Update on Micheling Agilis tires

[booster]

I don't think I could go to the larger size tire in the size you're running or I would just to be able to stay with Defender LTX M/S.

I generally like the same or slightly larger tires, but when I had my 2-1/2 inch lift installed, the front tires scrubbed on the Airstream installed mud flaps. I trimmed off the part of the mud flap that extended into the wheel well and it solved the problem.

I was surprised the lift make the front scrub where they didn't previously, but the front tires do come awfully close the rear of the wheel well on tight turns. For that reason, I'm afraid of going up-sized on new tires.

I take it this was not a problem on your Roadtrek 190?

The larger tires are close but don't hit anywhere on the Roadtrek and we have on front wheel that sits a bit to rear and it still clears.


From you pic it looks like your van has aluminum wheels on it, and if so they would almost certainly be the wrong offset for the Chevy vans which are +28mm. Most aluminums are either zero or -6 from that era. The offset outboard like the aluminum wheels gives, make the wheel and tire move more for and aft as the wheels turn, increasing the possibility of hitting. If you have a steel wheel as a spare, it would probably be the right offset so you could put it on and see if you get more clearance. The bigger tires will be .5" bigger on the radius so come .5" closer on the OD to the ground effect stuff and wheelwell rear.


Wife and I sat down and talked about the whole tire thing. For reference she is more risk aversive than I am so very aversive, especially on tires for some reason. All the talk about why are the Agilis changing over time and miles has her scared to some degree and me very hesitant.


The digging I have done showed up that I can get some 2008ish GMC Sierra 3500 aluminum wheels in the correct 28mm offset and 17" diameter. They are 7.5" wide so perfect the a 265-70-16. By luck we can get that tire size in a Michelin LTX MS2 tire which is an XL load capacity with the same 3415# load capacity as our current tires, the same 31.6" diameter, same cross section, slightly wider tread. Bonus is S speed rating that actually is what Chevy specs stock. All of this should make our current spare work fine with the new setup.


Worrying about tires when on a trip would really suck, we both agreed and decided to just do it and see how it goes.


The extra cost to just going to MS tires in our size is not all that bad, depending on what you define as bad. The used, OEM, "reconditioned" (junkyard spiffed up a little most times) wheels are just under $800 to the door. The new tires are about $50 more than the 16" MS tires would be. Will need new metal bolt in valve stems for probably $30 extra. About $900 total to get MS2 instead of MS and with the S rating instead or R of the MS. 70 series tires should handle a bit better but time will tell on that.


Will it all be worth it, we will see how it works out. If the tires handle well, it probably will be as the 16" seem to be getting phased out as Michelin has already gotten rid of the 245/75/16 in some tire lines with 265 probably also on the chopping block in the future. 17" tires should be available longer, I hope.


If we were just doing a tire size increase, going to 17" and 70 series MS2 tires would be no brainer, I think, as the costs would be very close to a wash with the correct offset steel wheels getting as expensive as they are now. If we like the new tires, at least we can probably get $400-600 for our old wheels with Agilis on them.

 

[rowiebowie]

Your last post brings back memories of the several times in the past on my other vehicles when I would trade out my stock tires and rims for a nicer OEM rim/tire upgrade in size. It was easy to calculate (as you have done) that an inch larger rim but lower profile tire would cancel out to the same diameter. But those days are behind me.

And yes, I remember rim offset being discussed in earlier posts when I joined the forum. I don't recall exactly how I measured my rim offset (I didn't remove a rim so it was not precise) but my rough calculation came out close to original specs and not wildly off. After 8 years of ownership and being well satisfied with the drive, ride, and handling of my 9,000+ pound beast I don't figure on worrying about that now.

The Express 3500 turns like the Queen Mary and don't ask it to stop on a dime with the somewhat mushy brake pedal and all that weight. On the other hand, the long wheelbase make it track straight and I marvel that the ride isn't half bad for what you usually see as a Plumber's van on the road. On any semi straight road with halfway decent pavement, I consider it a pleasure to drive it. It isn't perfect, but it drives a lot better than it has right to. Plus, it doesn't hurt that the Express is one of the most dependable vehicles I've ever owned, and I certainly can't say that for the Airstream coach portion.

Congrats to you since it looks like you have your solution. I enjoyed this thread.

Since I'm not going on any long out of town trips until Spring due to my Wife's recent heart surgery, I will take my time and consider my tire options again after the first of the year.

 

[booster]

Your last post brings back memories of the several times in the past on my other vehicles when I would trade out my stock tires and rims for a nicer OEM rim/tire upgrade in size. It was easy to calculate (as you have done) that an inch larger rim but lower profile tire would cancel out to the same diameter. But those days are behind me.

And yes, I remember rim offset being discussed in earlier posts when I joined the forum. I don't recall exactly how I measured my rim offset (I didn't remove a rim so it was not precise) but my rough calculation came out close to original specs and not wildly off. After 8 years of ownership and being well satisfied with the drive, ride, and handling of my 9,000+ pound beast I don't figure on worrying about that now.

