Vibration

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MattP
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Joined: Mon Sep 01, 2014 7:02 pm

Vibration

Post by MattP » Sun Feb 04, 2018 12:06 am

I have a Modcon Imperial forward fold. At about 80 to 100kph it has a shimmy which is felt through the seat of your pants in my FJ Cruiser. Feels exactly like the wheel balance is out on the rear tyres of the car but the car is perfect with the trailer removed. The only change I made was changing the rims to match the car, same height but slightly different offset so the tyres are slightly closer to the chassis. To rectify the problem I had the wheels balanced, changed tyres and wheels balanced again, trailer suspention/brakes/bearing/ alignment serviced by vehicle components (told them about the shimmy) all to no avail. Tried the trailer on three four wheel drives and it shakes them all. Moving the load around (forward/aft), changing the trailer hitch length, and pin height (DO35) also has little effect. Ball load changes from 130kg unloaded to 200kg loaded, also have no effect. Frustrated as we are trying to fix this before a two month trip away. Any suggestions? I could put the old wheels back on but that would require rechanging the studs and reverting to having one spare for each of the car and trailer instead of 2 matched spares. Thanks

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robcaz
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Re: Vibration

Post by robcaz » Sun Feb 04, 2018 8:43 am

Hi Matt,

Are the lug nuts the correct size? It seams as if the bolt holes in the rim are not the correct PCD to the hub, so the tapered heads on the lug nuts do not seat into the tapered holes properly. Have you tried having the rims balanced while on the trailer? Hope this helps.
happy camping
Rob & Carol
Australian CamperTrailers Group co-owner


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We're just two lost souls swimming in a fish bowl, year after year

MattP
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Joined: Mon Sep 01, 2014 7:02 pm

Re: Vibration

Post by MattP » Sun Feb 04, 2018 10:47 am

Yes. I replaced the studs to suit the original Toyota lug nuts which came with the extra FJ wheels I purchased for the trailer. Good idea about an on camper wheel balance.

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robcaz
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Re: Vibration

Post by robcaz » Sun Feb 04, 2018 11:23 am

Hi Matt,

Also if the wheel nuts are enclosed, they may be bottoming out on the studs before fully seating into the rim???
happy camping
Rob & Carol
Australian CamperTrailers Group co-owner


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We're just two lost souls swimming in a fish bowl, year after year

MattP
Posts: 6
Joined: Mon Sep 01, 2014 7:02 pm

Re: Vibration

Post by MattP » Sun Feb 04, 2018 11:42 am

That's a very good point, I never thought of that.
I will check. Thanks very much!

robcaz wrote:Hi Matt,

Also if the wheel nuts are enclosed, they may be bottoming out on the studs before fully seating into the rim???

MattP
Posts: 6
Joined: Mon Sep 01, 2014 7:02 pm

Re: Vibration

Post by MattP » Sat Feb 17, 2018 4:28 pm

The studs turned out to be OK. However, putting hubcentric spacer rings to centralise the FJ wheel on the trailer hub seems to have fixed the problem. The FJ shank nuts (not bevelled) don't seem to be good enough on their own to centralise the wheels on the trailer hub. The hubs on the FJ have a ring to centralise the wheel which are obviously absent on the trailer hub/drums.

MattP wrote:That's a very good point, I never thought of that.
I will check. Thanks very much!

robcaz wrote:Hi Matt,

Also if the wheel nuts are enclosed, they may be bottoming out on the studs before fully seating into the rim???

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robcaz
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Joined: Sat Oct 12, 2013 4:07 pm
Location: Stockton NSW
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Re: Vibration

Post by robcaz » Sun Feb 18, 2018 2:26 pm

Hi Matt,

Thanks for getting back to us & glad to hear you have found the solution to your problem. My next question was exactly that, are the rims on the trailer hubcentric or lugcentric to match the hubs?
happy camping
Rob & Carol
Australian CamperTrailers Group co-owner


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We're just two lost souls swimming in a fish bowl, year after year

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