Date: Fri, 18 Nov 2016 14:48:22 -0500
Reply-To: Eric Wunrow <VW@ERICWUNROW.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Eric Wunrow <VW@ERICWUNROW.COM>
Subject: Re: Vredestein Comtrac Winter tire
In-Reply-To: <CACvdLxM4btt9_VE-__nFvL-M6iuy0xyZBehC41oziCjbDZAOJw@mail.gmail.com>
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Hi, David:
Sorry for the delay, been chasing lighthouse images in Florida and am finally back on the box.
Perhaps the primary point in my lengthy post was that, for me anyway, I found balancing pressures towards less pressure in the rear compared to the front makes the bus turn in much better. Because it really does!
But as mentioned, there's lots of factors here in regards to C vs. D ratings, tire diameters/sizes, whether the fronts and rears are matching tires and sizes, how much cargo you're hauling, where said cargo is positioned, and even how heavy the driver/passenger(s) is/are. And as I said, pressure and heat buildup tests tell the story regardless of VW's recommendations and tire theory.
My bus is an '84, and for that VW recommended 36F and 48R on my door plate — for the 185R/14 size. Perhaps it's telling that for my bus VW recommended 33% more pressure for the rear, and nine years later adjusted that to running only 23% more. This is heading towards the pressure balance theories I quoted.
Regardless, my bus had far more front tire rollover with such low pressure on the front compared to the rear, and that is one dangerous trend in a panic move.
Considering the factory recommendations, I'm unsure why you think a C-rated tire would be inappropriate for the rear at 50 psi max. when even VW recommended 48 for my year van. If the tire is designed to hold the weight of said rear tire, then technically it's enough to safely hold the bus.
But that said, as mentioned I plan to only run D-rated tires here on out, mostly because we're running a bit heavy so need tires that'll safely hold more weight, and I like the beefier sidewall capability of D-rated tires on backroads — and on extreme loading like a crash-avoiding maneuver.
Eric
Eric Wunrow Pictures
303. 988. 8717
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On Nov 12, 2016, at 10:15 PM, David McNeely <davmcneely40@GMAIL.COM> wrote:
> Eric, the pressure you quoted as the factory recommended for the Vanagon
> refers to the 205-65 R14 XL tire. The 185R14 LT tire was recommended at 43
> psi front, 53 psi rear, at least for the 1991 Volkswagen Vanagon GL
> Campmobile, according to my owner's book and the door placard. I have
> consistently run mine at that with minimal load, 45 psi front, 55 psi rear
> when hauling camping gear. It handles well in town and on highway at those
> pressures when driven at not over 65 mph (I usually drive slower than that,
> 55-60 mph). When driving on back roads, I sometimes bump the pressure up
> or down a little depending on the condition of the road. I have run both
> Kumho 857 (listed as a trailer tire, but not having the trailer tire
> designation, and sold in Europe as a van or bus tire), and Hankook RA08 at
> those pressures. The Hankook seems the better tire, with longer life.
>
> Right now, I am trying to find a winter tire. I thought the Vredestein
> Comtrac Winter was available, but it seems that some dealers list it in our
> size, but when queried, say that it is "out of stock." Vredestein does not
> list the tire in our size on its web site, so I don't know what is going on.
>
> But no one seems to offer a winter tire in either 185 R14 LT or 195 R14 LT
> (whether C or D load range).
>
> I've never used a load range C tire, and given that the maximum pressure is
> 50 psi, it would not be appropriate for the rear.
>
> mcneely
>
> On Sat, Nov 12, 2016 at 1:34 PM, Dennis Jowell <dennisjowell@gmail.com>
> wrote:
>
>> Eric,
>> Thanks for the information I certainly will study this and adjust my new
>> tires accordingly thanks again for your response
>> Dennis J
>>
>> Dennis Jowell
>> Scotch Hollow Farm
>> Newbury, Vermont
>>
>>
>>> On Nov 12, 2016, at 12:54 PM, Eric Wunrow <VW@EricWunrow.com> wrote:
>>>
>>> Are they C-rated? Looks like they are on the size description.
>>>
>>> Every C-rated tire I see is 50-lb. max pressure, and D-rated is 65 psi.
>> I don't know if these are standards, but suspect they are.
>>>
>>>
>>> I should pre-qualify that though I've only done 35,000 miles in this,
>> our first bus, 95% of these miles have been on two-laners; and I've studied
>> this constantly, since I love dialing handling in and we live full-time in
>> our Westy.
>>>
>>>
>>>
>>> Now, coming from a lifetime around racing (53 years since road race 1) —
>> where one learns to feel a 5% change in one's ass or never gets good — and
>> thus knowing some things about tires and tire companies, 50 would be
>> something of a minimum "safe-max," if you will. Meaning, more pressure
>> could mean an easier blowout, on the hottest day of the year, at too high a
>> speed (think errant Ford Explorer/Goodyear lawsuit here) with a vehicle
>> weight on the max tire limit. Worst-case, in other words, and tending to be
>> conservative based on potential legal fallout and more.
>>>
>>> But that said, considering we're driving boats here ("I beg your
>> pardon!"), I believe the corner weight (tire) load ratings on our vans are
>> right on the edges anyway. The suspension we have puts loads on hard
>> cornering that I think go beyond simple weight-bearing load ratings. If
>> pushed hard enough, some of you have likely noticed the outside-front tire
>> acts like it wants to fold under, and less tire pressure worsens this
>> intensely.
