New and need help.

[ryan51173]

Hi Everyone,

I just started my bike the other night and got pretty far. Came up with my own prefab mounting kit. The question I have is .....How much pressure should be on the tire from the spindle? Currently I have a peice of 1/2" black iron (gas pipe) attached to the shaft/spindle. That is rock solid and holds. My rear tire is knobby and could be part of my problem. The more I crank down my setup it's almost impossible to pedal and still have some slipage. Now my friction drive is tiliting on angle due to having it cranked down so much. So, I added a side attachment to even out the spindle. I'm concerned I might burn something in the engine with this much downward pressure!
What could the problem be?
Knobby tires? Smooth spindle? Tire pressure? Is there a measureing guide on what the correct downward pressure should be?
Every video I've seen the spindle hardly looks like it's pushing down on the tire.

to note:
I was only able to crank over the engine once on the bike. Any suggestions would truly help.


Thanks,
Ryan (newbie)

 

[Al.Fisherman]

What the heck are you working on. A picture or two sure would help. Do you have any idea how many different kits and engines we all put on a bike.

 

[oldguy387]

Ryan - If you are talking about the bottom bracket, I think I can understand somewhat as to what you are talking about. As Al said, some pics. If you are talking about chain flex between crank set and chain set/cogs, there is not a written rule.

 

[rohmell]

Better to have a bearing on each side of the spindle.

 

[MarkSumpter]

As stated pictures would be a big help in diagnosing your issues but from what I gather by your post you are trying to make a friction drive. Correct?

If so knobby tires and a piece of slick pipe are going to barely give you enough surface tension to drive the bike without slippage (which will cut the tires down fast) let alone if you are trying to bump start it. If this is the case you are better off pull starting the engine.

And as Rohmell said it is always good to have as much support as possible on both sides of a shaft. And you are also correct that if you exert too much pressure for long periods of time on a shaft you can expect to have bearing / bushing and seal issues in short order.

On a side note no matter how you are designing your drive if you are using clamps on an aluminum frame you should make sure to put a piece of steel (like a partial section of EMT conduit) between the frame and clamp to distribute clamp pressure over a larger area to avoid serious frame damage.

 

[Vistaman73]

no response in over a week, i dont think he's coming back. another one of those people....