Speedo accuracy

D

David French

Guest

• Jul 4, 2004

• #1

I'm thinking of moving to a slightly larger tyre size. 5% larger in fact.
My speedo currently reads about 5% fast, so the larger tyres would
compensate for this & the speedo should read accurate.

But, if were to throw caution to the wind and go to 10% larger tyres, my
speedo would then read about 5% slow. How does this leave me from an MOT
point of view - ie, would I need to recalibrate the speedo? What's the
allowed tolerance for MOT purposes?

Thanks,
David

 

M

mark solesbury

Guest

• Jul 4, 2004

• #2

Speedo is not part of the MOT test.


"David French" <[email protected]> wrote in message
news:[email protected]...
> I'm thinking of moving to a slightly larger tyre size. 5% larger in fact.
> My speedo currently reads about 5% fast, so the larger tyres would
> compensate for this & the speedo should read accurate.
>
> But, if were to throw caution to the wind and go to 10% larger tyres, my
> speedo would then read about 5% slow. How does this leave me from an MOT
> point of view - ie, would I need to recalibrate the speedo? What's the
> allowed tolerance for MOT purposes?
>
> Thanks,
> David
>
>

 

D

David French

Guest

• Jul 4, 2004

• #3

"mark solesbury" <[email protected]> wrote in message
news:[email protected]...
> Speedo is not part of the MOT test.

Bonza. Thanks.

 

A

Alex

Guest

• Jul 5, 2004

• #4

On Sun, 04 Jul 2004 21:20:26 GMT, "mark solesbury"
<[email protected]> wrote:

>Speedo is not part of the MOT test.
>

However, a correctly reading speedo is a requirement of the
Construction and Use regs, meaning you could be fined if a VOSA
official takes your vehicle for an inspection. And it is not a defence
in law against speeding either.

Alex

 

T

Tom Woods

Guest

• Jul 5, 2004

• #5

On Sun, 04 Jul 2004 23:31:45 GMT, Alex <[email protected]>
wrote:

>However, a correctly reading speedo is a requirement of the
>Construction and Use regs, meaning you could be fined if a VOSA
>official takes your vehicle for an inspection. And it is not a defence
>in law against speeding either.

Does a GPS count as a working speedo in the eyes of the VOSA people?

My speedo is dead at the moment, but ive got a gps fixed onto the dash
instead. GPS tis probably more accurate anyhow!

 

A

Andrew Renshaw

Guest

• Jul 5, 2004

• #6

Not a chance - you have to have a working speedo - GPS would not count. You
would be looking at maybe £30 fine after a Court Appearance.

A

"Tom Woods" <[email protected]> wrote in message
news:[email protected]...
> On Sun, 04 Jul 2004 23:31:45 GMT, Alex <[email protected]>
> wrote:
>
> >However, a correctly reading speedo is a requirement of the
> >Construction and Use regs, meaning you could be fined if a VOSA
> >official takes your vehicle for an inspection. And it is not a defence
> >in law against speeding either.
>
> Does a GPS count as a working speedo in the eyes of the VOSA people?
>
> My speedo is dead at the moment, but ive got a gps fixed onto the dash
> instead. GPS tis probably more accurate anyhow!
>

 

T

Tom Woods

Guest

• Jul 5, 2004

• #7

On Mon, 05 Jul 2004 11:40:57 GMT, "Andrew Renshaw" <andrew.hart.i hate
[email protected]> wrote:

>Not a chance - you have to have a working speedo - GPS would not count. You
>would be looking at maybe £30 fine after a Court Appearance.
>
I hate speedo's. Never work properly in my landy! I shall put it on
the list of jobs right after fixing the exhaust back together
properly!
The speedo worked perfectly for a couple of months after my last
rebuild efforts. It was even accurate! It had a new cable and head
then too.

