Need help on 45-80 MPH shaky problem.....

[mx54life]

I have less than 300 miles on these Toyo 195/50/15 and Konig 15x8 +20 combo now I have tried to resolve this vibration or shaking problem on speed between 45-80+ MPH. BTW I am riding on an Eibach and Tokico Illumina kit and alignment set per Flying' Miata spec. I have had the front wheels balanced a couple of times on different places and today I have placed some hub rings on four corners but still the shakes are noticeable especially over higher speeds.

Any suggestions on what I may be missing? Thanks in advance.

[★ revlimiter ★]

Shaking is almost always tire balance. Suspension, brakes, etc have nothing to do with it. You need to get the tires correctly balanced.

Having a wrong-size hubcentric ring can also throw things off. You really don't need them at all. A wheel will mount lug-centricly quite well. You just have to be careful torquing the wheel down.

[mx54life]

Shaking is almost always tire balance. Suspension, brakes, etc have nothing to do with it. You need to get the tires correctly balanced.

Having a wrong-size hubcentric ring can also throw things off. You really don't need them at all. A wheel will mount lug-centricly quite well. You just have to be careful torquing the wheel down.

That is what I was thinking so I did go to two different places but both resulted to same shaking the second one seems more worst. Both actually claimed the tires where balanced zero so I don't know what else to think or do. Thank you.

[— kung fu jesus —]

Try rotating the tires front to rear

Borrow another set of wheels/tires from another car to determine if it is your wheels and tires.

Check for flay in the steering and front bearings. Inner/outer, lower ball joints.

Check the drive line for slop or bad components (driveshaft, differential input, halfshafts)

Check for play in the rear bearings.

Inspect rotors for hotspots, grabby/sticking calipers. Lube caliper slides, inspect guide boots for tears.

[mx54life]

Try rotating the tires front to rear

Borrow another set of wheels/tires from another car to determine if it is your wheels and tires.

Check for flay in the steering and front bearings. Inner/outer, lower ball joints.

Check the drive line for slop or bad components (driveshaft, differential input, halfshafts)

Check for play in the rear bearings.

Inspect rotors for hotspots, grabby/sticking calipers. Lube caliper slides, inspect guide boots for tears.

thanks did not think of these......

[— Phatmiata —]

Honestly, this was an issue with all NA Miatas.

Its called the infamous 60 mph shake. You will never get rid of it with an alignment, it will always come back.

You can get 3 alignments per month or until your wallet is empty, or you can just buy some stiff stuff to tighten up the Miata chassis. Problem solved.

Buy a hardtop (costs about $900 to $1600 depending on condition)
http://www.ebay.com/itm/like/3014777...466&rmvSB=true

Buy a Rollbar (costs about $300 to $1100 depending on style+options) this will reduce the shakes about 95% of the time
http://www.miataroadster.com/boss-fr.../i-411849.aspx

Buy some Cowl Braces (costs about $200 to $300) this will help tighten up the front end a bit more, add a front STB for even more stiffness
http://www.v8roadsters.com/cowl-stabilizer-braces/

Buy some Frame Rails (costs about $125 to $300) this will tighten up the unibody of the NA, the first gen miatas need the most help IMHO
http://www.v8roadsters.com/frame-rails-1/

Buy a Front Strut Tower Brace (costs about $100 to $400) this helps box in the front suspension of the miata, easy 10 minute install
http://www.rspeed.net/RSpeed_R_Speed.../nab-30981.htm

Buy a Rear Strut Tower Brace (costs about $100 to $300) this helps box in the rear suspension
http://miataroadster.com/beatrush/be.../i-540833.aspx

Buy some Sway bars (costs vary $100 to $500) this helps tighten the car, lots of options to choose here!
http://www.planet-miata.com/index.ph...h-item&idn=290

[The Driver]

^ Hey Royal Phatness, OP said 40 to 80 MPH. That is not the 60 mph shimmy...

[— Phatmiata —]

you are correct, but it is an NA miata? And this is generally the 60mph case, maybe mx54life can pinpoint the exact speed because 45 ~ 80 mph is a pretty broad range.

