Speedo Gear for 35's and 5:13 gears??

[BKennedy]

I already did a search and no one seems to have posted this before for this gear/tire size ratio. Does anyone have any idea what speedo gear I need for:

35" Tires and 5:13 gears with an automatic tranny to get the speedo close to right? Or if not, could I be pointed in the right direction?

Thanks

 

[Alec]

from what tires, what gears, and what speedo?

 

[BKennedy]

Oh, yeah, that might help a little.....

I went from 32" tires and 4:10's with a 20 tooth speedo gear, black in color.

 

[etc]

I'm gonna jump in here and ask whats the relation in gears. Like the higher the ratio =???

Basically how the gearing works and the effects of different ones?

 

[udmsvt]

Originally posted by BKennedy
Oh, yeah, that might help a little.....

I went from 32" tires and 4:10's with a 20 tooth speedo gear, black in color.

was it right with the 20 tooth and that setup?

will the same gear work on a 5-speed?

whatcha gonna do with the old one?

 

[BKennedy]

Well, I am going to leave it in there until I know what I should have in there to even out the speedo. Yes the speedo was even, I checked it with a radar gun plus had the calibration checked.

I think my speedo is now fast by 9-10 miles per hour. If I could get close to the real speed, I would be happy. My Explorer is a toy, usually the only time it gets driven on the pavement is to and from a off-road trip, or I just feel like driving it around town after watching it sit in the garage for a month.

 

[410Fortune]

actually your speedometer is off by a percentage, not by a number of miles per hour.

You see as you go faster and faster it will be off more and more.

SO you could say, at 45 miles per hour the speedometer is off my 9 miles an hour. But at 55 it could be off by 11 or 12.

You are going to need the gear with the most teeth I believe, 21 or 22......

 

[Alec]

I also believe a 21 or 22.

 

[Dannyboy]

You could change speedo gear, or get bigger tires LOL.

How does it do with 5.13 on 35s? I'm considering going to this gear since I will have to regear my Dana 44. I'm running 4.56s and the power is alright, but I could use a little more engine braking on steep descents.

 

[410Fortune]

Brian (truckmagic) is the only person I am aware of running 5.13 and 35's on a 4.0L 4 door Ex.

Top speed is pretty low............FYI

With a D44 you may be able to get 4.88.......they make 4.88 for the 8.8 but not for the reverse rotation D35

I dont know if it would be worth going 4.88 from 4.56......

 

[udmsvt]

Originally posted by 410Fortune
Brian (truckmagic) is the only person I am aware of running 5.13 and 35's on a 4.0L 4 door Ex.

Top speed is pretty low............FYI

With a D44 you may be able to get 4.88.......they make 4.88 for the 8.8 but not for the reverse rotation D35

I dont know if it would be worth going 4.88 from 4.56......

doesnt alaskanjack have a sport with 5.13s?

 

[Dannyboy]

Originally posted by 410Fortune
Brian (truckmagic) is the only person I am aware of running 5.13 and 35's on a 4.0L 4 door Ex.

Hmm, thats funny cause I could have sworn I read BKennedy had 5.13s and 35s someplace.:mattmoon:

 

[BKennedy]

Man, don't check the mail for a few days and I get a full comedy routine when I come back.

Yes, the top speed is lower, but that was not what I was going for. It turns around 3500rpm at 80 miles per hour, but what more do you want for a lifted Explorer?? If I was going for top end, I would have kept my Porsche, it did 172! But, it did not handle the rocks very well.

The good news is, The Explorer has no trouble in the power department when in the dirt, and it goes slow down very steep grades, especially when I installed the Detroit locker in the rear. I also love the towing power when pulling my pop-up trailer.

So, if I took a vote, would you say I should go with the 21 or 22 tooth speedo gear?? (by the way, I knew about the percentage issue. The speedo reading 64 seems to be going 55 actual speed)

 

[tdavis]

Ok..

FYI, it doesn't matter if it's a manual or automatic transmission in a 1st generation 4wd explorer - they all use the same set of speedo gears, which is for a manual transmission. They can do this because the speedo is in the transfer case - and that part doesn't change between transmissions. This is different for gen2/3 Explorers, and 2wd Explorers.

If you goto here, you'll see the part numbers for the speedo gear. Use the manual list, ignore the automatic list.

Since you was already running the 32" tires with a 20 tooth speedo and 4.10 gears, 33" tires with 4.56 gears would still be spot on, 35" tires with 4.88 is also within specifications with the same speedo gear.

Doing the math:

New teeth = (current teeth * speedo reading) / real speed

teeth = (20 * 60)/50 = 24 teeth

You can put a 22 tooth if you can find one in it will still read slow. You probably need to see a speedo shop, they can sell you a gear box that will put you speedo/odo right on.

 

[BKennedy]

Thanks Tom, now I know enough to give up on trying to get the speedo right. I will just have to live with estimating my speed, which I am fairly good at. Unless I can find a 24 tooth gear.

 

[BKennedy]

Oh, and Tom Rios also is running 5:13's in his Navajo

 

[tdavis]

Originally posted by BKennedy
Oh, and Tom Rios also is running 5:13's in his Navajo

yes, but he's also got 37's. So that evens it out - he can get it closer than you can.

 

[AlaskanJack]

My, buddy put 33's and 4.56 in and he needed a 21 tooth gear. What better reason do you need to go bigger on tires than to get your speedo correct. hehehe

Hmm all these guys running 5.13's now huh, well maybe I better go lower gears when I swap my axles 5.30's I think is the next jump and I will run 36's

 

[Gopher]

Check to see if there is more of a selection of teeth for a f150. I know when i went to ford they didnt have the speedo for the ex, but i got anohter one that was a bit shorter. It fit in there and worked.

 

[BKennedy]

Well, I checked with my local Ford dealer and they do not have a gear bigger than 21 teeth. I don't think that would be worth buying, since I already have a 20 tooth.

I thought that since its reading high, I would need a gear with less teeth, but I guess that is why I ask questions first. When I went with the 4:10's and 32" tires, it was reading slow and it took a gear with more teeth to even it out.