The difference in diff ratios between countries.

[Loz]

I'm surprised how much the [diff] ratio's can change depending which country the car was made for.
For example, US BMW's seem to have lower ratio diffs across the range.

Why is this? :amuse:

 

[pgarner]

Re: Ratios between countries

made a new thread for this loz


wonder if its because the US doesnt have corners so dont need the lower speeds

 

[Loz]

Re: Ratios between countries

That was a good idea, cheers PG. :bigsmile:

 

[kain35m]

Re: Ratios between countries

We have low gear ratios because our roads are looooong straight and boring. We have to be able to cruise along at 80mph for 8 hours without dying from a droning 3k RPM.

that is, assumng you were asking a real question and not screwing around.

It's great if all you ever do is road trips, but if one decides to autocross/road race with any kind of turns, one is pretty much forced to switch gearing. It's not cheap either.

 

[pgarner]

Re: Ratios between countries

thought thats what it would have been

 

[HDi fun]

Re: Ratios between countries

We have low gear ratios because our roads are looooong straight and boring. We have to be able to cruise along at 80mph for 8 hours without dying from a droning 3k RPM.

that is, assumng you were asking a real question and not screwing around.

It's great if all you ever do is road trips, but if one decides to autocross/road race with any kind of turns, one is pretty much forced to switch gearing. It's not cheap either.

What you are describing are actually high gear ratios. Low ratios mean more revs for a given road speed.

 

[Loz]

Sorry, it's diff ratios I was referring to, when answering another thread I noticed that US BMW's generally run lower ratio diff's to the equivalent European cars & that was what I was questioning.

Is it perhaps US cars might run larger rims as standard possibly?

 

[HDi fun]

Sorry, it's diff ratios I was referring to, when answering another thread I noticed that US BMW's generally run lower ratio diff's to the equivalent European cars & that was what I was questioning.

Is it perhaps US cars might run larger rims as standard possibly?

I was referring to overall gearing ratios, whether that be 'box, transaxle/final drive or overall wheel (tyre/rim) diameter.

US BMW's probably run lower ratio diffs because they're all automatic. Of course, the European autos will have the same ratio final drive. This is in keeping with your findings and posts re the 318i auto/manual ratio differences.

Rim and tyre (tire) dimensions are identical. Even if you specify larger rims the overall wheel diameter is the same give or take +/- 1.5%.