I have a few Raleigh Twenty bikes. Though there all the non folding bike.
I like modding bikes. Especially bikes like 20s that have some unusual parts that are needin changed anyway. Or limit the performance of the bike.
For instance the UK market 20s had 20 X 1 3/8" wheels. These are ok. But they were steel rims on a 3 speed hub. With a steel front hub thats narrower than modern hubs, and has a smaller diameter axle, 5/16" British standard cycle thread. Instead 3/8" axles that are more common these days. So this means that you need a different spanner to take off the front wheel. Well you can get larger wheel nuts to fit on the 5/16" axle, that takes a 15mm spanner.
The bottom brackets a steel tube, Not too thick metal. Its over 70mm wide. It has a different thread pitch than usual. Its possible to get axles that fit into a 73mm wide shell. But getting them to be secure in there, either means to rettap the shell. Which is a bit risky as you may damage the frame and the shell isnt as strong as other bikes are.
You can use the original cups on a different axle. Ive done this a few times. Its ussually ok. The Raleigh cups seem to be very strong as Ive not seen any that were worn.
Or you can get Phil woods cups to use a cartridge Bottom Bracket. These cups are expensive though. And most cartridges these days have one cup formed on the axle. So isnt removable.
I have narrowed and retapped a few Raleighs to the more usual 68MM width. But its fiddly and now Im not working at the bike shop i dont have access to the BB tap.
Also if you replace the 451 wheels with 406 wheels, they are a little smaller. So the brakes need adjusting, or replaced. I have modded a frame to use 406 brakes by replacing the flat metal brake bridge with a tube bridge nearer the wheel. The shorter brake arms are, the less flex there is in them. Raleigh used single pivot brakes on the 20. Commonly pressed steel long reach sidepulls on the UK bikes. Although Ive seen Alloy brakes on some of them.
I had modded a 20 to be a sort of chopper.
I cut the top of the headstock off the frame, as the 20 uses a long steerer tube. I modded the BB to take alloy cranks. I removed the bridges from the rear stays. But I never got further than that.
I tried various stuff on this frame. Even got a 26 X 1.5 mountain bike wheel in there.
This gave me the idea to fit 24" wheels.
That is one of my favourite size wheels. I have a couple of Raleigh Phaser bikes. They were kids roadster bikes that came with 1 or 3 speed gears.
But I modded one into a MTB and the other into a BMX.
I tried 24" 451 wheels and forks on the 20.
But since I had cut the headstock above the frame tube, instead of below. The bike was pretty high, the steering would be slower than it was as stock.
I was toying with the idea of cutting the rear stays off and slipping in a rear triangle from a 24" wheeled mountain bike. This would give more gears, better brakes.
I was messing with the frame. Its got damaged chainstays and down tubes. So I cut off the BB and rear stays.
The 20 takes a 28.6mm seat pin. This is reasonably common these days. The seat tubes tapered at the top to hold the seat pin. 28.6mm is a common outside diameter for the seat tube of bikes. So I cut up a 24" wheeled MTB. I cut the top tube in front of the seat tube. I cut the downtube in front of the BB shell. This frame has no hole in the front of the seat tube or the bb shell. Those are for letting gasses out during welding.
heres the donnor frame before cutting up.
My tape measure is to see if its a 24" wheel frame. They have 13" from wheel drop out slot to brake bridge.
I smooth off the rough metal and stripped the paint off the seat tube. Heres it with the 20 font end sitting on top.
I have cut more off the 20s frame. So it can use a 28.6mm front mech. I have cut the seat stays from the MTBs seattube. Then slipped the 20 seat tube down. Then welded around the seat tube just under above the seat stays. And below the 20s top tube. I welded around the seat stays, to join them onto the 20s seat tube. The frame is 18". I reangled the down tubes, got to extend them. Thinking of welding a flat peice of metal to them. To take cable adjusters. So the gear cables can go through the frame and then under the BB shell.
This is going to be interesting.....
I am looking forward to the next installment.
Trigger's broom, me thinks!
Nice - I look forward to seeing more. Getting close to the notion of hiring an oxy-acetylene torch to get the bridges on my own R24 together actually. Had a go at brazing with a propane blow-torch at the weekend after chopping up a freecycle clunker for dropouts and bridges [of which the bridge has been nicely reshaped so I can fit nice caliper brakes on to the chainstays and keep the seatstays simple and uncluttered] but the heat wasn't really there for me. I need the big man's toys to melt brazing rod. I look forward to such incendiary pyromaniac fun in the near distant future...
Well guys, I feel like a bit of a loser here because I've abandoned my R24 project. The choice of good HP narrow tyres for the 507 size I've got is very limited if not non-existant. Next time I''ll check these odd sizes better before I buy.....Anyone need a set of Velocity 24" MTB rims?
In the place of the R24 project I'm building up a R20 consisting of 451 Velocity rims with a Sachs 3x7 rear hub and a Shimano LX Deore front hub, not the same as a R24 but still fun to build.
