Michelin XAS Tires

[Bob_Spidell]

TPMS works fine with plain old air (if that's what you're asking). The nitrogen 'fad' has come and gone IMO (and I'd bet most the cars with green valve stem caps are running plain ol' air; I have one).

 

[GregW]

I would call air "Nitrogen gas with impurities".

 

[twas_brillig]

Supposedly, one advantage according to anciente wisdom was that N2 was more stable with temperature variations. Me, I don't think so: VP/zT=VP/zT . z is pretty close to 1 at atmospheric pressures, and none of the other variables actually vary a lot. If pressure goes down, add some of that there cheap N2 that's contaminated with 02 etc. The bulk of the air in the tyre will still be N2. Doug

 

[Editor_Reid]

Drove the Healey ~450 miles last weekend on my new XAS tires with no tubes installed. No issues. Tire pressure checked the same as before the trip (28 PSI at Richard Mayor's suggestion).

 

[54ragtop]

Yoda, you were right about Dayton being a tire hub. That might have been true before Goodyear got ahold of Cooper Tires. Cause it seems that some of the great Cooper Tire lineup has disappeared. I guess Goodyear just wants us to buy something they make rather than something better and cheaper! Oh well that's capitalism, if you can't beat them with a superior product, buy them out and stop making the competing lines!

 

[John Turney]

Supposedly, one advantage according to anciente wisdom was that N2 was more stable with temperature variations. Me, I don't think so: VP/zT=VP/zT . z is pretty close to 1 at atmospheric pressures, and none of the other variables actually vary a lot. If pressure goes down, add some of that there cheap N2 that's contaminated with 02 etc. The bulk of the air in the tyre will still be N2. Doug

The reason nitrogen alone is suppose to be more stable is that there shouldn't be any water vapor in it. Compressed air is usually saturated with it. Because water vapor isn't a "perfect gas", pressures will vary more than dry nitrogen (contaminated with oxygen or not).

 

[equiprx]

The reason nitrogen alone is suppose to be more stable is that there shouldn't be any water vapor in it. Compressed air is usually saturated with it. Because water vapor isn't a "perfect gas", pressures will vary more than dry nitrogen (contaminated with oxygen or not).

Nitrogen is also a larger molecule so it leaks less.

 

[Patrick67BJ8]

"I'll bet the Japanese engineers were upset when their Corporate let a bunch of Chinese engineers tour the factory and take pictures."

What goes around comes around. The Chinese are more protective (smarter than us?), but its manufacturing has been stagnating for a number of years and is now in decline. They are now losing manufacturing at a good pace to Vietnam, Thailand, Indonesia, India, Mexico and Brazil.

I met several fairly high-up Chinese officials at a dinner 7 years ago. They said they were trying to shift their economy away from manufacturing because of regional competition and severe pollution.

BTW, your Dad's restoration is amazing!

Not to change the subject, but what is that tool you’re using on the cylinder head?

 

[Legal Bill]

After an extremely long restoration, I started my BJ8 on a set of Vredestein sprint classic 185VR15 mounted on a set of 72 spoke tubeless Daytons. I found the steering to be very heavy both in parking lots (where it was a bear to make a three point turn) and at speed where the steering felt a little numb and overweighted. I new the wheel would turn a bit easier with a narrower tire, but I was disappointed in the steering feel and thought this was just how the car was supposed to be and decided to live with the heavy parking lot steering.

I then spent many years chasing the cowl shake problem and had two different local wire wheel "experts" balance and rebalance my wheels and tires. The shake remained. Thinking that the wheels were not the problem I then spent time and money on having my brake drums balanced and my prop shaft checked for balance (it was fine). In 2021 I carefully checked the wheel bearings and found that my left front had a bit of play so I went through the process of reshimming the left front wheel bearings and got that one to just about 0. I still had cowl shake. So for 2022 I did some more research and found a local mechanic with the correct adaptors to spin balance the wheels. While having my wheels balanced for a third time I asked the mechanic to measure my wheels for run-out. I tried to do it in my Garage and came up with numbers that were just within spec. But using better tools and instruments, my mechanic and learned that 3 of my 'new' Daytons (with less than a thousand miles on them) were out well beyond spec. After the speed balancing I still had the shake.

The wheels would need to be tuned and I decided to send the wheels and tires to Hendrix. At this point it was 12 years after I installed the Vredesteins and even though they still looked new, Allen H said he could not touch them except to remove them. They were too old. So now I also needed new tires. Well, maybe this surprise expense would be my chance to see if different tires would have a better feel that the 185s. Allen understood my complaints about the 185s. He recommended the 180 XAS Michelins or the 165 Vredesteins (with a strong preference for the XAS). After researching price and availability, and thinking a lot about what I didn't like about the 185s I decided to sacrifice the appearance factor and go with the 165 Vredesteins. I just wanted to get away from the heavy feel of the 185s and couldn't bring myself to pay all that money to drop down only 5 MMs to 180s.

