Tag Archives: geometry

Road, Track and most Triathalon bicycles are designed for a very specific purpose that doesn’t include comfort, picnics, staying relatively dry or carrying anything other than a water bottle filled with very light water. So essentially this rules them out for this project.

Mountain Bicycles with suspension are again great at what they do, but not great at touring as you loose a fair bit of cyclist effort into the suspension. Modern suspension systems limit the loss, but now we are getting complicated about something that I don’t necessarily need and I’d really like to keep things simple – less maintenance and less things to break. Mountain bicycle frames without suspension and cross country frames are worth considering, and so it would come down to geometry. Often these bicycles use 26 inch wheels and so are unlikely to have toe over lap issues. There is a category of MTB called Monster Cross that looks interesting – My explanation of it would be cross country touring. What I end up with could be classed at the light-weight end of this spectrum if I go with a MTB frame.

Touring Bicycles are built for comfort, efficiency and carrying weight – but not necessarily speed. They can be tweaked for cross country episodes – but aren’t a serious mountain vehicle. They have slightly more relaxed geometry and often these bicycles have 700c wheels. Touring bicycles have a nice utilitarian look about them, and they are usually pretty high quality bicycle builds with lots of thought and design invested in them – and this brings up to randonneuring.

Randonneuring is essentially touring as a sport/ passtime. Very long distance events where you have a time limit, but not necessarily a winner. Just people who have finished. Because these events are usually long, over various terrain, and riders are expected to cater for themselves, cyclists usually have water, food, clothing, lighting systems, etc on their bicycles – It’s a touring picnic thing, and you have to be home by the time the light poles come on in the street (as per mum’s request). So what is all this about? With this sort of organised picnic trip comes technology. Randonneuring bicycles are gaining in popularity and there is an interesting history of frame design that goes along with the sport.

When touring, I’ve shied away from carrying loads on the front wheel because the extra weight has a detrimental affect on the handling. It just didn’t feel right. I have always gone with rear panniers and racks, and when things got heavy, I opted for a bob trailer. Well through Randonneuring I’ve come across low trail geometry bicycles. The trail is the amount of distance there is between the point on the ground following a straight line from the head tube angle, to the point on the ground that is at the centre of the contact patch for the wheel. As the trail decreases your handling quickens, and weight transfer across the centre plane of the bike is less pronounced. Low trail geometry is something that was used with ye olde cycle couriers of the 40’s and 50’s transporting loads of newspapers or whatever. Anyway this is now finding it’s way into the randoneuring community, and by this route back into cycling generally. Joshua Putnam describes Bicycle Steering Geometry very nicely on his site. Velo Orange have a very nice frame called the polyvalent¬† that uses low trail geometry here.

The longer the chain stays the more they flex – so the more of your pedal power goes into them. You find track bikes have chain stays only long enough to accommodate the rear wheel. Whereas touring bikes will have longer chain stays to use the flex to absorb road vibration and bumps.

In summary – I am interested in low trail geometry, but am not sure how much load I would actually put on the front of the bike. If I was getting a custom frame I would probably be looking for something at the low end of ‘mid-trail’ or the high end of ‘low trail’ – say 45-55mm.

What about aesthetics? I like the classic straight top tube, and am leaning away from oversized tubing. In a word – classic.