The Express 3500 turns like the Queen Mary and don't ask it to stop on a dime with the somewhat mushy brake pedal and all that weight. On the other hand, the long wheelbase make it track straight and I marvel that the ride isn't half bad for what you usually see as a Plumber's van on the road. On any semi straight road with halfway decent pavement, I consider it a pleasure to drive it. It isn't perfect, but it drives a lot better than it has right to. Plus, it doesn't hurt that the Express is one of the most dependable vehicles I've ever owned, and I certainly can't say that for the Airstream coach portion.

Congrats to you since it looks like you have your solution. I enjoyed this thread.

Since I'm not going on any long out of town trips until Spring due to my Wife's recent heart surgery, I will take my time and consider my tire options again after the first of the year.

It will be interesting to see what you decide to do when the time comes. I remember the discussion from that time now that you mention it. I think I even tracked down the wheels to find the offset. Alcoa wheels, maybe? Or the old brain could be farting


I have really gotten used to having the extra 10% of load capacity so I didn't want to back on that for this situation. I had looked at this same option a few years ago and it was different because all the 265/70/17 tires had a couple of hundred less capacity that the 3415# we can get now which is the same as our current tires, so I passed on it then.


I will miss the ease of cleaning the Wheelskins wheel covers though. Pop them off, soak in the laundry tub and hose off, but I may like the hopefully lighter wheels to put on and off. The tires weigh the same as what we have.

 

[booster]

I think I found rowiebowie's post about his wheels, which are Alcoa.


https://www.classbforum.com/forums/f46/later-years-roadtrek-aluminum-wheel-specs-11109.html


The appear to be this wheel and +6mm which is very possible that it was somewhat popular an offset in the past as Campskunk said his 2004 Roadtrek had AR wheels that were that offset and that is stock offset for my 1996 Buick Roadmaster.



Not a far off as the -6 that most Roadtreks came with but still 22mm offset outboard on each wheel.



https://www.southwestwheel.com/p-5242-alcoa-16x7-8-65-classic-style-aluminum-wheel-167041.aspx

 

[rowiebowie]

That's my wheel! I can see I've neglected them as they don't look nearly as nice now as they did then. They don't look too bad at a distance, but they are getting rough and lost some of their shine. I need to find out what to use that will polish them up without removing any coating, although it may be too late to save it now.

When I get time to take on the project, Youtube will be my friend. There are hundreds of videos out there.

 

[booster]

We got a hot day today at 85* which is pretty unusual here for late September, but all the weather has been odd lately so shouldn't be surprised.


I took the van out for a monitored tire test to see if they were adding extra temperature that could be bumping up the pressure on them.


Bottom line is that they did not heat up any more than they did when newer, running about 30* above ambient in the rear and 25* above ambient in the front using the infrared heat gun. Pressure increase was also the same as it was before at 8psi in the front and 10psi in the rear at 75mph on full sun warmed concrete. Blacktop would be higher as it gets hotter.


The handling change is not temp related but is related to pressure somehow, it appears.



My guess is that the internal structure of the tire is changing how they contact the pavement at driving speeds. Maybe getting more flexible or stiffer? I have no clue.


I have read, and section width vs tread width seem to confirm, that the Agilis was made to have stronger but more flexible sidewalls for better ride quality. Perhaps what is going on is related to how those changes age over time and high speed miles.

 

[booster]

I did decide to go with the 265/70/17 tires on GM Sierra pickup aluminum wheels that are 17/7 with 28mm offset. The tires are same OD and section width of the Agilis but have a lower profile by a bit and 1/2" wider tread. Same 123 load index also. We got Michelin Defender LTX MS2 load range E tires.

Tires got mounted yesterday on 4 factory wheels that were reconditioned. I put them on yesterday afternoon and filled them to our old standby 62/76 pressures we ran with the previous generation MS2s that we like sooo much.

I got in a short 30-40 mile test run today on two lane county roads and 4 lane 65mph 4 lane highway. 15-25mph winds.

The results were very good to this point with van feeling like it always did with the previous MS2s. Stable, good tracking, minimal input, low movement from wind gust hits. Only gained 4-5psi on a 68* sunny day. It was so much easier to drive I was very surprised.

A 80-82* degree day is predicted for tomorrow with high winds up to 35mph so I am going to duplicate the test I ran before removing the Agilis tires from the van. I am very interested in seeing the comparison of pressure gain in particular.

I hope to have data on the longer temp and pressure gains tomorrow and will put them up then.

 

[GallenH]

We got a hot day today at 85* which is pretty unusual here for late September, but all the weather has been odd lately so shouldn't be surprised.[/QUOT

Well it looks like we have at least a week at 110º here in Phoenix. Highly abnormal for this time of year. October usually means temps drop below 100º regularly.

