20" Rear Wheel Mod question from Old Posts

[vegan777]

I want 20" wheels on the back of the DW what would you change to do it ?

...to preserve the original ground clearance you need to make some adjustments to the frame. Since a 20" tire is 3" shorter from center to ground, the axle needs to be 3" closer to the ground. I might be a bit leary of extending the rear downward sloping tubes and might just shorten the tube that goes from the main boom upward to the cross piece that holds the downtubes.

By the way, since both the bar I would shorten, and the downward slanting tubes holding the axle that bpach would lengthen are at an angle you will have to use trigonometry to figure out how much lengthening or shortening will give you 3 vertical inches. Since the angle between the main boom and the slanting upright going to the rear is 41 degrees, by my calculations you would need to make the 13" slanting upright tube 8.42" instead of 13". Someone should check my math before cutting http://www.lucidscience.com/forum/icon_smile_shock.gif

http://www.atlantamusclecars.com/Paint/Mods.PNG

This will give you a stronger frame, but the higher part of the seatback will have less support, so you may wish to add a bit more support at the top of the tube behind the seat.

You may also want to consider that you will need higher gearing to give you the same top speed as the 26" tire would, but that may not be a concern. trikeman

stormbird - since both the gear cluster and the disc brake sit off to the sides of the center main tube, I don't see any clearance problems there if you shorten the tube, but its something to check...

You might be better off doing the rear of the DW more like the Kyoto cruiser for 20" wheels. The four "fingers" off the rear of the frame would need to be longer for sure. AZ

[Patrike]

If you go for the Kyoto rear end it will look more like the new Greenspeed Anura which has 16" rims. I thought a bit small but the angle with the front elevated up is an acceptable look -- I think.

http://www.greenspeed.com.au/anura_main.html

I to will think about the 20" wheels - I would keep the over all design and just shorten the elavated rear section support beam the difference between a 26 and 20 wheel to the amount -- Might have to add an extention for the back seat support. Overall not much of a change in plans -- I think.

Patrike

[TheKid]

You could easily lengthen the four tubes 3", which would give you a slightly lower main frame in the rear, than using 26" wheels. It will also shift your body weight forward, so you'll need to add to the frame stiffener. You might want to consider that Brad's plans are designed so you could alter them to suit your needs, in fact he often encourages it. In this instance for example, you could shorten the seat tube, weld the rear end on, then add to the seat tube to make it longer. Or you could extend the four rear end pieces just a little longer to keep your weight more rearward, and of the seat is too low, add a piece to the main frame to raise the seat. You could also order the Streetfighter plans, and use the specs for that rear end, which uses 20" wheels if you don't feel confident with your own alterations.