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-   -   Tadpole alignment (http://www.bikeforums.net/recumbent/306059-tadpole-alignment.html)

blochow2001 06-05-07 01:38 PM

Tadpole alignment
 
What is the best way to give my Sun tadpole a front end alignment? I noticed the other day that the linkage was loose, and when I stepped back I noticed the right tire was plowing, or the front of the tire was pointed toward the center of the bike. This must have recently gotten lose as the tires show no strange wear patterns.

What I am doing is measuring the distance between the two rims front and back, and trying to get that measurement as clsoe as possible. In my mind, if the wheels are parallel to each other they should be in alignment. At this point I am about 1/8" off...the front of the wheels are wider apart than the back. Is it possible to get this closer, or am I approaching this in the wrong manner?

mchell 06-05-07 03:24 PM

I think you're going about this the correct way. The specs on my 06 Catrike Road indicate that the "toe in" should be no more than 1/16" narrower at the front of the rims, measured parallel to the ground at the axle level. I check mine every 100km or so and it has never changed.

Mike

Shaman 06-05-07 06:54 PM

This is a topic of much discussion on the Recumbent Forums (BROL-Bentrider Online). In general, yes, you got it right. A few other things to consider include measuring at the same elevation off the ground in front and in back of the tires. Most tadpole trikes have wheels that lean in on the top. changing the height of the measurement in front and rear of the wheel gives you a false measurement.
Also consider making the measurement with your weight (or equivalent weight) on the trike. Frame deflection will change the Toe Adjustment some.
Some people go all out by marking a "chalk line" on the tire and measuring this so you know you are in the true radial center of the tire. In my book, it is good enough to measure at the rim or even at a spoke nipple. Just cut up an old tape measure and lay it across the spokes.
Also make sure the wheels are actually pointing straight forward. If the trike has appropriate ackermann steering geometry, as you turn the wheels do actually diverge from a parallel attitude.

Wheelchairman 06-06-07 02:14 AM

You're going about it right. Usually if you set your toe to about 1* toe in, then it should fall into neutral toe when you sit all your weight on the trike.

jeff-o 06-07-07 08:21 AM

The best way to measure the toe-in is to stretch a tape measure between the spoke ends, not the rims. It's much more accurate this way (and easier, too!) The fronts of the wheels should be closer together by about 1/16". Once you've got this set, get the trike up to about 10mph, stop pedaling, and release the handle bars. If the trike tracks straight then everything is set properly. However, if the steering begins to oscillate wildly, then the toe-in needs a bit more adjustment.

Redrom 06-07-07 09:24 AM

So, the best way to do this is to stick your toe-in the spokes at 10 mph.

jeff-o 06-07-07 10:20 AM

Quote:

Originally Posted by Redrom
So, the best way to do this is to stick your toe-in the spokes at 10 mph.

LOL :)

I wouldn't recommend doing precisely that, no...

Wheelchairman 06-07-07 07:56 PM

I may also add, that another good area to measure from is the center seam of your tyres. It is after all, in most cases, your contact patch. Not a viable option for most- tyres arn't new forever :D

blochow2001 06-08-07 07:15 AM

Thanks for the replies, they are much appreciated. Also, if I do decide to stick my toe in the spokes at 10mph then I better make sure I stretch first.

Redrom 06-08-07 07:35 AM

Quote:

Originally Posted by blochow2001
Thanks for the replies, they are much appreciated. Also, if I do decide to stick my toe in the spokes at 10mph then I better make sure I stretch first.

Or, like with the tape measure, make sure it's an old toe you're not using anymore...

Tizzyfit 07-20-07 01:07 PM

Quote:

Originally Posted by Redrom (Post 4596587)
So, the best way to do this is to stick your toe-in the spokes at 10 mph.

THANKS for the laugh, I needed one this morning!


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