>>>
>>>
>>> I'm not talking about pretending your bus is an F1 car here... I'm
>> talking about avoiding a crash or correcting an error in dramatic moments.
>>>
>>>
>>> But the real points I want to make are these. I know what everyone talks
>> about for tire pressures, and what VW said at the time, 36F and 48R — when
>> tires still sucked by comparison to today — to me are entirely backwards.
>> Our buses tend to have lots of push — understeer — despite the weight being
>> mostly in the rear. This is from a combo of things like stiffness, weight
>> transfer, high center of gravity, etc., but the only way I've ever gotten
>> good steering from my van is to run MORE pressure on the front. Think of a
>> stiffer tire holding the weight better, then transferring weight to a
>> softer outside rear that still has enough pressure to hold the grip.
>>>
>>> The best for my 14-inch wheels so far — MILES beyond having equal-sized
>> and/or varied- or equal-pressure tires all around before — has been
>> 185/95-14 fronts (D-rated), and 27x8.5 rears (C-rated, all of them BFG
>> All-Terrains). I ran all at their max pressures of 65 front, 50 rear. The
>> beast finally handled, and mileage also got better by maybe up to one mpg
>> over the suggested (IIRC) factory pressures of 48 front, 36 rear. But this
>> said and for the stated reasons, I personally wouldn't want to run any more
>> pressure than the max. recommended by the tire maker — and if in doubt on a
>> hot highway run, I like to pull over and feel the temperature on the tread.
>> Compare pressures when cold to when hot, more than a few lbs. pressure gain
>> is telling. Too little or too much pressure extreme will show in hot tires,
>> and ultimately if carrying lots of weight or living in extreme heat we
>> should all carry a tire temp gauge, a pyrometer (note to self...).
>>>
>>> I am unclear to date how much of the handling balance from tire
>> pressures is due to pressure vs. the sidewall stiffness contrast between C
>> and D, though, but am confident enough to know when I get larger wheels I'm
>> always going to put slightly larger tires in the rear — and have all four
>> be D-rated for their safety benefits — and most likely still run more
>> pressure in the smaller fronts. I'd guess 65F and 60R, if pressed — when
>> hot.
>>>
>>>
>>> But keep in mind, on ice these theories change. The worse it is, the
>> less pressure I want on all four. I went down to 12 on the rear once (25 in
>> front) to drive through deep sand 3.5 miles on Pismo Beach. The bite was
>> amazing, but mostly sans throttle (!). On really bad ice, I might start at
>> 25 all-around and test the tire bite in an empty parking lot before
>> proceeding into the storm. I suspect I'd still want less pressure in the
>> rear, and perhaps even more of a variance than in the dry. But that I don't
>> yet know for sure.
>>>
>>>
>>> Also keep in mind things change depending on where your side-to-side and
>> front-to-rear weights are centered. With all the cabinets on the left, and
>> in our case three batteries including the starter battery on the left (two
>> under the sink weigh 154 lbs. total), I am constantly adjusting weight
>> rear-ward and as far right as I can. In our case, more weight than normal
>> is up front, and that is certainly making my fronts want more pressure and
>> sidewall stiffness, so results will vary and testing is the only way to
>> know. Our lives depend on those four rubber-to-road points of contact.
>>>
>>>
>>> Happy Motoring,
>>>
>>> Eric
>>> Eric Wunrow Pictures
>>> 303. 988. 8717
>>>
>>> VW@EricWunrow.com (for this list's emails)
>>> EW@EricWunrow.com (for private messages)
>>>
>>> <EW Email Sig.gif>
>>>
>>>> On Nov 12, 2016, at 6:11 AM, Dennis Jowell <dennisjowell@GMAIL.COM>
>> wrote:
>>>>
>>>> David
>>>> I just got my Vredestein Comtrac All Season 195R14C C/6PR BSW tires
>> installed yesterday although not studded they ride quiet and has a nice
>> aggressive tread. The new tires replaced my RA08 tires.
>>>> A question ! What PSI would be advisable for the Comtrac tires ?
>>>> 45 F and 55 R ? On my 88' GL Westy camper.
>>>> Dennis J
>>>>
>>>> Dennis Jowell
>>>> Scotch Hollow Farm
>>>> Newbury, Vermont
>>>>
>>>>
>>>>> On Nov 11, 2016, at 9:54 PM, Alistair Bell <albell@SHAW.CA> wrote:
>>>>>
>>>>> I had a set a few years ago. Worked well on hard pack and ice. Didn't
>> have any real time in deep fluffy. But I had a flat on one which couldn't
>> be repaired so only one season of experience.
>>>>>
>>>>> I liked them for the time I had them.
>>>>>
>>>>> Alistair
>>>>>
>>>>>
>>>>>> On Nov 11, 2016, at 6:39 PM, David McNeely <davmcneely40@GMAIL.COM>
>> wrote:
>>>>>>
>>>>>> I know that the Comtrac All Season has been discussed here. Does
>> anyone
>>>>>> have any experience/knowledge of the Comtrac Winter tire?
>>>>>>
>>>>>> http://e-tiresunlimited.com/ALL%20TIRES/Vredestein/vred_
>> comtrac_winter.htm
>>>>>>
>>>>>> It is pricy, but there seems to be little in the way of winter tires
>> in 14"
>>>>>> with the load capacity for our vehicles.
>>>>>>
>>>>>> There is a studded version, also, but I will be driving to California
>> this
>>>>>> winter.
>>>>>>
>>>>>> Thanks, mcneely
>>>
>>
>
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