kgh

So will I! Ride in Mk3 always available

I took the MX5 to Anglesey on 6th March with some of the Nutzers. With more front camber and higher tyre pressures I hoped that the tyre wear on the R888s would be reduced. Unfortunately the plan didn't work. The tyre wear in the middle of the outside half of the tread was slightly less pronounced because it was over a slightly wider area. Grip from the front seemed initially better but ran out quite quickly if pushing hard. I guess this was the result of the higher pressure. Some pictures showing the front camber working I'm not sure if I'm imagining it but it seems to me that the outside of the offside tyres are carrying all the weight. The airfield at Blyton near Gainsborough has been leased by a chap keen to develop a driving centre. The plan is quite ambitious and involves building a tarmac track nearly two miles long. To get experience in running a track day, and some income, MazdaOnTrack organised a day there on 19th March. It's a 320 mile round trip for me and as I cannot carry more than 2 spare wheels I didn't want to risk totally wearing out the R888s so I went on the Toyo T1Rs which had done about 9000 miles. The car was great. The additional front grip reduced the car's tendency to understeer and the rear stayed in line. A little exhuberance was all that was need to make the rear step out in a controllable way. I got the video camera that you can see in the above photos working; the key seems to be switching it on. Here are the results (watch out for the car on the extreme left as I approach the circuit entry) The circuit, laid out on the main runway, was dusty early on but a clean line developed although it stayed very slippy off that line. It was a good day and I hope the plans are fulfilled. Some more pictures are here I talked to the chaps preparing MX5 Mk3 race cars about the tyre wear. They are experiencing the same and have found no way to avoid it. It looks like part worn road tyres are going to be my best option.

I was thinking that the 205/40/17 tyre would be a better fit to my 17x7 wheels than the 215/45/17 and would reduce the tread width and distortion. Track day distances are greater than sprints and tyre temperature does become a problem. I was thinking that I should swap the tyres side to side if it was dry (hopefully remembering to put them the correct way round before driving home)

The consenus on toe is to use zero toe all round. The stiffer sidewalls help the turn in and front toe out is not necessary. I would assume that 'zero toe' means zero dynamic toe. Thanks. This is one of the articles I found. The Mk3 is considerably heavier than the Spec Miata and the standard Mk1 I have heard other MX-5 drivers saying that they intend to refit the tyres so that they can use them on the opposite side. This does suggest that they also experience uneven tyre wear but at the time I wasn't having this problem so I didn't look into it any further. I am ploughing a bit of a lonely furrow with the Mk3 on the track at the moment. There are a number of Mk3 race cars in development at the moment so I may be able to get help from them.

My Toyo R888s are showing the same type of wear (without the delamination) so I decided to research the problem using my friend Google. The results seem to be that this type of wear is caused by the tread part of the contact patch (ie the bit between the sidewalls) distorting under the cornering forces. The distortion occurs because the sidewalls are very stiff. If the distortion results in a bulge this soon wears away giving the impression of a shallow groove worn away in the tread. Some of the R888 information I found referred to the "Groove of Doom". The cure is to increase type pressures and increase camber. The effect is apparently worse if the wheel width is at the lower end of the allowable range. I had found a list of recommended tyre pressures for the R888 based on the weight of the vehicle. So I set the pressures to 29psi cold and saw them rise to 34-35 hot. The Google searches suggest that the tyre pressures should be 40+ when hot. So I think I need to do this 1) Get the R888 refitted so I can swap them side to side (and get a bit more use out of them) 2) Change the alignment setup from Fast Road to a more aggresive track set up 3) Use higher cold pressures to achieve 40+ psi when hot. 4) Consider using 205/40/17 instead of 215/45/17 when I replace the tyres As always comments and suggestions are very welcome.

I, too, enjoyed this day in the December sunshine. That's an interesting comment about Surtees and McLaren from Sean. One of the joys of the MX-5 on track is the corner you can take without braking or lifting. Surtees and McLaren are like this but it leaves you very little time to do anything about the turn in for Clearways and if you're not sure exactly how you intend to do it you have a bit of a problem. :cool03: My bit of a problem ended in an unintentional drift round most of Clearways. The back end stepped out and opposite lock stopped it but didn't bring it back into line until the drift bled off enough speed whereupon it snapped back quite quickly leaving me heading in the right direction. A few more laps and I figured the best approach was to ignore McLaren, the exit from Surtees takes you to its apex anyway, get the car straight at or just after this apex and use the width of the track to bake hard and change down for the entry to Clearways. This seemed to wotk. This was the third outing for my Toyo R888s and the first fully dry day. They certainly give a lot of grip so all I have to do now is work out how to use it. The R888s showed the same sort of wear I had with the Yokohama Paradas but I think I can shed some light on the problem. I will post more in the Tyre section. Ken

Mazda MX-5s are notoriously delivered with high tyre pressures. They set them high at the factory for shipment and the dealers are supposed to set them correctly as part of the PDI

Not knowingly. The wear, front and rear, is in only one of the tyre blocks in the tread pattern and is in every one of these blocks. It seems unlikely that the kerbs could be so exactly aligned with the tyre tread. I suspect overheating is the culprit and I need to drive shorter sessions.

Clockwise.

I took my MX5 Mk3 (NC) to Cadwell Park for a few laps (well 120+) on Friday. I kept the tyre pressures to 30-31psi, measured when hot, all round. When I changed the wheels on Saturday I found this:- The nearside front has large chunks missing fron the blocks to the right of the large groove whilst the offside front is fine. The rear tyres showed the same wear pattern but with smaller chunks missing. The tyres are Yokohama Parada Spec 2. Any thoughts?

Point taken :blush02: but hay at least i'm trying to be innovative :tongue2: .. I have a highly modded NC ready to trial a set so we can go from there. Don't get me wrong I'm not being negative. Intuitively it seems best if the arb arms are horizontal when the vehicle is at rest but I can find no geometric/trigonometric reason why this should be so. Any play in the joints will obviously reduce the arb's effectiveness so the rose jointed droplink should improve things if there is any wear in the existing droplinks.

I'd be up for this except I'm still waiting on the P5 suspension mod. Does that make a difference? I am intrigued by this statement 'The benefit of these will mainly be felt by the "as sold" owner who wants to reduce the body roll during cornering.The links can be used to add preload to the existing anti-roll bars' If you preload for left hand corners do you have to dash out with a spanner before right hand corners?

Stop being such a fanny and just buy some

A fraction.... Drops that i have imaged where between 15 and 20mm and they needed attention. A tell-tail sign apart from any handling changes is the steering wheel position. I looked up the cars last alignment report (7th July 2008) which showed the ride height to be 355mm all round which can't be right When your machine is working again I'll arrange to drop in and let you see it. Are you on 16" or 17" wheels? 17" Then assuming the height is still the same then it's needs checking again. I measured the heights again this morning and the height is 340mm all round. Interestingly since the last alignment I have acquired a second set of wheels and have changed sets 3 or 4 times. I change the wheels one side at a time using two jacks. This would shift a lot of weight to the other side (even more than the body roll when cornering ). Could this have an effect?

A fraction.... Drops that i have imaged where between 15 and 20mm and they needed attention. A tell-tail sign apart from any handling changes is the steering wheel position. I looked up the cars last alignment report (7th July 2008) which showed the ride height to be 355mm all round which can't be right When your machine is working again I'll arrange to drop in and let you see it. Are you on 16" or 17" wheels? 17"