 

S

SpamTrapSeeSig

Guest

• Jul 6, 2004

• #8

In article <[email protected]>, Tom Woods
<[email protected]> writes
>On Mon, 05 Jul 2004 11:40:57 GMT, "Andrew Renshaw" <andrew.hart.i hate
>[email protected]> wrote:
>
>>Not a chance - you have to have a working speedo - GPS would not count. You
>>would be looking at maybe £30 fine after a Court Appearance.
>>
>I hate speedo's. Never work properly in my landy! I shall put it on
>the list of jobs right after fixing the exhaust back together
>properly!
>The speedo worked perfectly for a couple of months after my last
>rebuild efforts. It was even accurate! It had a new cable and head
>then too.

A bicycle speedometer costs under 10UKP and usually is adjustable for
both wheel diameter and miles/kilometres. I can't imagine there is a
requirement for a *specific* type of speedometer to be fitted, although
you might have to rig some sort of night time illumination for it.

I bought some for the children's bikes that were around 5ukp per set.
they'd need to be modified for the Landy (mainly by lengthening the
cable, but it's readily do-able - it's only a reed switch at the far
end). Use screened, audio-type cable to minimise ignition interference
(but mine's Diesel, so even that doesn't matter!). Personally, I'd fit
it to a rear wheel, or better still the rear prop shaft close to where
it exits the centre diff. You only have to glue a tiny magnet on
somewhere to actuate the switch. If you know the rear diff. ratio you
can calculate the effective wheel diameter easily.

Gotta be worth looking at the ones in Asda...

(*now* you can laugh)

Regards,

Simonm.
--
simonm|at|muircom|dot|demon|.|c|oh|dot|u|kay
SIMON MUIR, UK INDEPENDENCE PARTY, BRISTOL www.ukip.org
EUROPEANS AGAINST THE EU www.members.aol.com/eurofaq
GT250A'76 R80/RT'86 110CSW TD'88 www.kc3ltd.co.uk/profile/eurofollie/

 

S

Simon Isaacs

Guest

• Jul 6, 2004

• #9

"SpamTrapSeeSig" <[email protected]> wrote in message
news[email protected]...
> In article <[email protected]>, Tom Woods
> <[email protected]> writes
> >On Mon, 05 Jul 2004 11:40:57 GMT, "Andrew Renshaw" <andrew.hart.i hate
> >[email protected]> wrote:
> >
> >>Not a chance - you have to have a working speedo - GPS would not count.
You
> >>would be looking at maybe £30 fine after a Court Appearance.
> >>
> >I hate speedo's. Never work properly in my landy! I shall put it on
> >the list of jobs right after fixing the exhaust back together
> >properly!
> >The speedo worked perfectly for a couple of months after my last
> >rebuild efforts. It was even accurate! It had a new cable and head
> >then too.
>
> A bicycle speedometer costs under 10UKP and usually is adjustable for
> both wheel diameter and miles/kilometres. I can't imagine there is a
> requirement for a *specific* type of speedometer to be fitted, although
> you might have to rig some sort of night time illumination for it.
>
> I bought some for the children's bikes that were around 5ukp per set.
> they'd need to be modified for the Landy (mainly by lengthening the
> cable, but it's readily do-able - it's only a reed switch at the far
> end). Use screened, audio-type cable to minimise ignition interference
> (but mine's Diesel, so even that doesn't matter!). Personally, I'd fit
> it to a rear wheel, or better still the rear prop shaft close to where
> it exits the centre diff. You only have to glue a tiny magnet on
> somewhere to actuate the switch. If you know the rear diff. ratio you
> can calculate the effective wheel diameter easily.
>
> Gotta be worth looking at the ones in Asda...
>
> (*now* you can laugh)
>

I know someone who failed SVA on a kit car because they used this speedo,
and it got to about 60ish and stopped reading. The speedo has to be capable
of displaying the top speed of the vehicle.

Also, when you change the batteries, if you leave it too long, the mileage
disappears, and it can be reset.

Probably be worth talking to a friendly MOT tester....

