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GabbyVerse 12-09-2019 10:36 PM

New & looking for information
 
Hello everyone,


Been researching Skoolies for about a year now and have been lurking in the forums and reading a lot. I admit there is a lot of useful information here and definitely helps with my plans on building one.



My question is taking a single rear axle from a Bluebird, Thomas or International to a tandem like in the Crowns. Has anyone done this? What would the expected cost and benefit be? Will this help increase the weight limit for the GVWR. Most importantly if it is possible how long will it take to do the conversion?


Cheers!

banman 12-09-2019 11:02 PM

GVWR is set by the manufacturer and dot. Nothing you do is going to change that legal limit...

Are you wanting to make a toy hauler?

GabbyVerse 12-09-2019 11:29 PM

Quote:

Originally Posted by banman (Post 362961)
GVWR is set by the manufacturer and dot. Nothing you do is going to change that legal limit...

Are you wanting to make a toy hauler?


No, I was just thinking it will help distribute the load limit from a single axle by making it a tandem. Also, it adds another set of brakes and possibly add to a faster ride up inclines considering I am looking to convert a full size bus ~40ft to an RV.


I am just looking at ways to do this and so far I have two options.


1. Get a chassis that already supports the tandem and putting the bus shell on it.


2. Getting a bus and getting the modifications done.


Either way it is going to cost to get it done but like electricity I am looking for the path of least resistance....lol.



Cheers!

Ronnie 12-10-2019 07:35 AM

There are only two ways to go faster up inclines, more power or less weight. Adding another axle adds a lot of weight, and adds more gears to turn which takes more power, so you will be slower up hill all other things being the same.

brokedown 12-10-2019 07:41 AM

How fast are you trying to go up inclines? A BBAA with 8.3 and MD3060 is going to do pretty well up hills. Are you addressing a real problem?

Sehnsucht 12-10-2019 10:09 AM

If you're talking about taking a single drive axle bus to a tandem drive axle bus, you're basically looking at an entire rear end replacement and perhaps even more further forward. I think a non-drive tag axle wouldn't be too difficult to add but once you expect both rear axles to have power you'll need two new axles because the existing single axle doesn't have a rear output to power the second axle. Additionally, tandem drive axles like those in semi trucks have a further gear reduction which means the same RPM that got you 60mph with the original axle will result in about 45mph with a pair of reduction-gear tandem unless you can figure out how to alter the stock transmission gearing or swap in a 9+speed transmission. Then you have the compatibility of the donor axles and transmission, both for mounting and also for electrical/electronic integration. Tandem drives will likely have functionality for differential lock and inter-axle lock, something completely foreign to your ECM. Therefore, you'll probably be looking for non-electronic parts like air-activated lockups and these are getting rare.

As mentioned, speed will probably end up going the wrong way with this type of Frankenstein mashup so even though it may have power to climb it won't have enough top end to do so. As Brokedown said, better to just look for something with an 8.3L or comparable and an MD3060 transmission that will have plenty of power and speed to keep any reasonable skoolie satisfied. Just remember these aren't sports cars or fighter jets, they're not going to climb like such.

PNW_Steve 12-10-2019 10:17 AM

Adding a tag axle would decrease the load on the existing axles.

If it were me..... If I wanted a tandem or a tag axle I would buy a Crown or a Prevost.

Or:

https://www.hendrickson-intl.com/Auxiliary

Sehnsucht 12-10-2019 12:32 PM

Quote:

Originally Posted by PNW_Steve (Post 363006)
Adding a tag axle would decrease the load on the existing axles.

If it were me..... If I wanted a tandem or a tag axle I would buy a Crown or a Prevost.

Or:

https://www.hendrickson-intl.com/Auxiliary

Agreed and there are a number of plusses to going the motorcoach route over the skoolie route. Sounds like the OP may be better served overall by shopping for one of these just to save the headache of trying to make a school bus into something its not.

o1marc 12-10-2019 12:55 PM

Quote:

Originally Posted by banman (Post 362961)
GVWR is set by the manufacturer and dot. Nothing you do is going to change that legal limit...