Its raining here. So wont be outside welding it. Thats ok cause I can weld in the garage.
I will look out tubes to extend the down tubes today.
Ive got loads of cut up frames to get the right size tubes.
Also got loads of frames that are available to get cut up.
thats 50 26" frames, Ive got other sizes of bike frames too.
As for it being Triggers brush. I had a cat called Rodney, named after Mr Trotter. And my brothers called Dave. :)
I did more welding yesterday.
I tried to take more pictures, but they didnt come out very well. Do digital cameras take worse pictures when there old? My Vivitar doesnt like to picture shiny surfaces. Oh well. Its an excuse not to wash my bike. :)
I then looked though some of my scrap metal to get tubes to extend the down tubes.
I have the rear end from the 20, and from a folding 20. So there the right diameter.
But I was wanting to fit a tube inside them to hold them to the tubes that are there. But I couldnt find a tube the right diameter. I think I'll take a tube and slot it and squeeze it.
I could take off the downtubes and fit new ones. But theres a big brazed joint onto the downtube. And Brass takes forever to file away..
I found a set of rigid 24" MTB forks in my garage.
I was filing down the welds a bit this morning.
But got bored so copper greased the shifter claws in my Marins shifter pods. I got it a while ago at a boot sale for £10. But the shifters never worked cause they were gummed up. It started raining when I finished that.
heres a pic I took yesterday. The 24" MTB wheel is in for size. Obviously it would fit as the rear triangle from the MTB hasnt been messed with much. Thats an alloy 28.6mm seat clamp on the frame.
Picture looks funny though. It was overcast when I took it. So even light. Not harsh sunlight.
I cut a tube for one of the downtubes. Actually it was the handlebar brace from a Raleigh Burner BMX. Its the same diameter as the downtube. I got a slightly thinner tube to sleeve inside it. I filed and sawed it so it would go inside. I filed the tube end to the BBs profile. Then clamped it up in the vice. Welding today is not good.
I got sick fed up and went for a blast on my Marin. Its good. And it wasnt raining..whoo hoo
You're a genius!:thumb: Looking foward to see the finished machine! :giver:
Admire your creativity here.
Consider the finished bb height when setting up the front fork and the finished headtube geometries.
On my own Raleigh Five-Twenty project, it was more by luck than by design that the finished BB height was just over 10.75 inches, provided good crank clearance, no pedal strikes when cornering and at the same time it did not appearing too high.
Another option available to you is to incorporate a S&S tube coupler in the middle of the main tube.
this allows you to increase the virtual top tube dimension such that an abnormally long stem is not required. This feature also increases clearance between the travel circle of the shoe and front tire.
You also may choose to use brass brazing techniques, if the welding gets too messy.
Lots of luck, G.R.
Oh...I havent done any work on it for a while.
Been riding my other bikes too much.
did 40 miles on my Marin today.
I was going to extend another R20. But the tubing sizes are specific to Raleighs. Ive got a few old Raleigh frames. Biancas and others. So could cut them up. I just use bits I have. I cant braze.
I had cut off the MTBs front end. I layed it over the frame and Then set the 20s lower headstock to where the MTB head stock was. Should just be the same geometry as the MTB. Was little difference in Top tube length.
Was toying with the idea of fitting a SA chrome stem and chrome riser bars. So it would look like a 20. Not sure though. Dont want to fit a long stem to it.
Im 5 foot 8 inch tall. So hopefully it will be an ok reach with a short stem
Holy Crap! and I thought I had a spare parts/frame collection:roflmao2: I can weld, braze and solder...but not well enough for someone to pay me to do it.:p
All of the R20's I have seen here in the US have been the folding version. Mine is coming along.:thumb: but nothing like griftereck has.:innocent:
Ive had a couple folding 20s.
but didnt appreciate them at the time.
So the folding one I have now is cut up into little parts. I had the intention of making a longer Chopper.
I did build a chopper out of a Raleigh Denim. Thats a 18" wheel version of a 20. I got a push lawnmower handle welded to the headstock and seat tube. And sissy bar tubes welded to the seat stays. I put 20" alloys that had a 3 speed Shimano hub, with twistgrip. With Mk2 Chopper bars and seat on it. Was ok. But kept on breaking spokes. Was old wheels from the dump. This was years ago, before I learnt about building wheels. I managed to break a pedal spindle. I had Lyotard 460 rat trap pedals on it. I had heard that your not supposed to straighten bent spindles. But thought that was, buy a new one..talk. I was climbing a hill a mile away. It broke. I kicked the ground with my toes. Thought I had broken them. I skuffed skin off the back of my right hand as the twist grip revolved when I lurched forward, my hand rubbed on the big MTB levers. :o
I keep on meaning to do more work on my R24. But its sunny here. And the welds need filed down. So isnt the most exciting work.