--
Simon Isaacs

Peterborough 4x4 Club Vice Chairman, Newsletter Editor and Webmaster (how
much more....)
3.5V8 100" Hybrid, now LPG converted
Part owner of 1976 S3 LWT, currently under restoration
Suzuki SJ410 (Girlfriend's) 3" lift kit fitted, body
shell now restored and mounted on chassis, waiting on a windscreen and MOT
Series 3 88" Rolling chassis...what to do next
1993 200 TDi Discovery (the Pug 106 is dead, long live the Pug)

Peterborough 4x4 Club http://www.peterborough4x4.co.uk

 

P

Phil Gardiner

Guest

• Jul 6, 2004

• #10

Andrew Renshaw wrote:

> Not a chance - you have to have a working speedo - GPS would not count. You
> would be looking at maybe £30 fine after a Court Appearance.
>
> A
>
> "Tom Woods" <[email protected]> wrote in message
> news:[email protected]...
>
>>On Sun, 04 Jul 2004 23:31:45 GMT, Alex <[email protected]>
>>wrote:
>>
>>
>>>However, a correctly reading speedo is a requirement of the
>>>Construction and Use regs, meaning you could be fined if a VOSA
>>>official takes your vehicle for an inspection. And it is not a defence
>>>in law against speeding either.
>>
>>Does a GPS count as a working speedo in the eyes of the VOSA people?
>>
>>My speedo is dead at the moment, but ive got a gps fixed onto the dash
>>instead. GPS tis probably more accurate anyhow!
>>
>
>
>
The main reason for a GPS not being a valid speed measuring device is
that it doesn't work in tunnels. On a slightly less major point the
multipath radio propagation effects can effect the positional accuracy
on a sample to sample basis such that the speed could be significantly
in error.

--
Phil Gardiner
Please don't forget to check the alt.fan.landrover FAQ before posting
your question - http://www.aflfaq.dyndns.info

 

P

Phil Gardiner

Guest

• Jul 6, 2004

• #11

Simon Isaacs wrote:

> "SpamTrapSeeSig" <[email protected]> wrote in message
> news[email protected]...
>
>>In article <[email protected]>, Tom Woods
>><[email protected]> writes
>>
>>>On Mon, 05 Jul 2004 11:40:57 GMT, "Andrew Renshaw" <andrew.hart.i hate
>>>[email protected]> wrote:
>>>
>>>
>>>>Not a chance - you have to have a working speedo - GPS would not count.
>
> You
>
>>>>would be looking at maybe £30 fine after a Court Appearance.
>>>>
>>>
>>>I hate speedo's. Never work properly in my landy! I shall put it on
>>>the list of jobs right after fixing the exhaust back together
>>>properly!
>>>The speedo worked perfectly for a couple of months after my last
>>>rebuild efforts. It was even accurate! It had a new cable and head
>>>then too.
>>
>>A bicycle speedometer costs under 10UKP and usually is adjustable for
>>both wheel diameter and miles/kilometres. I can't imagine there is a
>>requirement for a *specific* type of speedometer to be fitted, although
>>you might have to rig some sort of night time illumination for it.
>>
>>I bought some for the children's bikes that were around 5ukp per set.
>>they'd need to be modified for the Landy (mainly by lengthening the
>>cable, but it's readily do-able - it's only a reed switch at the far
>>end). Use screened, audio-type cable to minimise ignition interference
>>(but mine's Diesel, so even that doesn't matter!). Personally, I'd fit
>>it to a rear wheel, or better still the rear prop shaft close to where
>>it exits the centre diff. You only have to glue a tiny magnet on
>>somewhere to actuate the switch. If you know the rear diff. ratio you
>>can calculate the effective wheel diameter easily.
>>
>>Gotta be worth looking at the ones in Asda...
>>
>>(*now* you can laugh)
>>
>
>
> I know someone who failed SVA on a kit car because they used this speedo,
> and it got to about 60ish and stopped reading. The speedo has to be capable
> of displaying the top speed of the vehicle.
>
> Also, when you change the batteries, if you leave it too long, the mileage
> disappears, and it can be reset.
>
> Probably be worth talking to a friendly MOT tester....
>
> --
> Simon Isaacs
>
> Peterborough 4x4 Club Vice Chairman, Newsletter Editor and Webmaster (how
> much more....)
> 3.5V8 100" Hybrid, now LPG converted
> Part owner of 1976 S3 LWT, currently under restoration
> Suzuki SJ410 (Girlfriend's) 3" lift kit fitted, body
> shell now restored and mounted on chassis, waiting on a windscreen and MOT
> Series 3 88" Rolling chassis...what to do next
> 1993 200 TDi Discovery (the Pug 106 is dead, long live the Pug)
>
> Peterborough 4x4 Club http://www.peterborough4x4.co.uk
>
>
Not quite true. The speedo has to be capable of reading to 70mph on an
SVA test and (from memory) within -0% to +10% of actual speed. I know
this as I have the SVA speedo test certificate for my non land rover
vehicle (it was very marginal as at 70mph it was reading 76mph). As the
SVA is a subset of the Construction and Use Act i suspect that providing
the bike speedo can read up to 70mph then you will be complying with the
act. There is no requirement for any sort of type approval for a speedo.

