I live in Scotlandand have a 1996 Gleneagles1.8 MX5 (Miata)which has done 45K miles. I've replaced all the springs and the complete rear brake system. I have 4 new tyres with wheels balanced. For the past 6K miles I have had a vibration which is really noticeable above 60 mph but can be sensed at lower speeds. It is not there all the time and on really smooth roads it can be minimal. My own thoughts are varied and cover dampers, loose ball joints, bushes and an very outside chance of the drive shaft. I'm not sure whether it is front or rear aalthough my wife thinks rear. I however would guess front. Any thoughts out there?

 

Generally speaking, if you feel it in the steering wheel, it"s in the front. If you feel it more in the seat of your pants, it"s in the rear.
I can think offour other things right off the bat that it might be:
1) Bad universal joint, or an out of balance drive shaft.
2) You mentioned replacing the tyres recently. It is possible to get an out-of-round tyre from the factory. It doesn't happen often but does happen.
3) You might also have a bent rim, either from road damage or from a less-than-professional tyre installer.
4) Have you tried re-torquing the lug nuts to spec?

 

Fairly sure its not wheels or tyres as I had the problem before changing the tyres and I've done a bit of swapping about of wheels with no resultant change. I have a sneaky and hopeful suspicion that it could be a ball joint. Is your response based on heresay or practical experience? Are there any recommendations for checking the joints? I've done loads on Land Rovers but my MX5 is relatively new to me and I haven't tackled this area. My next job which I should get round to in a couple of weeks is timing belt and after that I'll start investigating. Land Rover ball joints are cheap. MX5's are not so I'd like to get it right before I start changing what doesn't need to be changed.

 

Well, since this is an onlineforum, we are clearly thousands of miles away from each other and I couldn't possibly see/inspect your car from that distance,literally speaking I would say that my "suggestions" ("I can think offour other things right off the bat that it might be...") are technically heresy. ANYTHINGI could say or suggest from this distance wouldbe heresy, or just an opinion.
As far as practical experience goes:
Yes, I have experienced bent wheels, out of balance, or misaligneddrive shafts, bad u-joints. I have also once spent two years chasing a vibration that in the end turned out to be that one-in-a-million out of round tyre. Very frustrating and confusing.
I have also experienced bad clutches for one reason or another, engines w/really bad camshafts that made the car sound like a frantic, out of controlsewing machine, squeaks in braking systems that would seemingly never go away, steering systems that seemed to have their own mind as to where the car shouldgo, and many, many other symptoms over the years.
However, that said, these suggestions are to help point you in a direction only... suggestions.Take the advice or not.That is entirely up to you.

 

Rich, it's hearsay, unless you're a heretic. Then it's heresy. [8D]

 

Yup. Blame it on the spell checker and me, not paying close attention to it.

 

I blame you. It's more fun that way.

 

I knew it was the wrong choice of words as soon as I hit the button. And what's more I can't spell either although I did try to use the spell checker but I couldn't get it work. What I really meant to say was it would be great if you had first hand knowledge so I could get some real practical advice. No offence meant and apologies if any taken.

Getting back to the tyres. I've had bad tyres which have been impossible to balance and recently had a good tyre go bad through sitting for a prolonged period slightly deflated and I've been able to isolate these. I've found that rubber on the car hasn't lasted in certain areas. When replacing the springs I replaced all the rubber boots are they had shredded and I've also replaced the two rubber diaphragms under the gear lever as they were shot. So when I get seriously looking it would be nice to see a damaged ball joint gaiter or abush that has seen better days.

I'll report back when and if I find anything nasty.

p.s. managed to get the spellcheck working but no success with uploading photos - says file are too large - but I see them as less than 500K. I'll solve that one another day.

 

Here, I wrote this to help. This site is a little strange (unusual) when it comes to posting photos.
https://www.mazdaforum.com/m_73651/tm.htm

 

Well well well!! It was the wheel balance after all. I spoke to a local garage that didn't specialise in tyres and asked them to have a look as I had checked everything I could and found nothing. I also read a couple of web notes that suggested very careful balancing so I spelled out very clearly what I wanted them to do. They had to tell me if they found imbalance what that was prior to any rebalance. This they did and they said that all wheels were out. This was just 2 weeks after I had bought new tyres from a place I had bought loads of tyres previously. They rebalanced the wheels carefully and the difference is dramatic. I still feel that there is slight play somewhere - 12 year old bushes, shockers, ball joints but I'm happy driving my little car now. Thanks for all you help and comments.

However, I seemed fated to constantly work on this car because now my driver's window won't work...........but I'll make that the subject of another post