Help with Sigma Speedo for RT Needed

[Mr. Frank]

I'm installing a Sigma bicycle speedo on my RT. Does anyone have an accurate measure of the circumference of the Metzeler Z6 120/70X17 front tire?

[Bokrijder]

Simple -- roll the motorcycle exactly one revolution of the front wheel and measure the distance traveled. I place the valve stem at 6 o'clock and mark a line on the garage floor, roll the bike forward until the valve stem is again in exactly the same 6 o'clock position, place a mark, and now measure between the two marks.

Motard
1150GS
R50

[Mr. Frank]

Thanks for the reply. What I'm stuck on now is figuring a way to put Velcro on the back of the very concave unit. I want that to be flat to mesh with the dash. Any ideas?

[BradfordBenn]

A little wadded up velcro as a shim?

[Bokrijder]

If the velcro suggestion does not work, try filling in the concave area with auto body filler. A small can can be purchased for a few dollars at an automotive parts supply house. After the filler has been applied, but not fully hardened, it can be easily carved with a sharp knife. An exacto works very well. After hardening, a bit of sanding will touch it up. Flat black paint, if required, can be applied. There is a chance that the filler will not adhere well to the Sigma plastic case. If this is the case, glue the fabricated part to the Sigma mount. The mounting pad for the Sigma can be purchased separately, so if things go awry, you can buy another pad. Through the years, I have bounced back and forth between mile and kilometer geographic areas. The sigma has been a good solution plus the unit is very accurate. If you like to push posted speed restrictions, the unit will probably pay for itself.

Motard
1150GS
R50

[jimcameron]

I'm installing a Sigma bicycle speedo on my RT.


Mr. Frank

Just to enlighten me, why are you doing this?

Thanks,
jim

[Mr. Frank]

Mr. Frank

Just to enlighten me, why are you doing this?

Thanks,
jim

I'm trying to figure out how fast I'm really going in light of the infamous BMW speedometers. The error seems to range from about 10% at low speeds to about 6% at an indicated 80. If one is trying to go 5 or 9 over, it's nice to know your speed. Many people use a GPS for thiis.