silverlight wrote:BlockChains Gana
What sort of shifting mechanism is that ?
Looks very different !!!
Vintage, yesteryear and retro biking
I think that it is Campagnolo's Cambio corsa shifter. I can't tell if it's got 2 rods or 1. If it is one rod it is the rarer Paris Roubaix. Basically to shift the rider reached down to the lever on the rear brake stay which opened the quick release skewer then the other lever was turned to the direction of the cog you wanted whilst back pedalling the cranks. Once the required gear was selected the quick release was refastened. You have to remember that this was all down whilst pedaling in racing conditions .
The Gana is fitted with the one lever Campagnolo Paris to Roubaix system. The earlier two lever system is known as the Campagnolo Corsa.
First notice that the fork end or drop out has a tooth rack cut in the top of it. The axle has as a mating spline, this allows the wheel when unclamped to move backwards and forwards without getting out of line.
In the Corsa system you unclamp the axle with the top lever and then select the required gear with the lower lever whilst pedalling backwards.
The weight of the rider and forward motion automatically adjust the chain tension. The top lever is then re locked and you can pedal forward again. The shortcoming with the system is the chain tends to over tension which makes for very inefficient peddalling.
The second Paris to Roubaix was developed to over come the over tensioning and speed up gear changing. Here only one lever is used, the first part of the arc of motion opens the axle clamp, as you continue the chain moving arm is picked up and you back pedal to change sprockets. Now the cunning bit - as you close the lever the tiny ratchet and paul that can be seen in the picture is bought into play and it rotates the axle slightly forward making sure the chain is not over tensioned.
There was a final version where the chain moving arm works on the bottom of the chain so you pedal forward to select the required sprocket but these are seriously rare.
I have ridden both systems and with concentration and practice gear changing can be done reasonably quickly. The Gana with long wheel base and good fork geometary is a total joy to ride of course.
When you stop and realise that for a good many years before these appeared people like Simplex and Cyclo had what we now consider conventional systems that worked easly and perfectly you realsie Campagnolo were not always the smartest kid on the block. However then they realised the Gran Sport the best of all.
It is said that when the Italian Ace Gino Bartelli first tried the Corsa system he said "it is nearly as good as a one gear bike and not a lot heavier".
When I first tried the Corsa I rang Warren Meade and asked him how he rode his Olmo Campagnolo Corsa and he said "I usually ride it in the gear I start off on"!
My Shogun Tri-Sport weighed 10.5kg on the bathroom scales. But I thought that was too heavy as it feels really light to me so I weighed it again and it came in at 11! I'm going to stick with the first weight (or maybe buy some better scales).
"...for many people your life is not worth the effort it takes to pay attention or the extra few seconds they may need to wait before they can safely get around you."-BikeSnobNYC
57cm c-c square repco victory tri a (tange infinity?) frame - 2130g
Last edited by kukamunga on Fri Feb 27, 2009 9:28 pm, edited 1 time in total.
God save the ABC & SBS.....
And going for a tidy sum in 24 hours time!
300g difference from that to a Repco Superlite...hard to believe...
MY RIDES: My Velospace Profile
A late 80's 50cm (?) Tange Infinity Victory Tri-A for sale on eBay at the moment (not mine). Might be a nice sub-2kg frame for a shorter person.....
God save the ABC & SBS.....
Ahhh.... steel is real! you know (what this means is steel is for life, barring unforseen collisions)
Aluminium alloy is the next best thing - OK until next.... month, year, quite likely. Next decade - probably not. I've just seen an aquaintance who uses a Giant alloy MTB for his commute. It would only be 5-8 years old, tops. Frame is stuffed, cracked at the top of the seat tube. Already broken and been repaired once, now broken again . It's cactus! The only broken steel frames I've seen have been in some sort of crash or got bent and fatigued later.
Steel really is real - real lifespan.
Riding bikes in traffic - what seems dangerous is usually safe; what seems safe is often more dangerous.
1.5kg sounds reasonable for an alloy frame. looking at ride magazine, the lightest (carbon) frame you can buy off the rack comes in at ~800g, and you'll be paying thousands for the honour. i doubt you could pick up a sub 1000g alloy frame.
could i expect to find a 1500g steel frame, custom or otherwise?
how much would the lightest available (traditional geometry) 54-58cm steel frame weigh in at?
Quite a few on this site at less than 2kg, some as light as 1690gms.
Another weight: I weighed the Malvern Star Triathlete frame I'm selling here and here.
It's a huge frame - 62 x 57 cm. Bathroom scales give it as 2.3kg including headset races (give or take a fair bit... they're bathroom scales after all).
They sure do use light gauge tubing on decent quality frames:
(and I'm pretty sure it's butted tubing, so even thinner in the middle).
late 80's / early 90's 53cm sq Olympic Cycles (Nottingham bike shop built) frame - no idea what tubing - 1710g + 645g fork
Good bit of digging there Munga.
My Surly CC with Brooks saddle, Nitto steel seatpost, touring/commuting wheel and front disc brake (including SPD pedals, bottle cage, computer and lights) weighs 11.6Kg.
Tube Family Vs Frame Wt
Excerpt from the Used Bike Buyers Guide, (it does not list the actual frame size).
=>> The tubesets can be compared by weight within a family but not family to family as my source(s) often included different tubes in each set of weights, i.e. some included the fork steerer tube and fork blades.
TUBING: (MOST COMMON WITH AVERAGE WEIGHT FOR COMPARISON PURPOSES).
MAKE TYPE WEIGHT (IN GRAMS)
REYNOLDS 501 2025
REYNOLDS 531C 1800
REYNOLDS 531P 1700
REYNOLDS 653 1700
REYNOLDS 753 1650
COLUMBUS AELLE 2345
COLUMBUS GARA 2305
COLUMBUS CROMOR 2190
COLUMBUS THRON 2250
COLUMBUS SP 2300
COLUMBUS SL 1930
COLUMBUS SLX 1960
COLUMBUS TSX 1950
COLUMBUS NEURON 1885
COLUMBUS PRX 2310
COLUMBUS EL 1935
TANGE INFINITY 2405
TANGE 2 2290
TANGE 1 2220
TANGE PRESTIGE 1950
ISHIWATA 022 2200
ORIA ML 25 2100
VITUS 181 1790 - for racing.
VITUS 888 2030 - a plain gauge set for touring frames
VITUS 980 1507 - a "Course Professionel" Serie Extra Legere set.
Super Vitus 983 1624 - a "Course Professionel" set
SV980 "Profil Arcor" 1615 - "aero" shaped set
SV888 "Vitus Profil" 2030 - P/G aero set
STEEL FRAME COMPONENT WEIGHTS
Who is online
Users browsing this forum: Google [Bot]