Are you wanting to make a toy hauler?

Not correct. The GVWR can be changed at DMV by the owner.

PNW_Steve 12-10-2019 01:11 PM

Quote:

Originally Posted by o1marc (Post 363034)
Not correct. The GVWR can be changed at DMV by the owner.

This may come as a huge shock........

It varies by state.....

If you re-rate your GVWR in one state, you could run into challenges traveling to other state.

Here is a good discussion of this subject. Posts 3&4 are particularly relevant.

https://www.expeditersonline.com/for...lowered.21578/

Sehnsucht 12-10-2019 01:15 PM

Quote:

Originally Posted by o1marc (Post 363034)
Not correct. The GVWR can be changed at DMV by the owner.

I don't think so. I think what you're referring to is the registered weight class of the vehicle being licensed which would apply in states where the cost of registration is determined by the vehicle's weight capacity. I don't think your local license branch is going to certify that your mods to the vehicle are adequate to qualify it for a higher weight capacity than the manufacturer specified. They would be taking a huge risk and putting the state agency at risk of liability if they did something like that and then you had a wreck or failure that resulted from the vehicle being overweight.

o1marc 12-10-2019 01:16 PM

Quote:

Originally Posted by PNW_Steve (Post 363036)
This may come as a huge shock........

It varies by state.....

If you re-rate your GVWR in one state, you could run into challenges traveling to other state.

Here is a good discussion of this subject. Posts 3&4 are particularly relevant.

https://www.expeditersonline.com/for...lowered.21578/

The challenge would only come when LEO wants to check your weight. When was the last time a Skoolie was involved with weighing?

o1marc 12-10-2019 01:18 PM

Quote:

Originally Posted by Sehnsucht (Post 363037)
I don't think so. I think what you're referring to is the registered weight class of the vehicle being licensed which would apply in states where the cost of registration is determined by the vehicle's weight capacity. I don't think your local license branch is going to certify that your mods to the vehicle are adequate to qualify it for a higher weight capacity than the manufacturer specified. They would be taking a huge risk and putting the state agency at risk of liability if they did something like that and then you had a wreck or failure that resulted from the vehicle being overweight.

Who said anything about raising it. I want to lower it by 10lbs, so it's less than 26001. It's moot on a Skoolie here as they are exempt from weight requirements.
My local DMV said I could do it.

brokedown 12-10-2019 01:29 PM

I got my weight on my TC2000 changed. I just brought them a certified weight slip from the local Pilot's CAT scales along with Florida's weight affidavit form (https://www.flhsmv.gov/pdf/forms/82105.pdf) completed by and signed by the scale operator. I did it for the same reason, to be below that 26k that some states will try to screw you with. Was easy to do and I did it on the same visit where I changed the title to a motorhome and got my license plate.

ermracing 12-10-2019 01:47 PM

We got ours dropped below the 26k line here in NH as well for the same reasons. Scale slip and a letter from the local International dealer was all the DMV needed.

PNW_Steve 12-10-2019 02:26 PM

Quote:

Originally Posted by o1marc (Post 363038)
The challenge would only come when LEO wants to check your weight. When was the last time a Skoolie was involved with weighing?

When was the last time you had your tanks dipped?

I drove diesel rigs for 30+ years before I got checked.

I was putting down Main St. headed for the supermarket and see party lights in my rearview....

What's up? I know that I wasn't speeding. Tags were current.

I pulled over and saw that I was being pulled over by an unmarked red F150 sporting a WSP Trooper.

He walked up to me carrying a long hose contraption. I was puzzled. He informed that he was going to check my tanks for red diesel.

I struck up a conversation with him as he went about dipping my tanks. Turns out he was "commercial enforcement" and not only did he have his tube gizmo, he also had a portable scale.

I don't know how things work in Georgia but here in Washington they do random stops for weight and equipment checks. Oh.. I forgot, fuel check.

