brunsje Posted March 15, 2016 Report Share Posted March 15, 2016 Freightliner Cascadia 2013; I am installing 315 front tires to replace the existing 295's. There are about 3/4" taller. Will this have any impact on my alignment? Thanks, JohnnyB 2014 ShowHauler Motorhome 45' Jacksonville Beach, FL 32250 Link to comment Share on other sites More sharing options...
Phil D Posted March 15, 2016 Report Share Posted March 15, 2016 No, there won't be any alignment changes, but it will change the performance of the truck somewhat, unless you offset the taller tires with lower gearing. The truck will be somewhat "lazier", as far as acceleration goes, and your shift points will be slightly higher. It will, however, raise your truck's theoretical maximum speed. The thing about your proposed change that would most concern me would be finding a replacement tire along the way, should that be necessary. Your current size tires (and their European equivalent, the 275/80R22.5) are as common as fly droppings. Tires larger than that won't be found everywhere. Phil 2002 Teton Royal Aspen 2003 Kenworth T2000 - Cat C12 380/430 1450/1650, FreedomLine, 3.36 - TOTO . . . he's not in Kansas anymore. ET Air Hitch Link to comment Share on other sites More sharing options...
beyerjf Posted March 15, 2016 Report Share Posted March 15, 2016 Didn't even know that size existed. Any particular reason for going non spec? Jeff Beyer temporarily retired from Trailer Transit 2000 Freightliner Argosy Cabover 2008 Work and Play 34FK Homebase NW Indiana, no longer full time Link to comment Share on other sites More sharing options...
HERO Maker Posted March 15, 2016 Report Share Posted March 15, 2016 Above comments are correct except, if I read your posting correctly, you are installing these on only the front steer wheels and not the drive wheels. Phil's comment about performance would then not apply. Depending on where the speed sensor is connected, you might not be getting the correct info on the speedo. Rocky & Sheri Rhoades '01 Volvo 770 2016 DRV Mobile Suites, HoustonHERO Makers Ministry Link to comment Share on other sites More sharing options...
Scrap Posted March 15, 2016 Report Share Posted March 15, 2016 The 9in wheels will have a different offset and and taller/fatter tires will fit different so the steering stops will probably have to move out to accomodate. If that happens then the poppets will have to be reset, which an alingnment guy and his turn plates really helps with. Trucks 3 yrs old and loosened up now, might not hurt to do one anyways? Link to comment Share on other sites More sharing options...
Jack Mayer Posted March 15, 2016 Report Share Posted March 15, 2016 Read the above carefully. There are MANY reasons not to do as you are suggesting. unless you have investigated everything carefully and really have a reason for those tires I would never recommend them. Jack & Danielle Mayer #60376 Lifetime Member Living on the road since 2000PLEASE no PM's. Email me. jackdanmayer AT gmail 2016 DRV Houston 44' 5er (we still have it) 2022 New Horizons 43' 5er 2016 Itasca 27N 28' motorhome 2019 Volvo 860, D13 455/1850, 236" wb, I-Shift, battery-based APU No truck at the moment - we use one of our demo units 2016 smart Passion, piggyback on the truck -------------------------------------------------------------------------See our website for info on New Horizons 5th wheels, HDTs as tow vehicles, communications on the road, and use of solar powerwww.jackdanmayer.com Principal in RVH Lifestyles. RVH-Lifestyles.com Link to comment Share on other sites More sharing options...
peety3 Posted March 15, 2016 Report Share Posted March 15, 2016 I'd also be concerned that you're changing the geometry of the tire by going wider at the tread but not wider at the wheel. I'll change the apparent shape of the sidewalls, which could/would impact the handling, feel, and stability of the truck. Link to comment Share on other sites More sharing options...
brunsje Posted March 15, 2016 Author Report Share Posted March 15, 2016 Thanks for the inputs, you guys are great!! I am considering changing the steers from 295/80/22.5 on 8.25" rims to 315/80/22.5 on 9" rims. As a motorhome I have 15,400# on my front steer axle. I desire a lot of margin for future Alaska trips. The 9" rims are rated to 10,000# and the tires are rated to 9000# each or 18,000# on the front axle. I can also run lower pressures on the 315's. I will get a bit more rubbing when turning hard right on the steering box, which I already do with my 295's. I'll have the hard stops adjusted soon after installation. I have checked with WABCO on the Anti-Lock Brakes and I am well within the margins allowed. Never thought of the speedometer, I'll check that out! Thanks, JohnnyB 2014 ShowHauler Motorhome 45' Jacksonville Beach, FL 32250 Link to comment Share on other sites More sharing options...
Nuke-E Posted March 15, 2016 Report Share Posted March 15, 2016 I can't speak to the Cascadia, but I know there's a guy (Chip was his first name I think) that went to floatation tires on his Showhauler. I know he did it without changing anything other than wheels and tires, and had been incredibly happy with the swap, but that was on a Volvo. He said he didn't rub at either lock. Instead of 110 psi, I think he was running about 70--said the ride was much improved, fuel economy drop was negligible, and he gained some margin on the wheel/tire assembly. If I remember right, he was over 16,000 lbs. With the long wheelbases we have, it's tough not to have a heavy front axle. I expect mine to lose about 200lbs as part of the battery project, which gets it back on the good side of things (until I fill the empty space with more stuff!) 45' 2004 Showhauler -- VNL300, ISX, FreedomLine -- RVnerds.com -- where I've started to write about what I'm up to Headlight and Fog Light Upgrades http://deepspacelighting.com Link to comment Share on other sites More sharing options...
Big5er Posted March 16, 2016 Report Share Posted March 16, 2016 As a motorhome I have 15,400# on my front steer axle. I desire a lot of margin for future Alaska trips. The 9" rims are rated to 10,000# and the tires are rated to 9000# each or 18,000# on the front axle. I see what the rating is for new tires, and what the new rims are rated for but I'm curious, what is the rating on the front axle? MY PEOPLE SKILLS ARE JUST FINE.~It's my tolerance to idiots that needs work.~ 2005 Volvo 780 VED12 465hp / Freedomline transmission singled mid position / Bed by Larry Herrin2018 customed Mobile Suites 40KSSB3 2014 smart Fortwo Link to comment Share on other sites More sharing options...
Nuke-E Posted March 16, 2016 Report Share Posted March 16, 2016 I see what the rating is for new tires, and what the new rims are rated for but I'm curious, what is the rating on the front axle? I believe they've been putting 16,000 lb axles for most of their motorhomes the last few years. 45' 2004 Showhauler -- VNL300, ISX, FreedomLine -- RVnerds.com -- where I've started to write about what I'm up to Headlight and Fog Light Upgrades http://deepspacelighting.com Link to comment Share on other sites More sharing options...
peety3 Posted March 16, 2016 Report Share Posted March 16, 2016 Thanks for the inputs, you guys are great!! I am considering changing the steers from 295/80/22.5 on 8.25" rims to 315/80/22.5 on 9" rims. As a motorhome I have 15,400# on my front steer axle. I desire a lot of margin for future Alaska trips. The 9" rims are rated to 10,000# and the tires are rated to 9000# each or 18,000# on the front axle. I can also run lower pressures on the 315's. Many states have a 600 pound per inch of tread width limitation, which I believe would cap you at 14,880. (315mm * 2 tires / 25.4 mm per inch * 600). You'd need 12.8" or 325mm tread width to maximize your 15,400 axle, according to my napkin. Link to comment Share on other sites More sharing options...
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