FivestarWhat do all these terms mean? Mirraco’s product development master Jean-Luc Ferre gives you an insight on what goes on to make frames lighter and stronger. Interested? Read on………

Weight is a big factor for BMX bikes these days. What can be done to a frame to save weight?

Jean Luc: Obviously, reducing the thickness and diameter of the tubing plays a big role. There is a limit, though, in how far we can go for both. Using single, double or triple-butted tubing is another mean of reducing weight by optimizing tube thickness where needed. Other ways of reducing weight:

- Designing smaller and thinner dropouts (5 or 4mm thick), heat-treatment is required in that case,

- Using smaller BB shells and bearings (Euro is most likely the lightest type),

- Reducing the thickness of the head tube (same, heat-treatment is required in that case).

Jean LucWhat are butted tubes?

Jean Luc: Butted tubes feature optimized thickness where needed, mostly at the end(s) where they are welded together and where strength and thickness (for welding) is mostly needed. These tubes are thinner in the center where stresses are reduced, again within a certain limit, especially for BMX where thin tubing can be easily dented from crashing on ramps, rails, ledges, etc.

JLFWhat does heat treating do?

Jean Luc: Heat -Treatment increases the hardness of the material (very useful for dropouts, BB shells and head tubes) and for tubing re-distributes the material’s molecules after welding, especially around the welds. It is a treatment that releases tension built in during welding and makes a frame simply harder, stronger and most likely stiffer as well. This allows in return to reducing the thickness of the tubing used, which saves weight.

jlf-4.jpgAll these extra treatments cost extra money, right?

Jean Luc: Yes, it does. Usually, specific (giant) ovens are required. This equipment costs a lot of money and the process takes time, around 24 hours for a small batch of frames, so all this comes in addition to the basic frame cost.

Brakeless frameDo the limited edition Blend and Black Pearl bikes come with all the latest tech stuff?

Jean Luc: Yes, their frames come with CNC machined heat-treated MID BB shells & integrated head tubes, double-butted tubing, short 5mm thick dropouts, etc.They weigh around 5.4 lbs, which is pretty good for frames built as completes that retail around $1,000 with all the branded components featured.

The Blend Ltd features:

- Snafu’s Alloy crankset, sprocket, stem and Magnesium pedals,

- Snafu’s brand new Stout hubs set (with recessed spoke heads in the flanges),

- Lightweight double-butted forks and bars,

The Black Pearl Ltd features:

- Lightweight (very light) Colony bars and forks,

- Wellgo Magnesium pedals (215 grms each !),

- Odyssey hubs set w/ a Vandero 3/8″ front,

- Odyssey’s Vermont sprocket,

- a Fly Bikes stem

Both bikes have in common,

- Lightweight Pivotal (Macneil) seat and post,

- Shadow Conspiracy’s latest 1/2 link chain,

- Odyssey Monolevers,

- Lightweight Fly brakes

- City Lite Welded Sun Rims,

- Double butted spokes,

- 1-pc driver cassette hubs with hollow 14mm axles,

- Lightweight 3/8″ axles

To wrap this up, how much do the Blend Ltd. and Black Pearl Ltd. weigh?

Jean Luc: We just got another set of samples that are exactly like the production bikes. The Black Pearl Ltd is the lightest at 26.7 lbs because of lighter parts and a low profile frame. The Blend Ltd weighs in at 27.8 lbs, which is still very good for a production bike.

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