Allegro Bay tire pressures

[dirt40]

Hello all. We will be picking up our new 38BB hopefully in the next couple weeks. wondering what tire pressures you guys settled with. Yes I know we have to weigh the coach and luckily we have a cat scale close.

[fredcat]

We have our 38BB since March. We are running cold 105 to 110

[dirt40]

Originally Posted by fredcat

We have our 38BB since March. We are running cold 105 to 110

How is the ride? The reason I ask is because when we got our itasca the dealer put new tires on it and it drove terrible. they had the tires maxed out at like 110-120. We weighed it and checked the specs and now I run them at 85.

[Karlos]

We have a 2018 32SA on a 24,000 pound GVWR Ford chassis. The door jamb label on the Tiffin says to inflate tires to 100 psi.

I'm running Michelin XRV 255/80r22.5 tires and can look up the recommended Michelin tire inflation for a given load. The 24,000 pound chassis is nominally spit (per Ford) at 9,000 on the front axle and 15,500 pounds on the rear axle. Looking up the Michelin tire inflation recommendations puts tire inflation at both axles at about 85 psi, not 100 psi.

Now, before you jump on those numbers, you need to do a thorough chassis weighing to see what load each corner is actually carrying. You want to check the recommended inflation for the tire brand of your choice also.

cheers,
Karl

[High Road Travelers]

Using the Michelin tire chart and my actual weight on my 2018 32SA 24K chassis I run 80 lbs in each tire, and could go a little less if I wanted. But 80 lbs. provides a safe ride and less harsh than over inflated tires.
Thanks,

[jzeurcher]

We have the exact same coach. Allegro Bay 38BB. Had 4 corner weight checked within a week after our purchase. I am running 90 lbs front and 110 rear. Rides great and not harsh. That’s 10 lbs more air pressure per tire than the tire charts call for. Drives great.

[dirt40]

Originally Posted by jzeurcher

We have the exact same coach. Allegro Bay 38BB. Had 4 corner weight checked within a week after our purchase. I am running 90 lbs front and 110 rear. Rides great and not harsh. That’s 10 lbs more air pressure per tire than the tire charts call for. Drives great.

Did the 4 corner weigh show that you needed more air in the rear or is that for your peace of mind?

[jzeurcher]

The rear tires are carrying a lot of weight even though they are duals. I can get the weights later and then post.

[fredcat]

Originally Posted by jzeurcher

We have the exact same coach. Allegro Bay 38BB. Had 4 corner weight checked within a week after our purchase. I am running 90 lbs front and 110 rear. Rides great and not harsh. That’s 10 lbs more air pressure per tire than the tire charts call for. Drives great.

The pressures we gave are for us, but when I said cold you need to remember, we live in the Phoenix area!

Our 2023 AB 38BB rides great loaded. This time of year our fronts are 105 and rears are 110.

[jzeurcher]

Outside temp are not relative to the air pressure you are going to put into your tires. The cold air pressure that is stated on your tires only means that you have not driven your coach recently and the air pressure has stabilized. Now yes the area that you are parked at does change the air pressure because of outside temps. You still set your tire pressure to that cold pressure reference.

[jadatis]

If you give tire specifications, I will make you an extra safe pressure/loadcapacity list, with build in reserve, and per axle given.
Saves you precalculations.

Then whenever you weighed, you only have to look back those axleweights back in my list, and use the cold presdure with it.

In front, you could loik back the GAWR's, that is what the vehicle maker also uses.

Need next:
1. Maximum load or loadindex, single/dual
2. Loadrange or better pressure behind AT, and if ST.
3. Speedcode.
Sizes would be nice too, and howmany axles and if dualload.

[dirt40]

Originally Posted by jadatis

If you give tire specifications, I will make you an extra safe pressure/loadcapacity list, with build in reserve, and per axle given.
Saves you precalculations.

Then whenever you weighed, you only have to look back those axleweights back in my list, and use the cold presdure with it.

In front, you could loik back the GAWR's, that is what the vehicle maker also uses.

Need next:
1. Maximum load or loadindex, single/dual
2. Loadrange or better pressure behind AT, and if ST.
3. Speedcode.
Sizes would be nice too, and howmany axles and if dualload.

Thank you. We don't have the coach yet so it might be a week or two.

[jzeurcher]

These are the weights for our 2022 Tiffin Allegro Bay 38BB super C. Okay we did a 4 corner weight performed last year with 3 people onboard full tank of fuel and don’t remember how much water in tank.
Front left 4640#
Front right 4340#
Rear left. 10530#
Rear right 9680#
Total weight 29190#
This calls for 75# air in front tires
105# air in rear tires
Rode good but really felt steered loose on fronts. Drove better with 90# in front. So I run 90# in front and 105# in rear.
Now we just bought the coach and had everything from our old coach loaded haphazardly everywhere just to get home and then loaded everywhere it should be.
We ran over the scales a mont later with everything loaded correctly with 1 person on board full tank of fuel and at least 100 gallons of water.
Front axle. 8920#
Rear axle. 20380#
Total weight. 29280#
GVWR is rated at 33000# for this coach.

[jadatis]

Then if you give me the tirespecifications, I will make a list for those as described in my earlyer post here. Then if by accident they are the same as topicstarters, he can use it to when he weighed.

Then most likely you will see that front in my list comes to that 90 psi, and mayby rear higher then 105.

About your remark in post #10.

My idea is that cold pressure is when temperature of gascompound in tire is the same as the air outside the tire.

That is when no external factors, and standing long enaugh, so not driven for 3 hours or more will do mostly. .

Only that last has become the definition in time.

And to my opinion the cold measured pressure has to be calculated back to a reference-temperature before comparing it to recomended or determined cold pressure.

A long story I made for that in another topic on other forum to explain why. Was burned down for it by the " tire-specialists" in that topic, so I searched the internet for prove of others that go from a reference temperature.
Found RIMEX for earthmovers who even has a calculator for it and uses index temperature of 68 degrF. A belgian firm B alert, for trucktiremanagement uses 15 degrC/ 60 degrF in his examples.

Will spare you all the details, because to much off-topic here.

But for who it interests, mail me at my hotmail. com adres with username jadatis, and I will send you back the word document and more.

Combine my mail adres yourselfes, spamm machines cant this way..... I hope.

Lets see if we can keep this topic below 40 posts.