mécanique·RV

Au sujet des pneus du motorisé

Ma question sur la page Safarifriends. Recap:

Jim: Get realistic weight to calculate correct air pressure. 255 tire is H rated, maybe overkill for shorter coach (mine is 34, is it short?)
Wolfe102001When replacing the OE 9R22.5, a better choice is a Michelin 255/80R22.5 (G rated) or other brand’s 265/75R22.5 (G)
KayToyo M122 255/70R-22.5, 2500$, ride difference incredible
JohnC: Toyo 9R22.5, 1850$, 95 psi as starting point
John: 265/75R22.5 (G): wider tread, more weight, less pressure, nice ride, does not recommend 9R22.5 because this tire calls for 6.75 inch rim width (but that’s what I have, no?), SMC’s mistake? Best price: Toyo. Some members have had tire cracking issues with Michelin.
Recap by John

Like Brett and myself mentioned that the 265/75R22.5 is the best suited tire to replace the 9R22.5, but the 255/70R22.5 is still a safe and usable tire, if one does not mind a minor speedometer error and and slightly higher rpm on highway speeds. Many Safari (and other coach) owners use the 255 in place of the 9R with out any issues. I have had both sizes and have had no issues with either. The advantages of the 255 is better stability and handling (lower profile tire) and is a more common size, which is a plus if you need a replacement along the way. Also, you get a bit better acceleration and hill climbing with the shorter tire. The down side: slightly harsher ride, minor speedometer error, about 300 rpm higher revs at highway speeds (than you Jim, for doing the math).

The advantages of the 265 are: smoother ride, correct speedometer speed, and same rpm at highway speeds. The downside: handling not as tight/crisp as the 255s, the size is not as common,  and the price is a bit higher.

One thing is for sure, either tire size is able to carry a lot more weight than the 9R. Either will work fine, it all depends on your needs, preferences, and your situation. Like, I mentioned, I ran both sizes w/o issues, I just personally didn’t care for the higher rpm because my coach has 5.29:1 rario stump puller gears, and the 8.3L Cummins likes to work on the low end where they build a lot of torque at very low rpm. I miss the crisp handling, so there are always trade offs…

Patrick, your head is probably spinning with all this info, but I believe that you have been given enough information to make an informed decision on what your needs require. And one more thing, double check the tire charts, but if I remember correctly Michelin’s 255/80R22.5 carries less weight then other brands that have the equivalent tire in 265/75R22.5. Also, consider contacting Mel and asking him about his Michelin experience, as he is one of the group members who had tire cracking issues with in 2.5 years of buying his Michelin tire. Good luck, and enjoy the ride.

John
’95 Safari Serengeti 38ft, 300 Cummins 8.3CTA, Allison
6spd.
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La page de Jim Exler sur les pneus.

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Ma question sur l’installation à Plattsburgh de pneus
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Voir la page des avantages aux membres FQCC pour la réduction de 33% sur les pneus Michelin. Liste des prix Michelin 2017

Michelin XD2 255/70R22.5 74493, prix régulier: 785 $, escompte: 526 $

Michelin XRV 255/80R22.5, prix régulier: 791, escompte: 530$

Chez Simpletire.com (US), différents prix pour fin de comparaison, voici la page des 6 pneus 265/75R22.5 (Toyo à 285$, Yokohama à 298$, Goodyear à 436$)

Chez PneusDD: (chemin pour se rendre à Terrebonne, 450-477-6444)

Goodyear 265/75R22.5: 639$
Bridgestone 265/75R22.5: 561$
Michelin 255/80R22.5: 530$
+ 120$ pour la pose (20$x6) + 30$ pour le torque de 4 pneus

Commande faite du Toyo M154 (265/75R22.5) chez Multi-pneus (450) 454-2522, chemin le 12 avril 2017 auprès de Sylvain, 3 semaines pour le transfert depuis Vancouver. Update: rappel le 24 mai et on me dit que ça va prendre encore 3-4 semaines pour arriver (container en retard à Vancouver!)

Prix: 395.20$ + 150$ pour la pose.  Par contre la fiche Toyo recommande un rim width entre 7.5 et 8.5! Ma largeur de rim est de 6.75! John se fait rassurant :
You are worrying too much as this is not an issue. Older brochures use to show « approved » rim width, showing multiple sizes, now they show just « measure » (which is ideal) rim width, showing only one size number. Take a look at this brochure by Goodyear that is posted in the files section, it show both the 265/75R2.5 and the 255/70R22.5 with an approved rim width of 6.75, 7.5, and 8.25. These size tires have been run on my coach for ten years at a time with out any issues. Well anyway, buy what you feel comfortable with…
Une question datée du 27 avril sur le groupe safarifriends revient sur le sujet des Toyo que j’ai achetés. Bill Edwards met en garde:
I agree that the Toyos are a great tire and good bank for the buck. I have them on the 2001 Zanzibar and were OEM though rated under speed rated. Whatever you have installed be sure to ck the speed ratink, it should be L at 75 MPH not J 65!
Pneus posés et balancés (avec des billes à l’intérieur) le 14 juillet 2017 (un peu plus de 2900$). 100 psi chacun. Un post sur safarifriends sur la bonne pression à mettre. Lu également ici: il faut peser sur une balance le poids individuel sur chaque pneu et utiliser le poids maximal sur un essieu donné. Utiliser ce poids max pour déterminer à l’aide des tables la pression à mettre sur tous les pneus de cet essieu.

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