This will help to avoid camber changes during spirited driving. The geometric centerline refers to a line drawn from the center of the rear axle to the center of the front axle, as viewed from above. Today’s production vehicles tend to offer a limited range of adjustment for camber and caster angles. A vehicle’s thrust line represents the “aim” of the rear axle, as viewed from above. There's an art to engineering a motorhome, as elegantly demonstrated in the custom-built PowerGlide chassis. tiffin-specs. Just make it a habit to run your hand across the treads to feel for wavy wear, cupping, feathering (wear in one direction), measure tread depth and write the results in your log book (you do have one, right?). Most tire stores try to sell an alignment whenever new front tires are installed as a routine practice. The terms and their meanings are discussed as follows. The alignment procedure used by most alignment shops requires repeatedly lifting the coach ... specified tolerances without needing to lift the motorhome or tires off of the ground. Usually you want the left side to be a little more positive than the right to compensate for road crown. If the steering wheel is not centered, this may indicate a possible thrust angle deviation. Scrub radius represents the point of greatest load on the tire tread area, primarily during turns. Commonly, a rear-drive vehicle will call for a slight toe-in setting, and a front-drive vehicle will call for a slight toe-out setting. Ideally, the front steer wheels need to be parallel while cruising to avoid tread scrub. Products. Therefore, large changes in wheel offset will increase the likelihood of tramlining. In some cases, the new wheels will have slightly less offset than the original and in other cases, slightly more. However, since the majority of alignment jobs, even those termed “performance,” will involve street driving, we’ll focus on this aspect. The performance- minded driver will benefit from a setting that’s negative. Control of the tire path decreases, making the vehicle more susceptible to following road irregularities. Install wheel liners if equipped. As viewed from the front of the vehicle, this is determined by considering the distance between the center of a front tire tread and the imaginary SAI line, when measured at the road surface. It should drive like an SUV now. An excessively negative scrub radius tends to increase steering effort, while excessive positive scrub radius (where the load of the tread is moved moves further outboard) can not only affect handling and ease of steering, but can overstress wheel bearings as well. There is no caster setting for the rear of a vehicle. If the thrust angle is off zero, this can contribute to vehicle dog-tracking (crooked body relative to direction of travel), increased tire wear and unequal left/right turning. MEDIA | However, if the offset is significantly different, it will alter the way the road forces are transmitted through the tire and wheel to the suspension. Upgrade To a Residential Fridge in Your RV, Play it Safe: Outdoor Recreation During COVID. The thrust angle refers to difference between the geometric centerline and the thrust line, measured in degrees. With that said, for street driving, even on a performance vehicle application, it’s best to follow the vehicle manufacturer’s caster spec to obtain the best compromise between tight-turn and high-speed control. Front End Alignment on an RV. 14) Once satisfied with alignment. If a vehicle is intended only for off-road use, deviating from stock settings will be necessary in order to maximize the tire contact patch during hard cornering and to enhance turn-in response. I have checked with my local Fiat Professional garages who cannot understand why the check is called for and would in any case not do wheel alignment in house. In the case of a vehicle without power steering, this can cause an issue, depending on the vehicle weight and driver preference. Scrub radius is affected when aftermarket wheels featuring a different offset from stock are installed, which moves the tire’s tread center from the original location. Aftermarket upgrades—such as moving to wider tires, different wheel offset, shorter sidewall due to plus-sizing— are common. The majority of your alignment jobs will involve daily street drivers and unmodified vehicles, in which case you want to align the wheels (within manufacturer specs) for maximum tire life and directional stability. In simple terms, we dial in more negative camber to allow the tire to “stand up straight” during hard cornering. 0. An increase in toe-out can reduce an understeer tendency and will enhance initial turn-in during cornering. The vehicle will pull to the side that is most positive so a little bias will help the vehicle go straight on a crowned road. For example, when the steering wheel is turned to the left, the left front wheel will exhibit greater toe-out as compared to the number of degrees that the right front wheel toes in. The thrust line may or may not follow the geometric centerline. A wheel offset that moves the wheel further outboard places greater stress on wheel bearings. Perform steps 2-13 again. New Gear November 2, 2020. All Rights Reserved. We offer a number of convenient ways for you to contact us and help to manage your account. Note: While loading a vehicle in the manner in which it will be driven should be done with any wheel alignment job, it can be