Tire Report

[type26owner]

Just had four 165/65R13 Bridgestone RE92 mounted on 4.5J steel wheels. First impressions for possible trackday use:

1. The truest tires I've ever seen at least with regards to the radial runout. The worst one was only about 0.5mm (.020") out of round when spun lug-centrically. Two of the tires had zero runout. The worst one only required 4 ounces of weights to do the static and dual plane balancing. One required no weights.

2. Least amount of steering wheel dithering ever. Essentially there is none at any speed.

3 The sidewalls appear to be stiff enough to allow me to lean on them when going 10/10ths and not terrify me. This parameter is by far the most important one for this driver to feel comfortable when high speed cornering.

4. The grip level is okay for a $41 (TireRack) tire . Set the fronts at 24 psi and rears at 26 to test tomorrow on my way into work. So far the grip keeps going up as I keep dropping the tire pressures. Good sign!

Kiyoshi was wise to recommend these tires. Thanks!
-Keith

[type26owner]

Oh Boy! I'm liking the handling of these cheap tires. By far the best ones I've ever had on the Elan. If you want a smooth ride then forget installing these cause with the stiff sidewalls it makes them ride rather harshly over the bumps.
-Keith

[type26owner]

There tires have changed the overall demeanor of the car for the better. It now feels like the nervousness is much less. Rides like it weights 2400 lbs with road pressures of 22front/24rear. Less steering wheel high frequency feedback and less events that try to wrench the wheel out of my hands. Hey, maybe heavier tires is a good thing but I'm baffled as to why.

My expectations were for all bad consequences except for the cornering stability from the stiffer sidewalls. Really pleased with all the differences though. Only downside is the fact I'm buzzing my engine even more with the one inch and half smaller diameter.
-Keith

[type26owner]

Never have had a tire so sensitive to air pressure on the racetrack like these RE92s! If the the rears tires got the hot pressure built up to 28psi or above the car would SNAP oversteer like crazy. When this happened it felt and recovered like the rear tires had been greased. Had four loss of control moments due to this overpressurized rear tire effect where I had to perform an Alain Prost blown turn recovery technique. One of those moments was at about 90 miles per hour just before the apex at turn One at Thunderhill. Only recovered it when I was on top of the white painted berm on the outside of the turn. Very high pucker factor momentarily there! Just had to make sure the rears didn't build up too much pressure. That was tough to do today with the 30+ mph steady wind and the constantly changing ambient temperature. Had plenty of grip and the car was neutral handling with 24 in the fronts and 26 psi in the rears. Very pleased with high speed stability from the increased sidewall stiffness. For the very first time was able to make it through Turn Eight without lifting at close to redline in fourth gear. Will be wearing a big shitty grin for the rest of the week. Wow, these tires are by far the best I've ever taken out on the racetrack.

Might add they don't make any embarrassingly loud noises at the limit of adhesion. What little noise they did make make was low frequency and at a low intensity. Better then most of the cheap tires I've tested.

Cold pressures as measured this morning are 19 fronts and 21.5 psi on the rears. I'm going to need telemetry for the rear tire pressures or some accurate leakdown valves to be comfortable taking these to the traction circle limit again.
-Keith

[poiuyt]

The oversteer is probably a combination of the high pressure, low weight and stiff sidewalls. Without enough weight to make the sidewalls flex you are probably riding the edge of the tire as the suspension works and lifting the tread off the ground to some extent. This would explain snap oversteer.

I've been interested in your comments because I'll be looking for tires for my S4 and there's not much available in the US in 155X13.

My car will never see a track - it's a street car (2500 miles since May) and show car only.

Steve Becker
1969 Elan S4

[mac5777]

Hi, this is for Steve, the non racer. I too, am looking for good tires for my California 67 elan coupe for pleasure, not racing. I have 145/80x13 that came with the car and would like a little more rubber on the ground. I found a tire dealer that has four makes of that size,155s. I want to keep the tall tires to keep the RPM's down on the Hwy. Dunlop SP40 155/80x13 had the quietest, rounded, soft rubber for traction, for about $57.00. Tomorrow I'll look at them. What part of the US are located?

Regards Sarto
Elan coupe S3 LHD
36/5785

[type26owner]

Steve,
Inflated these tires to 40 psi when I first installed them. Went about three blocks and applied the brakes hard at 50 mph. Almost spun it out going straight. Pulled over and started lowering the pressures immediately and it improved dramatically. The cornering problem I had from the tires heating up on the track and the pressure going to high actually affected the torsional stiffness and the contact patch size. The result was the slip angle without any warning or making any noise would abruptly go to zero causing the snap oversteer. Below the critical pressure and they would really grip and would sing out announcing they were nearing their limit of adhesion in a much more gradual driver-friendly way.

You've got a real performance car that needs performance tires to bring out the best in the car and driver. You'd be silly to install any other tire in this price range. Even if you never push the limit these tires will give you more control in an emergency braking situation at least in the dry. I don't want to point out the other tires directly but some of the ones folks have mentioned have quite horrible handling and IMO can even make the car dangerous at times.
Regards,
-Keith

[khamai]

Keith,

Was the 24/26 tire pressures when hot? You noted the 19/21.5 the next AM, if I use the old 10 degrees = 1 psi that about a 50 degree delta! It must have been REALLY hot at THill.

Just curious, cuz I've been running 24 all around as a guess for the street with RE92 on Panasports and 26 w/ stock 4.5in wheels. I've not done any really testing or stressing to set the pressures so I'm really interested in what you're learning.

