Why aren't tyre gauges certified and tested?

[Albino]

I normally use my own gauge as like most sane bikers I know that petrol station gauges are usually innacurate. Unfortunately though I was going for a fang in the weekend and had the need to rely on a petrol station gauge. I called off my ride because it didn't feel right and I didn't trust the handling. Not happy.

If i had crashed it would have been my fault. But I know better than people like my mother who puts air in her car tyres blindly accepting that the gauge is accurate even though it might be 10psi out.

As we all know the correct tyre pressure is important for the handling of a motor vehicle.

So why aren't these gauges certified and tested? Any one?

And does anyone know if the SCU checks tyre pressures after serious crashes? And if so, what is the percantage of crashes where incorrect pressure was a factor?



Cheer.

[hellnback]

Yeah the SCU do check tyre pressures after a serious crash. Not sure what the percentages would be of that being the main cause of a crash, but after watching the programme on tv most of them were from driver error.
As for the cert and testing of a pump, fuck knows? Obviously no-one thinks it's important enough to warrant it... or that it's the owners responsibility not the garage?

[slowpoke]

So why aren't these gauges certified and tested? Any one?



Because no-one is prepared to pay for it, least of all 99.9% of patrons.
What would be the point anyway, how many times do you see people just drop the gauge etc on the forecourt concrete?

[bert_is_evil]

How do you test if your own guage is accurate? I got a michellin one from Motorad a while back thinking "hey, it's a tyre brand so it must be ok" but now the indicator needle only goes down as far as 10psi (I carry it under my seat, perhaps that's why?) - don't know whether to just add 10psi onto the reading or bin it and get another one.

[Paul in NZ]

Are you telling me you didn't ride because you thought the servo guage could have been 10% out??????

Jesus christ - no wonder I'm happy with my old piles of shit, if it's within a few pounds it's fine. I'd never ride any place if i had to be that accurate about it....

[dasser]

Albino, Who said all petrol station gauges are not accurate ?
Who said the brand new gauge you buy from some shop are any better ?
The only way to know for sure is to have your gauge calibrated by
a IANZ laboratory. You might get some change out of a hundred maybe.
but you will have a nice calibration report of you gauge.
Petrol stations would pass this cost on and it would no longer be free air.
I think most petrol service station gauges are of the 1 % type gauges.
and I would guess the newer digital gauges better than that. 0.1 %

How many motorcycle owner's use the manufacture specs when pumping up their tyre's or is it just abit of a guess?? 30 psi she's right.

Like hellnback said most crash's from wrong air pressure in tyres would be very small if any.

To find a IANZ lab goto www.ianz.govt.nz
If you get stuck PM me and I'll help find a IANZ lab close to you.

[janno]

Gauges are extremely delicate. If you've ever bought your own diving gear or gas bottle gear you soon learn to treat them like glass.

So the servo ones getting happily dropped and knocked about day in day out - it's a wonder any of them read within cooee at all.

[vifferman]

Even though I've got an accurate gauge at home, I carry a pen-type gauge in my jacket pocket anyway. I don't generally use the servo tyre pumps because I can't fit the stiupid fitting on either tyre without severely bending the valve stem to one side. I have yet to find a service station tyre thingo that fits any bike I've owned.

[Albino]

Are you telling me you didn't ride because you thought the servo guage could have been 10% out??????



Ha - yeah, was recovering from the flu and was going for a fang to clear the cobwebs. Bike didn't feel right so i decided to not push it.

Dasser - good points. I know one of the stations gauges was out because i went 20m down the road and tried another one which gave a 12psi difference. Maybe they were both only 6psi out :shrug:

I just thought that with all this going on about road safety that there might be some emphasis on something other than enforcement and speed reduction. Wait - man, am i that dumb?

[Blackbird]

From personal experience, the Accugage brand are accurate to within 1psi or so - have had my 2 checked on our calibration bench at work. Anything with bourdon tube construction (like a barometer) is likely to be pretty accurate. However, because of the construction, they're also more expensive.

With respect to Paul's commenta about tyre pressures, I didn't care too much when I had lighter bikes (err... my old Triumph or GB 400 for example), but the Blackbird is quite sensitive. 42 psi F/R are the recommended cold pressures, and I can feel the handling change if it's around 38 psi for normal road riding.

[vifferman]

From personal experience, the Accugage brand are accurate to within 1psi or so - have had my 2 checked on our calibration bench at work. Anything with bourdon tube construction (like a barometer) is likely to be pretty accurate. However, because of the construction, they're also more expensive.
Mine was about $32, IIRC.