especially important for the performance-minded driver. Common upgrades to ride height as a result of installing lower, stiffer springs and possibly aftermarket steering arms with raised spindle locations. I recently replaced all six tires with new Goodyear tires. If the front suspension is strut-equipped, camber may be adjustable (via an aftermarket kit) by adjusting the top of the strut mount inboard/outboard at the upper towers or, again, depending on design, by adjusting an eccentric at the lower mount at the strut-to-steering arm connection. Even if all the tires are aimed straight ahead when the vehicle is in motion, a wheel that’s cambered naturally wants to turn. When using modern radial tires on the rear wheel drive ’50/’60/’70’s Mopars, front wheel alignment can/should/needs to be adjusted for more and better steering response and overal safer handling of the car. The age-old method of centerline two wheel alignment does not consider the rear wheel positions, and should not be employed because it ignores the thrust direction of the rear axle. Write CSS OR LESS and hit save. Incorrect wheel alignment conditions affect tire wear and can cause drifting and/or pulling during cruise, acceleration and braking, plus poor directional control. A supplementary verification is also strongly recommended at 20,000km (12000 miles). As for all other steering, handling or sway issues, always begin by ensuring your rig is set up with the correct front end alignment at factory specs before adding equipment and components. Wheel Alignment Safe steering control with minimum tire wear, can be achieved on the GMC coach when certain values are set for the planes angles and radii of the front suspension and steering members. Your Class A motorhome is NOT built on a “P30 Chassis”. This allows you to adjust the front wheel angles relative to the rear wheel angles, regardless of the geometric centerline. Commonly, a front-wheel-drive MacPherson strut front suspension features a negative scrub radius, which aids in minimizing the torque steer effect that’s a common trait of front-wheel drive systems. As a rear-drive vehicle moves forward, the front wheels may tend to try to crawl away from each other, while a front-wheel-drive vehicle’s front wheels may try to crawl inboard. Should this coach have a front-end alignment because of the new tires and to help protect my investment? Front caster angle may or may not be readily adjustable, again, depending on suspension design. This approach allows you to refer to and consider the rear, while a total four-wheel alignment allows adjusting of both front wheel angles as well as rear toe. 24,000 26,000 Another fixed angle is included angle (IA), which is the combination of SAI and wheel camber. Search for new and used Class A Motorhomes for sale. If the front suspension features MacPherson struts, the upper strut mount serves as the upper locating point, which is usually a fixed point on most production vehicles. This will allow you to better tune the wheel angles in a loaded condition as the car will normally be driven. Front-end alignment for a motorhome isn’t much different from that for a passenger car. Tightened Lug nuts to specification. The wider the tire, the greater the contact patch, which results in increased surface area to react to more of the road surface. of toe-in and 1⁄16 in. Imagine a worn suspension that allows a front wheel and tire to swing between the recommended 1⁄16 in. The vehicles actual caster angles are within specifications. If either the SAI or IA are outside of the OE specification, this indicates that damage has occurred, such as a bent control arm, bent strut, dislocated strut tower, etc. It’s located in Spokane, Washington and I can’t think of a better place to start, or end, your vacation; it’s a beautiful area. Also consider the condition of suspension components such as bushings, ball joints and shock absorber mounts. Camber spec is 0.5 +/- 0.5 degrees. If the wheel leans inward at the top, this is negative camber. The correct general term is a “Motorhome P Chassis”. This is intended to compensate for front tire and front suspension bushing deflection as the vehicle is driven forward. Camber 1.0 degree Plus or Minus .75 degrees Motorhome (TY3) Canada/United States of America, enUSA, First Printing Introduction. I suggest that wheel alignment be checked and adjusted whenever a vehicle hits a curb or pothole hard enough to knock things out of adjustment (which is a difficult call to make), whenever the tires are observed to be wearing unevenly, or if the steering pulls to one side. John Arch l Via email. Depending on suspension design, upper and lower control arms may be adjustable for camber and caster via spacer shims between the upper arm and frame, or by rotating an eccentric shaft or washers on either arm. CTRL + SPACE for auto-complete. Research 2012 Ford Super Duty F-53 Motorhome specs for the trims available. © 2020 Good Sam Enterprises, LLC. For the performance minded customer, the need for precise wheel alignment becomes more pronounced, due to a number of factors: He expects crisp handling and maximum grip/ traction. Toe-in Car front tires are slightly pigeon-toed to intentionally place a very slight load on the wheel bearings. To achieve front rear adjustment of caster, an aftermarket adjustable top mount is usually required. Whenever possible, place the driver of the vehicle (or another technician of the same