Speedo Tolerances on clios

[Bear Head]

How far out would you say a 55 plate clio 182 would be on the speedo to actual speed?

The reason I ask is if I go through the "your speed is" signs an indicated 32-33 on the speedo is only shown on the "your speed is" sign as 30 mph.

I just wondered if this was because the signs were out or my car?

I've got spacers if that makes a difference. Cheers.

 

[Jack!]

About 10%.

 

[JakeyCUK]

If I out cruise control on and set it to 30mph my speedo shows about 26-27 and my sat nav shows 30-31mph, so yea about 10%

 

[Adamm.]

Spacers wont make a difference lol.

 

[Steven103]

By EU law the speedo can not under read. It can over read, but only by a maximum of 10% + 4 KPH.

http://www.unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/r039r1e.pdf

Of course this goes out the window somewhat when people fit different brand tyres, different size wheels, different inflation pressures etc.

 

[Bear Head]

If I out cruise control on and set it to 30mph my speedo shows about 26-27 and my sat nav shows 30-31mph, so yea about 10%

Yeah this is what I don't get! my speedo shows like 33 if I set it at 30! weird!

Just wanted to know for speed cameras too etc!

 

[MRBILLYUK]

If i set my cruise control to 30mph and go through one of those signs the sign usually shows 28mph, roughly 5% out , that's what my sat nav and also my gps speed camera detector displays . Like wise if is set my cruise control to 80mph the indicated speed on my sat nav and speed camera detector both show 78mph , roughly 2.5% out

 

[Bear Head]

If i set my cruise control to 30mph and go through one of those signs the sign usually shows 28mph, roughly 5% out , that's what my sat nav and also my gps speed camera detector displays . Like wise if is set my cruise control to 80mph the indicated speed on my sat nav and speed camera detector both show 78mph , roughly 2.5% out

Ah okay. I today, went through a mobile speed van at an indicated 32 possibly 33 and was hoping I'd be okay, but speedo Tolerances should leave me okay.

 

[JakeyCUK]

Even if you were doing 33mph I think that's just on the limit to not get a ticket anyway! You'll be fine :smile:

 

[McGherkin]

10% is a fair bit out IMO. The speedo appears to be offset by +2mph and then a <5% error on top of that. At 135mph my speedo was only overreading by 5mph on standard wheels, fairly new tyres, normal pressures etc etc.

 

[Bear Head]

Even if you were doing 33mph I think that's just on the limit to not get a ticket anyway! You'll be fine [emoji2]

Ah that's good, even on mobile units? I was doing probably 32 maybe 33 on the speedo so should have been what? realistically 31 at the most

 

[McGherkin]

ACPO Guidelines is 10%+2mph for a speeding ticket, so in a 30 that's 35mph.

 

[DrR]

Every car ive ever driven, speedo 30, speed sign says about 27.

 

[GrahamS]

pressure wouldn't make a difference to the speedo reading, the rolling radius of the tyre is still the same.
They are over as in all cars. Speed cameras are calibrated accurately though In the average speed camera section on the m25 you could set cruise to 57 and not get done.

 

[Bear Head]

ACPO Guidelines is 10%+2mph for a speeding ticket, so in a 30 that's 35mph.

Ah so that's actual speed too isn't it so that'd be like an indicated 37 ish wouldn't it?

pressure wouldn't make a difference to the speedo reading, the rolling radius of the tyre is still the same.
They are over as in all cars. Speed cameras are calibrated accurately though In the average speed camera section on the m25 you could set cruise to 57 and not get done.

Ah so the mobile units are calibrated as the same as static cameras? Sounds like ill be okay.

I'm genuinely really conscious but as we know the car's are pretty quick and when you're talking it only takes a second and you're jumping up the speedo

 

[N4TH4N]

Every car ive ever driven, speedo 30, speed sign says about 27.

Me too.

 

[N4TH4N]

Ah so that's actual speed too isn't it so that'd be like an indicated 37 ish wouldn't it?

Ah so the mobile units are calibrated as the same as static cameras? Sounds like ill be okay.

I'm genuinely really conscious but as we know the car's are pretty quick and when you're talking it only takes a second and you're jumping up the speedo 😧

You'll be ok. What were the circumstances was it poining towards you or from the rear. Same side of the road?

 

[Bear Head]

You'll be ok Alex. What were the circumstances was it poining towards you or from the rear. Same side of the road?

Haha I'm Toby but the fucker was pointing right at me haha :/

 

[N4TH4N]

Sorry lol ive had a few!! Oh well from your speed you'll be fine in my experience. Ive gone past one at 34 (Speedo) and been fine

 

[Bear Head]

Sorry lol ive had a few!! Oh well from your speed you'll be fine in my experience. Ive gone past one at 34 (Speedo) and been fine

Haha I like how you said it so confidently made me smile at Alex haha eh dear

Ah good. I mean I must have realistically been doing 31 actual speed. definitely wasn't doing 34 or 35.

