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Mon Nov 05, 2007 6:35 pm

Okay I am new to the VW Bus world with a recent purchase of a 1967 with all original equipment, engine, and RGB rear axles. Are the RGB any good meaning are they reliable for a daily driver ? What speeds can I expect to see and if they are a bad option what is bad about them. I drive 55 mph everywhere I go anyway, speed scares me due to a horrific car crash years ago. I love my new bus just dont understand the RGB thing.

Mon Nov 05, 2007 7:50 pm

When the bus was first designed, they borrowed the 25hp engine from the beetle. Obviously a bus is larger, heavier, and has more frontal area for wind resistantce. The bus was also concieved as a commercial vechicle, capable of carrying a 3/4 ton load up a hefty grade ( I think It was rated at a 22% grade, but I could be wrong...) RGB's by design also give the back of the bus raised ground clearance, needed for post-war germany and the less than ideal road conditions.

The only way to get a larger heavier vechicle to haul a load up a hill like that was a "gear reduction". Essentially the overall drive ratio in all gears was lowered by the use of one small gear turning a bigger gear. It helped carry heavy loads, and helped climb hills. The main drawback is that the bus was limited on the top speed by RPM. The lower geared the transmission is the more RPM it turns at any given speed compared to a higher geared counterpart. That means the puny 25hp engine could haul a large load without stressing the engine. It was no speed demon, but it'd get you there, with all your cargo in tow.

With the increase in engine displacement throughout the years, the gear ratios changed accordingly. By the end of production, the '67 bus had a 1500sp engine with much more power than the 25hp, had a better cruising speed, and could carry a heavier load. (with the larger brakes starting in mid-year '63 the bus was now rated at 1 ton carrying capacity).

The limit of your particular RGB's and your bus depends on the transmission ratios, the gear ratios of the boxes themselves, the overall tire height, and the powerband of your engine. Most buses with "big nut" RGB's can cruise around 65mph with no problems.

RBG's can be used in conjunction with so-called "freeway flyer" transmissions for increased top speed, but without a more powerful engine to pull it, will bog down on hills or with headwinds. Also, inbetween gear acceleration will not be as rapid (with more time spent in each gear).

RBG's are very reliable if properly maintained. They were used in buses from 1949-1967 with very few problems to report. The boxes themselves have four bearings each, all eight of which (both sides) are submerged in gear oil. One quick way to kill your RGB's is to run the boxes dry...

Also, the Reduction Boxes really don't like burnouts, clutch dumps, or hot-rod style driving. As long as you take care of them, they'll take care of you. I've been driving RGB equipped buses for many moons, and they've always held up nicely.

A RGB will tell you when it's not happy. Tell-tale signs of problems are a humming or groaning sound from that particular wheel. I have a tendancy to rebuild the boxes before I start driving the bus just for peace of mind. Get good quality bearings, replace the lock nut, the cap, and the gasket with good quality items from wolfsburg west, and inspect the gears and the stub axle for damage or wear. Replace all questionable items. (side note, all boxes have a "whine" as they are straight-cut gears)

I prefer keeping the RGB's even in high hp big engine situations. I tend to go off-roading and camping in the middle of nowhere. I need the ground clearance, and I love the torque. The stroker motor with the RGB's is a stump puller (I've even towed a full sized Chevy 2500 truck with it) and it still cruises at around 65-70mph on the freeway. My current transmission has a 4:12 R&P with a .84 4th gear.

Some people will tell you that IRS or a Straight Axle is the way to go, but I think the factory hit the nail on the head with the use of such a rugged, well built transmission that does what its designed to do... No more, no less.

RGB ratios

Mon Nov 05, 2007 9:19 pm

Wow,
Excellent reply.
If your '67 is going to be driven at 55mph, it will be very happy keeping the RGB's.

Mon Nov 05, 2007 10:42 pm

I think that the "12 volt" 1967 transaxle is the best one and you should keep it in your bus. I have one in my 1963 camper that I restored and had one in my 1957 bus, which I am now re-restoring, for about 20 years. The gearing is better than it was in the small stub axle transaxles, the stub axle is thicker and has a roller bearing instead of the weaker ball bearing, and the brakes are bigger. Keep it!

