How Much Lighter Are Rim Brake Bikes?

 A Weight Comparison in 2025

Lightweight vs Modern: Do Rim Brakes Still Win the Weight War?

For years, rim brake bikes have had a key advantage over their disc brake counterparts—they're lighter. But how much lighter, really? And does the weight difference still matter in 2025 with modern carbon layups and component integration?

In this article, we’ll explore:

How much weight do disc brakes add

Real-world weight comparisons

When and why that matters for road cyclists

⚖️ What’s the Actual Weight Difference?

On average, a rim brake bike is:

250g to 450g lighter than its disc brake equivalent.

This weight difference comes from:

Brake calipers vs disc brake rotors and calipers

Simpler frame construction (no thru-axles, rotor clearance)

No hydraulic levers, hoses, fluid

Lighter wheelsets without disc hubs or rotors

Example: Specialized Tarmac SL7

Tarmac SL7 Disc (Ultegra Di2): ~7.2kg

Tarmac SL6 Rim (Ultegra Rim): ~6.7kg
→ Difference: ~500g

 Real-World Frame Weight Comparisons (2025)

Frame Model	Rim Brake Frame	Disc Brake Frame	Weight Difference
Colnago V3	~820g	~935g	+115g
Cannondale SuperSix Evo	~850g	~950g	+100g
Giant TCR Advanced SL	~830g	~940g	+110g
Canyon Ultimate CF SLX	N/A (disc only)	~860g	—

 Note: Many brands no longer offer rim brake versions of their top-tier frames.

 Does Weight Matter for Climbers?

Yes—but only in specific scenarios:

Where weight matters most:

Hill climb races (short, steep, all-out efforts)

Pro-level mountain stages

Riders under 65kg seeking sub-7kg builds

Where it doesn’t matter as much:

Endurance or gravel riding

Flat or rolling routes

Beginner or mid-pack racing

 1kg of extra weight = ~5–7 seconds slower per 10-minute climb (depending on gradient & rider weight)

 Can You Build a Disc Brake Bike Under 7kg?

Yes—but it’s harder and more expensive.

With ultralight parts:

Lightweight disc brake builds can hit 6.8–6.9kg

Rim brake bikes can go below 6.5kg easily

UCI limit is 6.8kg, so most pro disc bikes hit that mark exactly

But getting there with discs requires:

Carbon rotors or ultralight steel rotors

High-end carbon wheels (30mm or less)

One-piece carbon cockpits

Tubeless setups

 Rim Brake Builds Still Have a Role

Riders who want:

Simpler mechanics

Travel-friendly bikes

Sub-6.5kg weight goals
still turn to rim brakes.

In fact, some hill climb racers and retro bike enthusiasts continue to source frames and groupsets to build ultra-light setups.

Conclusion: Rim Brakes Still Win on Weight—but with Limits

Factor	Rim Brake Bikes	Disc Brake Bikes
Weight	Lighter	Heavier (by ~300–450g)
Braking	Worse in wet	Superior overall
Modulation	Less precise	Better control
Parts support	⚠️ Fading	Widely available
Cost for ultralight build	Cheaper	Expensive

So yes—rim brakes are still lighter, and that edge remains relevant in 2025. But for most riders, the trade-off between weight and performance means disc brakes are the smarter choice unless you're chasing grams in very specific race situations.