With respect to Paul's commenta about tyre pressures, I didn't care too much when I had lighter bikes (err... my old Triumph or GB 400 for example), but the Blackbird is quite sensitive. 42 psi F/R are the recommended cold pressures, and I can feel the handling change if it's around 38 psi for normal road riding.
Yeah, I can notice if the front tyre (with its cracked'n'leaky valvestem) drops 1 PSI, as it starts to wander, and the bike flops into corners if it gets to about 35.

[Cajun]

i have a small air compressor at home, and check my pressures at home while tires are still cold

I also use a digital gauge, to double check them (since i know my supercheap air pump gauge is out by about 3-4psi compared to digital)

But you can pick up a small compressor kit for wee over $100 i would think, should look at picking one up and doing it yaself from home

[NordieBoy]

A digital gauge goes with me on the bike.
My Mitre10 tyre filler attachment thingy for my compressor is about 1psi out from my digital.
On the DR there's not a lot of difference in handling from 20psi to 36psi.
36 for road and 20 for dirt.

There is a big difference in tyre wear though.

[slowpoke]

You could start a whole thread on tyre pressures.
Personally I reckon you shouldn't be too anal about it....I mean do people adjust tyre pressures depending on the prevailing weather conditions? A tyre at 38psi is going to react quite differently in 5deg C conditons as opposed to 30deg C, not to mention whether you are trundling through traffic or whoopin' through the twisties.
As per the Robert Taylor suspension thread ambient temperature also has a major effect on suspension performance, yet how many people adjust suspension depending on ambient temperature?
Given that suspension does wear, how many people go through a process of optimising suspension on a regular basis?
Lets be realistic about this, a couple of psi either way is hardly going to be noticeable for general road riding given the variables involved.

[MSTRS]

Lets be realistic about this, a couple of psi either way is hardly going to be noticeable for general road riding given the variables involved.

No it's not. However 10/15psi will. And that may not be not uncommon from servo gauges.
Advice is to carry one you trust at (whatever the reading you settle on) and use that to set your tyres when using servo airpumps. Your own gauge may also be wildly inaccurate, but as long as it gives the same reading at the same pressure each time and you are comfortable with that pressure, so what...

[Paul in NZ]

You could start a whole thread on tyre pressures.
Personally I reckon you shouldn't be too anal about it....I mean do people adjust tyre pressures depending on the prevailing weather conditions? A tyre at 38psi is going to react quite differently in 5deg C conditons as opposed to 30deg C, not to mention whether you are trundling through traffic or whoopin' through the twisties. .


I agree....

[Kickaha]

And does anyone know if the SCU checks tyre pressures after serious crashes?

Yes they do, and the results from some of them are quite interesting

We have our gauges checked and calibrated yearly, but the general public don't normally get to use them, it cost us about $180 to get three gauges checked

[kiwi cowboy]

Because no-one is prepared to pay for it, least of all 99.9% of patrons.
What would be the point anyway, how many times do you see people just drop the gauge etc on the forecourt concrete?

shell station in mosgiel dunedin has a gauge that u didigitly dial in the presure u want in a pannel on the wall then u just put the end on the valve and it beeps [from memory] when preasure is up and has a fitting that u can get on bikes.seemed to be pretty accurate an safe from abuse.:yes:

[Kickaha]

.seemed to be pretty accurate an safe from abuse.:yes:

A common misconception that I see is that a digital gauge is more accurate than a analog gauge, any gauge is only as accurate as the guy who calibrated it

[sunhuntin]

we had our airhose removed by the boss. people would just throw it on the ground, where it would then get run over or stepped on. my first year, we spent something like $200 getting it repaired. so now its gone entirely. cant say i miss it... i never trusted it either, and it was a bitch getting dragged away from more important jobs to go squat in the rain doing some ol biddys tyres.

people bitch and moan about us not having one, but i tell them how much was wasted getting it fixed, and then say 'if we could charge $2 or $3 per tyre to recover our costs, it would be there. but then youd be complaining about air being charged for instead!' now i just say it got stolen... stops the complaints, lol.

[FROSTY]

I bought my gauge from a performance car shop. Cost me $60.00
its got a rubber cover around it to protect it from shock damage.
Re the electronic gauges.I agree they are no more accurate than the other kind BUT at least they don't get dropped and loose acuracy that way

[kiwi cowboy]

A common misconception that I see is that a digital gauge is more accurate than a analog gauge, any gauge is only as accurate as the guy who calibrated it

maybe but at least with the control unit on the wall its less likely to get damaged from abuse.

[Chrislost]

I normally use my own gauge as like most sane bikers I know that petrol station gauges are usually innacurate. Unfortunately though I was going for a fang in the weekend and had the need to rely on a petrol station gauge. I called off my ride because it didn't feel right and I didn't trust the handling. Not happy.

If i had crashed it would have been my fault. But I know better than people like my mother who puts air in her car tyres blindly accepting that the gauge is accurate even though it might be 10psi out.


