How fast will this thing go?

drtbreau · 09-23-2020, 01:32 PM

I am picking up my bus in a couple of weeks and making a 1700 mile trek home and I’m trying to figure out what to expect for speed (or lack there of).

2004 International 3800, 6 window, T444e (c175), with Allison 2000 transmission, and gear ratio 6.14, I don’t know the size of the tires.

cadillackid · 09-23-2020, 01:47 PM

the size of the tires is a big one.. 6.14 is a really low rear, with 11R22.5 tires you would still be able to run 55-60 with 19.5 tires you would be crawling along....

drtbreau · 09-23-2020, 02:00 PM

The 'label' says Front tires 225/70r19.5f/ rims 19.5x6.75 and rear 245/75r22.5g rims 22.5 x 7.50

musigenesis · 09-23-2020, 03:03 PM

My gear ratio is 6.17 and I also have a 2000-series transmission. I do 60 mph at 2400 RPM; max speed is about 67 mph full out.

CHEESE_WAGON · 09-23-2020, 05:14 PM

Quite honestly, these things weren't built to be speed demons, and the faster you go, the more dangerous they are. In my four years driving 18-wheelers, I found I got my best mileage and most enjoyable driving under the following conditions...

65-70 mph zone - 60-63 mph
60-65 mph zone - 58-60 mph

Reason being is that the average idiot is going to cut in front of you with inches to spare or hang beside you for miles if you drive the speed limit, neither of which is safe. Most members here will need at least 500-700 ft (approximately 13-17 seconds) to stop their rig under normal conditions at 65 mph.

See my post (#22) in this thread...

You might want to brush up on this to prevent bad situations...

https://www.skoolie.net/forums/f9/re...ist-33026.html

cadillackid · 09-23-2020, 07:15 PM

my little red bus has a mathematical top speed of something like 105.. I have driven it at 70.. it runs perfectly there but I dont like it.. I like that bus cruising at 65...

my DEV bus has a mathematical top speed of 68 and ive run it up there before.. but I dont like it.. I love to drive it about 62 on the interstate.. but often I take the backroads and drive it 55-60 where it really finds its sweet spot..

when I want to get someplace in a hurry i hop on an airplane

drtbreau · 09-23-2020, 07:49 PM

Thanks, not planning on going fast. When I saw the gear ratio I just got worried. I’m used to driving a Jeep with a death wobble....I’m not in a rush!

Truthseeker4449 · 09-23-2020, 07:56 PM

Quote:

Originally Posted by drtbreau

The 'label' says Front tires 225/70r19.5f/ rims 19.5x6.75 and rear 245/75r22.5g rims 22.5 x 7.50

19.5" rims in the front and 22.5" rims in the rear? That sounds rather odd, and the tire sizes aren't even close.

CHEESE_WAGON · 09-23-2020, 08:00 PM

Quote:

Originally Posted by Truthseeker4449

19.5" rims in the front and 22.5" rims in the rear? That sounds rather odd, and the tire sizes aren't even close.

Sounded strange to me too. Unless it's a Vista, for which plenty of bad has been said on this forum. I think some of those may have had different rim sizes for front vs rear. OP, any pics?

cadillackid · 09-23-2020, 08:01 PM

makes me wonder if the bus was really slow so they swapped the rims in the rear? ive seen smaller tires in thew rear than front for busses that have flat floors inside but never the other way around

Sehnsucht · 09-23-2020, 08:29 PM

As Cheese Wagon said these weren't designed for speeding anyways but there are two factors and he touched on one - stopping distance. Just because you might be able to keep up with traffic doesn't mean you can stop as quickly and I'm gonna be honest most drivers are idiots. They are going to race to get in front of you just to slam on their brakes a few feet from the car in front of them or to take that exit at the very last possible second. The other factor is simply aerodynamics - school buses are enormous bricks! All that wind resistance is dragging on your fuel economy but also what happens when you get hit with an unexpected crosswind? It's something truck drivers and bus drivers become all too familiar with but for the novice just getting into a bus and driving that maiden voyage cross country it'll be a ride awakening indeed to get into a windy situation and suddenly be broadside in the road or rolled over in a ditch because driving 70 makes the bus so much easier to roll from a crosswind than at 55. Just some things to consider when the first notion is always 'how fast will it go'.

drtbreau · 09-23-2020, 08:44 PM

Here are a couple pics

CHEESE_WAGON · 09-23-2020, 08:54 PM

First one I've ever seen with mismatched rim sizes from the factory...

Truthseeker4449 · 09-23-2020, 09:41 PM

It's a pretty little thing that's for sure, nice score.

Native · 09-24-2020, 03:06 AM

It is indeed pretty!

Interesting, in the photo it looks like the backs are 19.5" low-profile and the fronts are 22.5".

cadillackid · 09-24-2020, 04:29 AM

I’ve seeen smaller rear wheels to account for low fender wells and creates a flat floor inside.

I guess only way to really know is for seller to take a pic of the tire label ..

All those tires fill up the fender wells more than any on my little red bus do and it has 19.5s on it

Even with overdrive and either tire size a 6.07 rear it’s not gonna be a speed demon but would have pretty quick acceleration off the line.

jazty · 09-24-2020, 09:53 AM

Interesting.. Here are the final heights for front and rear tires.
225/70r19.5 = 31.9"
245/75r22.5 = 37"

A 5" height difference is pretty noticeable. Strange that the front are actually smaller. As was mentioned, for a hump-free, flat floor it might make sense to have shorter rear tires. I can't see the logic in having it the other way around.

I do wonder if the actual installed tires are different sizes than the name plate shows, however.

musigenesis · 09-24-2020, 10:06 AM

I assume smaller tires are cheaper (?) - maybe this was ordered by a school system in the hope of saving money on the steer tires? Seems like all else being equal, the smaller tires would wear quicker on the same-sized vehicle, so you wouldn't really be saving any money that way even so.

WARGEAR · 09-25-2020, 08:28 AM

Have the seller take a photo of the actual tire info of the actual tires installed on the vehicle. A label doesn’t mean jack diddly squat if the wheels have been swapped. Plus you’ll know 100% what you’ve got.

CHEESE_WAGON · 09-25-2020, 09:41 AM

CK has a point, but I can see another reason why this bus might have been ordered this way. If the ordering district asked, some manufacturers will mount axles above or under the leaf springs as requested for height requirements (Chicago, for instance, has some very low bridges).

Above the axle requires lower-profile tires and/or smaller rims. Very common with car-carrier semis. If that were not doable on the front suspension/axle for some reason on this particular bus, such as independent front suspension like an RV (not common, but I suppose it could be had, as we've seen a few five and six lug 3+-tonners), that would require different size wheels on the front vs rear to keep it level. In any case, I suspect smaller drives vs steers will cut the top speed quite a bit unless it has some really tall gears in the differential.

I know the tag states the steers are smaller, but it certainly doesn't appear so in the pic, though I do realize the angle could be the reason for that.

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