I Made My 5.5kg BMC Even Lighter - Diminishing Returns Hit Hard
Tom Bowers Cycling
January 11, 2026
In Part 2 of my attempt to build a genuinely raceable 5kg hill climb bike, things start to get a lot harder.
After Part 1, I took on loads of your suggestions and made a series of logical weight-saving changes, removing inefficiencies, optimising parts I already had, and revisiting some decisions from earlier in the build.
Want to try any of the parts I mention check out the AliExpress link https://s.click.aliexpress.com/e/_EjQrqc0 or enter the search code [AYB4DU] on the AliExpress homepage to see all the AliExpress bike parts I’ve featured recently
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Discount Codes:
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2026/01/12 00:00:00 PST - 2026/01/18 23:59:59 PST
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Timestamps
0:00 Intro
0:57 Your Suggestions
2:48 OSPW
4:10 Tyres
6:06 Skewers
6:44 Shifter Clamps
8:00 Chainring
9:10 ZTTO SLR gen 3 Cassette
11:10 Shorter Chain
12:28 Conclusions and Final Weight
#aliexpresshaul #bikeupgrade #aliexpress #roadbike #weightweenie
Keywords: 5kg bike build,5kg bike,sub 5kg bike,lightweight bike build,ultralight bike,hill climb bike,hill climb cycling,BMC hill climb bike,BMC lightweight build,weight weenie bike,cycling weight saving,road bike weight reduction,cycling upgrades,bike weight reduction,AliExpress bike parts,AliExpress cycling,AliExpress bike build,cheap bike upgrades,cycling engineering,custom bike build,road bike build,cycling performance,climbing bike,road cycling content
Sunshine Savings/Seasonal Savings
CrankBigrock Carbon Crank 24mm For Sram Cranks
Created: August 14, 2025The reviewer mentions the Bigrock cranks as an upgrade installed in a previous video (part one). They state that the cranks were installed with their stock spider and a 4-bolt chainring, which was light but didn't save much weight versus their previous SRAM Red crankset. However, the Bigrock cranks did fix the chainline 'in a quite considerable way.' The reviewer notes the cranks are set up to work with 3-bolt SRAM direct mount chainrings, which allowed them to upgrade to a lighter E13 direct mount chainring for further weight savings and a cleaner look.
AI-Summary
Pros
- Fixed the chainline 'in a quite considerable way.'
- Set up to work with 3-bolt SRAM direct mount chainrings, enabling a lighter chainring upgrade.
Cons
- When installed with the stock spider and a 4-bolt chainring, it 'didn't save me much versus my SRAM Red crankset.'
MyBikeParts
Bigrock Carbon Crank162.5/165/167.5/170/172.5/175 Cycling Parts 354g Bicycle Crankset For BCD 110 Axis 24mm For Sram Cranks - AliExpress 18
StemOGEVKIN Bike Stem Extension Carbon Computer Mount Holder Rack for GPS/Cycling Computer/Camera/Light Bicycle Accessories 3K Black
Created: December 27, 2025The OGEVKIN Bike Stem Extension Carbon Computer Mount Holder Rack for GPS/Cycling Computer/Camera/Light Bicycle Accessories 3K Black is not mentioned in this video.
AI-Summary
Creator Links
MyBikeParts
HandlebarKocevlo SL Road Carbon handlebar ultra light 150g Compatible internal cabling system Gravel road bike handlebar 31.8mm
Created: June 12, 2025The reviewer briefly mentions the Kocevlo SL Road Carbon handlebar ultra light 150g Compatible internal cabling system Gravel road bike handlebar 31.8mm but does not provide detailed analysis.
AI-Summary
Pros
- It is ultra light at 150g.
Creator Links
Hubs & AxlesBike Quick Release Skewer,Titanium Alloy Axle,Ultralight QR HUB Lever for MTB Road Bicycle,Ti Skewers for 100/130 100/135 Frame
Created: January 13, 2026The reviewer is replacing their existing ZTO titanium/aluminum skewers with a new, lighter set of 'risk' skewers from AliExpress to save weight.
AI-Summary
Pros
- They are extremely light, weighing under 40 grams.
- They are the lightest ones the reviewer could find.
Cons
- The reviewer implies a potential downside of ultra-light skewers in general is that they sometimes lack large end caps, which these new ones might also have.
- The reviewer notes they must be tightened down properly to avoid problems.
MyBikeParts
ScrewsRisk Titanium Alloy Shifter Lever Clip Ring Fixing Bolts, Bicycle Shift Clamp Ring Bolt Screw Nut For SRAM Shimano R8000 FORCE
Created: January 13, 2026The reviewer installs the Risk titanium shifter clamp hardware as part of a weight-saving upgrade. They state it works perfectly and provides a significant weight saving compared to the stock clamp.
AI-Summary
Pros
- Provides a significant weight saving (10g total for both shifters).
- Works perfectly.
- Is from a favored AliExpress brand (Risk).
MyBikeParts
CassetteZTTO Ultralight 11/12 Speed Road Bike Cassette 11s 12s 11-28/30/32/34/36T ULT Sprocket Freewheel 112g~146g 11V 12V Gravel K7 HG
Created: January 13, 2026The reviewer discusses their experience with the ZTTO Ultralight SLR Gen 3 cassette, which they have purchased as a replacement for a previous ZTTO cassette that failed. They note it is a newer, supposedly improved generation.
AI-Summary
Pros
- Offers a massive weight saving (around 127g).
- ZTTO has reportedly gone back to the drawing board to improve it.
- The weight has been increased slightly from the first generation, which is theorized to improve durability.
Cons
- The reviewer's previous first-generation ZTTO cassette failed 'pretty disastrously'.
- They are skeptical about its durability, especially under high power (e.g., 450+ watt hill climbs).
- They explicitly state they are not ready to endorse or recommend it yet.
- They position themselves as a 'guinea pig' to test its longevity.
MyBikeParts
ZTTO Ultralight 11/12 Speed Road Bike Cassette 11s 12s 11-28/30/32/34/36T ULT Sprocket Freewheel 112g~146g 11V 12V Gravel K7 HG