Cheer.

geez my shot suspension that puts me sideways off most bumps might need looking at!
along with the fact i havnt looked at my tyre preasure for aobut a month :/

each to their own but isnt that taking it abit far!!!!

[pritch]

The local tyre retail chain that I deal with for the vehicle fleet where I work tell me that their gauges are calibrated. The Manager at the local Honda dealer tells me their gauges are also calibrated, tyre pressures being critical for racing bikes.

I bought a Supercheap Auto digital gauge and it read one pound heavier than the calibrated ones so I just allowed for that. Later I bought a more expensive one and it reads spot on.

If that's anal, tough. I chronograph my loads too :-)

[Albino]

Wow, I really did think that most people would have a problem with tyres being out by 10psi. Even in my wagon I wouldn't drive around with 20psi or 40psi, let alone so much on the bike.

Checked the rubber yesterday and it was at 49psi on the back according to my gauge.

:scooter:

[Paul in NZ]

Youre exaggerating - not every servo guage is out by 33%

[Albino]

Youre exaggerating - not every servo guage is out by 33%

Which bit am i exagerating? I went to a service station, the gauge was out by 10psi and I asked why these aren't certified.

Is it the topic or me that's a sore point with you?

[Paul in NZ]

Which bit am i exagerating? I went to a service station, the gauge was out by 10% and I asked why these aren't certified.

Is it the topic or me that's a sore point with you?

No, no axe to grind other than I'm questioning your logic about abandoning a ride because you left your personal tyre guage at home.

If the gauge is out 10% and lets say I run 36 psi in the rear of the Guzzi and the Triumph then there will be a 3.6 psi potential variance, not 10 psi. 10 psi i would notice (but I would not fall off) but 3.6? Given all the other variables in road riding - no I doubt i would either care or notice.

Tyre pressures are not absolute figures - there is no single figure thats perfect for your bike with every tyre summer or winter. In an ideal world - a rough rule of thumb is to set the cold pressure so that when the tyre reaches it's full heat the pressure rises by 10% so even the distance to the gas station is a factor. ie you could check your pressure at home with your sub atomic particle ray calibrated super gauge and it is (say) 32psi. You ride 20 km and pick up your fat mate for a pillion experience and decide you need gas so you drop into the servo and decide you better check that tyre and look at that - the readings different than at home.... um - yes - because the tyres now hot.

In the winter i usually (if I remember) drop my pressures by 10% deliberatly so the tyre picks up heat quicker. If I'm loaded with wife and wifely luggage headed for the open road i crank it up a bit.

Some servo guages will be wildly inaccurate - a very few dangerously so but very very very few of them will be so significantly out that it causes a safety hazard and hence in my opinion, it would be a monumental waste of time and energy to certify the damn things.

Given the wide variety of conditions you face on a ride having my tyre pressures that perfect is my last concern - it just does not make that much difference and if it does to your machine my hats off to you because I admire your dedication in using such a wildly tweaked hi-po race bike on public highways - a true enthusiast.... I'm just a silly old bastard with average bikes runing average tyre pressures measured by a $10 gauge that has lived in my pocket for 15 years... And I never check them against the digital one at the servo - amazin I aint dead i spose...

[bert_is_evil]

I went to BP Roadmaster some time back and it actually let (a dangerous amount of) air out of my tyre, then beeped an error code and refused to work! I told the guy at the shop to stop people using it and limped to another servo grumbling to myself.

[Aerox50]

If the gauge is out 10% and lets say I run 36 psi in the rear of the Guzzi and the Triumph then there will be a 3.6 psi potential variance, not 10 psi. 10 psi i would notice (but I would not fall off) but 3.6? Given all the other variables in road riding - no I doubt i would either care or notice.


Try my pirelli Tyres on the Scooter (Yamaha Aerox). recommended is 23PSi cold.... I notice if they are 19.4! thing accelerates like poos and doesnt handle the best (sure its a scooter and not the best acceleration anyways) but 3.6PSi out is noticable.

[Albino]

No, no axe to grind other than I'm questioning your logic about abandoning a ride because you left your personal tyre guage at home.

Try reading posts before feeling the need to argue them. The only time I mentioned 10% was in my reply to your last post and I edited it straight away after posting.

The gauge was out by 10 psi.

[Skyryder]

Generaly in winter I run about -2psi from the recommended psi. on the grounds that a softer tye grips a bit better in the wet or marginal conditions. But it's not something that I get in too much of a sweat over. Unless you are running in the optimal conditions where you corner way out close to your edge and comfort zone the tyre pressure should not be too much of a problem. However for max tyre life the optimal psi should be closely adhered to, given road surface variation of course.

