(US) Cobra Tire Redux

[5E]

Thank you all for the fine past discussions archived here (2004, 2008,
2009) on this topic.

Without having read all of that three years ago, I put a set of good
touring passenger tires with adequate load rating on my Cobra and have
been careful to keep them maximally inflated. It's a 2002 with the 13
inch wheels, and I'm currently running P185/70 R13 like BB was
looking to replace in '08. I've had zero issues, and without knowing
better would have replaced them with another set of passenger tires in
the same size. It's comfortable with the Outback on smooth interstate
up to 72mph, with some sway if I bump it up to get around a truck on a
downhill.

It's been 3 years, so I was looking to replace them anyway. A spike
in blow-outs among people I know this year (and not just old tires)
has added a sense of urgency, and prompted my research here and on the
tire sites. And now, presto-chango, I have Decision Paralysis. If I
understand the situation correctly, my options are:

1. Repeat 13 inch passenger tires. A look around the lot at M-ASA,
Uvalde, and NCI shows a lot of P-rated tires on Cobras, and it's all
I've ever used. But then, I didn't know any better...

2. ST tires. Would require changing to 175/80 R13, but I doubt I'd
notice the difference. 13 inch ST tires available locally sound
horrifically cheap, and no warranty. Spoke with TireRack, who have
only Goodyear Marathons--a couple of poor (blow-out) reviews online.
And 65mph speed limit unless you add 10psi--do our Cobra wheels have
an inflation limit? (DiscountTireDirect has Maxxis and Carlisle.)

3. Bigger wheels. Initially not a priority, but I had trouble finding
13 inch tires in Uvalde and closer to home. Would make LT tires (not
available in 13 inch) an option.

Trailer's in the driveway this week, and it's time for action. Anyone
else been down this road recently?

Thanks,
Erik

[Dave Nadler]

On Sep 28, 5:32*am, 5E > wrote:
> Thank you all for the fine past discussions archived here (2004, 2008,
> 2009) on this topic.
>
> Without having read all of that three years ago, I put a set of good
> touring passenger tires with adequate load rating on my Cobra and have
> been careful to keep them maximally inflated. *It's a 2002 with the 13
> inch wheels, and I'm currently running *P185/70 R13 like BB was
> looking to replace in '08. *I've had zero issues, and without knowing
> better would have replaced them with another set of passenger tires in
> the same size. *It's comfortable with the Outback on smooth interstate
> up to 72mph, with some sway if I bump it up to get around a truck on a
> downhill.
>
> It's been 3 years, so I was looking to replace them anyway. *A spike
> in blow-outs among people I know this year (and not just old tires)
> has added a sense of urgency, and prompted my research here and on the
> tire sites. *And now, presto-chango, I have Decision Paralysis. *If I
> understand the situation correctly, my options are:
>
> 1. Repeat 13 inch passenger tires. * A look around the lot at M-ASA,
> Uvalde, and NCI shows a lot of P-rated tires on Cobras, and it's all
> I've ever used. But then, I didn't know any better...
>
> 2. ST tires. *Would require changing to 175/80 R13, but I doubt I'd
> notice the difference. *13 inch ST tires available locally sound
> horrifically cheap, and no warranty. *Spoke with TireRack, who have
> only Goodyear Marathons--a couple of poor (blow-out) reviews online.
> And 65mph speed limit unless you add 10psi--do our Cobra wheels have
> an inflation limit? *(DiscountTireDirect has Maxxis and Carlisle.)
>
> 3. Bigger wheels. *Initially not a priority, but I had trouble finding
> 13 inch tires in Uvalde and closer to home. *Would make LT tires (not
> available in 13 inch) an option.
>
> Trailer's in the driveway this week, and it's time for action. *Anyone
> else been down this road recently?
>
> Thanks,
> Erik

Hi Erik - Not all Cobra trailers are the same.
You haven't said what size and weight trailer.

You should have, in the original paperwork
for the trailer, the recommended tire type
and inflation. If you have the import docs
you'll have the port weight of the complete
rig.

For my 18m Antares 20E trailer I just mounted:
Vredestein Comtrac 185R14C 102/100R
Load range D max load 1874lbs/850kg per tire
Speed rating R = 106 mph (170 km/h) H.D. Light Truck Tires
Max inflation 65PSI for 1874; use Spindelberger recommended 61 PSI for
1200 lbs

Hope that helps,
Best Regards, Dave "YO electric"

[hretting]

I have 14" rims and looking to replace my tires. Dave...where did you
get Vredestein Comtrac. I have never heard of them. I've been told to
get heavy duty D rated TRAILER tires as they have an extra side wall
to help with the heavy swaying. I'm concern as the rims are metric and
the tires will be purchase locally. I'm looking for specific size
numbers as you show in your post.
R

Don"t tell Murray as my tires are 9 years old. Got lucky going to R4S.

[Dave Nadler]

On Sep 28, 11:05*am, hretting > wrote:
> I have 14" rims and looking to replace my tires. Dave...where did you
> get Vredestein Comtrac. I have never heard of them. I've been told to
> get heavy duty D rated TRAILER tires as they have an extra side wall
> to help with the heavy swaying. I'm concern as the rims are metric and
> the tires will be purchase locally. I'm looking for specific size
> numbers as you show in your post.
> R
>
> Don"t tell Murray as my tires are 9 years old. Got lucky going to R4S.

Hi Henri - Light Truck tires have the stiffer sidewalls you seek.
These specific tires are recommended for trailers as well
as light trucks. Google should find you a dealer; mine were
ordered by Direct Tire which is a Boston-area top-notch
tire and brake company.

These particular tires may be overkill for a smaller and
lighter trailer; check your Cobra paperwork for the
specific tires recommended for your trailer.

Hope that helps,
Best Regards, Dave

[Eric Greenwell[_4_]]

On 9/28/2010 8:05 AM, hretting wrote:
> I have 14" rims and looking to replace my tires. Dave...where did you
> get Vredestein Comtrac. I have never heard of them. I've been told to
> get heavy duty D rated TRAILER tires as they have an extra side wall
> to help with the heavy swaying. I'm concern as the rims are metric and
> the tires will be purchase locally.
>
If you have 14" rims, they will take standard 14" tires. The bolt
spacing might be metric, perhaps.

What I've read agrees with Dave N: go for the higher speed rated LT
tires if you can. The LT tire construction has more tread stability the
comparable ST tire, and the higher the speed rating, the more stable the
trailer will be. Unfortunately, the choices of LT tires are limited in
the 14" size.

You don't say how heavy your trailer is, but if it's over 2000 pounds, I
suggest the Michelin Agilis LT 195R14C, 2090 lbs max load, and use the
tire pressure required for 1.2 x (your load). If your trailer is less
than 2000 lbs, these are probably much more tire than you need. Also,
check the tire diameters, as they differ.

I use the Michelin Agilis LT 185R14C tire on my 2500 lb trailer, but
that size isn't available any more.

And now for my usual lecture... It's not "sidewall stiffness" per se
that is important to stability, but lateral tread stiffness (how easily
the tread distorts with a side load). They don't give you that number,
but for trailer stability: belted tires are preferable to unbelted,
higher speed ratings are preferable to lower speed ratings, lower aspect
ratio preferable to higher aspect ratio.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl
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