Different gear ratios?

01JettaTDIDriver · Feb 8, 2006

Hello All!

I have been driving my '01 Jetta for 1.5 years now and simply love it! I have averaged 46.3mpg. Recently, my good friend and colleague made a purchase of a '99 Beetle TDI. Both of us are driving manual trannys.

We were talking this morning about RPM's at specific speeds and noticed that we are no where near the same! I was curious why there is such a difference in gear ratios between the two cars?

Here is what we have found:

Jetta - 2000RPM - 59MPH
Beetle - 2000RPM - 79.5 MPH

Is this typical? I just did not expect such a drastic difference. I am still getting a touch better mileage, but this is puzzling. Thanks!

SpamJ · Feb 8, 2006

Sure it wasn't KM's?

Even with my new longer gears I'm running 70 at 2250 RPM. Something fishy with that Beetle.

catmandoo · Feb 8, 2006

ride with him and check for yourself,you can really feel the difference between 60 and 80.i'll bet KM's too

ta79pr · Feb 9, 2006

we've got two tdi beetles in my family, 98 and 99. both are about 2550@70MPH. If your friend's isnt set in KM then I want his setup.

bhtooefr · Feb 9, 2006

79.5 km/h = 49.3990098 mph

Either way, that's wonky.

Could either the tach or speedo be out of whack?

99slugbugchick · Feb 13, 2006

ta79pr said:
we've got two tdi beetles in my family, 98 and 99. both are about 2550@70MPH. If your friend's isnt set in KM then I want his setup.

I'm Sean's friend who just bought the 99 Beetle TDI (I LOVE it!). I am quite sure I am not looking at KM's - if you've ever driven in Michigan on the freeways you KNOW if you're going 80KPH vs 80MPH.

And I'm also sure its 79MPH at a little under 2000 RPM. As I bought it used I do not know what the previous owner did to it, but those are the numbers. If this isn't stock, any ideas what may've been done to it?

Thank you - this forum is AWESOME!

Debi

bhtooefr · Feb 13, 2006

Is your speedo GPS verified? Although, you'd know if it was THAT far off, I'd think.

Also, could the previous owner have upgraded to a .681 5th?

david_594 · Feb 13, 2006

Lito, So your sayign that I could have gotten the .681 gearset in the US instead of having to have one shipped over from europe? That doesnt seem right and your ratios dont add up:

Your numbers put the Jetta at 2.56 overall drive and NB at 2.649 overall drive. This gives the beetle a shorter ratio in 5th which would mean it would be turning higher RPM's than the Jetta.

ta79pr · Feb 13, 2006

are the above posted gear ratios absolute? I have 2 NBs in the family, 98 and 99 tdi, both get approximately 2400-2550@70mph. I want more details on slugbugs rig. are there other NB owner/drivers who can give their specs?

tongsli · Feb 13, 2006

David, No. I can't find that .681 in ETKA. Several years ago, this question came up and I found some info on VW's site with those ratios.

Of course, now I can't find it again so I'm taking down that info unless and until I can find it.

ta79pr · Feb 13, 2006

ok, i went out and did it, on a nice flat road, cold day (45F) 2250@70MPH. I did just clean the manifold and EGR, so perhaps that is why i remembered RPM of a few hundred higher. I want her tire size or gear set, cause 2k@80mph sounds real smooth.

david_594 · Feb 13, 2006

2K at 80 RPM in a 5 speed would be insane and not practical at all. Not worth it nevermind the fact there is no real way to get there. You would have to shift out of 4th at like 70 mph.

99slugbugchick · Feb 13, 2006

david_594 said:
2K at 80 RPM in a 5 speed would be insane and not practical at all. Not worth it nevermind the fact there is no real way to get there. You would have to shift out of 4th at like 70 mph.

I'm not sure I'm following - you're saying 80 mph at 2k rpm would be insane, or 2000 mph at 80 rpm? If the former, I must say I disagree. I am quite happy with the numbers - and I'm still getting 45 mpg consistantly. I can take a pic of my dials at speed if that would help.

bhtooefr · Feb 13, 2006

I suspect that that's exactly your problem.

Your dials.

I think one or both is out of whack.

ta79pr · Feb 13, 2006

does vagcom get info for rpm readings from the same source as the gauge?

JoeBleed · Feb 14, 2006

How about giving us a rpm/speed for each gear. say 2000rpm what speed are you going in each gear?

There is always the posibility that the PO change the final drive geras. Or the guage is wrong.

Interesting to see.

Growler · Feb 14, 2006

I just got the .681 installed on my 2000 beetle last night.

2000 RPM for me is indicated right near 68mph.
2500 rpm for me is indicated right at 80mph.

both with the new gearset in. and since its been over a month since I have had a useable 5th gear, I cannot remember what they were before the swapout.

david_594 · Feb 14, 2006

Its 11%! So take whatever you are currently turning in 5th gear at a given speed and subtrac 11% of that.

99slugbugchick · Feb 14, 2006

well, its starting to sound like there might be something wrong with my tach. I'm pretty sure the speedometer is right. But I tested it today, and got:

1st gear 2k rpm 17 mph
2nd gear 2k rpm 32 mph
3rd gear 2k rpm 46 mph
4th <blah> 62 mph
5th <blah> 81 mph

When your engine is idling, what does your tach say?

bhtooefr · Feb 14, 2006

Your tach should read 933 when idling.

ta79pr · Feb 14, 2006

i thought it was 903

nicklockard · Feb 14, 2006

01Jetta, what sized tires are on the car?

david_594 · Feb 15, 2006

Sad to say your tach has issues... Should be more like

1st gear 2k rpm 17 mph 13 mph(ish)
2nd gear 2k rpm 32 mph 20 mph(ish)
3rd gear 2k rpm 46 mph 33 mph (ish)
4th <blah> 62 mph 44 mph
5th <blah> 81 mph 59 mph

The ish'es are ones I am half guessing/half remembering off hand. I think my 4th and 5th gear numbers are pretty much dead accurate though.

99slugbugchick · Feb 15, 2006

Well, you guys were right. My tach is a bad tach.

When idling, its pretty much at zero (which I didn't really notice before). How the heck does a tach go bad? Must've been hanging with the wrong crowd.

bhtooefr · Feb 15, 2006

Could it somehow be miscalibrated?

01JettaTDIDriver · Feb 15, 2006

nicklockard said:
01Jetta, what sized tires are on the car?

My current tires are the same as the full sized spare -- 195/65R15

BTW - 99SlugBugChick's dials are just fine

We will be looking at her tach though. Thanks for all of your valuable input all! Awesome resource.

JoeBleed · Feb 15, 2006

When you shut the car off does the tach needle bounce and then go below zero?

if so someone may have had the needle(s) off and didn't align them back properaly.

Or it could very well be something else.

99slugbugchick · Feb 16, 2006

no bounce - its almost like they zero'd it like you zero a non-digital ohm meter (for any other sparkys out there). When the car is idling, its pretty much at zero. I don't know how the thing works - where does it get its info? It doesn't really matter, though - it seems to be working consistently - just off. 01Jetta can take it for a spin and see what he thinks.

Different gear ratios?

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