Skyryder

[Paul in NZ]

Try reading posts before feeling the need to argue them. The only time I mentioned 10% was in my reply to your last post and I edited it straight away after posting.

The gauge was out by 10 psi.

I did read your post and then you edited it - I responded to the original..... Don't get wound up - I'm a nice guy and I'm sure you are as well, we just have a differnt opinion on a trivial topic, I'm not having a go at you or anything...

Getting back to your original question - regardless of the effects of air pressure in your tyres - why are the gauges not certified? Having grown up around service stations and garages I guess the answer would be because they are provided free of charge as a service to the customer at the customers risk. Certification would cost money and would place responsibility onto the service provider, the air hoses would disappear very quickly if costs increased. (I've repaired and replaced them many times when my dad had a station - people abuse them chronicly)....

Another issue you could find is that the gauges would not be certified for use on motorcycles because there is not enough volume/capacity in the smaller tyres bikes use. The digital sensing pumps can struggle (which is why you can't use em on push bikes) as they overinflate and release pressure to get to the correct level (last time I looked)

One solution you could consider is getting your own pump at home (which is what we do) and doing the pressure check before you ride off. I have an ancient tyre pump at home (still get em at the warehouse) and it is amazingly effective on motorcycle tyres. 5 or 10 strokes is all thats required to top off a tyre - no effort at all and it's what I use 9/10 times. Alternatively i have a supercheap compressor that i use to spraypaint the bike tanks etc and it was like $110 on special complete with all sorts stuff - probably cheaper than a really good certified gauge...

You may see certified pressure gauges at servos but you won't see many off them. Like many free services and free advice on the internet - they are worth what you pay for em...

[mbazza]

I also find that service station gauges Never fit bike tyres without bending the valve stem! I also have trouble getting my slide guage which is accurate enough, to fit any of my fires.
Has anyone fitted those 90 degree extension dohickies? Do they change the balance of a tyre? Cheers - :bye:

[Paul in NZ]

I also find that service station gauges Never fit bike tyres without bending the valve stem! I also have trouble getting my slide guage which is accurate enough, to fit any of my fires.
Has anyone fitted those 90 degree extension dohickies? Do they change the balance of a tyre? Cheers - :bye:

I have a removable 90 deg one - bloody god send on the Guzzi...

[scrivy]

My roadrace sidecar has a optimum hot running PSI of between 14-16 on all 3 tyres. Usually I kick the tyres to make sure they're not flat, and go hard. Adds to the fun of the race. Have also been known not to check the pressures for a whole weekend. Also tried it up to over 20 PSI (which is over 33% more), just makes for even more fun!! Makes me piss myself when people at the racetracks talk about 1/2 a PSI to gain an advantage!!
But I do race on three wheels, not two. More important for two wheelers - but not to the point of stopping riding!! Anyone remember Stroudy at Ruapuna this year?? Went out really hard for a few laps and was dicing up the front, only to slow down nearer the end of one race?? Was found to have over 45 PSI in his rear!! Didn't stop him going hard for half the race!!

[pritch]

Has anyone fitted those 90 degree extension dohickies? Do they change the balance of a tyre? Cheers - :bye:


I have one but the thought of leaving it on the bike is scary. Just buy one if you need it, use it to inflate the tyres then put it in the toolkit.

[pritch]

I have an ancient tyre pump at home (still get em at the warehouse) and it is amazingly effective on motorcycle tyres. 5 or 10 strokes is all thats required to top off a tyre - no effort at all and it's what I use 9/10 times.

I had a Warehouse pump but it broke. Memories of pumping up CF Bedford tyres from flat didn't promote the idea of another one at all. (When you own British or Italian bikes you also need to own a van.):dodge:

Your comment about just needing to top tyres up got me interested again.
In case anyone is interested REPCO currently have a $10.00 off Michelin foot pumps. Currently $29.99 and $39.99 respectively for single or twin pump models. More expensive than the Warehouse but hopefully better quality?

[Cynos]

No it's not. However 10/15psi will. And that may not be not uncommon from servo gauges.
Advice is to carry one you trust at (whatever the reading you settle on) and use that to set your tyres when using servo airpumps. Your own gauge may also be wildly inaccurate, but as long as it gives the same reading at the same pressure each time and you are comfortable with that pressure, so what...

I found a servo gauge that reckoned my front tyre was 17psi, when four other servo gauges saida 28psi, as did my pen gauge.

[_Shrek_]

A digital gauge goes with me on the bike.
My Mitre10 tyre filler attachment thingy for my compressor is about 1psi out from my digital.
On the DR there's not a lot of difference in handling from 20psi to 36psi.
36 for road and 20 for dirt.

There is a big difference in tyre wear though.

:shit: NordieBoy i leave mine at 23 & 30 for road and dirt, still get good kms out of my tyres as well