[— kung fu jesus —]

Completely unrelated, but I had a shimmy in my e30 in this range. The driveshaft u-joints were worn and notchy at the rear where it bolted to the differential. It took me a while to diagnose it. The Miata driveline is a lot different, but it can cause similar issues. Most people don't know the stock driveshaft isn't balanced. When the u joints go bad, it puts a lot of stress on the differential. The e30 driveshat is a 2 piece design (like a Nissan 240), with a center support bearing and a flex disk between the transmission's output flange and the front of the driveshaft. In comparison, the Miata driveshaft is FAAAR less complicated and simple. To check for rear driveshaft issues, simple unbolt the four bolts/nuts at the rear, swivel the flange in you hands to feel if it 'catches' or feels stiff. It's a long shot but not our of the realm of possibilities. Remember that if you pull the front out of the transmission, your fluid will start to leak out.

I would swap wheels and tires first, though.

[mx54life]

Honestly, this was an issue with all NA Miatas.

Its called the infamous 60 mph shake. You will never get rid of it with an alignment, it will always come back.

You can get 3 alignments per month or until your wallet is empty, or you can just buy some stiff stuff to tighten up the Miata chassis. Problem solved.

Buy a hardtop (costs about $900 to $1600 depending on condition)
http://www.ebay.com/itm/like/3014777...466&rmvSB=true

Buy a Rollbar (costs about $300 to $1100 depending on style+options) this will reduce the shakes about 95% of the time
http://www.miataroadster.com/boss-fr.../i-411849.aspx

Buy some Cowl Braces (costs about $200 to $300) this will help tighten up the front end a bit more, add a front STB for even more stiffness
http://www.v8roadsters.com/cowl-stabilizer-braces/

Buy some Frame Rails (costs about $125 to $300) this will tighten up the unibody of the NA, the first gen miatas need the most help IMHO
http://www.v8roadsters.com/frame-rails-1/

Buy a Front Strut Tower Brace (costs about $100 to $400) this helps box in the front suspension of the miata, easy 10 minute install
http://www.rspeed.net/RSpeed_R_Speed.../nab-30981.htm

Buy a Rear Strut Tower Brace (costs about $100 to $300) this helps box in the rear suspension
http://miataroadster.com/beatrush/be.../i-540833.aspx

Buy some Sway bars (costs vary $100 to $500) this helps tighten the car, lots of options to choose here!
http://www.planet-miata.com/index.ph...h-item&idn=290

I have a HT, 4-pt. Roll Bar, RB sway bars, FM butterfly frame rail support and cowl bars support. If the front and rear braces would be the final answer I will get them too. But I will go thru Kung-fu Jesus suggested first. The shake thus starts at around 45 MPH but it begins very lightly and becomes pronounced at 60+ and worst at 80+. Livable but may be a way out to ND lol. Thank you guys for the kind suggestions.

[— Phatmiata —]

Wow all that installed and you still have a vibration? When did this start? What was the last upgrade to your car? Has it always been like this? I would agree that you might have something else going on, you should not have any shakes with all that stiff stuff installed!!

[— kung fu jesus —]

I'm going to add some more food for thought. If your new wheels and tires were balanced by two different shops, take a peak at how many weights were needed to balance them. If any of the wheels have an unusual amount of weights stuck to them, I would be suspicious of the shop(s) that mounted and balanced them. I have had troubles with a certain nation-wide chain that touts using the best equipment, but two different stores were telling me different stories when I repeatedly returned with balancing issues. This included road-force balancing. I finally went to a third, independent shop who found two of the tires were out of spec. When I returned to the chain to deal with the warranty on the tires I bought through them, I showed them the paperwork from the indy shop. They relented and found the same issue. When I questioned them why neither shop found the issue before, the manager relented that the equipment may not have been 'reset' or the installer may not have been experienced enough on that equipment to recognize the issue. It was pretty exasperating and aggravating.

[mx54life]

Wow all that installed and you still have a vibration? When did this start? What was the last upgrade to your car? Has it always been like this? I would agree that you might have something else going on, you should not have any shakes with all that stiff stuff installed!!

This was an existing issue (before the add-ons) I notice even from when the car had 16's on so I upgraded so to speak to a 15 rims. I then added those mentioned to stiffen the car. It comes and goes tho' but winter time is the worst. I wonder if the polyurethane bushings that I also installed has got something to do with it. I am now hesitating to install the coilovers before I get this issue resolve. I also wonder if this car is crap. Sad because "she" runs very well with her JRSC M45 that took me to a year to tighten all loose ends.

[— kung fu jesus —]

How many miles are on it, the car?

[mx54life]

How many miles are on it, the car?

81,652 miles