Sigma BC800 Setup....(help needed)

essexbloke · Post by **essexbloke** » Mon May 02, 2005 8:06 pm

Hi all, fitted the above over the weekend....

Got totally lost with configuring it... Anyone got one? how do i work out the 4 digit figure needed for wheelsize? The manual might as well been written in arabic cos it confused me!!!!

Some layman terms help would be appreciated.....

Thanks,

Ps, if it helps, i'm on standard wheels, with Michelin Macadam 100's.

Ta....

Stormin Ben · Post by **Stormin Ben** » Mon May 02, 2005 11:36 pm

I'm guessing it wants the wheel circumference, probably in mm

So wheel = 17" diameter = 431.97mm
Height of tyre = 180mm x 55% = 99mm

Total diameter = 99 + 431.97 + 99 = 629.97
Multiply by Pi to give you circumference

Number you are looking for is 1979mm (approximately

)

Ben

cupasoop · Post by **cupasoop** » Tue May 03, 2005 12:16 am

Theres a write up on the front page of this site

http://www.vtr1000.org/faq_bikecomp.htm

essexbloke · Post by **essexbloke** » Tue May 03, 2005 8:42 am

Stormin Ben wrote:I'm guessing it wants the wheel circumference, probably in mm

So wheel = 17" diameter = 431.97mm
Height of tyre = 180mm x 55% = 99mm

Total diameter = 99 + 431.97 + 99 = 629.97
Multiply by Pi to give you circumference

Number you are looking for is 1979mm (approximately )

Ben

Strangly enough, it does sound about right, (but call me stoopid), but where did you get the 55% from? i'm totally lost with this calculation.....

(but i am gonna punch in 1979mm & see what happens.....)

Stormin Ben · Post by **Stormin Ben** » Tue May 03, 2005 11:43 pm

The rear tyre is a 180/55
This means the height of the tyre is 55% of the width (180)

Tada!!!

Ben

essexbloke · Post by **essexbloke** » Wed May 04, 2005 8:22 am

Ah........

think i understand now....(not a chance)

ok then. you gave me the figure according to the rear tyre, but the sigma's fitted to the front, (120/55/17)

whats the figure for that one? (still lost on working it out)

(thanks)

(is this right?) - 120 x 55% = 66

so, 66+431.97 (17")+66 = 563.97

x Pi = 1770 ???????

cupasoop · Post by **cupasoop** » Wed May 04, 2005 10:01 am

Dont forget to take away the number you first thought of

Post by **sirch345** » Wed May 04, 2005 10:35 am

Cupasoop don,t ever change mate, you crack me up

RAINMAKER · Post by **RAINMAKER** » Wed May 04, 2005 1:21 pm

Kaz.......its the cheesey stuff under the foreskin

essexbloke · Post by **essexbloke** » Wed May 04, 2005 1:38 pm

Lol.........

Kaz, it's a little computery thingamyjig (commonly used by cyclists) to give them an accurate speedo/trip.

My trip has died on the storm, so have fitted one instead of shelling out 300+ to Mr Honda... (+ it has the benefit of providing a 100% accurate speedo reading & records max speed travelled, good for bragging down the pub)

course, it's only any good if you calibrate correctly, hence my probs....

PS,
so far i've got a maximum speed of 234mph!!!! beat that!!! (yup, not set up correctly)

L8RGYZ · Post by **L8RGYZ** » Wed May 04, 2005 6:09 pm

essexbloke wrote:Ah........ think i understand now....(not a chance)

ok then. you gave me the figure according to the rear tyre, but the sigma's fitted to the front, (120/55/17)

whats the figure for that one? (still lost on working it out)

(thanks)

(is this right?) - 120 x 55% = 66

so, 66+431.97 (17")+66 = 563.97

x Pi = 1770 ???????

One small, but critical error. Your front tire is a 120/70ZR17.

So... 120 x 70% = 84

Net result is 1883 according to my calc.

essexbloke · Post by **essexbloke** » Wed May 04, 2005 7:43 pm

Doh..... (ha, ha, notice you're the only one to spot the ...err... deliberate mistake......)

Thanks....

Galaxieman · Post by **Galaxieman** » Thu May 05, 2005 4:33 am

Don't forget to divide the final number by the conversion listed in the manual (1.61 according to my manual) or even though you've got the dial set to display 'MPH' you're really displaying KPH. I didn't do that on my Sigma 1200, and my test run around the block netted a max speed of 94 'MPH'. I thought it was a bit off, and a quick review of the manual highlighted my error.

-Jim

essexbloke · Post by **essexbloke** » Thu May 05, 2005 8:28 am

Ah ha.........at last.....

Got home last night, punched in the final correct no. took it out, was reading approx 45mph when i was only doing 30... & 145 @ 100mph

that explains it...........

So then, lets get this right....assuming 1883 is correct, Divided by 1.61 = 1169 as the final figure.........

Do we all agree?

Galaxieman · Post by **Galaxieman** » Thu May 05, 2005 8:58 pm

I've got mine set at 1170, and it seems dead on. I figured it was stupid to try and re-do all the calculations I already did and just went and pulled mine off the bike to check. 1883/1.61 = 1169.565 so 1169 or 1170 are both about right. Have fun with it. Does the 800 have a max speed capture like my 1200 does? Best I've seen is 140.3 since the wreck last summer... Keep us posted.

-Jim