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Topic: Turning radius with larger tires (Read 560 times) previous topic - next topic

Turning radius with larger tires

I am preparing to out new tires on our unihome 280 and there is little to no choice on tires in the 275/80 size. I cannot seem to go up a load range locally without going to the 295 tires and then there are lots of brand choices. I am aware that you need to adjust the steering stops and the box to keep the tires from touching the airbag pedestals. My question is for the people who have done this, have you noticed the increase in turning radius and do you really miss that little bit?
Toby a 94 u280
Cummins 8.3
6 speed Allison
Exhaust brake


Adopted by Derek and Annabelle

Re: Turning radius with larger tires

Reply #1 –
I'll be interested in whatever answers you get.  We have same model coach, and our tires are approaching the 6-year-old mark...
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Turning radius with larger tires

Reply #2 –
I would wonder if the larger tires would put extra wear on the wheel bearings?
1993 U-240 "La Villa Grande"..CAT 3116 w/ Pacbrake PRXB...Allison 3060 6-speed..
Previous: 1983 Airstream 310 turbo diesel, 1979 Airstream 280 turbo diesel
                                      Build # 4297
                                      PNW natives
                      Home base:  'Cactus Hug' (Ajo, Arizona)
                        DW Judy & Chet the wonder dog
                        Full-Timers 'Sailing the asphalt sea'

Re: Turning radius with larger tires

Reply #3 –
According to Michelin charts, going from 275/80 XZA3 (LRH) to 295/80 XZA2 (LRH), you're adding about 11 pounds per tire.  Some really clever physics major on the Forum should be able to calculate added stress at the bearing.

Don't look at me - I'm a English major...  8)

Tire and Retread Selector | Michelin Truck

Tire and Retread Selector | Michelin Truck
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Turning radius with larger tires

Reply #4 –
Assume (please confirm) that you are considering 295/75R22.5 to replace the 275/80R22.5 and not 295/80R22.5 as replacements.

Without knowing which 295 you are considering, you will get a wide range of comments.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Turning radius with larger tires

Reply #5 –
"The diameter difference between brands of the same size will be greater than any diameter difference between 295/75 and 275/80. This means a 0.1" difference is of no consequence. "

I have run both Goodyear and Toyo 
295/75 tires on both coaches with no alterations. I had a small amount of rubbing on front airbag plates on the 89 GV but nothing on the 96 U270.
Doug W.
96 36' U270 CSGI #4946
04 Toyota Tacoma 4x4
PNW

Re: Turning radius with larger tires

Reply #6 –
So, the 40 footers take a larger tire than the 255/80R/ 22.5/ XRV that we with "short" coaches run ?
1993 U-240 "La Villa Grande"..CAT 3116 w/ Pacbrake PRXB...Allison 3060 6-speed..
Previous: 1983 Airstream 310 turbo diesel, 1979 Airstream 280 turbo diesel
                                      Build # 4297
                                      PNW natives
                      Home base:  'Cactus Hug' (Ajo, Arizona)
                        DW Judy & Chet the wonder dog
                        Full-Timers 'Sailing the asphalt sea'

Re: Turning radius with larger tires

Reply #7 –
Correct, Mike.

The larger/heavier coaches take a larger tire.

BTW, your 255/80R22.5's ARE an upgrade/upsize. OE was 9R22.5 (look on the GVWR plaque)!
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Turning radius with larger tires

Reply #8 –
Quote from: wolfe10 –
BTW, your 255/80R22.5's ARE an upgrade/upsize. OE was 9R22.5 (look on the GVWR plaque)!
Or, if you go to Beamalarm and check the "Specifications" for each model, it lists the factory standard tire.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Turning radius with larger tires

Reply #9 –
Quote from: wolfe10 link=msg=229552 date=14607537  your 255/80R22.5's ARE an upgrade/upsize. OE was 9R22.5 (look on the GVWR plaque)! [/quote

I've not ever had "fat tires". That being said, why the upsize? No tire dealer I've ever been to has weighed the coach on all fours, so are the "fattys" a money maker for the dealer? Granted, our coach rides perfect, but, I'd think the suspension and the custom shocks we have does the trick, rather than the tires. The only better ride was a Marathon/Prevost I drove a while ago, "Like driving on a cloud". 
1993 U-240 "La Villa Grande"..CAT 3116 w/ Pacbrake PRXB...Allison 3060 6-speed..
Previous: 1983 Airstream 310 turbo diesel, 1979 Airstream 280 turbo diesel
                                      Build # 4297
                                      PNW natives
                      Home base:  'Cactus Hug' (Ajo, Arizona)
                        DW Judy & Chet the wonder dog
                        Full-Timers 'Sailing the asphalt sea'

Re: Turning radius with larger tires

Reply #10 –
I am currently looking at both 295 sizes as I am still exploring options. Experience either way would be beneficial.
Toby a 94 u280
Cummins 8.3
6 speed Allison
Exhaust brake


Adopted by Derek and Annabelle

Re: Turning radius with larger tires

Reply #11 –
Toby, I put Firestone 560 295x 75 r on our u300 and have had good luck with them, no rubbing.
Andy & Eileen
MONTROSE COLORADO
1992 U300  40' 6V92 TA
2016 4 Runner
1998 Jeep Grand cherokee

1998 Jeep Grand Cherokee) Build # 4135 Skp# 122921
 

Re: Turning radius with larger tires

Reply #12 –
I think you will have an issue with the 295 80 tires, but not so much with the 295 75 tires
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins