transmission speedo reduction gears and stuff

[pbureau@attbi.com (ATS - Patrick Bureau)]

AL, they never matched Trannies with  Wheels.

they had 2 stock size wheels 13" and 14" wheel, (respectfully 175/70/13 and
185/60/14)
yes for 15" wheels the correct size tires is 195 or 205/50/15 on the car.

195/50/15 is 0.1388% differential against 175/70/13
195/50 are 22.67" in diameter against the 175/70/13 that are 22.65" in
diameter
0.02" of a diameter differencial will not give you 10% spedometer faster
sorry.

205/50/15 is 1.83% differential against 175/70/13
205/50.15 are 23.08" in diameter against the 175/70/13 that are 22.65" in
diameter
0.43" of a diameter differential will not give you 10% spedometer faster
either.

I have this setup, 7" mind you and I think in this particular case width is
not a factor in changing speed accuracy of your dial.
and my dial is dead on the money, you might check instead:

A) another cluster installed to see if readings go back to normal
B) ensure you have the proper gear on your spedometer cable :)

ATS - Patrick

=>-----Original Message-----
=>From: scirocco-l-admin@scirocco.org
=>[mailto:scirocco-l-admin@scirocco.org]On Behalf Of Allyn
=>Sent: Tuesday, February 26, 2002 10:57 PM
=>To: scirocco list
=>Subject: transmission speedo reduction gears and stuff
=>
=>
=>OK, this has been a burning question for quite some time:
=>    The rieger (FN tanny) speedo reads about 10% faster than
=>actual speed. I figure that is due to
=>the gear in the tranny, no big deal really, but the rieger has
=>195/50's up front (yes, i know, they
=>dont belong on 9" wide wheels, but i wasnt the one that put em
=>on, damn it). I would think that
=>195/50's ought to at least be close to any kind of silly old 13"
=>70/80 series that would have been
=>used back in the original FN tranny days, but it isnt close
=>enough as it is still 10% off (i.e.
=>tires must still be bigger for it to match).
=>    So, on to my question: What is the exact tire size that was
=>used with FN trannies to give a
=>CORRECT speedo reading??? Even better, is anyone using an older
=>style tranny with some other
=>wheel/tire size that makes the speedo correct, and/or how far is
=>it off by?
=>    Also, can someone give me the quick version of what the deal
=>is with the 2 types of speedo
=>gears?
=>Thanks
=>Al
=>
=>Allyn Malventano, ETC(SS), USN
=>87 Rieger GTO Scirocco 16v (daily driver, 170k, rocco #6)
=>86 Kamei Twin 16V Turbo Scirocco GTX ('it has begun', rocco #7)
=>87 Jetta 8v Wolfsburg 2dr (daily driver, 260k, 0 rattles,
=>original clutch, driveshafts, wheels :)
=>
=>
=>
=>
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