this post is written to try and share little of my hard and often expensively earned knowledge of buying and running vintage bicycle frames , it is never intended as a hard and fast rule book,
there are many things to consider when venturing into the world of vintage bikes , the first and most obvious is sizing , as in rider fit and parts fit , only you can decide what the right size is to fit you , but bare in mind that you may spot a handsome frame that is vertically the correct size but it may have an abnormally long top tube , this was actually quite common back in the 50's and 60's , a tight or steep head angle was often coupled to a slack or shallow seat angle , this means the saddle needs to be slid quite far forward on its rails and coupled to a short stem to get the cockpit to a comfortable length . the described set up is exactly what my higgins ultralight has ,
it has a 75° head angle with 71° seat angle , i have a 100mm stem and short reach(70mm) short drop bars with my saddle all the way forward , my flying scot continental has a similar set up , if a frame has similar angles then check the forks are of the correct rake or off set , the steeper the head angle the greater the fork rake must be to maintain stability .
rear end spacing ,
this varies a lot , 110 120 126 130 , to name a few , while most frames can be manipulated in or out a few mm i wouldn't go pulling a 110mm frame over a 135 hub , not only does it stress the frame and dropouts it can also damage the rear hub axle by bending it , drop outs can have slots cut specifically for a certain hub such as a sturmey archer , trying to get a 10mm axle in will usually involve a bit of filing , front drop outs on old forks can have 5/16 slots , a modern 9mm axle wont go in them , if you decide to file the dropout be methodical, if you file only the back edge of the slot on front dropouts you wont effect the strength or alignment , if you do both sides of one drop out you must then do the same on the other dropout , take your time and consider that once it has been removed it cant easily go back on.
wheel sizing ,
26x1 3/8
26x1 1/2
27x1 1/4
etc
i choose frames that will convert easily to 700c , brake drop and clearance are the major concerns , 26x1 1/4 fit frames can usually take a 700c with shorter drop brakes and narrower tyres without issue , the bottom bracket height does rise a little though and mudguard clearance can become difficult,
27" wheel frames can also be converted easily , these are great with 700c wheels if you plan to run big tyres just as i do on my old Vindec SW special ,
cable stops and gear bosses ,
a lot of old frames have no fittings at all so clip on stops etc must be used , a few of my bikes have one gear lever boss so alternative mountings and guides must be used to run a multiple chainwheel set up .
hidden damage
after 60+ years of probable abuse and hard riding you can expect to find small issues that will need attention ,as an example here is a pic of the small cracks i found in the Nervex lugs on my vindec,
these are small and are only in the lugs, both top and bottom of the head tube , the actual tubes still seem fine , the cause of these cracks is known to me as the frame had over sized 30.5mm cups pressed in when i got it, i will be fixing these small issues by doing a bit of filling with some bronze , this sort of cracking is rather typical for the old Nervex lightweight lugs ,
its things like this that make me stay away from so called 'restored' frames as a nice new paint job can hide a plethora of damage , i once had a customer with a beautiful scot continental , but it weighed a ton, after inspection i found that the fork and frame had lots of holes that had been filled with bronze brazing which had doubled the frame weight and destroyed the ride quality , i also found that there was a lot of car body filler !
bottom bracket shells
i couldnt even begin to count the number of nice old frames i have seen being built up by young ,enthusiastic guys and girls at my old place of work that were assembling vintage frames into fixed gear street machines , only to have them shout me over for help as the bottom bracket wont screw in , when i have a look they are trying to ram in an italian bb into an english shell or they have wound in the non drive cup into the drive side , there are bottom brackets available that called threadless BB's to sort out damaged shells, another quick and dirty fix is to flow some bronze into the stretched shell and then re-cut the threads , if you do this i would strongly recommend you use a cartridge type BB , they are far better at not stressing the shell edges.
some vintage bikes have odd width shells , my scot continental has a 64mm wide shell , finding a cup and cone bb set to fit it is next to impossible , i ran a shimano cartridge item but still used a lockring on the non drive side so it looks correct,
chain stays and seat stays ,
these can look fine on the outside but be rotten and rusty on the inside , always check inside the chainstays , seat tube and downtube at the bb junction , carry a small torch when going to view a frame you may intend buying .
seat lug's ,
these can stretch over many years of use and tightening , check that they are in a good usable state as they can be costly to sort out ,
more soon ;-)
No comments:
Post a Comment