Early 1970's Puch Cavalier
A perfectly average example of one of the thousands of ten speed racers produced during the seventies, Puch was, and is a venerable Austrian brand, who followed the crowd during this period, and produced racers for the masses. Incorporating a frame heavier than the earth, (Steel naturally) it certainly feels tough, and takes crazy levels of torque to get going. It has Huret derailleurs, front and rear, paired with Simplex downtube shifters. I have adapted to these, even to the extent that I can change up or down while out of the saddle with my hands, or can change up with my knees - gaining an excellent advantage during a sprint! The Weinmann sidepull brakes were the basic standard for these bikes, and are fairly flexy and weak - not great in the rain! Old as they are, only certain types of brake block can be used, and the range is limited - this generally means that braking is OK in the dry, but non existent in the rain - especially with those polished steel rims! A week or so ago, I befell a meeting with a pothole, and have buckled both rims - new ones are on their way, as straightening them would have weakened them even more than normal! They were bent before, and braking was a jolting, affair, perilous when attempting to signal at the same time.....
It's more versatile than it would appear, I have taken it through mud up to the axles, and, although a lower bottom gear would be welcome, it tracked though admirably. Unlike my friend Blogger on a bike (http://bloggeronabike.blogspot.co.uk/) who has 45mm mtb tyres, I do have to make a concious effort to stay upright, but think it makes the whole affair much more fun! On the road, speeds of 15-18 can be maintained, but at the cost of several years of your life - a ride on a modern entry level road bike seems an epiphany!
So, onto my second bicycle - a 1980's Britsh Eagle Mexicana Mountain bike. Probably equal with the Puch in terms of simplicity, save for the cantilever brakes, it makes a good steed for when the ice sets in, and skinny racing tyres are a recipe for a broken neck. It has Shimano SIS, (Shimano Indexed System) 18 speed gearing, which employs a similar parallelogram shape derailleur at the back, and a beefy front derailleur at the chainrings. This system works well, the shifters are essentially downtube models, but mounted on the handlebars, and fitted with indexing. Note though, that while the cassette is indexed, the front derailleur is not, and relies on a watchful eye between your legs ;) It was given to me with APS cantilever brakes, but these were, (Uncharacteristically) weak, so I swopped them out for a set of V brakes I had lying around, which are a great improvement, in both power and bite. I suspect that the frame is steel, despite feeling suspiciously light, especially compared to my Puch! As a mountain bikes, it has 26in wheels, and mountain bike gearing, which slows it down significantly on the road. It's also a pig on the hills, which is less than perfect, as my aforementioned friend and I live in a well known town in Cheshire, where you have to go uphill to get anywhere. I try to use the Puch as much as possible for this reason ,but my friend is stuck with his Mountain bike, so has little choice in the matter!

