A lot of hype surrounds the selection of a tubeset for a bicycle frame. Each tubeset has characteristics that make it suitable for the intended use but often the reasons behind the choices are overplayed.

Read the press, blogs and forums and you'd be forgiven for thinking there's a heirachy among tubesets. Certainly, this is somewhat justified but somehow or other, Titanium has crept in there and is touting itself as a contender for the top spot. Consider this, even 'humble' 4130 CrMo has roughly the same strength as branded Ti 3Al/2.5V tubes and can be as much as 20% stronger in some cases.

However, strength is not everything and it's the inherent flex of these two materials which have attracted frame builders. To further clear things up (or perhaps confuse you even more), take a look at the following comparison chart.

Like everyone else, we use different materials for our various models. A selection of our tubesets can be seen below.

We use a selection of tubes for our steel frames. Our own 'PYPE' is a custom drawn 4130 CrMo double butted (DB) and heat treated (HT) tubeset. This builds into a lightweight frame that is both supple and strong. Reynolds 631 or Columbus Zona would be comparable in strength, weight and elongation (flexibility). Our 'BLX' tubeset is also custom drawn 4130DB CrMo, but this time without the heat treatment. Both of these tubesets would fall into the category of Aerospace Grade tubing. 4130 CrMo would be our normal choice for the rear stays of our bikes.

We also build with Reynolds 631, 725 and 853 and periodically, we'll select tubes from the other specialist manufacturers like Columbus and Tange.

Our standard Ti frames use plain gauge (PG) 100% seamless cold drawn Certified Aerospace Grade Ti 3Al/2.5V tubing. Our dropouts are cut from Ti 6Al/4V plate. It's not so much about what the frame is made from but more about how one uses the material.

By selecting from a number of different tube gauges and diametres, we are able to balance strength, weight and 'feel' to give you a frame that captures that 'feel' that only Ti and Steel can offer.

Bottom line, whatever your material choice, you can be assured that the tubeset selected meets the design specification of the frame.

Our MTB frames are designed to take a 90-130 mm travel fork.

• Compact frame - steeply sloping TT
• Traditional 'A' - seatstays
• Double bent stays
• Disc specific (no V-brake bosses)
• Clearance for 2.5" tires

The design is compact up front which gives great standover height. The top-tube is long enough to give you balance and stability going down and keep the front wheel planted going up.

Hardware/components:

• Seatpost diametre is 27.2 mm.
• Front derailler is 31.8 mm (Ti frame) and 28.6 mm (CrMo frame).
• Seat collar size is 31.8 mm (Ti frame) and 30 mm (CrMo frame).
• BB width is 73mm (Ti & CrMo frames)

Average frame weights are:

• Sirius Ti weighs 1.4 kg/3.1 lbs (18.0"/medium - non-sliding dropouts)
• Sirius R853 inclusive of dropout hardware* weights 2.46 kg/5.4 lbs (18"/medium)

*weight of aluminium sliders, bolts and screws is 0.185 kg/0.40 lbs/6.4 oz).

As a comparison, an Orange P7 frame (Reynolds 631, sliding dropouts) is 2.74 kg/6.0 lbs

PDSP offers a Ti semi-custom build facility to give you a frame tweaked to your requirements. The frame maintains our proven geometry and design but tweaks are available in the following areas.

• Butted tubing
• Various finishes (sand blasted, brushed, polished)
• Custom painting
• Gussets/no gussets
• Engraved headbadge
• Sliding dropouts
• Guides, stops and boss positions
• V-brake bosses/disc specific

Contact us for more details or to discuss your requirements.

So, here's some of our favourite links to those with considerable technical know-how.

• Learning the lingo: Impress friends and influence people by learning the secret lingo that all those wicked smart engineering types use when discussing frame materials!
• Frame & Geometry Variables