--
Phil Gardiner
Please don't forget to check the alt.fan.landrover FAQ before posting
your question - http://www.aflfaq.dyndns.info

 

M

mark solesbury

Guest

• Jul 4, 2004

• #12

Speedo is not part of the MOT test.


"David French" <[email protected]> wrote in message
news:[email protected]...
> I'm thinking of moving to a slightly larger tyre size. 5% larger in fact.
> My speedo currently reads about 5% fast, so the larger tyres would
> compensate for this & the speedo should read accurate.
>
> But, if were to throw caution to the wind and go to 10% larger tyres, my
> speedo would then read about 5% slow. How does this leave me from an MOT
> point of view - ie, would I need to recalibrate the speedo? What's the
> allowed tolerance for MOT purposes?
>
> Thanks,
> David
>
>

 

D

David French

Guest

• Jul 4, 2004

• #13

"mark solesbury" <[email protected]> wrote in message
news:[email protected]...
> Speedo is not part of the MOT test.

Bonza. Thanks.

 

A

Alex

Guest

• Jul 5, 2004

• #14

On Sun, 04 Jul 2004 21:20:26 GMT, "mark solesbury"
<[email protected]> wrote:

>Speedo is not part of the MOT test.
>

However, a correctly reading speedo is a requirement of the
Construction and Use regs, meaning you could be fined if a VOSA
official takes your vehicle for an inspection. And it is not a defence
in law against speeding either.

Alex

 

A

Andrew Renshaw

Guest

• Jul 5, 2004

• #15

Not a chance - you have to have a working speedo - GPS would not count. You
would be looking at maybe £30 fine after a Court Appearance.

A

"Tom Woods" <[email protected]> wrote in message
news:[email protected]...
> On Sun, 04 Jul 2004 23:31:45 GMT, Alex <[email protected]>
> wrote:
>
> >However, a correctly reading speedo is a requirement of the
> >Construction and Use regs, meaning you could be fined if a VOSA
> >official takes your vehicle for an inspection. And it is not a defence
> >in law against speeding either.
>
> Does a GPS count as a working speedo in the eyes of the VOSA people?
>
> My speedo is dead at the moment, but ive got a gps fixed onto the dash
> instead. GPS tis probably more accurate anyhow!
>

 

T

Tom Woods

Guest

• Jul 5, 2004

• #16

On Mon, 05 Jul 2004 11:40:57 GMT, "Andrew Renshaw" <andrew.hart.i hate
[email protected]> wrote:

>Not a chance - you have to have a working speedo - GPS would not count. You
>would be looking at maybe £30 fine after a Court Appearance.
>
I hate speedo's. Never work properly in my landy! I shall put it on
the list of jobs right after fixing the exhaust back together
properly!
The speedo worked perfectly for a couple of months after my last
rebuild efforts. It was even accurate! It had a new cable and head
then too.

