J Alderman
|
| posted on 29/6/04 at 12:05 PM |
|
|
SVA and speed
Hi Chaps
Just had my SVA yesterday morning at Leighton Buzzard, and have unfortunately failed on the calibration of the speedo.
I have a bike speedo fitted ( CATEYE Astrale 8 ) It is supposed to be good for up to 180 mph!.
My question is has anyone had any sucsess with bike speedo's in the SVA test. If so where is the best place to put the pickup, mine is on the
right drive shaft. Would the diff input flange be a better place
Regards
James
|
|
|
|
|
andyps
|
| posted on 29/6/04 at 12:26 PM |
|
|
Not tried it myself - but have you calibrated it correctly for wheel/tyre radius when mounted on the car - the radius is smaller then because of the
weight squashing the tyre. This even applies for accuracy when using that type of speedo on a bike.
Andy
An expert is someone who knows more and more about less and less
|
|
|
J Alderman
|
| posted on 29/6/04 at 12:40 PM |
|
|
Yep
The correct circumference has been input,
We spent an hour testing various sizes to try and get past. but the changes we made did not seem to correlate with the test results.
I thinking that it could be something to do with fact that the rolling road used in the test does not take into account the different wheel speeds
caused by a slightly sticky diff etc
James
|
|
|
theconrodkid
|
| posted on 29/6/04 at 01:09 PM |
|
|
how many magnets you got,that will upset it at different speeds
who cares who wins
pass the pork pies
|
|
|
greggors84
|
| posted on 29/6/04 at 03:40 PM |
|
|
How were they at Leighton Buzzard? As thats where i intent to have my SVA test.
Chris
The Magnificent 7!
|
|
|
Lightning
|
| posted on 29/6/04 at 04:01 PM |
|
|
Mine was ok on the sva mounted on one of the rear drive shafts.
This was the second attempt though.
The first speedo from halfords although was supposed to be good for 120 mph on closer inspection this was for a largish wheel size. As the speed
increased I think the pickup could not differentate between pulses ie too fast as the road wheel are smaller and hence greater revolutions.
I used a VDO C10 as suggested by Hellfire and this was OK
Dont know if this is of any use,
Steve
|
|
|
J Alderman
|
| posted on 29/6/04 at 04:12 PM |
|
|
Thanks Chaps
The lads at Leighton Buzzard were ace.
Dave & Kev I think they were really helpfull and allowed us to alter things as we went. They were unhappy that we could not get it through.
I had hear bad things about the place but this was from a person who obvouosly not read the SVA manual.
Lighting
That is interesting.
I am a bit confused as to what to do i.e. mount the sender on the diff flange or get a new cike speedo ?
James.
|
|
|
spunky
|
| posted on 29/6/04 at 04:32 PM |
|
|
My tuppence worth.
Didn't use a bike speedo for SVA but fitted one to aid callibration of the Telemetrix jobby.
mounted the sensor on the rear calliper and the magnet on the wheel rim. Bigger diameter equals more accuracy and less margin for error.
To get an accurate circumferance, mark the tyre and road/drive/garage floor and rool forward one revolution and mark floor again then measure.
John
The reckless man may not live as long......
But the cautious man does not live at all.....
|
|
|
Peteff
|
| posted on 29/6/04 at 04:34 PM |
|
|
What we did.
Halfords speedo using a fridge magnet fixed on the inside of the rear wheel rim with JBWeld and a cable extended with speaker wire. Pickup on a
bracket from the bottom damper mount and it was spot on using the tyre circumference measured with a piece of string. Stick it where you want after
it's through as long as it reads close enough.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
|
|
|
andyps
|
| posted on 29/6/04 at 07:16 PM |
|
|
Another thought about the radius - if it is sat between two rollers (I am guessing it is a bit like the brake test machine at an MOT station) what
does that do to the deflection of the tyre?
Andy
An expert is someone who knows more and more about less and less
|
|
|
NS Dev
|
| posted on 30/6/04 at 07:53 AM |
|
|
Peteff, what about illumination of the bike speedo? Though about using an LED, did you do this?
|
|
|
Peteff
|
| posted on 30/6/04 at 09:07 AM |
|
|
A numberplate light from the Sierra pointing back at the speedo from the top of the steering column, nothing high tech.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
|
|
|
NS Dev
|
| posted on 30/6/04 at 06:15 PM |
|
|
Sounds fair enough, I'll relax then!!
|
|
|
