Hi,
We are on the hunt for a Barth as i think they are amazing to look at.
Since they are hard to find I have been searching all over the country. A man in Port Townsend said top speed was 55 and cruises best at 55. not meant to go over that. We would have to drive it nearly 2000 miles back to Northern Illinois.
Guess that isn't a good idea?!!!
Any help or info appreciated. This one had a 454. He is asking $12k
Thank you

sorry he said cruises best at 50mph

My '78-24' had a sweet spot of about 64mph, when everything sounded just right. Beyond that it was victim of the
bow wave and Mpg suffered. Keep in mind that many classic
RVs were built in the era of the national 55mph limit, and power tran combos may have been designed for that.

For planning purposes, I'd estimate about 8-9 mpg with the
454 cid/TH400 tranny combo, uphill/downhill, empty/loaded, sea level/mountains, summer/winter. A larger diameter fuel
line will probably decrease mpg☹️

The Barth in question probably does have an optimal cruising speed of 55 mph. However, it ought to be CAPABLE of exceeding that.
According to Wikipedia, For 13 years (January 1974[1]–April 1987[2][3]), federal law withheld Federal highway trust funds to states that had speed limits above 55 mph.

The engineer types here might know for sure...
I suppose that, during the oil embargo and double nickel speed limits, manufacturers geared and tuned vehicles accordingly.

My Breakaway, with 190hp 5.9L Cummins, seemed to cruise best @ 62 mph. Sadly, it would not go much faster than that. Later Barth diesel pushers, with newer/better transmissions, can be expected to have somewhat higher cruising and max speeds.
IMHO

As usual, no easy answer...

Motorhome handling varies a lot from one brand to another and even from one model to another. Generally, longer is better as long as the rear overhang is not too long. Tag axles are great.

We are making several assumptions:

Tires are properly inflated, balanced and in good condition. Front end is tight, alignment correct.
Ujoints are good, drive shaft is in balance
Shock absorbers good.
Chassis is level front to back.
Brakes good.

The rest depends on tire size, rear axle ratio and how fast you want to spin your engine. The shorter coaches are often around 4.10 ratio, while the larger ones like my 86 are often 4.58 ratio. With the 4.58 ratio you will see around 3000 rpm at 60 mph, fairly fast for big block. That is where I run my 86. It will easily run 75-80+ but will be turning like 4000 rpm.

The 4.10 axle will drop engine rpm about 10% so 60 mph is more like 2700 rpm.

A lot depends on driveline noise and vibration. You will often find a sweet spot as mentioned, where it seems smooth and mileage is reasonble.

So IF your coach handles well at a particular speed, smooth and steady, vibration is acceptable, fuel/oil consumption OK then run it.

This one?https://olympic.craigslist.org/rvs/6130872296.html
I think the top speed will exceed your desire to be aboard. I had a 1976 GMC 3500, essentially the same drive train and it would exceed the speedometer limit, less frontal area but probably the same drive train, a robust, not quite bullet proof. Just
Recommendations from that experience:
1. Change oil frequently after initial purchase.
2. Change transmission fluid and filter every 5000 miles for the first two or three times.
3. Change the differential fluid immediately.
4. Change the coolant and make sure it is the right type.
5. Replace all tires unless they are under 5 years or 7 years if you are taking it home in freezing temps.

Whereas cars of this age were normally geared for 3000rpm=72mph this vehicle is probably closer to 60 at 3000. Now we are used to lots of gears and 70=~2000 engines will spin the 3K just noisier and thirstier.
Look at and print off the buyer's inspection list.
Good luck,
Tim

My '75 will do at least 85 and I have a witness!!!!

When son David and I went to pick up said '75 and finally got out of Indianapolis and got on the expressway I looked at the speedo and it was at 87 miles per hour with no more noise than normal, handling was fine and the 454 was not in a strain. Since the speed limit was not 85 I slowed down but I would not recommend this speed.

Mary,
I got a kick out of that. :-)
We are thinking that we will just be patient and see if one comes for sale closer to home.

Seems too risky to spend $12k and not really know what we are traveling cross county in.

Thanks everyone for their input.

P.S. I am not good at being patient and really want a nice 19-24'.

Wise to shop around. Some are more "turn key" than others. A close inspection is always good when dealing with old machinery.

Good luck.

This could be a waste of time with potential for education. There have been quite a few coaches sold on this site and some may be ready for new owners. This would give a bit of history telling when it was documented to be in some type of condition. Examples would be http://tinyurl.com/Mackscreek
And
http://tinyurl.com/85Regal
Good luck, Tim

My 86 cruises just fine at 70. RPMS around 3200. Of course mileage isn't so good but I've been averaging about 7.5 for our trip thus far over 4000 miles, some generator use when running, ac on 80% of the time and a motorcycle on the back. I did hit the low 80mph range for a spell trying to get clear of some traffic but I wouldn't recommend driving that speed all that long.

I have a 1974 26' foot that have a hard time even getting to the 50 mph mark....from the speeds posted above I'm guessing I might have an issue?

Hey Shakespeare,

Don't worry 50 miles per hour is a good safe speed. After all the National was 55 for years.

I'd check the timing and the centrifugal and vacuum advance if the engine is running smoothly.

quote:

Originally posted by Crazyshakespeare13:
I have a 1974 26' foot that have a hard time even getting to the 50 mph mark....from the speeds posted above I'm guessing I might have an issue?

Yes, indeed.
other possibilities include very dirty air filter and/or fuel filter, damaged or otherwise-clogged exhaust, very bad spark plugs.