 

[booster]

We just got back from doing the same route test I did on the Agilis, except it didn't get as hot or as windy as predicted. 75* with 10-15mph winds with lots of random gusts. There was a lot of traffic so that is kind of good for checking for disruption by other vehicles, particularly trucks.

Speeds from 65 to 75+mph in traffic with winds and no issues at all. Very much like our old MS2 tires were before the Agilis. One hand lightly on the wheel was easy. Not noisy or harsher. The van felt very planted.

Started out from the cool garage at 63* and 61/73 pressures on the TPMS which tend to be 1-2* under what all my gauges say.

Stopped and a rest stop after about 50 miles and pressures read 68/82 and temps of all 4 tires within a degree or two off 100*F.

So 7 psi change in front and 9 psi in the rear.

Outside temps with heat gun showed 37* temp increase, pressures using the 2% rule would say closer to 50* internal temp change.

I think most useful is the 25* above ambient which is just fine.

Not an inexpensive swap out with the new wheels and center caps also, but very well worth it for the improvement we got.

 

[booster]

Beautiful day in Minnesota today. 70*, wind under 10mph, clear skies.


We did our annual "apple run" to our favorite orchard in SE Minnesota and the trip always includes a loop from home just north of the twin cities to Winona, MN. Go south on one side of the Mississippi and back north on the other side which is very scenic trip.


We took the van this year as a final test on the new tires and wheels, as the trip is almost all two lane that is hilly, curvy, and very grooved from heavy truck traffic for a good test.


Tires performed very well, as expected, and very much like the old style MS2s we had. Good pressure gains and temps as the earlier tests.


What was very surprising was that we got 1mpg better for the 285 miles than we have in the van on the same trip in the past. I did not drive carefully for mileage and there a many small towns to go through. In the past we got 14.5mpg consistently and this time in was 15.5mpg which we know is good for that kind of drive when compared to other similar two lane with lots of towns trips we have done. That may confirm the 10% mileage penalties that the pickup truck folks talk about a lot. Our next real trip will be our yearly 1800ish mile trip to Custer State park. By coincidence, that trip also always comes out at about 14.5mpg lately.


Here are the wheels we decided on. GM Sierra 8 bolt pickup wheels from the mid 2000s. 17 X 7.5 with the correct +28mm offset. They are reconditioned factory wheels. The hub center are aftermarket that come with no logo on the center, just black. The textured writing center caps are for some other GMC and are attached with silicone caulking. Tires are 265/70/17E load range 123 so 3415# load capacity that is 370# higher than the stock size tires on the Chevies.

In the driveway

At Lake Pepin today at a boat launch wayside rest area

 

[booster]

I am putting an update here, but will also be starting a new thread on the topic.


A problem has come up in relation to the 17X17.5 aluminum Silverado and Sierra wheels mentioned for our recent upgrade to them.


THIS DOES NOT APPLY TO OEM GM WHEELS IN ANY WAY, EITHER USED OR RECONDITIONED, SO THOSE ARE JUST FINE WITH NO ISSUE.


The problem is with the very easily found REPLICA wheels that look identical to the factory wheels but cost less than reconditioned OEM.


The replica wheels are listed by application for, I think, all of the 8 lug 2500HD and 3500 pickups from about 2000 to 2010 and they do fit them.


The problem is that they DON'T HAVE ADEQUATE LOAD CAPACITY for any of the applications they list, including 2500 Suburbans and Yukons with 8 lug holes.


The wheels are marked at 1150kg or about 2500# so 5000# on a single wheel axle. The pickups listed have the same 6048# rear axle load rating as our Chevy class Bs on the 3500 chassis so clearly will not be adequate to support the load.


I never would have even known this, as the load capacity is not listed on any spec list, on any seller's site, and manufacturer is still unknown (only that they are in Indonesia as that is marked on the wheel).


After the reconditioned wheel vendor messed up and shorted me one wheel I scrambled to find another, and did at a local yard so the ones on the van are good. I ordered another reconditioned from a vendor and was sent a replica instead, so I then saw the load rating on it. It was accepted back, but the distributor that actually shipped it (dropship so dealer never saw it) went dark when asked why they could sell a wheel that doesn't meet specifications for the recommended vehicles. I contacted about a half dozen other sellers and only one even answered the question and did state 1150kg but went dark when asked how they could sell it for the vehicles listed.


The sellers all tout meeting all the same specs as the GM wheel, including SAE J2560 which is also on the wheel itself. They clearly violate J2560 section 3.5 which addresses the load ratings issue so I notified SAE of that.


The selling dealer, who was not happy about it but it was a first time of selling a replica of that type and from that vendor, is working with me to find out how to keep these wheels from being sold for those vehicles listed in the application listing. I have a complaint into NHTSA about it, SEMA has been notified and is looking into it, as well as SAE.


It is kind of scary knowing the the pickup coming down the road meeting us may be loaded to max capacity and pulling a 10K trailer besides. A collapsed wheel could be a major crash problem. Those pickups, especially because the earlier years of them are non DEF for the diesels, seem to be pretty popular in the towing crowd.