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Shimmy shimmy shimmy

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Shimmy shimmy shimmy
#1
  This topic is about my 1980 Triumph TR8
Charlie D Gold Member Charles Dankmeyer
Arnold, MD, USA   USA
I have been going thru the steps to rid my car of the dreaded front end shimmy. The new tires have now been balanced three times at two different shops. First shop, then second shop said they were balanced, back to first shop who said they are balanced. Did all 4. I was taught that if it was a balance problem you could "drive through it" which is what I typically experience. Starts about 50, continues to 55 or 60, then goes away. BUT, it is inconsistent. Sometimes it shimmies, sometimes it doesn't. Sometimes a bump triggers it, sometimes it doesn't. There is a lot posted on this issue and one of the suggested remedies is the front wheel bearings. I have a hard time wrapping my head around an inconsistent shimmy and wheel bearings. Before I go throwing parts and labor at this, has anyone had success ridding the shimmy with a wheel bearing change? I am running 15" wheels and as far as I know the wheel bearings are original--75K miles. Also, if wheel bearings are really a potential solution, has anyone used Ted's wheel bearing upgrade? Thanks as always! And Happy Holidays to All!
Charlie D

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Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, OR, USA   USA
1980 Triumph TR7 Drophead "The Great Pumpkin"
1980 Triumph TR8 "Wedgie"
In reply to # 1585195 by Charlie D I have been going thru the steps to rid my car of the dreaded front end shimmy. The new tires have now been balanced three times at two different shops. First shop, then second shop said they were balanced, back to first shop who said they are balanced. Did all 4. I was taught that if it was a balance problem you could "drive through it" which is what I typically experience. Starts about 50, continues to 55 or 60, then goes away. BUT, it is inconsistent. Sometimes it shimmies, sometimes it doesn't. Sometimes a bump triggers it, sometimes it doesn't. There is a lot posted on this issue and one of the suggested remedies is the front wheel bearings. I have a hard time wrapping my head around an inconsistent shimmy and wheel bearings. Before I go throwing parts and labor at this, has anyone had success ridding the shimmy with a wheel bearing change? I am running 15" wheels and as far as I know the wheel bearings are original--75K miles. Also, if wheel bearings are really a potential solution, has anyone used Ted's wheel bearing upgrade? Thanks as always! And Happy Holidays to All!
Charlie D

Charlie:

A couple of things here. First, you need to make sure that the castle nuts on your front end are tight enough. The manual says something like "Tighten until finger tight, then back off one flat". I have found that to be too loose, so I tighten until they are finger tight, period. I also grasp the tire at 12 o'clock and tip the wheel in and out from the car body while tightening the castle nut, to make sure the wheel bearings get fully seated as I tighten. There should be no perceptible tipping motion to the wheel if the wheel bearings are fully seated. Sometimes the castle nut will hang before the bearings are fully seated if you do not tip the wheel in and out while tightening the nut.

Secondly, you mention you have after market wheels. If the wheels have trim rings, for example, they must be balanced with the trim rings in place. Tire shops will remove them while balancing, but they affect the balance when reinstalled. TR6s have this problem, for example as the stock wheels have trim rings. TR7s also have this problem, because they have trim rings as well. So I will ask if you had the wheels balanced exactly as they will be installed on the car, or was something removed or added before they were balanced?

Next, have you checked your tie rod ends? Make sure there is no slop in them. Also, the tie rods fasten to the end of the steering rack with a ball joint and a large nut. It is possible that this has loosened (unlikely, but possible). So get the front end off the ground, grasp the tire at 3 and 9 o'clock and try to tip it in and out. If there is any slop, fix it before proceeding.

Lastly, are your front struts in good working order? You mention hitting a bump will sometimes cause the shimmy to start, which is consistent with worn out struts. They do not have enough damping to prevent the wheel from oscillating after it is disturbed. I had a Toyota Celica back in the day that had this exact problem. New struts fixed it right up. The front end was particularly prone to shimmy if I was negotiating a curve at speed and one of the front wheels hit a pothole or was otherwise disturbed.

Personally, I doubt that the wheel bearings are bad. If they are, you will feel roughness as you rotate the tire by hand (wheel off the ground, of course). The one time I have encountered a bad wheel bearing, it made a growling noise as I motored down the road, that could be felt through the car body if you laid your hand on a metal surface. Normally they complain loudly if they are failing.

Vance



1980 Platinum Metallic TR8, frame off restoration, complete.
1980 Vermilion TR7 Sprint replica, in progress.

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Rover827 Avatar
Rover827 Rich Truett
Berkley, MI, USA   USA
1979 Triumph TR7 "Haggis"
1981 Triumph TR8
1982 Triumph TR8
To ensure the wheels are properly balanced find a shop that uses a Hunter Roadforce machine.

This balances the tire to the wheel and then balances the tire and wheel as an assembly. If you still have the shimmy, I would next take a look at the brake rotors. Some warpage there will cause a shake like you describe.

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robtr8 Rob Stephenson
Lake St Louis, MO, USA   USA
I mentioned the dreaded shimmy to my buddy who was checking my TR8's alignment on his Hunter Eagle Eye. He tightened the sway bar end nuts really tight which induced a bit more caster. Problem solved.



1980 TR8 - MBT-RX, Overdrive Plus, GM-D9605, GS62, TS-SW2502S4 (2X), Glenn's Wilwood kit, Ted's everything else.
2006 XC90 V8 - AVH3300NEX, PDX-F4 (2X), PDX-M12, GB10, GB25, AR6K, GB12D4 (2X), Craven, IPD.
2008 328xi - AVH7800BT, GM-D8604, GM-D9605, MT230, GB40, XE 200, Primo 12"
2011 XC60 T6 RD - She won't let me.

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havfam George Haversang
Montville NJ, USA   USA
If it were me, The first thing I would do is a front to back tire rotation. If ANYTHING changes you know that you have a problem with tires. I have had tires that balance fine but are not round. They did exactly as you describe. Did one or more wheel require a lot of weight to balance? IF so, That is not a good sign.

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Charlie D Gold Member Charles Dankmeyer
Arnold, MD, USA   USA
I went for a longer drive yesterday expecting to feel the shimmy when I got to 50-55 or so. Nothing. I even went on a road with some rough spots to try to trigger the shimmy. Nothing. I have made no changes since my last post on this. I have never had a mechanical problem cure itself. I have been more than frustrated when the mechanical or electrical problems are intermittent. Breaking in new tires? makes no sense with all the balancing that was done. Very strange. Anyone else experience this?

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tirebiter Avatar
tirebiter Jeff Garber
Dighton, MA, USA   USA
Ice or snow build up ?

RobTR8 mentions my fix from years ago. Maybe it still works. Add a thick washer to each end of the sway bar. Make sure the hole in the washers are big enough to go over the sway bar shoulder. Compress the large, soft bushings even more than stock.

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Maki65 Iain Makinson
OVERTON MORECAMBE, Lancashire, UK   GBR
I had this issue for some while. However, after going through all the usual suggestions around wheel bearings, balancing etc, I found the culprit to be adjustment of the steering column. This was done underneath the dash where there is a metal block on the column with two screws. these were slackened off and the column adjusted accordingly. I first realised this may be the issue by pulling on the steering wheel, if there is any play at all you need to remove it as it will cause judder/shimmy. mine has been spot on since.

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