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KenS999

West Dundee, IL

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Posted: 11/08/21 09:21pm Link  |  Quote  |  Print  |  Notify Moderator

I had a leaf spring break on my 2017 Forest River Cherokee Wolf Pup 16fq while on the interstate. According to the service tech that came out to replace it... it is a 25-1/8" 4 leaf for a 3500 lb axle. I want to replace the other original one so I do not repeat the same issue. Seems like available options for a replacement leaf springs is 25-1/4" length. My question is ...will the 1/8" difference affect the spring height and causes a side to side alignment issue or create installation headaches when trying to line up the leaf spring eyelets.... or is the 1/8" difference in fact negligible? Thanks.

pianotuna

Regina, SK, Canada

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Posted: 11/08/21 10:20pm Link  |  Quote  |  Print  |  Notify Moderator

Hi,

I had my springs rebuilt. I did not align the wheels. Now in the spring it will be new tire time.


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, soon to have SiO2 batteries, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

JBarca

Radnor, Ohio, USA

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Posted: 11/08/21 10:22pm Link  |  Quote  |  Print  |  Notify Moderator

I'll pass along what I know on this, but I need to clarify what you are asking first too.

Are asking, can the one side the tech replaced be a 25 1/8" and the other, you will replace with a 25 1/4" long "unloaded" eye to eye length be OK?

If that is what you are asking, the answer would be no in my opinion. You would negatively affect/change the thrust angle of the axle to the tow ball to be beyond tolerance. I'll explain a little.

For proper axle alignment to have the trailer track straight ahead with the body of the camper, the dimension from the center of the tow ball to a "place" where the wheel mounts to the axle on the left side, needs to be the same from the tow ball to the same "place" where the wheel mounts to the axle on the right side within a tolerance.

See this sketch I made, this is on tandem axle and yours is single axle, but the front axle has the same needs. The tolerances are what I received from Dexter axle.
[image]

Since the main leaf spring mounts to the front spring hanger, the leaf spring distance from the hanger bolt to spring pack center pin creates the center of the wheel on each side. The center pin in the leaf spring pack aligns to the axle seat. While the 1/8" eye to eye would result in 1/16" at the spring center pin distance, the wheels could be more then the 1/16" off on purpose by using the different length springs as there is other error in the system already. The hangers are not welded on "exactly" the same on the left and the right, the excess play in the axle seat hole to the spring pin can be shifted against you, and then you intentionally added in a 1/16" offset and you can be way out of tolerance. The tires will wear prematurely and the camper may dog track to one side when towing.

Since trailer axle alignment is poor to start with on an RV in many cases, I would not introduce on purpose known error the entire recommended tolerance from the start.

I looked quick and they do make the 25 1/8" eye to eye. BUT you have to confirm the spring arch height is the same as the other spring and that the tech did not make a mistake and it was not a 25 1/4" spring.
https://www.etrailer.com/Trailer-Leaf-Sp........uspension/Universal-Group/SP-212275.html

NOTE: The arch height is normally measured from the center of the eye to the surface of the main leaf at the center. But some web sites are showing the arch height at the top of the center pin which I feel is not accurate.

Ideally go back to the tech and get the same brand and spring they put in. Also, check the axle weight and each wheel to make sure you are not over weight which may have caused the first leaf spring to fail.

Hope this helps

John

* This post was edited 11/19/21 08:12am by JBarca *


John & Cindy

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time2roll

Southern California

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Posted: 11/08/21 10:44pm Link  |  Quote  |  Print  |  Notify Moderator

I believe 0.125" is a rounding error. However I would replace all springs at the same time. I also moved up to about 4500 (2250 each) rating on my 3500 pound axles. Has never rode better for the last 10 years and many thousands of miles.

Bought mine here: http://www.stengelbros.com/trailer-suspension-parts/trailer-leaf-springs/

Installed myself over a few weekends.


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wa8yxm

Davison Michigan (East of Flint)

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Posted: 11/09/21 04:39am Link  |  Quote  |  Print  |  Notify Moderator

I have had springs rebuilt as well. Cheaper than full replacement and the spring builders make 'em the same size.

Also done it for others.
not that hard... Well no harder than replacement.


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MT BOB

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Posted: 11/09/21 07:09am Link  |  Quote  |  Print  |  Notify Moderator

Much ado about nothing. You have only 1 axle. Leaf springs are not really made to exacting specifications. Where they are clamped to the axle is not a "tight" fit,allowing adjustment for alignment. This is also how it is done on cars, trucks and trailers with leaf springs,front and rear. And,because there is no "steer" in a single axle trailer,alignment is usually moot,as comes close anyway, or can even be checked with a tape measure. The important thing is how the vehicle sits when loaded, should be level(not if trailer is poorly loaded), which is why springs are generally replaced,or rebuilt in pairs,per axle.There are occurrences where there are different springs,right to left,but yours would not be one of these.

JIMNLIN

Oklahoma

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Posted: 11/09/21 07:01pm Link  |  Quote  |  Print  |  Notify Moderator

delte ...wrong reply


"good judgment comes from experience, and a lot of that comes from bad judgment" ............ Will Rogers

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