Twin motored PK Ripper--A little over the top!

[recumpence]

The new 20 inch bike I am building will, indeed, use a radical new motor, but not the 4 inch Astro. There are a number of reasons for that. I will get deeper into that on a later thread.

Anyway, I am very focussed on small bike builds. I like the compact design for loading into a trunk, the lighter weight, and the additional strength afforded by the smaller wheels (large wheels tend to be weaker and give more load to the frame). Gear ratio is also easier to deal with for smaller wheels. Also, the fun factor is high on small bikes for bashing around town. :wink:

Matt

 

[Wheazel]

Matt, did you settle for any personal favourite "sweetspot" wheelsize? Always a compromise between comfort+rollresistance and all the stuff you mentioned.

 

[recumpence]

I would love 22 inch tires. But, since there are none like that, I lean toward 20s for street and 24 for dirt.

Matt

 

[Ypedal]

I like small nimble, powerfull bikes.. small bike big fun...

My 100v BMX is a riot, not intimidating to sit on, both feet flat on the ground with knees bent, light weight, but hit the throttle while not leaning forward and it's a hilarious outcome lol..

 

[recumpence]

No doubt. It is cool lifting the front wheel while leaning over the bars.

Loads of fun........

Matt

 

[Miles]

I would love 22 inch tires.

I'm with you on this, Matt.

There are a few narrow 451 rims available (Sun, Velocity et al) but not much choice in tyres for them...

This looks the most promising: http://www.kendausa.com/en/home/bicycle/bmx/small-block-eight.aspx

 

[recumpence]

I know you can get Pireli moped tires that are 22 inch and fit 20 inch rims. They seem very well suited for ebike use, but are much heavier. For a true communter, those may be great. I like to really go light weight on my builds, though and freestyle tires are plenty capable on the road. Bicycle tires also respond better to pressure adjustment for ride quality due to their thinner sidewall.

Moped tires would last FOREVER on a bicycle, though.

Matt

 

[Miles]

If one could get 2.0" section tyres for 451 size rims, that would be 22"

1 3/8" is the largest I've found.

 

[Byte]

Question; how did you mount the rear disc caliper to the bike? It looks like you didn't chance anything on the frame. Cause I thought BMX frames are only made for rim brakes?

And another one: Is the rear wheel 19" of 20"? Cause unicycles also use 19" tyres...