 

[N4TH4N]

You'll be fine m8

 

[GrahamS]

I drive through 3 speed cameras a day and haven't been done yet. Touch wood!!!
Seriously though speedos always over read by a small amount but speed isn't something which can be argued so the cameras have to be calibrated correctly. All have to be calibrated the same.

 

[warwickstingray]

If you got done with 33 on the speedo in a car then lorries would be piling up the points as tachos and lorry Speedos are pretty much bang on. This is why lorry drivers get cheesed off with people flying into the inside lane at average speed monitored road works and dropping down to anything between 45 and 48mph. some lorry drivers keep it on the limiter through 50's as many like the ones I drive stop at 54. Supermarket trucks seem to be 52 or possibly lower. Don't slow down up hills like my base model rubbish though.

My fiesta XR2 was a full 10% out. Just over 130 was 118 on GPS and a Daewoo matiz is only do 63 at 70!

The ECU will be getting an accurate speed reading it just feeds a bullshit one to the Speedo.

 

[Bear Head]

If you got done with 33 on the speedo in a car then lorries would be piling up the points as tachos and lorry Speedos are pretty much bang on. This is why lorry drivers get cheesed off with people flying into the inside lane at average speed monitored road works and dropping down to anything between 45 and 48mph. some lorry drivers keep it on the limiter through 50's as many like the ones I drive stop at 54. Supermarket trucks seem to be 52 or possibly lower. Don't slow down up hills like my base model rubbish though.

My fiesta XR2 was a full 10% out. Just over 130 was 118 on GPS and a Daewoo matiz is only do 63 at 70!

The ECU will be getting an accurate speed reading it just feeds a bullshit one to the Speedo.

Ah so you think ill be okay then mate? Haha I was doing an indicated 33 maybe 32 but even if it was 34 by the sounds ill still be fine, although like I say it was a mobile van and not a static if this makes a difference?

 

[warwickstingray]

Did the same thing in a Berlingo van a couple of times in the pharmacy job I had before my Class 2 licence and nothing happened. When the Cameras were operated by Separate entities there were stories of zero tolerance polices on the basis that speedos do tend to over read and anyone doing the speed limit on their speedo would never receive a speeding ticket. However it was rare and I've only met one person caught doing 31mph and I'm still not convinced they were telling the truth. Now the police operate a lot of them I would expect it to be highly unlikely they wouldn't be using the 10%+2mph rule. Don't you think it's weird the number people that get caught doing 36mph in a 30? What with speedos over reading by 5-10%, the general guidelines suggesting 10%+2 and people tending to gravitate towards 10mph above the speed limit.

I wouldn't expect a ticket if you were genuinely doing 32-33mph on the speedo. My experience of french cars since 2000 is that they read about 2mph fast at 30. You'd be really unlucky if your local speed team was operating a zero tolerance policy. if you were doing 40ishmph and you jammed the brakes on you'd have more reason to worry. did you actually see the window open? I had some near misses a few years back and as I drove passed the window was closed so I was safe.

We have a police bike with a handheld around the Avon area. He likes the 20's. b*****d!!

Autocar do a speedo accuracy test and I have a full 182 test in the room where my son is napping if I remember i'll dig it out when he wakes up and see what they found.

 

[Steven103]

pressure wouldn't make a difference to the speedo reading, the rolling radius of the tyre is still the same.

The rolling radius is not the same. The circumference is not even the same. Rubber stretches & changes shape under load. A completely flat tyre clearly has a much lower radius. Now extrapolate that to a "half flat" tyre, then 1.8 bar, 2.0 bar, 2.2 bar etc.

 

[Bear Head]

Did the same thing in a Berlingo van a couple of times in the pharmacy job I had before my Class 2 licence and nothing happened. When the Cameras were operated by Separate entities there were stories of zero tolerance polices on the basis that speedos do tend to over read and anyone doing the speed limit on their speedo would never receive a speeding ticket. However it was rare and I've only met one person caught doing 31mph and I'm still not convinced they were telling the truth. Now the police operate a lot of them I would expect it to be highly unlikely they wouldn't be using the 10%+2mph rule. Don't you think it's weird the number people that get caught doing 36mph in a 30? What with speedos over reading by 5-10%, the general guidelines suggesting 10%+2 and people tending to gravitate towards 10mph above the speed limit.

I wouldn't expect a ticket if you were genuinely doing 32-33mph on the speedo. My experience of french cars since 2000 is that they read about 2mph fast at 30. You'd be really unlucky if your local speed team was operating a zero tolerance policy. if you were doing 40ishmph and you jammed the brakes on you'd have more reason to worry. did you actually see the window open? I had some near misses a few years back and as I drove passed the window was closed so I was safe.