Tue Nov 06, 2007 3:29 am

Another reason for the RGB's, (!I BELIEVE!) is the higher engine speed draws more cooling air through the engine compartment. Maybe someone more knowledgable than me can weigh in on this.

Tue Nov 06, 2007 6:09 am

I love my reduction boxes.
I did however put in a slightly modified gearbox with a taller 3rd and 4th.
When I run through the mountains with my straight axle split buddies, and bays, I always run off and leave them in my dust. :lol:

Tue Nov 06, 2007 7:20 am

j.pickens wrote: Wow,
Excellent reply.

X2
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Tue Nov 06, 2007 8:38 am

Well, that answered all my questions about the RGB's.

Bravo, I say, Bravo. =D>

Tue Nov 06, 2007 1:54 pm

Thanks, I try...

Tue Nov 06, 2007 2:12 pm

I guess that really is the official word. Awesome post.

Tue Nov 06, 2007 4:16 pm

Ya, that is the official word, the double official word is KEEP YOUR RGB.

Tue Nov 06, 2007 5:52 pm

Agreed

Tue Nov 06, 2007 7:21 pm

Yo heart RGBs.

Sun Nov 18, 2007 2:27 am

DannyboyUpstate wrote: I guess that really is the official word. Awesome post.

Awesome reply, this one should become a siticky, or something like that. =D> =D> :bus_blue: \:D/

Sun Nov 18, 2007 7:06 am

big bus mike wrote: Some people will tell you that IRS or a Straight Axle is the way to go, but I think the factory hit the nail on the head with the use of such a rugged, well built transmission that does what its designed to do... No more, no less.

But I want to go with IRS anyway! 8-[

j/k :lol:

Well, I am indeed considering it though it ain't gonna happen any time soon if at all. Just today I may FINALLY get to install the stroker in the Dormy. We're camping in the desert for Thanksgiving so that should be a good "test" for this set up! :P

Sun Nov 18, 2007 11:30 pm

Damn Mike, be all smart and shit... what's up with that?

Mon Nov 19, 2007 7:44 am

RGB's were so good that VW did away with them in 1968 on the VW bus. Not to mention more moving parts to wear out and service.

IF you want the motor running at high RPMs; at 60 mph RGB's are FOR YOU!

Unless you change the gear ratio in the tranny.

Umm yeahhhh....

Mon Nov 19, 2007 8:00 am

2true wrote: RGB's were so good that VW did away with them in 1968 on the VW bus. Not to mention more moving parts to wear out and service.

The 1968 and later bus transmissions had a different R&P, and a case that's a lot stronger than the type 1 case.

I think it's funny how my 36hp bus with RGBs will pass the straight-axle kids up the hills.

Mon Nov 19, 2007 8:09 am

2true wrote: RGB's were so good that VW did away with them in 1968 on the VW bus. Not to mention more moving parts to wear out and service.

IF you want the motor running at high RPMs; at 60 mph RGB's are FOR YOU!

Unless you change the gear ratio in the tranny.

Umm yeahhhh....
VW also did away with many things across the years., including air-cooled engines. You could always buy a new car, you know ;)

What is 'high rpms'? Statements like yours without definations don't mean anything. BTW, there are a number of stock gear ratios for splittie buses.
If I take "high rpms" to mean over VW recommended top speed rpms, (which is ~3,000 to 3,900 depending on the engine,) I can look in the owners manuals and see that some are rated with a top speed of 60mph or over.

Once again, it depends on the actual gear ratio, and tire size of the bus in question.

FWIW, bay buses often have delayed maintainance on the CV joints and rear wheel bearings.

Mon Nov 19, 2007 8:12 am

thom wrote: 2true wrote: RGB's were so good that VW did away with them in 1968 on the VW bus. Not to mention more moving parts to wear out and service.

The 1968 and later bus transmissions had a different R&P, and a case that's a lot stronger than the .type 1 case

I think it's funny how my 36hp bus with RGBs will pass the straight-axle kids up the hills.

Didn't know there was a type one case transmission.