick-looking design, it does mean that if you want to swap chainring sizes, or need to replace either ring due to wear, you’ll need to replace the whole unit in one go.

On the scales, our test crankset weighed 574g with 46x33t chainrings and 172.5mm crank arms – 6g less than the claimed weight of 580g.

In comparison, our FC-R9200-P power meter crankset (with 172.5mm cranks but larger 52x36t chainrings) weighed 750g.

SRAM Red AXS chain weight

• 236g

The new Red chain still uses SRAM’s Flattop design and enlarged rollers, but now features hollow-pins and slotted inner and out plates to save weight.

As a result, SRAM claims the new Red chain is 13g lighter than the previous version at 236g.

Our unused chain of 114 links plus quick link tipped the scales at 249g, though perhaps SRAM doesn’t include the chain quick link in its claimed weights.

Shimano’s CN-M9100 chain, in comparison, weighed 240g for 112 links and SM-CN910-12 quick link

SRAM AXS batteries weight

SRAM’s AXS batteries remain unchanged, with one required per derailleur.

A pair comes with a claimed weight of 24g each, though our pair weighed a smidge more at 50g for a pair.

Direct comparisons to Shimano’s Di2 groupsets are trickier here as they use a single, larger battery (the BT-DN300). This is typically housed within the bike’s frame or seatpost. The front and rear derailleurs are connected to this via wires.

The Shimano BT-DN300 battery, wires and mounting kit we used for our Dura-Ace R9200 groupset review weighed 78g.

SRAM Red AXS 2024 groupset total weight

Our complete SRAM Red AXS 2024 groupset weighs 2,548g – 52g more than the claimed weight of 2,496g.

It may be possible to achieve SRAM’s claimed weight using the lightest possible options for every component, such as a smaller cassette or brake rotors.

In any case, it’s lighter than the previous generation Red eTap AXS groupset, which weighs 2,650g.

Perhaps more significantly, though, it undercuts Shimano’s flagship offering, which weighed 2,579g.

However, with an overall difference of just 31g, this won't make any noticeable difference to performance.