To cut this already too long story short, I am very pleased with the 165 Vredesteins. Yes, they do not fill the wheel well as much as my 185s, let alone the high spec ratio 180 XAS. But the ease of turning the wheel in driveways and parking lots makes the car much more livable. And on the road I can actually feel the road through the tires and the steering wheel. It is smooch more nimble and pleasant to drive. Since I never tried the XASs, I can't say the road feel of the 165s is better. It probably isn't. But I am very happy with them. They do have me thinking about having my original leaf springs rebuilt and removing my replacement springs, just to lower the rear and reduce the gap between the tire and the rear fender opening. But that's another story.

 

[Michael Oritt]

Bill said: "They do have me thinking about having my original leaf springs rebuilt and removing my replacement springs, just to lower the rear and reduce the gap between the tire and the rear fender opening. "
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Beyond great handling one of the nice things about the 180 XAS's is that their larger diameter provide a bit more ground clearance and fill the wheel openings nicely. In any case you did well to go with Allen and getting a smooth ride begins with trued and well-balanced wheels and tires.

 

[Bob_Spidell]

The BN2/100M my dad bought came with the 'Massive Scuttle Shake' option, mostly due to it having the original 48-spokers which were well past their use-by date. New Nexens helped a bit, but when getting them mounted the tech was pretty clear the wheels were in not-great shape (he used the worst one for the spare). A few years after we finished the restoration I finally bit the bullet and got a set of 4 Vredestein 165s--I think, if they're not 'low profile' they're essentially 80%, maybe 85?--with one Vred 155 for the spare, which barely fits in the slot in the boot, from Tom Monaco (he's a Vred distributor and, well, gave me a very fair price (NFI)). I got 48-spoke MWS wheels from Tom which, to me, look to be high quality (I think they're powder coated). All scuttle shake, every last bit, is gone; that may not last forever but for now the car is a joy to drive. Steering effort, I think, is a bit higher than it might be because I installed a Lempert 15-inch steering wheel, and with 0deg camber it almost oversteers a bit. Note no tire 'shaving' was required which, I'm told, voids the tire warranty if that matters to you.

I put Torrington upper bearings on my BJ8 steering with 185/70 Vreds and Dayton 6' 72-spokers and it did improve steering effort somewhat (hard to quantify). I'll add that, for the most part, I'm a 'Michelin guy,' havng found they make the best tires overall, and just put new CrossClimate 2s on my old Lincoln; they're all-season with the 3-peak rating for snow and ice, and ride beautifully (Bruce Erfer told me Michelin makes the 'roundest' tires). The old Bridgestones that were on it rode like crap from Day 1, but Bridgestone used to make a 185/70 that was a good tire on my BJ8.

 

[BoyRacer]

They do have me thinking about having my original leaf springs rebuilt and removing my replacement springs, just to lower the rear and reduce the gap between the tire and the rear fender opening. But that's another story.

If you want to "reduce the gap" by lowering the rear end of your car you need to use lowering blocks between the spring and the axle housing.

 

[Hamish Racing]

If you want to "reduce the gap" by lowering the rear end of your car you need to use lowering blocks between the spring and the axle housing.

Like the TR3a you can simply make longer rear spring hangers

 

[Legal Bill]

Boy Racer and Hamish Racing,

I think my previous post was unclear. I installed new rear leaf springs when I restored the car over 15 years ago. The new replacement springs available at the time were stiffer than the factory springs and resulted in a noticeably higher ride height, I'd estimate over 1 inch higher. This is a pretty well known issue and in my experience the springs did not "settle" over time. So rebuilding the original stock springs, which I still have sitting on a shelf, will lower the car. I suppose there may now be someone selling new springs that give the correct ride height and I'll look into that. I hope that explanation helps.

 

[BoyRacer]

So rebuilding the original stock springs, which I still have sitting on a shelf, will lower the car

What exactly will you do to rebuild your original stock springs? New bushes?

 

[Legal Bill]

What exactly will you do to rebuild your original stock springs? New bushes?

New bushes, new retaining straps (some of them are rusted out and I'm guessing the others won't survive disassembly), re-arch one of the springs so that they both have the same arc, bead blast the leafs and paint them before reassembly. That's what I'm thinking anyway.

 

[Bob_Spidell]

You'll probably need new packing/friction material between the leaves. I believe original was zinc sheet, some use teflon strips.

 

[Legal Bill]

You'll probably need new packing/friction material between the leaves. I believe original was zinc sheet, some use teflon strips.

You may be right. I don’t have them apart yet. But from what I can see the packing strips look to be in very good shape.

 

[steveg]

Air is 78% Nitrogen.