| Author | Message | ||
| Socks Rating: |
I have a MCI-9 what size tire and rims should I use 22.5 or 24.5. Is anyone running 11R 22.5 tires on a MCI-9 What should I run on the front? Is it ok to run 11R 22.5 ? | ||
| TWODOGS (Twodogs)
Rating: N/A |
sure....22.5 are fine | ||
| Larry Baird (Airhog)
Rating: N/A |
I run 11R 24.5s on my MC-7 only because it won't go fast enought on short tires. | ||
| bus nut Rating: N/A |
Larry what kind of increase did you see with the taller tires? Thanks Mark | ||
| TWODOGS (Twodogs)
Rating: N/A |
there is a 3 m.p.h. difference between 22.5 & 24.5 | ||
| Sean Welsh (Sean)
Rating: N/A |
"Is it ok to run 11R 22.5 ?" Depends on how heavy you make it. Most likely, 11R22.5 tires will not give you the load capacity you would need for a complete conversion on an MC-9 chassis. I would go to at least 12R22.5 tires, which will work on 8.25" and 9" rims. If you have 9" rims, you can also go up to the 315/80R22.5, which would give you even more load capacity, though that may be overkill and the tires are quite pricey. As for changing rims, 24.5 rims will give you a very, very slight increase in top speed based on tire circumference. You will also find tires in a given load range are cheaper and/or more plentiful in this size. However, you will also pay a price in ride quality. Unless you have some other reason to change rims, I would spend the money on better tires. -Sean | ||
| TWODOGS (Twodogs)
Rating: N/A |
just remember get high profile tires ...not low profile...and the weight issure isn't a factor...since we are not carrying 10,000 pounds of passengers and their luggage...I removed 2000 pounds of seats from my bus & installed 2000 pounds of living quarters...refrig....shower ..etc. | ||
| Larry Baird (Airhog)
Rating: N/A |
About 100 RPM at 75 MPH, makes me feel better. Larry | ||
| Larry Baird (Airhog)
Rating: N/A |
That would be less 100 Less RPM. | ||
| Brian (Bigbusguy)
Rating: N/A |
"11R22.5 tires will not give you the load capacity" WOW it will give you at least 20000#+ on a 4 tire axle . If you over load 11r22.5 tires your axles and bus would be over loaded and be over the weight to run on most roads in the USA. And you can get at least 12000 on a single axle. That would give you 44000#. Yes some buses may have a higher GVW but you will be over the weight you can run on most hwys. Even if you had a 46000# GVW you would need 8 tires on the rear to comlpy with the bridge laws and road weights. I would like to see some spec's on the axles your saying 11-22.5 would be over loaded. What is the tag axle rating on a MCI or other is it Over 12000#? Someone post some ratings. Im going with 24.5 just to keep the speed up but 22.5 would work at the max load and max hwy limit. Brian 4905 Klamath Falls Oregon | ||
| Brian (Bigbusguy)
Rating: N/A |
Also what is the front axle rating? Even if it was 20000# why would you want to that havey of a bus any way? There is also some type of rating that goes with the width of the tire tread but I dont know how to do it 20000# on a steer would need the stupid looking super singles any way. Brian 4905 Klamath Falls Oregon | ||
| Sean Welsh (Sean)
Rating: N/A |
Brian -- I don't have the plate #s for the -9, but 46,000 GVWR sticks in my head, which would likely be 12,000 steer, 20,000 drive, 14,000 tag. Most 11R22.5 tires would be very close to their max limits on the steer and drive axles, and could be over on the tag at full load. Which is why I wrote that it depends on how heavy your conversion ends up being. I should also probably have mentioned something about balance as well. I had to go with the 12R22.5 because I am at 11,000 on the steers and close to the 34,000 2-axle bridge limit on the back. By the way, I don't see any regulations requiring eight tires in the back to carry that weight -- the laws are all by axle (and sometimes by PSI), and don't account for number of tires per axle. Many highway trucks are now going to super-singles on the drivers. Larry -- not sure how you figured 100 rpm? My tables show a difference of 8 revs/mile between 11R24.5 and 12R22.5, and another 15 revs/mile between 12R22.5 and 11R22.5. At best, there are perhaps 25 revs/mile difference between any given 11R24.5 and the same brand/tread 11R22.5 That's a 25RPM difference at 60mph, and a 31rpm difference at 75mph. Or are you talking engine RPM? -Sean | ||
| TWODOGS (Twodogs)
Rating: N/A |
must be very lonely up there | ||
| Sean Welsh (Sean)
Rating: N/A |
Brian, Looks like you squeaked another post in while I was typing :-) On a 22.5x9 rim, you could put 315/80R22.5 tires, which would give you over 18,000 on the steer axle without going to super-singles. In fact, the 315/80R22.5 is now OEM standard equipment on most MCI coaches. The E-series (Renaissance) coach weighs 38,000 *empty* and carries a GVWR of 54,000!!! With 12,000 or so pounds of passengers and luggage, I have no clue how they could be under the bridge limit. I suspect they just aren't. FWIW, every single one of the current crop of high-end factory conversions (Marathon, Liberty, Vantare, American Carriage, etc.) is overweight right off the lot, vis-a-vis the federal bridge formula (which many states also use as their baseline weight limits). The fact is, though, that as non-commercial vehicles, they don't have to stop at the scales, and so they never get caught. I keep waiting for this to come to a head, but it never does. Of course, these same coaches are over-length in seven or eight states, and over-width in three or four, and even that does not seem to get them pulled over. YMMV. BTW, since I did not explicitly state it before, another reason to go to the 12R22.5 over the 11R22.5 is that it's a much taller tire, giving you most of the top speed advantage of the 11R24.5 without having to change rims. While the 12R22.5 is usually tested on 9" rims, they are all approved for 8.25" rims as well. I just upgraded to 9" rims anyway, just so I can go to 315's later if I want, but many older coaches came with 8.25" items. -Sean | ||
| Brian (Bigbusguy)
Rating: N/A |
Yes you can go 34000# or axle rating whichever is lower on the rears or the tires rating. And yes you would then need the higher rated tires. For now thay are getting away with it. Until some bridge falls down nothing will change. Hay if you have the power to move 54000# then go for it just hope it stops. I will just smile as I go by you on the hills   Brian 4905 Klamath Falls Oregon | ||
| TWODOGS (Twodogs)
Rating: N/A |
not to worry....he will never make it down to the border...funny...for the last 50 years the bus lines have been doing everything wrong...hmmmmmm | ||
| Larry Baird (Airhog)
Rating: N/A |
Engine RPM. | ||
| Tom Caffrey (Pvcces)
Rating: N/A |
I DO think that buses of all kinds get away with an awful lot. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher |
