Uploaded February 2026 | Updated September 2026, 2 weeks ago
We are looking at the new Light Fast wheels, they now have a wheelset claiming to weigh just 829g per pair! How did they achieve this weight, and is it actually safe to ride on real roads?
In this video, we strip these wheels back to the raw engineering. We measure the rim wall thickness, analyze the massive carbon spoke tension drop when a tire is seated, and do the math on the UCI impact tests.
The results raise a serious question: By removing material to hit a sub-1kg weight target, have we crossed the line of safety? The industry standard for impact resistance is usually 120 Joules (Princeton/DT Swiss), but these wheels are racing towards the bare minimum.
I also show you the one upgrade you MUST run if you plan on using super-lightweight wheels like these.
🎓 Mapdec Technical Skool: We have opened the doors! We have just 20 spots left for our first intake of "Alpha" testers. If you want to be part of a new community for serious mechanics, learn directly from us, and help shape the platform, join here: skool.com/mapdec
In this video:
The Weight Race: Comparing Light Fast to Scope, Princeton, and DT Swiss.
The UCI Test Myth: Why "UCI Approved" (40J) is considered a joke by engineers, and why the 95J limit on these wheels concerns me.
The Inspection: Rough rim beds, resin starvation issues, and why rim tape just won't stick.
The Tension Test: We measure a frightening drop in spoke tension when the tire is inflated.
The Verdict: The "Joules per Gram" calculation that reveals the true cost of weight saving.
Chapters
00:00 - The 829g Wheel Revolution
00:59 - How did they get this light? (Removing Material)
02:07 - GCN, Princeton & The Limit of Weight
03:00 - The Truth About UCI Safety Tests (40J vs 120J)
04:50 - Analyzing the 95 Joule Claim
06:18 - Why Safety Matters (My Crash Story)
07:18 - Rim Inspection: Wall Thickness & Carbon Spokes
08:55 - The Surface Finish Problem (Tape Won't Stick!)
10:30 - Spoke Tension Test (The Massive Drop)
16:32 - Weighing the Spokes (Light Fast vs Venoa)
19:40 - Join Mapdec Technical Skool
20:04 - The Conclusion: Joules Per Gram Calculation
22:25 - The "Green Noodle" Safety Upgrade (You Need This)
#cycling #roadbike #lightweightwheels #bikemechanic #mapdec #carbonwheels #engineering #uci #lightfast #bikeparts @princetoncarbonworks1235 @ffwdwheels
We are looking at the new Light Fast wheels, they now have a wheelset claiming to weigh just 829g per pair! How did they achieve this weight, and is it actually safe to ride on real roads?
In this video, we strip these wheels back to the raw engineering. We measure the rim wall thickness, analyze the massive carbon spoke tension drop when a tire is seated, and do the math on the UCI impact tests.
The results raise a serious question: By removing material to hit a sub-1kg weight target, have we crossed the line of safety? The industry standard for impact resistance is usually 120 Joules (Princeton/DT Swiss), but these wheels are racing towards the bare minimum.
I also show you the one upgrade you MUST run if you plan on using super-lightweight wheels like these.
🎓 Mapdec Technical Skool: We have opened the doors! We have just 20 spots left for our first intake of "Alpha" testers. If you want to be part of a new community for serious mechanics, learn directly from us, and help shape the platform, join here: skool.com/mapdec
In this video:
The Weight Race: Comparing Light Fast to Scope, Princeton, and DT Swiss.
The UCI Test Myth: Why "UCI Approved" (40J) is considered a joke by engineers, and why the 95J limit on these wheels concerns me.
The Inspection: Rough rim beds, resin starvation issues, and why rim tape just won't stick.
The Tension Test: We measure a frightening drop in spoke tension when the tire is inflated.
The Verdict: The "Joules per Gram" calculation that reveals the true cost of weight saving.
Chapters
00:00 - The 829g Wheel Revolution
00:59 - How did they get this light? (Removing Material)
02:07 - GCN, Princeton & The Limit of Weight
03:00 - The Truth About UCI Safety Tests (40J vs 120J)
04:50 - Analyzing the 95 Joule Claim
06:18 - Why Safety Matters (My Crash Story)
07:18 - Rim Inspection: Wall Thickness & Carbon Spokes
08:55 - The Surface Finish Problem (Tape Won't Stick!)
10:30 - Spoke Tension Test (The Massive Drop)
16:32 - Weighing the Spokes (Light Fast vs Venoa)
19:40 - Join Mapdec Technical Skool
20:04 - The Conclusion: Joules Per Gram Calculation
22:25 - The "Green Noodle" Safety Upgrade (You Need This)
#cycling #roadbike #lightweightwheels #bikemechanic #mapdec #carbonwheels #engineering #uci #lightfast #bikeparts @princetoncarbonworks1235 @ffwdwheels
