BMP Friction Drive Kit converted to V-Belt Drive

lowracer

lowracer

New Member
Ok.
I finally got my project to the point where I am happy.
Don't get me wrong, I love the simplicity & easy installation of the friction drivetrain, but since I already went the extra mile attaching a DIY rim to rim pulley system, I had to try this out & bought the BMP kit specifically for its 1/2" clutch drum shaft thru the 2 outer bearings. My 1.5" V-Pulley mounts onto the 1/2" BMP shaft perfectly & has a set-screw to keep everything tight. I just had to remove the 1.25" friction drive roller (2 set-screws). My top speed using the Robin EH035 w/friction drive setup was ~33 mph. With the V-Belt drive, top speed today was ~36 mph. I really like the BMP Kit & the company behind it. Jim @ BMP provided me with strong communication throughout my build. Here are my latest pics of the way I will probably leave things until I give in to my need for speed & go out & buy a higher displacement 2-stroke?
-Lowracer-
 

Attachments

  • IMG00125-20101023-1532.jpg
    IMG00125-20101023-1532.jpg
    72.7 KB · Views: 575
  • IMG00124-20101023-1531.jpg
    IMG00124-20101023-1531.jpg
    91.2 KB · Views: 670
  • IMG00113-20101022-1434.jpg
    IMG00113-20101022-1434.jpg
    92.3 KB · Views: 531
  • IMG00136-20101029-1747.jpg
    IMG00136-20101029-1747.jpg
    168.6 KB · Views: 547
  • IMG00133-20101029-1746 (2).jpg
    IMG00133-20101029-1746 (2).jpg
    164.6 KB · Views: 1,078
Last edited:
Nice setup. What size pulley do you have on the wheel?
I have a BMP kit and also a Whizzer wheel pulley, maybe I will give it a try.
 
bjpru66,
The rim hoop attached to the front wheel is the same size as the front wheel's spoked rim. MTB sized 26" (aka 559). I have a whizzer sheave that I tested out but it wont work due to the gearing (too tall for the Robin EH035). You would need a engine V-pulley smaller than what is being produced or go with a lower RPM larger engine (like a Honda 100cc or Briggs & Stratton 2.5-3.0 hp or Harbor Freight 2 hp & a V-Belt centrifugal clutch). The way that GEBE does it using a similar sized wheel pulley as a whizzer sheave is by using a smaller front HTD toothed flat pulley. My set up is close in gearing to a Friction drive using a 1.5" drive roller. I get a little more speed probably due to slightly taller gearing & less friction.
-lowracer-
 
Last edited:
Lowracer,

So where did you get the rim hoop that you used on the front wheel? Is that a standard 1/2" wide v belt and it looks as though you have a belt tensioner also.
I like your design and would like to give it a try with my BMP kit
 
bjpru66 said:
Lowracer,

So where did you get the rim hoop that you used on the front wheel? Is that a standard 1/2" wide v belt and it looks as though you have a belt tensioner also.
I like your design and would like to give it a try with my BMP kit
Click to expand...

bjpru66,
The rim hoop is a 26" Mavic Crossmax MTB wheel I had in the garage from years ago in my MTB racing days. It lays perfectly over the MTB front wheel (which any MTB 26" rim w/ machined braking surfaces should). The V-Belt is a STD 1/2" notched AX series V-Belt available online for about $15 or at your local auto parts store. Just need to measure the distance around the pulleys once installed & add 1 inch. The belts are sold by inside diameter. The belt tensioner I bought on eBay from a chinese supplier of Whizzer parts for about $15. I can look up his User ID if you need it. All hardware bolts & steel bar are from my local Lowe's home store.
-lowracer-
 
lowracer,
Thanks for the info..
One final question, how did you attach the rim to your front wheel? Hard to tell from the pics.
 
bjpru66 said:
lowracer,
Thanks for the info..
One final question, how did you attach the rim to your front wheel? Hard to tell from the pics.
Click to expand...

bjpru66,
The rims were cleaned up using sandpaper, then rubbing alcohol, before I glued them together with JB Weld. I let that dry laying them flat on the ground on the pulley hoop side. After riding it around like that awhile, & taking the advise of other forum users, I drilled 4 small holes thru both rims & bolted them together w/ stainless hardware & nylock nuts . Making sure to drill the holes below where the tube resides (thru the small channel between the tube area & the spoke hole exit point). Removing all the drilled mess was important before re-taping the rim & installing the tube again.
So far so good...
-lowracer-
 