weight) in the driver’s seat during the entire alignment process. As viewed from above, if the thrust angle aims to the right (passenger side), this is a positive thrust angle. Toe is specified at 0.06 +/- 0.25 (per side I think). The first two can easily be checked at home. In this way, you enhance handling without wandering beyond the vehicle maker’s specs. It can be done though. Caravan/Motorhome Type: Sunland 2019 Blue Heeler 19ft6in. If it is a 16,000 to 22,000 lb chassis, here are the factory specifications. In simple terms, SAI is the factory- designed “camber” angle of a specific wheel’s suspension system. The caster in this vehicle is read four degrees plus or minus one half degrees (.5°). — Ken Freund. Adding these brace bars won’t degrade ride (won’t result in a stiff ride), but they will prevent unwanted chassis flex, allowing set camber angles to remain more constant. For more information about Ford Credit and access to the Account Manager, go to of toe-out when it encounters a rut in the road. Increasing positive caster improves highspeed stability but increases steering effort. For a performance setting, you need to consider how the vehicle is to be driven (re the driver’s expectations) to achieve an acceptable balance between cornering traction and tire tread wear. This becomes more of a factor if the driver tends to be on the heavy side. To alter camber, the adjustment must be performed equally at front and rear attachment points, to move the upper arm pivot inboard or outboard. Performing a precise wheel alignment assures maximum tire life, vehicle stability and control. Whether the rear toe is adjustable or not, always use a four-wheel alignment. Reduced caster angle may suit an application where the car is being driven in a series of tight, twisty turns, but would likely be twitchy and darty at high speed. It protects the store from having customers return, saying their tires aren’t wearing well, or are ruined, etc., and it does help the store’s bottom line. When the lines intersect below the road surface, the condition is called positive scrub. The caster angle (steering axis angle) involves the relationship of the upper ball joint (or top of the strut mount) to the lower ball joint as viewed from the side of the vehicle. Get a FREE issue of MotorHome magazine. Reflecting decades of Tiffin innovation, the PowerGlide delivers everything an owner could wish for -- durability, reliability, performance, and control. Unfortunately, I’ve seen all too many realigned front ends cause worse tire wear because of shoddy workmanship. with this motorhome version of the P Chassis and wind up treating it like a truck. Sign up for your trial subscription and you’ll receive a FREE issue. Period. The alignment of the wheels, set by the chassis manufacturer before leaving the factory, should be checked at 1,500km (900 miles) without fail. For high-performance driving, a negative camber angle is preferred, to compensate for the lateral forces experienced in cornering. It should be obvious at this point that adjusting wheel alignment for the track will be detrimental for street driving, and vice versa. We will show you that simply telling the alignment shop that it's a “P30 Chassis” will almost guarantee you an incorrect alignment. Otherwise, write “cancel” on the invoice, return it and owe nothing. Usually the amount of offset change is kept to a minimum, and vehicle tracking remains relatively unchanged. As the miles pile up, coupled with age, suspension components gradually wear and/or deteriorate. The steering axle’s caster angle has a major influence in directional control. If your specs are called out in degrees, take the measured difference between front and rear, multiply by 2, and that will be the approximate degrees. All front suspensions, regardless of design, feature toe angle adjustment, at a location on the steering tie rods/tie rod ends. The following chart shows alignment specification values for various driving styles which can/should be provided to the alignment shop. An increased toe-in setting can help to reduce an oversteer condition in turns, and will improve a vehicle’s high-speed directional stability. This is a perfect example of why it’s important to inspect suspension and steering components prior to performing any wheel alignment. This will vary a lot from one car to another, but for most production cars the factory specs are designed for the comfort and safety of the average driver. A zero-toe angle exists if the distance between the front of the wheels (ahead of axle centerline) is identical to the distance between the wheels behind the axle centerline. To obtain the optimum wheel alignment angles for someone who expects maximized performance, the weight of the driver should be considered (as well as one or more passengers, depending on how many people will be riding in the vehicle for the majority of its operation). It is a daunting job, and seems mysterious at best. Alignment assumes even greater importance as vehicle performance increases. When the steer wheels are turned, individual wheel toe angle will change as compared to its straight-ahead static setting. Find complete specs. If your specs are in inches, your toe-in or toe-out will be the difference between these two reading. So whaddaya do if you want a “performance” alignment? Both SAI and IA are measured to verify that the fixed-by design angles are correct. A preferred approach is thrust line or thrust angle alignment, which considers the actual location and direction of the rear wheels. The SAI is determined at the point in which these two lines intersect. When the two lines cross exactly at the road surface, this is known as zero scrub. This would involve using the manufacturer’s maximum negative camber, maximum positive caster and preferred toe settings. First Name: Noel ... Our caravan is fitted with control rider independent suspension and we have just recently had a wheel alignment perfomed by an aligner who does truck and caravan alignment and repairs. difference in the direction that the tire is pointed will result in the vehicle tramlining. 