Speedo help

[kugzs]

my speedo is a long way out.
when the speedo reads 70 im actually going 55.

the stock tyres are
165 SR 13”
13” x 25.4mm = 330.2mm
165 x 82% = 135.3
330.2 + 135.3 + 135.3 = 600.8mm

i have 185/70R13 so the diameter should be 589mm

is this why my speedo is out? How can i fix it?

cheers

[sideshow]

what car do u have

if its cable speedo you have to fit a small gear box thingy inline

place in marayong does it called MIS ask for RON tll him sideshow sent you

if the speedo is electronic i can fit a unit and calibrate your speedo in one go

[CrUZida]

the stock tyres are
165 SR 13”
13” x 25.4mm = 330.2mm
165 x 82% = 135.3
330.2 + 135.3 + 135.3 = 600.8mm

Can you explain that figure for us?

It should be 80, or 85.


Either way, providing the rest of the system is not malfunctioning, it sounds like someone has either swapped the diff, or swapped a gearbox and left the speedo gear in there from the previous car.

You are going to have to find out what speedo gear you have, and work out what speedo gear you need.

[chrisellis]

a usefull reference in regards to tire size's.

http://www.miata.net/garage/tirecalc.html

[kugzs]

sorry guys i have a ta22 celica and its a auto.(at least for another week )


cuzida
i think that the stockies are 165SR13
i think SR means aprox 82%

below is the document (off toymods) that i got the info off

Toyota Celica TA22
(NSW RTA requirements as at 13/6/03 – May Not apply elsewhere)

Stock Tyres – 165 SR 13” (As per TA22 Celica Owners Manual – Scan Pictured below)

13” x 25.4mm = 330.2mm
165 x 82% = 135.3

330.2 + 135.3 + 135.3 = 600.8mm OD (601mm)

According to the RTA Vehicle Standards Information Sheet No. 9 “Guidelines for alternative wheels and tyres” The outside diameter of the wheel and tyre combination must be no more than 15mm over the largest diameter wheel and tyre combination specified for the vehicle and not more than 15mm below the smallest diameter wheel and tyre combination specified for the vehicle.

Therefore
Minimum OD is: 585.8 (586mm)
Maximum OD is: 615.8 (616mm)


Tyre Options. (May not list all legal options and not all sizes listed may be available)

13”

185/70 13” = 589mm
195/70 13” = 603mm
205/65 13” = 597mm
215/60 13” = 588mm
215/65 13” = 610mm
225/60 13” = 600mm
235/6013” = 612mm

14”

195/60 14” = 590mm
215/60 14” = 614mm
245/50 14” = 601mm

15”

195/55 15” = 596mm
205/50 15” = 586mm
205/55 15” = 607mm
215/50 15” = 596mm
225/50 15” = 606mm
235/45 15” = 592mm
235/50 15’ = 616mm
245/45 15” = 601mm

16”

195/50 16” = 601 mm
205/45 16’ = 591 mm
205/50 16” = 611 mm
215/45 16” = 600 mm
225/45 16” = 609 mm
235/40 16” = 594 mm

[love ke70]

those tyres shouldnt be making a difference
if you look at the circumference:
the 165/82R13 have a circumference of 1866.73mm
the 185/70R13 have a circumference of 1851.02 mm

so thats a difference of 0.84%
so at 70 it should be reading 69.41

either your diff ratio has been changed or the wrong speedo drive is in there.

hope i helped rule out one possibility

[Youngy]

what car do u have

if its cable speedo you have to fit a small gear box thingy inline

place in marayong does it called MIS ask for RON tll him sideshow sent you

if the speedo is electronic i can fit a unit and calibrate your speedo in one go

Awesome info sidey, I tried to find some contact info for MIS just now and didn't really get anywhere - do you have a number at hand?