 

S

Simon Isaacs

Guest

• Jul 6, 2004

• #17

"SpamTrapSeeSig" <[email protected]> wrote in message
news[email protected]...
> In article <[email protected]>, Tom Woods
> <[email protected]> writes
> >On Mon, 05 Jul 2004 11:40:57 GMT, "Andrew Renshaw" <andrew.hart.i hate
> >[email protected]> wrote:
> >
> >>Not a chance - you have to have a working speedo - GPS would not count.
You
> >>would be looking at maybe £30 fine after a Court Appearance.
> >>
> >I hate speedo's. Never work properly in my landy! I shall put it on
> >the list of jobs right after fixing the exhaust back together
> >properly!
> >The speedo worked perfectly for a couple of months after my last
> >rebuild efforts. It was even accurate! It had a new cable and head
> >then too.
>
> A bicycle speedometer costs under 10UKP and usually is adjustable for
> both wheel diameter and miles/kilometres. I can't imagine there is a
> requirement for a *specific* type of speedometer to be fitted, although
> you might have to rig some sort of night time illumination for it.
>
> I bought some for the children's bikes that were around 5ukp per set.
> they'd need to be modified for the Landy (mainly by lengthening the
> cable, but it's readily do-able - it's only a reed switch at the far
> end). Use screened, audio-type cable to minimise ignition interference
> (but mine's Diesel, so even that doesn't matter!). Personally, I'd fit
> it to a rear wheel, or better still the rear prop shaft close to where
> it exits the centre diff. You only have to glue a tiny magnet on
> somewhere to actuate the switch. If you know the rear diff. ratio you
> can calculate the effective wheel diameter easily.
>
> Gotta be worth looking at the ones in Asda...
>
> (*now* you can laugh)
>

I know someone who failed SVA on a kit car because they used this speedo,
and it got to about 60ish and stopped reading. The speedo has to be capable
of displaying the top speed of the vehicle.

Also, when you change the batteries, if you leave it too long, the mileage
disappears, and it can be reset.

Probably be worth talking to a friendly MOT tester....

--
Simon Isaacs

Peterborough 4x4 Club Vice Chairman, Newsletter Editor and Webmaster (how
much more....)
3.5V8 100" Hybrid, now LPG converted
Part owner of 1976 S3 LWT, currently under restoration
Suzuki SJ410 (Girlfriend's) 3" lift kit fitted, body
shell now restored and mounted on chassis, waiting on a windscreen and MOT
Series 3 88" Rolling chassis...what to do next
1993 200 TDi Discovery (the Pug 106 is dead, long live the Pug)

Peterborough 4x4 Club http://www.peterborough4x4.co.uk

 

P

Phil Gardiner

Guest

• Jul 6, 2004

• #18

Andrew Renshaw wrote:

> Not a chance - you have to have a working speedo - GPS would not count. You
> would be looking at maybe £30 fine after a Court Appearance.
>
> A
>
> "Tom Woods" <[email protected]> wrote in message
> news:[email protected]...
>
>>On Sun, 04 Jul 2004 23:31:45 GMT, Alex <[email protected]>
>>wrote:
>>
>>
>>>However, a correctly reading speedo is a requirement of the
>>>Construction and Use regs, meaning you could be fined if a VOSA
>>>official takes your vehicle for an inspection. And it is not a defence
>>>in law against speeding either.
>>
>>Does a GPS count as a working speedo in the eyes of the VOSA people?
>>
>>My speedo is dead at the moment, but ive got a gps fixed onto the dash
>>instead. GPS tis probably more accurate anyhow!
>>
>
>
>
The main reason for a GPS not being a valid speed measuring device is
that it doesn't work in tunnels. On a slightly less major point the
multipath radio propagation effects can effect the positional accuracy
on a sample to sample basis such that the speed could be significantly
in error.

