Saturday, April 13, 2013

Picture of A Modified Raleigh Twenty Design

 

 

 

 

Here we have a modified (Improved Design) this is more suited to the larger person, Longer Arms and Longer legs than a child. Not with excessive weight I would rate this as being suitable up to 100 kilo

After all it is still basically a child's bike, Now getting down to basics or modifications to the original Raleigh Twenty design:

Brakes originally had canter lever type which I personally never had any problem with, but a lot of people seem to find them inferior to V brakes.

Head Post steering changed to incorporate front suspension, and a longer raised handlebar

Top Tube lengthened for extra knee clearance from handlebar

this also gives more clearance from pedal to front wheel

Gears 3 speed improved to 6 speed with a derailleur changer  

This gives a basic Idea of the possibilities and Improvements that can be made.

 

Friday, April 12, 2013

Marken Rad Bicycle

The picture is of an Italian vintage bicycle, not a Raleigh but still a very nice old bicycle
very similar in design to the Raleigh Twenty and only has a coaster brake.
A coaster brake is operated by pedaling backwards this applies the brake.
The bike was in a very rough condition when I first acquired it and it has had a rebuild and a new paint job.
I will post more Information on this one soon.

Technical_Raleigh Twenty

Bottom Bracket Raleigh
 76mm wide shell. 26tpi / ISO is 24tpi)

Front Forks Raleigh
 Narrow Spacing (90mm) threading 26tpi

Frame
 The rear triangle is spaced at 114mm to accept Sturmey-Archer AW hubs.
Seat-Post
- 28.6mm diameter, chromed steel

Wheels /  Hubs and Gearing
wheels ISO 451mm or ISO 406mm, typically 28-spoke steel rims.
  Single speed with coaster brake
- 3-speed (Usually Sturmey-Archer AW, but sometimes AG dynohub)
- New-Zealand built versions offered a 2-speed "duomatic" rear hub with coaster brake.
- Some versions have Shimano 3-speed hubs.
- 46-tooth Chain-wheel and 15-tooth sprocket, giving gears of approx. 46 - 61 - 83 gear inches.

Brakes
- Standard Raleigh Brakes on ISO 451mm-wheeled versions
- Weinmann Long Reach Callipers on ISO 406mm-wheeled versions 

Handlebars
three main types of handlebar used on Twenties
1.) One-piece "All-rounder" bars.
2.) Two-piece "All-rounder" bars.
3.) Two-piece "North-Road" bars.

All production handlebars were held on by a clamp around the top of the forks, and the stems do not have binder bolts.

Please note: The stem has a height-limiter in the form of a loop of stiff wire which runs around the front brake bolt. To remove the handlebar and stem from the frame, you must first remove the front brake.

 

Anything about the Raleigh Twenty

Being an avid follower of  the Raleigh Twenty Site which unfortunately looks like it will dissapear soon
mainly I feel because of the annual cost of maintaining it.