Tire temps

[richard5933]

the temps...so long as the inner and the outer drives are about the same but for me some times the inner drive would be a little higher...
dave

When we started using the Tireminder TPMS, we noticed that the inner drives are about 5 degrees warmer than the outer. I figured it had something to do with air flow, and since both sides were the same I wasn't too worried. The temp didn't keep rising, but stayed consistently about 5 degrees higher inner vs outer. If one tire spikes different than the opposite one, that's a different story, I figured. Still pretty new to us, this TPMS thing, so I'm still establishing what 'normal' is for the system.

[luvrbus]

Inside hotter than out the outside is normal ,the inside wheel has a brake drum or disk brakes,  out here in the west it's not uncommon to see a 20+ degree swing when coming down grades using the brakes a little and setting a TMP off.Most drivers out here know that happens and don't even stop to check   

[windtrader]

The weights from the scale are front axle and the rear axleS (both drive and tag). I just planned on taking the total weight of the rear and dividing by 6, assuming each tire carries about the same amount. Richard doesn't have a tag so cannot confirm temps of the six tires. Anyone else set the tires at the same pressure on the drives and tag tires and monitor the temps?

[DoubleEagle]

It seems to me that the tire manufacturers charts are guides as to what pressure is required to carry a given load, and what maximums are allowed. The vehicle manufacturer considers that as well, but also considers cornering, tracking, and vehicle stability going down the highway. Going by the tire manufacturers guide only misses the unique setup of particular coaches. In cars, the tire pressures can affect the qualities of understeer and oversteer, why not in coaches? Eagle might be gone, but I'm still going by what they said is best.

[buswarrior]

Nope, the tag suspension has a separate regulator, set doesn't change, the drives are aired by the leveling valve.

Very different weights, the tags are way lighter.

Drive the coach forward on the scale to get drives off the plate, and get a reading with the tags alone.

You'll be using the minimum rating for them.

Happy coaching!
Buswarrior

The weights from the scale are front axle and the rear axleS (both drive and tag). I just planned on taking the total weight of the rear and dividing by 6, assuming each tire carries about the same amount. Richard doesn't have a tag so cannot confirm temps of the six tires. Anyone else set the tires at the same pressure on the drives and tag tires and monitor the temps?

[windtrader]

Will the typical truck stop with scales take 3 measurements, front, drive, tag? When I had it weighed there wasn't much issue with getting the two weights recorded.

[neoneddy]

Yeah I messed up. I've got 24 hours to do another weight in.

There were 3 pads, one for front, another for drives and another for the trailer. For whatever reason I figured "I better get the tags on the same platform as the drives".

In any case my PSI seems fine.  Probably due to brakes and load the tires are running warm, but nothing outside of spec.

Part of this is still chasing better MPG. Gah, got 5.1 in Wisconsin recently with a toad. I've been keeping it near 60-63. I'm starting to think I need to go faster. When I cared less I got 6.3-7 mpg.   I know these engines like to run 1700-1800 rpm if I'm correct.

[RJ]

While researching tire load inflation tables by various tire manufacturers a couple weeks ago for a FB thread, I found on three or four manufacturer's load inflation charts an *, which led to a footnote that basically said (paraphrasing here): "*These inflation guides are based on the Tire and Rim Association recommendations." TRA is the industry trade group, of which you have to be a member: http://www.us-tra.org/

Hmmm. . .

Further investigation discovered that nearly every manufacturer's tables were withing 5-10 psi of each other for the most common size bus tires, load ranges and axle weights (which are usually just labeled S or D for Singles or Duals.)

Interesting, eh?

FWIW & HTH. . .



TIP:  When weighing a three-axle bus, most CAT scale operators will allow you to pull forward just enough that the drives are off the scale but the tags are still on.  That will give you the weight on the tags.  (Helps to have a co-pilot to help spot you while doing this.)

[richard5933]

It seems to me that the tire manufacturers charts are guides as to what pressure is required to carry a given load, and what maximums are allowed. The vehicle manufacturer considers that as well, but also considers cornering, tracking, and vehicle stability going down the highway. Going by the tire manufacturers guide only misses the unique setup of particular coaches. In cars, the tire pressures can affect the qualities of understeer and oversteer, why not in coaches? Eagle might be gone, but I'm still going by what they said is best.

In theory I agree - tire pressure affects handling. But then how do we explain the chart that GM put into the Operator's Manual that came with my 1974 GM 4108? It lists pressures ranging from 50psi all the way up to 100psi. That's an awfully wide range of pressures, so I'm going to have to assume that their chart was based on weight loading more than anything else.

[DoubleEagle]

In theory I agree - tire pressure affects handling. But then how do we explain the chart that GM put into the Operator's Manual that came with my 1974 GM 4108? It lists pressures ranging from 50psi all the way up to 100psi. That's an awfully wide range of pressures, so I'm going to have to assume that their chart was based on weight loading more than anything else.

Despite the overall level of pressures, I believe it is the relationship of pressures that affects handling. It always seems that the steers have a higher pressure than the rest of the tires.

[luvrbus]

One thing that amazes me with bus people they will buy tires that exceed the load limit on their wheels by 2 or 3k thinking they are safer.I show some read it on the wheel you have 7500 lb rated tire on a 5000 lb rated wheel what is the point here you wasted money.I saw some Chinese aluminum wheels  22.5 that only had a 4500 lb rating watch those   

[DoubleEagle]

One thing that amazes me with bus people they will buy tires that exceed the load limit on their wheels by 2 or 3k thinking they are safer.I show some read it on the wheel you have 7500 lb rated tire on a 5000 lb rated wheel what is the point here you wasted money.I saw some Chinese aluminum wheels  22.5 that only had a 4500 lb rating watch those   

Now there is a combo to watch out for: Chinese wheels with Chinese Tires.

[Slug]

Getting near impossible to buy any tyres that aren't made in China here in Australia
Most brands now have them made there to the company's spec or they come out of Korea
Cooper is the only US sourced 4wd tyre
Bridgestone are from Japan, European brands can be anywhere including Mexico
But there again the Hummer H3 is made in China