--
Phil Gardiner
Please don't forget to check the alt.fan.landrover FAQ before posting
your question - http://www.aflfaq.dyndns.info

 

P

Phil Gardiner

Guest

• Jul 6, 2004

• #19

Simon Isaacs wrote:

> "SpamTrapSeeSig" <[email protected]> wrote in message
> news[email protected]...
>
>>In article <[email protected]>, Tom Woods
>><[email protected]> writes
>>
>>>On Mon, 05 Jul 2004 11:40:57 GMT, "Andrew Renshaw" <andrew.hart.i hate
>>>[email protected]> wrote:
>>>
>>>
>>>>Not a chance - you have to have a working speedo - GPS would not count.
>
> You
>
>>>>would be looking at maybe £30 fine after a Court Appearance.
>>>>
>>>
>>>I hate speedo's. Never work properly in my landy! I shall put it on
>>>the list of jobs right after fixing the exhaust back together
>>>properly!
>>>The speedo worked perfectly for a couple of months after my last
>>>rebuild efforts. It was even accurate! It had a new cable and head
>>>then too.
>>
>>A bicycle speedometer costs under 10UKP and usually is adjustable for
>>both wheel diameter and miles/kilometres. I can't imagine there is a
>>requirement for a *specific* type of speedometer to be fitted, although
>>you might have to rig some sort of night time illumination for it.
>>
>>I bought some for the children's bikes that were around 5ukp per set.
>>they'd need to be modified for the Landy (mainly by lengthening the
>>cable, but it's readily do-able - it's only a reed switch at the far
>>end). Use screened, audio-type cable to minimise ignition interference
>>(but mine's Diesel, so even that doesn't matter!). Personally, I'd fit
>>it to a rear wheel, or better still the rear prop shaft close to where
>>it exits the centre diff. You only have to glue a tiny magnet on
>>somewhere to actuate the switch. If you know the rear diff. ratio you
>>can calculate the effective wheel diameter easily.
>>
>>Gotta be worth looking at the ones in Asda...
>>
>>(*now* you can laugh)
>>
>
>
> I know someone who failed SVA on a kit car because they used this speedo,
> and it got to about 60ish and stopped reading. The speedo has to be capable
> of displaying the top speed of the vehicle.
>
> Also, when you change the batteries, if you leave it too long, the mileage
> disappears, and it can be reset.
>
> Probably be worth talking to a friendly MOT tester....
>
> --
> Simon Isaacs
>
> Peterborough 4x4 Club Vice Chairman, Newsletter Editor and Webmaster (how
> much more....)
> 3.5V8 100" Hybrid, now LPG converted
> Part owner of 1976 S3 LWT, currently under restoration
> Suzuki SJ410 (Girlfriend's) 3" lift kit fitted, body
> shell now restored and mounted on chassis, waiting on a windscreen and MOT
> Series 3 88" Rolling chassis...what to do next
> 1993 200 TDi Discovery (the Pug 106 is dead, long live the Pug)
>
> Peterborough 4x4 Club http://www.peterborough4x4.co.uk
>
>
Not quite true. The speedo has to be capable of reading to 70mph on an
SVA test and (from memory) within -0% to +10% of actual speed. I know
this as I have the SVA speedo test certificate for my non land rover
vehicle (it was very marginal as at 70mph it was reading 76mph). As the
SVA is a subset of the Construction and Use Act i suspect that providing
the bike speedo can read up to 70mph then you will be complying with the
act. There is no requirement for any sort of type approval for a speedo.

--
Phil Gardiner
Please don't forget to check the alt.fan.landrover FAQ before posting
your question - http://www.aflfaq.dyndns.info

 

D

David French

Guest

• Jul 4, 2004

• #20

"mark solesbury" <[email protected]> wrote in message
news:[email protected]...
> Speedo is not part of the MOT test.

Bonza. Thanks.