I can think of three times that I have been pulled over and made to demonstrate that seat belts, glass, lights, turn signals, horn etc. we're functioning properly. One of those resulted in a "fix-it" ticket for a crack in the windshield. I had ten days to finish it and stop by the local cop shop and show that it was repaired.

GabbyVerse 12-11-2019 03:46 AM

Quote:

Originally Posted by brokedown (Post 362979)
How fast are you trying to go up inclines? A BBAA with 8.3 and MD3060 is going to do pretty well up hills. Are you addressing a real problem?


Sorry for being a little vague but all the skoolie videos I watch on YouTube have all complained that going up an incline, even small ones, they come to a crawl. However, going back to those videos they have small engines in their buses so that might be a factor on my train of thought I did not take in to account. So now I know Big engine and good transmission will alleviate my concern. Thank you.


Cheers!

GabbyVerse 12-11-2019 04:04 AM

Quote:

Originally Posted by Sehnsucht (Post 363003)
If you're talking about taking a single drive axle bus to a tandem drive axle bus, you're basically looking at an entire rear end replacement and perhaps even more further forward. I think a non-drive tag axle wouldn't be too difficult to add but once you expect both rear axles to have power you'll need two new axles because the existing single axle doesn't have a rear output to power the second axle. Additionally, tandem drive axles like those in semi trucks have a further gear reduction which means the same RPM that got you 60mph with the original axle will result in about 45mph with a pair of reduction-gear tandem unless you can figure out how to alter the stock transmission gearing or swap in a 9+speed transmission. Then you have the compatibility of the donor axles and transmission, both for mounting and also for electrical/electronic integration. Tandem drives will likely have functionality for differential lock and inter-axle lock, something completely foreign to your ECM. Therefore, you'll probably be looking for non-electronic parts like air-activated lockups and these are getting rare.

As mentioned, speed will probably end up going the wrong way with this type of Frankenstein mashup so even though it may have power to climb it won't have enough top end to do so. As Brokedown said, better to just look for something with an 8.3L or comparable and an MD3060 transmission that will have plenty of power and speed to keep any reasonable skoolie satisfied. Just remember these aren't sports cars or fighter jets, they're not going to climb like such.


There's a lot of good information that you passed and it looks like there will be no other option other than to go with a single axle with a big 8.3 & decent transmission. Considering tandem buses are hard to find and those who own them are asking for a fortune for it.


Cheers!

Brad_SwiftFur 12-11-2019 04:31 AM

Quote:

Originally Posted by o1marc (Post 363034)
Not correct. The GVWR can be changed at DMV by the owner.


No. It *ABSOLUTELY* can't in GA unless you are a Vehicle Manufacturer and issue a new Certificate of Origin for the vehlcle (and by that, it *Requires* a state license, oddly enough from the same department and using similar forms for car dealerships.) Typically this might happen for trucks with tag axles added after the factory. However, you can *Register* it for a lower weight and that's what I believe you mean.


Also, be fair warned that some insurance companies may ask if the suspension is altered from factory and decline coverage if it is.

Sehnsucht 12-11-2019 04:34 AM

Quote:

Originally Posted by GabbyVerse (Post 363142)
There's a lot of good information that you passed and it looks like there will be no other option other than to go with a single axle with a big 8.3 & decent transmission. Considering tandem buses are hard to find and those who own them are asking for a fortune for it.


Cheers!

To be clear, tandem buses are hard to find in the used school bus market. If you're requisite is power and comfort, a motorcoach is definitely superior in those aspects. Its also bigger, heavier, and built differently which may or may not be conflicting factors for you.

As you look around this skoolie site though, I think you'll find not one owner complain that the bus they bought had too much horsepower! So aim for the biggest engine you can find which is likely a Cummins 8.3 or IC/Navistar DT530 and it'll most likely be mated to an Allison MD3060 which is sufficient to move a 40 footer down the road and climb adequately.


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