Speedo Gear Question

[Harry]

I am just hoping someone can verify this for me. I am (finally) having the 3:55 gears put in my mustang and am gonna have the speedo gear changed at the same time. I am thinking that I need the black 20 tooth gear.

I have an 8.8 inch rear, 16 inch tires size 245/50R16, T5 Tranny

Thanks

[SlowGT]

Off the top of my head, I think it's the pink one but I'm not sure. I'll look it up for you when I get home if you haven't got a certain answer by then.

[302 LX Eric]

You'll need a 21-tooth white gear.

With your setup and a Tremec 3550, you would need the 20-tooth black gear.

Hope this helps.
E

[mysweetlx]

Harry, try www.steeda.com. I'm pretty sure the one you want is part # 123-0023 which is the 23 tooth white speedo gear listing at $15.95.

[302 LX Eric]

Yeah, like I said, the 23 tooth white gear.

Hey, at least I got the color right.

E

[todd95GT]

go to the hanlon motorsports webpage. i think it's www.hanlonmotorsports.com , if not, type the name in your search engine. they have a chart where you enter your time size and gear ration and it will tell you which drive and driven gears you will need.

[Harry]

So, which is it? The Hanlon site says it's the 20 tooth gear, I would assume the black on, not the orange one. Where are the rest of you getting your information??

Thanks

Harry

[PKRWUD]

YOU NEED THE BLACK 20 TOOTH GEAR!

The 23 tooth white gear is only for the '93 Cobras.

Take care,
~Chris

[todd95GT]

time size and gear ration? what the heck was I thinking?

Go with what Hanlon says, which happens to be what Chris says, too. The chart tells you what the ratio is and which pair of gears will bring you closest to optimum.

[SlowGT]

try this math from the FMS 2002 catalog:

(drive gear teeth X axle ratio X tire rev per mile)/1000 = # of teeth on the driven gear.

(7 X 3.55 X 815)/1000=20.25 ==>black

815 is rpm for a 225/60-15. TireRack has pretty good info for finding rpm for your particular brand/size.

for T-5:
21T = red
20T = black
19T = pink

[302 LX Eric]

So is this why when I took out my old T-5, the speedo gear (the white 23T one) was all chewed up?

The shop that installed my gears (does a ton of gear swaps for Mustangs) said that the white gear was the proper one and installed for me.

What crap that is.

So, if my Tremec is a 6 tooth drive w/3.55 and 815, I get 17.3595. So, do I have the wrong gear? (I've got the 20T Black gear - That's what D&D told me I needed)

Ok, I'm offically confuzzed now!

Someone please set me straight.

E

[RPM427]

OK!! I just went through this mees this morning. listen up.

The following trannys have a 7 tooth drive gear:

- 1983-1989 T-5 OEM
- Pre 1993 T-5 Aftermarket
- 1996-1998 Cobra T-45 OEM
- All Tremec Transmissions

2.73 Gear Ratio / Maroon 16 Speedo Gear
3.08 Gear Ratio / Yellow 18 Speedo Gear
3.27 Gear Ratio / Pink 19 Speedo Gear
3.55 Gear Ratio / Black 20 Speedo Gear
3.73 Gear Ratio / Red 21 Speedo Gear
4.10 Gear Ratio / White 23 Speedo Gear

That means you Harry. You will need a BLACK 20 tooth speedo gear for your 3:55 gears.

This may be helpful to everyone else.

Manual transmissions with 8 tooth drive gears include:

- 1990-1995 T-5 OEM
- 1996-1998 T-45 OEM Except Cobra

2.73 Gear Ratio / Yellow 18 Speedo Gear
3.08 Gear Ratio / Black 20 Speedo Gear
3.27 Gear Ratio / Red 21 Speedo Gear
3.55 Gear Ratio / White 23 Speedo Gear
3.73 Gear Ratio / White 23 Speedo Gear
4.10 Gear Ratio / White 23 Speedo Gear

[302 LX Eric]

Thanks for that great info, RPM427

So, I guess I was right with the white 23-tooth gear for a 91 T-5 w/3.55s and the Black 20-tooth gear for my Tremec is correct too.

Thanks,
E

[todd95GT]

Just a suggestion... use the Hanlon chart at the website and replace the drive and driven gears. Just replacing the driven gear with a 23 tooth to compensate for not changing the other means you'll have a lot of teeth in a small little gear. The 23-tooth gears DO fail. For 23 bucks delivered you can get them both. I just ordered a 6 and 19tooth set for my upcoming swap to 4.10's.

[mysweetlx]

Originally posted by 302 LX Eric
Thanks for that great info, RPM427

So, I guess I was right with the white 23-tooth gear for a 91 T-5 w/3.55s and the Black 20-tooth gear for my Tremec is correct too.

Thanks,
E

I guess I was rght too ! Harry, w/ your stock T5, you need the white 23 tooth from Steeda. You're welcome.