| Author | Message | ||
| Captain Ron
Rating: N/A |
I located 4 used tires and rims for $500. saving me well over $1000 on new ones. my current tires are 41" tall the tires i'm putting on are 43" tall. Will I get better fuel mileage and top speed or will I lose torque and fuel mileage with the gain of top end? the aprox. RPM of my present tires are 485 I believe. the new ones are 474. the bus 4905. they also tell me nobody balances the drives but they would put a liquid balancer in not a powder. | ||
| TWODOGS (Twodogs)
Rating: N/A |
2" taller tire would mean..higher top speed & better mileage...&...a tiny bit less take-off power.....my 24.5 are 43" | ||
| Captain Ron
Rating: N/A |
1st gear is so low I guess it won't matter. I'm gonna "git-r-dun" monday. provided I can getr thawed out and started. | ||
| Bill Gerrie
Rating: N/A |
Captain Ron Michelin tires will not warranty a tire if it has powder or a balanceing sand inside. They say it will destroy the thin membrane that keeps the air in the tire. If Michelin says this for their tires I am sure it is true for others. I put Centramatic wheel balancers on all wheel locations and notice a real difference in the smoothness of the ride. These are a disc with some sort of a balanceing material in them that goes on the drum and then you install the wheel. A little pricey but worth it in the long run. Bill | ||
| Don/TX
Rating: N/A |
I agree on the Centramatics. I have had them on my trucks and buses for years, they don't cost, they PAY. That comfort from the smoothness of ride is only part of it, stops premature wear on the suspension system and tires as well. I just hate vibrations! | ||
| Don/TX
Rating: N/A |
Captain Ron, maximum torque on your bus is at 1200 rpm. Bigger tires will HELP you get a cruise within max torque range, not hinder it. | ||
| Ron Elkins (Captain_ron)
Rating: N/A |
Does any body know how much difference it will make in top speed and in fuel mileage? and will it affect the acuracy of my speedo? | ||
| gusc Rating: N/A |
Ron, You are effectively reducing your gear ratio. You may think you are getting worse fuel mileage because of fewer wheel revs thus less odometer distance with the same fuel use. It is possible you will actually have less fuel use, depends on your gearing. Obviously hill climbing will be worse unless you are now climbing with rpms very high. The closer you drive to torque peak the better your efficiency and if you are in the middle of the peak torque band you still have a reserve for acceleration and hill climbing. | ||
| RJ Long (Rjlong)
Rating: N/A |
Captain Ron - Just a day or so ago I posted a link to a RPM/MPH calculator on this BBS. If you'll go to the calculator, you can play with the numbers all you want to answer your question. (Once on the site, it takes about 30 seconds to get your answer, btw. But I'll let you do it for yourself. . .  ) Here's the website link again, the MPH calculator is on the LH side: http://www.freewebs.com/darisb/ Your 4905's stock rear axle ratio is 4.375:1. If you have a 4-spd stick, with the bevel gears the overall ratio is 3.535:1. If you have a V-730 automatic, the overall ratio is 3.806:1. You need to plug the overall ratio into the calculator to get the correct answer. Pay attention to this: The magic number with a GMC coach is 495 tire revs/mile. That's the size tire GM used during powertrain development. If you buy tires that turn MORE revs/mile, you'll lose top speed and increase your fuel consumption. If you buy tires that turn LESS, you'll get the opposite results. Simple. All the truck tire manufacturers have charts that give the revs/mile specs for their tires. Use them to your advantage. For the best ride and longest tire service life, balance ALL the tires properly - steer and duals. This isn't a truck, it's a bus. Use Centrimatics as an aid, not a substitute. HTH, RJ PD4106-2784 Fresno CA | ||
| Ron Elkins (Captain_ron)
Rating: N/A |
Acording to my calculations I will gain 3 MPH on top end if I can increase my fuel mileage to 9+ I'll be extatic currently get 8.33 with my foot stuck out the front or WFO |