# Triple Monocoque vs. Az1 construction



## mikagsd (Mar 22, 2008)

Does anyone know what the difference in these 2 construction techniques are and is there that big of a difference in the 2??


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## ukbloke (Sep 1, 2007)

mikagsd said:


> Does anyone know what the difference in these 2 construction techniques are and is there that big of a difference in the 2??


Read this thread. I wonder if PJ352 followed up with the phone call to get more info from Specialized?

From cyclequip's comment #26:



cyclequip said:


> The different construction designations refer to different manufacturing processes. Triple-monocoque is versatile and reliable but has drawbacks in the need to add extra material and weight to achieve strength at the joints. Monocoque frames refer to those where loads are carried by the skin or outer layer and not via internal trusses. In the bike industry it refers to one-piece frames and not lug-and-tube constructions. Triple monocoque is where Speshy join 3 main monocoque pieces into a one-piece after they have been cured in the mold. The load-bearing top layer can be designed to direct loads away from stress-riser areas where needed.
> Az1 refers to a more complex and expensive method of monocoque where up to 7 individual monocoque constructions are joined together. This permits greater control of stress-riser loads and tubes only carry tube loads and not both tube and joint loads as in triple-monocoque. The tubes are mitred and then joined with a jointing wrap with an additional top wrapping added before curing. This lessens the material needed in triple-monocoque with no strength sacrifice.
> IS uses a complex combination of both processes using a light front section (top, head and down tube) mated to an Az1 rear end.
> For 2009 the Az1 has been dropped on the basis of costs. This permits wider price points between the IS of the top frames and the triple-monocoque of the base models.


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## mikagsd (Mar 22, 2008)

UK...thanks for the link to the thread. I am purchasing an 07 Tarmac Pro frame and as I went onto Specialized's website under the archive, I started reading the differences in the 07 Tarmac's. Noticed that the entry level were TM and the higher ends were Az1.


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## mikagsd (Mar 22, 2008)

I checked out that thread, very good information. Sorry for starting a discussion that was already....I just didn't see it.


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## ukbloke (Sep 1, 2007)

mikagsd said:


> I checked out that thread, very good information. Sorry for starting a discussion that was already....I just didn't see it.


No worries, it is not always easy to find old threads. I remembered the content because I responded on it, so I knew what to look for. It doesn't help that the search function on this web site never hits for TLAs like Az1. Google's search is much more powerful.


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