ET mål beregner

Beregn hvilken indpresning (ET) din nye fælg skal have for at passe perfekt til din bil

Din nuværende fælg

Din nye fælg

Tommelfingerregel: Når du går op i bredde, skal ET typisk reduceres for at holde samme position. Eksempel: 7.5J ET35 → 8.5J ET25 (½ × bredde-forøgelse i mm).

Hvad er ET-mål (indpresning)?

ET (Einpresstiefe fra tysk) er afstanden mellem fælgens midterlinje og det monteringsflader der møder hjulnavet. Det måles i millimeter og bestemmer hvor langt ind eller ud fælgen sidder i hjulkassen.

Positiv, negativ og nul ET

Positiv ET (f.eks. ET35): Monteringsfladen er tættere på fælgens yderkant — fælgen sidder længere inde.

Negativ ET (f.eks. ET-10): Monteringsfladen er tættere på fælgens inderkant — fælgen stikker længere ud.

Nul ET: Monteringsfladen er midt på fælgen.

Sådan bruger du ET mål beregneren

For at fælgen skal sidde i samme position som din originale, skal du kompensere når du skifter bredde. Indtast bredden og ET-målet på din originale fælg, samt bredden på den nye fælg — så beregner værktøjet den ET-værdi der giver samme yderposition.

Eksempel

Original fælg: 7.5J ET35

Ny fælg: 8.5J (1 tomme bredere = ~12.7mm bredere)

Ny ET beregnes: 35 - (12.7 / 2) ≈ ET29

Med ET29 vil den nye 8.5J fælg sidde præcis samme sted udvendigt som den gamle 7.5J — bare 12.7mm bredere ind i hjulhuset.

Ofte stillede spørgsmål

Hvad sker der hvis jeg vælger forkert ET?

Forkert ET kan få fælgen til at ramme bremsekaliberen indvendigt, eller stikke så langt ud at den rammer skærmen eller er ulovligt. For høj ET (for langt inde) kan også give kørselsproblemer og tryk på hjullejer.

Hvor finder jeg min bils originale ET mål?

ET-målet er ofte præget på indersiden af fælgen (f.eks. "ET35"). Du kan også finde det i bilens manual, på typegodkendelsesdokumentet, eller på producentens hjemmeside. Brug vores fælgsøgning for at finde godkendte ET-mål til din bil.

Kan jeg bruge navringe hvis ET er lidt forkert?

Nej, navringe justerer kun fælgens centerhul — ikke ET. Hvis ET er forkert, kan det ikke kompenseres.

Hvor meget tolerance er der på ET-mål?

Typisk ±5 mm er acceptabelt, men det afhænger af bilmodellen og brede på fælgen. Tjek altid med producentens specifikationer eller brug vores fælgsøgning.

Skal jeg bruge spacere hvis jeg ikke kan finde den rigtige ET?

Spacere kan bruges til at kompensere for højere ET (flytte fælgen længere ud), men tilføjer spil og vibrationer. Det er altid bedst at finde en fælg med den rigtige ET fra start.

Find fælge til din bil →

Press-in (ET) / Offset

When you need new or used rims for your car, there are a few different factors that you need to keep an eye on. One of them is Offset, which you can read more about on this page, as well as how it is calculated. In common parlance, you will often hear people call Offset "ET".

The ET measurement is one of the important factors when it comes to rims for your car. The ET measurement, together with the width, determines how far in or out the rim sits on your car.

A rule of thumb is that you can go 10 +- compared to the measurements that your car was born with from the factory.

The ET measurement is measured from the center of the rim, the surface that meets your car's hub, out to the edge of the front of the rim. If the ET measurement is 0, it means that the center of the rim is 0mm from the car's hub.

The lower the ET measurement, the closer the center of the rim is to the car's hub.

Wrong ONE goal

If you choose rims with the wrong ET measurement, in the worst case scenario it could mean that they will either hit your fender edge, protrude beyond the fender edge or hit the inner fender, springs, shock absorber.

Really ONE goal

There is no 100% answer to what the right ET measurement is for your car. As it depends on the style you want to drive with. Some prefer the rims to sit all the way to the fender edge and others prefer the rims to sit a little inward from the fender edge.

Depending on your choice of style, you also need to keep in mind how the ET measurement is calculated, namely from the center of the rim to the outer edge. This means that if the rim width changes, then the ET measurement must also change.

For example, if you have 18" rims with a width of 7.5j and ET 45 on right now, then other 18" rims with a width of 8.0j and ET 45 will not fit like your current one. The new rims in 18x8.0j ET45 are 6.5mm further out towards the fender edge but also 6.5mm further in towards the inner fender.

The importance of the right ONE goal

As you have read above, the ET measurement is an important factor when it comes to rims. So how do you find the right ET measurement?

You can either use your current rim specs and go ahead with it if you think they fit perfectly, the way you want them, or you can use the guide below.

You need to know exactly what your current rims are before you can start calculating. If you don't know the measurements or it can't be seen on the rim, but the rims are original to your car, you can contact your local manufacturer car dealer and get the information there.

Information you need:

1. The width of the rim
2. ONE goal
3. Distance in mm from the outside of the rim to your fender edge
4. Distance in mm from the inside of the rim to whatever is closest. (shock absorber, springs, inner fender, etc.)

What style?

First you have to decide for yourself, what style do you want?
 - All the way to the edge, so that the rim is flush with the edge of the screen
 - The rims must fit under the screen edge

Calculation

Now that you have all the information you need, you can start calculating.

For example, your current rims are 19" 8.0j wide with ET 45 and you want your new rims to reach all the way to the fender edge. With your current rims, you have 15mm of space to the fender edge.

Then you can either find rims that have 15 less in the ET dimension, i.e. ET 30, or find rims that are wider than your current ones.
Some rims with a width of 9.0j and ET 42 will move the rims 15.5mm further out towards the fender but also 9.5mm further in towards the inner fender.

1.0 inch also written as 1.0j is 25mm, so if you go up 1 inch in rim width and keep the same ET measurement, it means that the rims now sit 12.5mm further out towards the fender edge and the inner fender.