Brian Iten wrote:
Not sure you want to put a bigger (round wise) tire
on the trailer. If anything, you would want to put
a wider tire on for more stability and less sway. Also,
if you go cheap, you usually always get what you pay
for. Not too sure if I would want a cheap tire on a
trailer with an expensive glider in it.....


At 14:42 11 August 2004, Samcgiltner wrote:

Check the current tire size. If you have P155/80R-13s
or even
P165/80R13s now, you can raise the height by going
to a P185/80R13 by
close to 3 inches. The tires will be much cheaper than
the wheels. 5
Ugly.




All depends on what you want to achieve.

Commercial vehicle tyres (i.e. made for trucks - not RV 1 tonners) have stiff
sidewalls. They also have hard compounds to handle the high loads, so may tend
to grip poorly with light load. So - less swaying but a tendency to lose
adhesion with little warning and very comprehensively. Not sure you want to go
backwards down the highway after hitting that patch of water under braking...

Normal road tyres have become progressively lower profile over the years, and
thus improve stability by reducing the ratio of sidewall to tread dimension. The
only problem is that the rims on the trailer are designed for the old 80 profile
tyres, so if you go beyond a point the (generally 5J) rim will not support the
tyre well, and it may even shed the tyre. Clearly you can't just go putting ever
wider tyres with the same circumference on the thing. In general two sizes up is
all it is advisable to go before you increase rim size. If the original was a
155x13 with an 80 profile then 175x65 is about it.

The rim is usually a standard german light car rim. Most appear to be Opel (GM)
rims. Safest bet to improve trailer dynamics is to fit similar tyres and rims on
the trailer. Match the trailer and prime mover's tyres - If your car has V rated
tyres, try to get the same tyre for your trailer, or at least the same rating.
Never fails to amaze me seeing a powerful new car with massive low profile tyres
roaring along with a trailer on 15 year old skinny low performance tyres barely
under control behind. A couple of rims from a breakers yard is not going to
break the bank.

Even if you do sort out the trailer with decent tyres, remember it does not have
the same suspension (most do not even have dampers at all) or dynamics that your
fancy uberwagen/baby hummer has. Just because your car feels rock solid does not
mean that the trailer is in it's safe envelope. Most trailers built in the
seventies and eighties are certified to 80kph/50mph - with uprated tyres and
hitches they may be fine at 120kph but not much more and not on bad surfaces, or
in windy conditions or heavy traffic.