Kiyoshi

[type26owner]

Kiyoshi,

Was the 24/26 tire pressures when hot? You noted the 19/21.5 the next AM, if I use the old 10 degrees = 1 psi that about a 50 degree delta! It must have been REALLY hot at THill.

Yep, they got really hot and the 24/26 heated pressures were ideal to suit my driving style. Their grip level increases substantially as a result of building up enough heat near the traction circle maximum. Compared them when hot to the Potenza S-03 Pole Position tires my brother has on his Caterham Super7 after we both just came off the track. They were similar in temperature, feathering wear, where they picked up rubber off the track and the amount of it and most importantly the compound appeared to be about the same stickiness. His tires are two inches wider with lower profiles and stiffer sidewalls then mine though. With these tires I'm guessing I reduced the performance difference by about half. Instead of him being 20 seconds faster per lap he's only about ten seconds now. Damn those Super7's are quick!

Guessing the ambient was about 35C by noon. The wind was steady out of the North at a high enough velocity to buffet the Elan around bigtime between Turn 6 & 8.

Before mounting these tires I dragged out my leftover Michelin MX4 and Dunlop SP40 and the Sumitomo HTR4 to compare the sidewall stiffness differences. The old tires all shared the same characteristics in that the sidewall appeared to be a single ply and there was a 3+ inch wide sidewall area where they were really soft, flexible and thin. The RE92's indeed had a hard insert which was connected to the bead and extended radially out for about 2 of those 3 inches. Only the last 1 inch wide area was flexible to a similiar degree as the other tires. Sure cured the tailwagging problem I had with all the other tires brands on the track.

I might add the amount of GGLC members participating is pathetic but the field is full and a lot of non-members have caught on to what a good deal it is. Come on out and do some drifting with us. I'm not going that fast but it sure is more fun than anything else I can imagine doing.
Regards,
-Keith

[khamai]

This year has been crappy for me getting to the track. I'm batting a 1000, every GGLC track day = biz travel. Geezzzz...

The 10/18 event is at Buttonwillow and co-hosted by Club111 (Lotus Elise club). We are working on getting some Elise guys there.

I saw John today and told him to save me a spot at Buttonwillow (10/18). I am determined to get one in this year!!! Don't think I'll have the Elan with me, got a tire rubbing issue in the rear that I plan to cure with some new springs (need to get wound, but I haven't found the time to do some measuring). So, I may just have to drive down in the Elise.

Great info!!!

Cheers!
Kiyoshi

[type26owner]

Lowered the fronts to 15psi to hook them back up in the pouring rain the other day and they did just that beautifully. Trouble is I now have some graining on the outside sidewalls about an inch past where the thread ends. Yikes! I'm still at the stock ride height front and rear which gives the fronts a bit of positive camber at the unloaded condition. How much negative camber by lowering the car do you racers use to stop this stuff. How low is too low to run the pressures? Brought the pressures back to 22 psi on all four corners until this is resolved. It will just plow straight ahead without even attempting to turn-in at 22 psi unfortunately on wet pavement.

Have been reluctant to do this until now because my 1-1/2 ton steel floorjack won't fit under there with ease if it's any lower. A new aluminum one would be nice for Xmas though.
-Keith

[rgh0]

Keith

My front camber is minus 1.5 degrees with the lower arms close to horizontal at normal ride height. The later chassis' had more neg camber built into them so you may need to do some work on your arms to get enough neg camber at a reasonable normal ride height depending on your chassis. My stiffer spring and roll bar setup also limits roll more than a standard car which prevents a positive camber developing under corner load on the outside tyre.

I have no problems with wet turn in running yoko A032R soft compound around 28 psi cold. In the wet the problem is more keeping the tail in line if I go into a corner to fast or get on the power to early. Only wet understeer problem I have had is acceleration though the long tightening sweeper onto the main straight at Phillip Island where I once came off at about 150 kph when I did not limit my speed going into the final section as it tightens and understeered off into the grass, fortunately a good run off area !!!

Rohan

[type26owner]

Rohan,
You're right if I'm to keep the same springs and therefore also the bump stop travel I'll need to remain at the same ride height. Either the top or bottom SLA must have the length changed. Probably since these tires have the sidewall stiffeners built-in they won't need all that much more negative camber to keep them from deforming onto the sidewalls. Can different length arms be purchased? Suppose I can always build my own.

Hey, this playing around tweaking the car is turning into a bunch of work.
-Keith
p.s. How does the Elan stack up against the Miata on the track? There's a trackday on Newyear's day with mostly Miatas so I'm wondering if I'll be just totally blown off by the Voom Vooms. It's at Sears Point though and I REALLY want drive on that track at speed for the first time.

[type26owner]

Of course wider wheels than the 4.5" stocks ones might very well alleviate this trouble also. 4.5" was the smallest Bridgestone approved size with it ranging up to 6". :huh:
-Keith

[rgh0]

Easiest way to get some more negative camber is to slot the outer holes in the top arms until you get the camber you wnt and then mig weld or braze washers on the outside of the arm in the new location. I think Spyder make adjustable top arms also if you want to play with the camber change more frequently than a once off setup change.

A standard Elan will blow a standard Miata (MX5 in Australia) away if both on comparable tyres. If non standard it just depends on who has done what and how much money hs been spent. A race prepared MX5 with a hi boost turbo motor and wide sticky tyres can be a quick car but so can a properly prepared Elan.

Rohan