Last edited:
Corgi1,
The set-up really doesn't require that tensioner I installed since you can simply loosen the BMP quick release & lift the engine channel to take up belt slack. I installed it to route the belt directly down the center of the rim. It had a tendency to ride up either side of the spoke bed & I like it straight & true. I just ordered some 10mm cloth Velox rim tape to run down the center of the spoke bed to make a flatter area for the belt to ride in & then another 17mm roll of Velox rim tape to run over the 10mm. May even change my gearing ever so slightly.
-lowracer-
 
I didn't even think of the cent. clutch I had just looked at a thread and click on links on 1912 Harley D. and my mind was still thinking that belt drive
 
Re: Velox. It's tough cotton tape but the glue won't take getting wet or pulling on it. Have you thought of heavy duty strapping tape? I wouldn't use any tape but would let the spoke holes channel away water amd provide grip. The pulley rim should develop a slight valley eventually.

5/5 for ingenuity, style, amd build quality.
 
Made some changes to the bike & took a few more pics to share.
Shortened the stem & lowered the handlebars.
Changed the seat & lowered it to get more aero.
-lowracer-
 

Attachments

  • IMG00134-20101029-1746.jpg
    IMG00134-20101029-1746.jpg
    176.2 KB · Views: 275
  • IMG00140-20101029-1813.jpg
    IMG00140-20101029-1813.jpg
    156.6 KB · Views: 328
  • IMG00131-20101029-1228.jpg
    IMG00131-20101029-1228.jpg
    156.2 KB · Views: 250
  • IMG00132-20101029-1228.jpg
    IMG00132-20101029-1228.jpg
    152.1 KB · Views: 305
  • IMG00135-20101029-1747.jpg
    IMG00135-20101029-1747.jpg
    175.4 KB · Views: 282
There is a new tape called Gorilla Tape that is a super strong duct tape. People on Youtube are using it for rim strip tape or even to convert to tubeless. I like tubes though. I will stay with them. It might work for your belt pulley though.
 
happycheapskate,
Thanks for the gorilla tape tip. I still haven't tried out the 2 different sized velox rim tape's I bought to get a smooth track inside my rim pulley. If I do it, it would allow me to run the v-belt further outboard inside the track & allow a slightly larger front tire. Right now I need to run a 1.25" MTB slick, but I could get away with a 1.5" if I do the modification.
I ran Stan's No-Tubes Tubeless System years ago in my MTB racing days with good success in the short term. The long term effects of using the liquid latex inside the tire caused the rims around the spoke holes to corrode & cause rim failures. The rim hoop I am using as my v-pulley is a direct result of that corrosion (Mavic Crossmax ceramic rim). At least I got some use out of that wheel by recycling it into the pulley...
-lowracer-
 
Have you tried something like this:

125427md.jpg

http://www.niagaracycle.com/images/sbsimages/125427md.jpg

26" Cheng Shin $10 tire raised center tread street/ mtb tire

There's no knobs on the sides, so it might fit. I can't say for sure, but it's $10 and could go on the back if it doesn't fit the wheel with the belt drive.

The only other way I can think of would be to use bolts and washers/brass spacers to space the drive rim away from the tire rim.
 
Happycheapskate,
I got 4 of the Kenda 838's from Niagara for around the same price & really like them for their meatyness.
There just isn't enough clearance to space it outward so tire selection is limited to 1.25 or 1.5 with the modifications I spoke of.
Seems like every design has its limitations...lol
Back to the drawing boards,
-lowracer-
 
That's good to know. A lot of Kenda's are great for traction and cheapness,but pretty floppy.

35-73-821md.jpg

http://www.niagaracycle.com/product_info.php?products_id=433346
$8 1.5" inverted treads.

I have these in 1.75 and 1.95, and they are awesome. They have noticeable limits when cornering hard offroad, but are predictable and fast. I really like them on my MB cruiser bike. Nashbar and Performance sell them too, but only in a 2.1 size I think.

Here is another, a "slick" 1.5 with chevron sipes. http://www.niagaracycle.com/product_info.php?products_id=1400

Hope I helped some! Your bike is cool!
 
Last edited:
You must log in or register to reply here.
Back
Top