Staton: What size friction roller?

[Happy Valley]

Curious on any recommendations you Staton friction drive users might have on roller size?

I know it varies so in my case the variables are:

210 lb. rider, mostly flat ground along the river valley where I live but there are some hills too. (most of the roads run along the river) Not long steep grades like western mountains but more rolling hills up out of the valley.
Engine wise, the Robin EHO35.

Appreciate any insight in this regard, thanks.

[billintexas]

I run the stanton 35 cc robin suburu with 7/8" roller on a moon dog by Kaluna.I get 22 mph flat land 15 up a steep hill and 25 plus down any hill.MPG suffers at 100mpg im 230lbs and dont peddle except take off..and some hills at least part of it anyway. Hope this helps.

[Happy Valley]

Yup it does, thanks Bill, and thanks too for mentioning the variable of what bike you're using. I'm thinking about a 26" wheel mountain bike.

So, I guess the smaller the roller the less it's laboring the engine?

[SirJakesus]

Yeah smaller roller and you get more torque from the engine but you get a lower top speed. The moon dog is 26in wheel as well so you're looking at the same setup and expectations.
Remember with these 4 strokes that they're not meant to be run at full RPM for extended periods. You may be able to get away with a larger drive roller and therefore less engine RPM and higher top and cruising speeds if you're willing to peddle a bit more. Generally following river valley roads is more than flat enough to go with a higher gearing. I'm going to order a staton friction kit soon for my girlfriends use but I'm ordering a couple drive rollers for different uses, especially if I remove the engine for some off roading on my current pedal bike.

[Happy Valley]

SirJakesus:

What size range in rollers will you order?

For my set-up I was thinking of going with a 1", maybe that's too small?

Ya think there's much difference in the 1 1/8"? 1 1/4?

[5-7HEAVEN]

My 35cc Robin had a 1.125" roller on my 20" Dahon bike. It was a good starting point. I believe this roller was a good match for my 190 lb. frame.

Now I have my friction drive with 2.2hp Mitsubishi engine on my 26" cruiser bike. A good match again, especially when I installed an exhaust and got more revs. I just ordered the 1.375" and 1.5" rollers for more top end. I might upgrade to an 10,000rpm engine.

The Mits engine was screaming at 30mph with the 1.125" roller. The Subaru pooped out on level ground at about 26mph.

5-7

[Happy Valley]

The Subaru pooped out on level ground at about 26mph.

5-7

5-7:

Pooped out, as in top end speed?

How was the Robin with the 1.125" power-wise from a stand still or up a slope?

I'm wondering along the lines of what SirJakesus said about having to wind the Robin engine too high in the power band.

[5-7HEAVEN]

In other words, I was out of the Subaru engine's power curve at the high end. I was also out of the Mitsu's power range at 30mph, but this engine's revs continued to climb.

5-7

[SirJakesus]

I have no idea what sizes I'm going to order Happy. I emailed Staton about it. I'm going with the mits43 engine and wanted to get something with a properly sized spindle to cruise 22-25mph without revving up too much but keeping in power band so probably 27-28mph top speed. This is for my girlfriend who is by no means a hot rodder and enjoys taking it easy and looking at scenery. I was also going to get something really small for the times she just wants to use her bike as a peddler and I want to use my Schwinn hardtail motored off road. So torque would be of utmost importance in that application.

[Happy Valley]

Yeah, well thanks Sirjakeus, you got me thinking about over-winding the little 4 stroke.