Hi Guys,
For those with tacho's,or just those that
are in the know. Is there much difference in RPM @ 60mph between the beetle models. For instance is a
super turning over 1000rpm less than an oval.
Or another way which has the tallest/shortest gearing.
I believe the new 1.8lt and 2lt beetles have significant
gearing differences.
Thanks
John

Hi John,

I wrote an article on this subject for the VW Club magazine back in 2009. It tells about the formula to work out road speed from RPM (you need to know the tyre circumference, gear and diff ratio), with at least a dozen examples listing their km/h per 1000 rpm, and inversely their RPM at 110 km/h.

To summarise:

VW 1200 - 29.7 km/h per 1000 rpm
VW 1500 - 31.4 km/h per 1000 rpm
VW Superbug L - 32.01 km/h per 1000 rpm

I didn't work anything out for the New Beetle, as it's a Golf underneath. But I did work out a few new generation models:

VW Mk2 GTI - 33.2 km/h per 1000 rpm
VW Mk3 VR6 - 38.8 km/h per 1000 rpm
VW Mk5 GTI - 41.6 km/h per 1000 rpm

You can't really compare the old four-speed air-coolers with modern VWs, with their five-six or even seven-speed boxes and totally different engines. Nice to compare though.

BTW - you can't buy a 1.8-litre New Beetle now. The only choices are the 1.6 (sedan) or 2.0 (cabrio). I'm sure I have the brochures somewhere and could work out their 1000 rpm speeds if needed. But they would be about the same as modern Golfs.

If you'd like to read the article, go to http://www.vwwatercooled.com/mag/2009/2009.html  and download the August 2009 issue. Enjoy!

our 2.0L cabrio (2003 model) does 3000 rpm at 100kmh in 5th gear.

Ok I found some New Beetle brochures. The 2010 brochure doesn't list gear ratios but I found them in the 2006 brochure.

New Beetle 1.6-litre petrol 75 kW:
195/65R15 tyres, 0.881 5th, 4.235 diff.
32.05 km/h per 1000 rpm (3120 rpm at 100 km/h)

New Beetle 2.0-litre petrol 85 kW:
205/55R16 tyres, 0.837 5th, 4.235 diff.
33.60 km/h per 1000 rpm (2976 rpm at 100 km/h)

Wow - your speedo must be out by 0.8 km/h...

What revs would a kombi 1600 box with 31inch muddles be doing at 100 and 110kph out of curiousity?

Hopin it ain't a real screamer with the low ratio's and all...

My Beetle does about 3200rpm at 100kmh... Top Gear

semi auto 1500 beetle with 4.375 to 1 diff ratio...

Supers have 3.88 to 1 diff ratios...

If Your engine doesn't have enough power Chris
with those large tyres.. and high diff ratio 3.88 to 1

You may have to drive in 3rd gear... only joking... lol

remember that top gear in a beetle is an overdrive....

LEE

Hi Lee,

Yes almost all VWs have an 'overdrive' top gear - that is, a ratio that is numerically less than 1.00. However - it's only an overdrive into the differential. Out to the wheels, you then multiply by the diff ratio, which gives you an 'overall' top gear ratio of around 3.5. Most modern cars have 'overdrive' gears on fourth AND fifth - I don't know what the ratios are on a VW 7-speed DSG...

Chris to answer your question we need to know the 4th gear ratio, the diff ratio and the rear tyre circumference. Let's see - 1600 Kombis have a 0.89 4th gear and a 5.375 diff (these figures are in your workshop manual). Now the rear tyre circumference will need to be measured, but let's assume '31" muddies" is the height. 31 x 25.4 = 787.4mm tall, x pi = 2.473m rolling circumference.

The formula then, is 2.473 x 0.06 / 0.89 x 5.375. This equals 31.02 km/h per 1000 rpm. So at 100 km/h, that equals 100/31.02 x 1000 = 3224 rpm. At 110 km/h, that equals 110/31.02 x 1000 = 3546 rpm.

This is rather higher geared than a stock 1600 Kombi, which only has 14" wheels and does 24.95 km/h per 1000 rpm (4409 rpm at 110 km/h).

You can use this formula for ANY wheel, gear and diff combo. You only need to know the TYRE CIRCUMFERENCE - GEAR RATIO - DIFF RATIO.

Speed = CIRC x 0.06 / GEAR x DIFF per rpm.

Thats excellent Phil Thanks for the lesson.

yea Lee i was hoping hte lower ratios of the kombi gearbox would help drive the big rubbers, but i got hp increase plans too :P lol... we'll see how it goes.

At least with the bigger tyres then, it has a better engine speed for highways....
I couldn't stand a 4000rpm dub engine screaming through dual cannons at 110kmh down the gold coast highway every week. Lol, will need a loud stereo to overcome it

Thanks Phil, Thats exactly what I was after. Also thanks
for the link to the club magazine, that will keep me occupied for a while.
cheers
John