We have a police bike with a handheld around the Avon area. He likes the 20's. b*****d!!

Autocar do a speedo accuracy test and I have a full 182 test in the room where my son is napping if I remember i'll dig it out when he wakes up and see what they found.

Ah I've got you mate. I'd be shocked if It was anymore than 33 I glanced down and took note of my speed. I then back off down to 30 and looked up to see the van! haha total coincidence haha

If you've got it that'd be lovely haha I mean it would mean at max I was doing 31 mph realistically so as you say on a 10 percent scheme it would've only been a max 1 or 2 over 30 so I think it be fine.

I'm a worrier lol. I'm only 20 and don't want points.

 

[warwickstingray]

Autocar recorded 31 on the Speedo at a true 30 and 63 at a true 60 and 119 at a try 110.

Like I said I did the same in a berlingo van whose Speedo reads the same as a Clio and nothing happened

Fingers crossed!

 

[Bear Head]

Autocar recorded 31 on the Speedo at a true 30 and 63 at a true 60 and 119 at a try 110.

Ah okay, I think that sounds about right. I believe mines nearer 32 like but I'm not sure as if that's official figures you can't really argue. I will hope for the best. :/

 

[warwickstingray]

As above post says tyre pressures can make a difference so a mph here or there at 30 is easily possible. This is why it's unlikely they would do someone for 31mph. My Sat nav and lorry tachometer disagree by 1mph.

 

[Bear Head]

As above post says tyre pressures can make a difference so a mph here or there at 30 is easily possible. This is why it's unlikely they would do someone for 31mph. My Sat nav and lorry tachometer disagree by 1mph.

Ah I've got you. I think i need to man up its me being a bell. I know they're more bothered about people really not caring about the law etc whereas I really wasn't being a dick.

 

[warwickstingray]

Probably happy that you slowed down showing your paying attention and give a monkeys! Take a breath and just deal with it if the worse happens. I worry too so I now what it's like!

 

[Bear Head]

Probably happy that you slowed down showing your paying attention and give a monkeys! Take a breath and just deal with it if the worse happens. I worry too so I now what it's like!

Haha yeah I suppose. The problem is the car is reasonably modified and at my age is already pushing the insurance envelope so to speak haha. I really never go daft because I can't afford to really lol.

I know you're right I just can't be bothered with a course or points lol but I think i will be okay im sure it'll all work out.

 

[TRH_Racing]

I set my CC at 30 and im at 32 mph ,, i have to have it at 28 to be going 30 !

 

[McGherkin]

Autocar recorded 31 on the Speedo at a true 30 and 63 at a true 60 and 119 at a try 110.!

Really? That's surprising given the results from earlier. Perhaps I'm just lucky!

 

[Bear Head]

I set my CC at 30 and im at 32 mph ,, i have to have it at 28 to be going 30 !

No mate the cruise control does actual speed so if you're doing 30 cc and your clocks say 32 you're really only doing 30

 

[Bear Head]

Really? That's surprising given the results from earlier. Perhaps I'm just lucky!

What do you mean mate?

 

[warwickstingray]

He means that his own results were different to that (see first few posts) By quite a margin at higher speeds. Autocar tend to use VBOX equipment which is accurate enough or should be. Autocar are not infallable and I was surprised at their results considering I'm sure my Cup was showing a bit under 120mph when I hit the limiter in 4th at combe and the Phase 2 gearing and the sport tyre options should give 112-114mph at 7000rpm in 4th which is closer to McGherkins findings.

Either way your still out the known danger zone.

Autocar did claim 5.8 30-70 through the gear by using the standing start times and not booting it in 2nd and 3rd so maybe the article was written in a rush!

 

[McGherkin]

What do you mean mate?

Well that implies an 8.18% error (9mph at 110mph), but that means that at 135mph the speedo would be reading 11mph over, i.e. 146mph. I tested mine as only being 5mph out at 135mph, an error of 3.7%.

However, given that my speedo is 2mph out at 30mph (6.7%), I'd say that the speedo is offset by circa 2mph, and a much smaller error is seen on top of that.


None of this is actually relevant to your own camera incident, you're fine

 

[Bear Head]

Well that implies an 8.18% error (9mph at 110mph), but that means that at 135mph the speedo would be reading 11mph over, i.e. 146mph. I tested mine as only being 5mph out at 135mph, an error of 3.7%.

However, given that my speedo is 2mph out at 30mph (6.7%), I'd say that the speedo is offset by circa 2mph, and a much smaller error is seen on top of that.


None of this is actually relevant to your own camera incident, you're fine

Hahaha right so if everyone and their findings suggest at 33 im only really doing 31 ill be sound. I feel better others agree. I'm so careful I drive the car like an old man tbh so I'm glad I aren't gonna get fucked over for a petty number when w*****s fly through in audis at 40 everywhere anyway.