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Headlamp aim


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Hi all,

I've seen the IVA regs for headlamp aim, with the diagrams showing vertical and horizontal percentage tolerance bands.   I understand that this can't be adjusted in the IVA test at the moment, due to Covid restrictions, so I have to get it right first time!  😬

First of all, I'm not sure I understand the definition of the tolerance bands, can anyone help?   My educated guess is that the zero-zero point is measured at the centre point of the circular headlamps and halfway between the two?   So if my headlamp centres are 680mm off the ground and 800mm apart, then the test equipment will set the zero point on a blank wall at a height of 680mm halfway between the headlamp centres?

My headlamps are less than 850mm from the ground, so the top of the beam must be between the 0.5% and 2% lines.    1% of 680mm is 6.8mm, so I think that means top of beam must be 3.4mm to 13.6mm below the 680mm mark.  Am I right?

The beam breakpoint must be between 0% and 2% lines to the left.  So if my headlamps are 800mm apart, the breakpoint must be between 0mm and 16mm to the left of the centre line?

If I put those marks on a wall opposite my garage and turn the headlamps on, should that be a decent approximation to the IVA test?   How far away should the front of my car be from the wall?

Thanks!

Pete  👍

  

Edited by peter_m7uk
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An IVA is just a stricter MOT, so if it passes the MOT, you are well on the way to getting through IVA.

With that in mind, just book your car in with a normal MOT garage (preferably a kit-car friendly one), specify that you don't want to record the results, just do the tests and they will let you adjust the headlamps on the spot.

For £50 (or whatever MOT fee it is now), they will check that and more importantly, emission figures as well so you know if the engine fuelling needs adjusting.

I did this a few weeks before my IVA and it worked a treat - the garage I went to were so interested in seeing a kit, they didn't even charge me 🙂 

Edited by nelmo
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i am with nelmo on this one take it for an MOT headlights emissions bargain for the money   although £50 is a bit steep 

had my van MOT yesterday class 4 and it was £40 so a car 30 to 35 

Edited by tractor
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Hello chaps, thanks for the answers.   The thing is, if I do it outside my garage, I save all the hassle of trailering a car to an MOT (I'm not going to drive it there!), plus the usual £40-50 fee!

Surely someone understands the regulations out there?  If my description is right, I'm happy to do it that way 👍

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Your car should be 7.62 meters (25 feet) from the wall.

If you want to be pedantic the headlight lens is 7.62 meters from the wall and the floor is flat under the car and all the way to the wall.

There is a breakpoint for each headlight, so if they are 800mm apart then each breakpoint will be 400mm from the car center line.

I hope that this helps.

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11 hours ago, peter_m7uk said:

 (I'm not going to drive it there!) 

Why not? The plan is to drive it eventually, no? 🙂 You're allowed to drive to an MOT without plates etc and it's an excellent shake down test before IVA. 

I thought MOTs were a fixed price everywhere? I paid £54 for mine a couple of months ago 😞

 

Edited by nelmo
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14 hours ago, IanS said:

Your car should be 7.62 meters (25 feet) from the wall.

If you want to be pedantic the headlight lens is 7.62 meters from the wall and the floor is flat under the car and all the way to the wall.

There is a breakpoint for each headlight, so if they are 800mm apart then each breakpoint will be 400mm from the car center line.

I hope that this helps.

Thanks for the info, Ian!  I've been reading around this more and I finally understand the percentages - They are a gradient.  So the 1% line depends how far you are from the wall.  For example, at 1m from the wall, the top of the beam must 1cm below the zero.  At 7.62m from the wall, the top of the beam must be 7.62cm below the zero line.  And so on.

Now I understand the rules, I can work it all out on a wall regardless of distance, but I'll try to keep to the 25 feet mark if that's what they use at the IVA test  👍

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For those suggesting an MOT, thanks for the advice, but if I can build an entire car I insist that I can set a pair of headlamps by myself too !!

I'm going to take the adjustable spanner I use for the headlamps to the IVA, but my understanding is that strictly speaking I won't be able to use it due to Covid rules....

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2 hours ago, peter_m7uk said:

For those suggesting an MOT, thanks for the advice, but if I can build an entire car I insist that I can set a pair of headlamps by myself too !!

🤣 building a car is a piece of cake compared to trying to understand government rules 🙂 

Good luck!

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