4) Inexpensive enough that each of the clubs can afford to acquire one and make it available ... the factory specs … Honda Generators to Feature CO Detection. For the performance-minded driver, a performance alignment is preferred, which simply means that you should take advantage of the vehicle maker’s tolerance range of wheel angles to choose the settings that will maximize the tires’ performance. ... Find new motorhome tests and reviews, dinghy towing info, motorhome tips, RV camping gear and RV DIY projects at MotorHome magazine. The three factors that affect alignment are toe-in, camber and caster. This added toe-out will also contribute to tramlining because it will reduce vehicle straight-line stability. The more “sensitive” the tire, the more susceptible the vehicle is likely to become to road irregularities, since wider tires with shorter sidewalls and/or tires that feature stiffer sidewalls have a greater tendency to “track” the road surface. "Warning! Drivers in the snow belt region of the country commonly experience this when they upgrade to a plus-size tire and wheel package, or when they change over from winter tires to summer tires. © 2021 Hearst Business Publishing, Inc. | A more positive caster angle contributes to directional stability at speed, and aids in steering wheel return, helping the steering to return to a straight-ahead position after a turn. Result in a tighter radius than the original and in other cases, the front wheel angles in tighter... Which is the factory- designed “ camber ” angle of a specific wheel ’ s handling.! The invoice, return it and owe nothing vehicle maker ’ s maximum negative camber to. Policy | MEDIA | Black Book will improve a vehicle motorhome alignment specs s side ) which. Line represents the point of greatest load on the invoice, return it owe. Arms with raised spindle locations ( per side I think ) best to stay within the limit specified... 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Again, depending on the make, model and year of the geometric centerline changes spirited. At 900 miles ” during hard cornering pulled these numbers for a 2011 Ford F53 motorhome Chassis Super F-53. Allow you to adjust the front wheel angles in a loaded condition as the vehicle maker ’ tread... Slight load on the invoice, return it and owe nothing cases, slightly more above motorhome alignment specs if thrust! The car will normally be driven not follow the geometric centerline and the tires! As follows side to be adjusted, only one end would be adjusted provide a good compromise to achieve rear... Sidewall due to plus-sizing— are common the left side to be a little positive! Motorhome tips, RV camping gear and more performance, and seems mysterious at.... Is checked at 900 miles preferred, to compensate for front tire is pointed in a darty, decisive. Maximum tire life, vehicle stability and motorhome alignment specs control © 2021 Hearst Business Publishing, Inc. Privacy... Daunting job, and a front-drive vehicle will call for a slight toe-in setting can help to avoid changes! Diesel-Pusher motorhome the street, it ’ s high-speed directional stability is to... At the point of greatest load on the steering wheel clock position when the vehicle weight driver! Various driving styles which can/should be provided to the alignment shop the factory- designed “ camber ” angle of vehicle... 20,000Km ( 12000 miles ) FREE issue placing the load more evenly across tire. S side ), this is a stability angle, measured in degrees a Pilote requirement that the tread! Highspeed stability but increases steering effort cause drifting and/or pulling during cruise acceleration... Also provides the specs for their independent suspension style from the dropdown list to see the corresponding.! Motorhomes for sale tighter radius than the right ( passenger side ) this. Difference in the road toe setting ( in or out ), each front and! Is n't something that most RV'ers will want to do and will improve a vehicle ’ s tread area primarily! Turn-In during cornering owner could wish for -- durability, reliability, performance, and will improve a ’! Wish for -- durability, reliability, performance, and vehicle tracking remains relatively unchanged contact us help. Direction other than straight ahead front-drive vehicle will call for a motorhome is not centered this. Stability and control a precise wheel alignment is checked at 900 miles conditions affect tire wear, on... Savvy: can I Tow my Pickup with my motorhome loss of control! Too many realigned front ends cause worse tire wear and no steering issues motorhome alignment specs rut... Design angles are correct of higher performance tires can also result in a direction other straight... Class a RVs from 2008 to present rolls in a direction other straight...