Ring and pinion advice.

[plotch]

I have a 75 standard with the stock transaxle. Using 225/75x15 tires in the back. Lots of clutch slipping to go slowly enough on the class 4 roads around here. The 75 has a different nose cone mount which might limit swapping.
Needing advice as to which gearing would work best. Hope to tackle the Trans america trail at some point, probably hauling a small trailer. Thanks residents of the dirtpile.

[DesertSasquatchXploration]

A 4.37 is great with 29 inch tires 235/75x15.

The rear tires you have its going to be a buzz box on the highway. 4.12 would be better if your doing a bit of on road driving. IDK what came standard in 75 you might have a 3.88 or 4.12?

[joemama]

I think '75 got the single side cover transmission. If so, stock its 3.88. You should read the sticky on this forum "Transmissions for Dummies". I had a class 11 bug with a 1776, the single side cover 3.88 trans, 215/75/15 tires, and it was a dog on the street, let alone trails. I also have a fiberglass buggy, that has a 1915, 30x9.5x15 tires, and its on its second trans with 4.37 gears. I wouldnt go with anything else. It might not be awesome on the freeway, but its fine, and great off road.
If you do have a single side cover transmission, its the strongest type 1 case built, so you might want to have it rebuilt and modified for 4.37. Both the transmissions on my buggy (one was swing axle, and the 2nd one is now IRS, and a single side cover with 4.37) are prostreet style, meaning 3rd and 4th are stock, not close ratio, so on the sand, or large hills, I rarely hit 3rd, staying mostly in 2nd. The prostreet has several other modifications to help it last. I actually had a 5 rib bus trans in my buggy for a while (4.86), but didnt like the slower shifting and heavier feel, so went back to the type 1 with the 4.37. More fun to drive.
I hope this helps.

[plotch]

Thanks guys. Yes it is a single side cover. On the hills around here it is sometimes hard to get out of second. I read all 28 pages last night. It needs to be edited to be of much use. PS: traction is great on the mud, wet leaves and rocks.

[plotch]

To purchase the correct ring and pinion, to fit transaxle AT 15 11 4; where do i look to determine 8 bolt or 6 bolt? Or if any of you know, thanks.

[Mal evolent]

6 bolt was for swingarm. 8 bolt is for IRS.
_________________
73 Beetle Baja, Ghia front brakes, Type 3 rear brakes, 2220 ( 94 X 80 ), Weber Progressive, Bosch SVDA, '97 Mustang seats

Baja Bugs for Volkswagen Virgins: Index

[plotch]

Thank you.

[Stinky123]

You want the lowest that you can get.

4.86 would be perfect....assuming the same price.

There is a rpm calculator on the net. That would help you answer the question if you want close ratio 3rd n 4th.

I wouldn't change tires just yet. But, 235/75 is more common and maybe even cheaper (because it is more common). They would be, theoretically, 75% of 10 mm taller (7-8mm, about 1/4").

You want 2nd gear to be ur best gear. IOW, as soon as you get rolling, you want to shft to 2nd. 1st is weak as it only has a few teeth on it. 2nd has more teeth engaged at the same time.

[Mal evolent]

RPM - MPO Calculator"

MPH = RPM X LRTR / GR X 168

whereRPM means RPM LRTR means Loaded Rear Tire Radius, and GR means FINAL DRIVE GEAR RATIO.

4th gear is an overdrive on my '73, .89:1, so you multiply the ring and pinion ratio by 89 for the final drive ratio/
_________________
73 Beetle Baja, Ghia front brakes, Type 3 rear brakes, 2220 ( 94 X 80 ), Weber Progressive, Bosch SVDA, '97 Mustang seats

Baja Bugs for Volkswagen Virgins: Index

[sodbuster]

[Stinky123]

https://spicerparts.com/calculators/engine-rpm-calculator

[claudio_nahmad]

Hey, im at a similar situation.

Ive a stock 1600 type 1 with 205/75x15 tires and a swing axle 4.12 tranny (mexican, stock), the final part of the project is to convert to IRS since there is a considerable camber problem, but im kinda stuck in the drawboard:

- Could buy a full used rear suspension but it comes with a 3.88 AT (~1972-ish single side cover, superbeetle) tranny, i'm against this option since the bug will loose torque at all gears, but the option seems ok since the suspension is in a good state.
- Could buy a used rear suspension without transmission and "convert" the swing axle transmission into IRS, -since 4.12 is ok for me- but im not sure about the process to do so.

Cannot upgrade engine to a bigger one for the moment, so in youropinion what would be the best way to tackle this problem?
thanks
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slow & relaxed
- stock 1600 (1584) cc type 1

[ORANGECRUSHer]

what type is rig is this?

bug bodied?
rail?

Makes a big difference.
If it was a bodied car I'd suggest finding a different car with irs. Yes it gets done, but unless you're really good at fabrication I'd leave it alone. IRS pockets can be welded in and use different spring plates and bars and arms obviously. With a body there's a little more concern about getting the right fit.

If it's a rail just find a trashed IRS pan or rail or even better torsion separated from the rig and weld in the torsion with the arms and all.

Not necessary to have the transmission with it in either case. Any IRS would do.
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Brian H.

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[Scott SD]

If it has a Mexican swing axle, most likely it is a 4.37 R&P. The Mexican boxes have all the worst parts VW ever used in a trans.