(Brace yourself, this is long.)
I've been looking into the tire possibilities and here's what I have learned
so far:
1) Goodyear racing does not offer anything of high enough load rating,
according to Carroll Shelby Ent., the western region distributor for
Goodyear Racing. We would have to have Goodyear custom build something for
us; VERY expensive and hence something we would want to do only as a last
resort.
2) Mickey Thompson Tires, which has provided many of the tires for
Bonneville racers, likewise does not have anything that could take the
weight of our coaches.
3) Standard over-the-road truck tires, whether from Goodyear, Michelin or
Bridgestone, are out of the question, being typically rated up to sustained
speeds of 65 or 75mph at maximum loads.
4) Bridgestone, nothing here, either.
BUT..........................................
5) Michelin's LT (light truck) series appears to be a possibility, depending
on how fast we go. This is the tire that comes standard on some high-end
"passenger" trucks such as the Toyota Land Cruiser, Lexus LX450 and Range
Rover. It also comes in a size (LTX 225/75R16 E 115/112R) and load range E
that fits our coaches.
The LT tires do not list a speed rating label on the sidewall but according
to Michelin Tech. their light truck tires with no speed rating label are
"suitable for sustained speeds at up to 105 mph for up to 1 hour at 100%
load. "
That doesn't mean that they self-destruct at speeds in excess of 105 mph,
however. Maximum load for this size load range E tire is about 2600 lbs.,
this at 80 psi. On my coach (which weighs in at 4400 lbs. on the front axle)
each tire carries a static load of 2200 lbs.
We would want to use the A/S tread version of this tire and could reduce the
rolling resistance and heat build-up by shaving and truing the tread, again
according to Michelin tech.
One more thing...
The engineer (Robert) at Michelin [(800) 847-3435] was very familiar with
the GMC and had an interesting story that I thought I'd pass on:
In 1980 Michelin France sent over to their U.S research center a new test
vehicle - a '75 Transmode! The floor had been partially removed and a test
axle installed which could be raised and lowered. The axle was fitted with
sensors which fed on-board computers to record the various forces and slip
angles experienced by tires under test. Braking and steering forces could be
applied to the axle as the GMC motored along the test track. This was the
primary research test bed for Michelin's passenger tire research from
1980-1993. It was used more or less continually for 8 and sometimes 16 hours
a day. Rear drum brakes were a problem (shoes would be worn out after a
day's testing) so they fit Corvette 4-piston fixed-caliper brakes with
drilled rotors. They also went through a lot of transmissions due to heat
build-up so they fit an automotive A/C condenser as an external oil cooler.
The 455 was very long-lived but eventually had to be replaced. They first
built a replacement engine with entirely new parts from GM but it failed
prematurely so they then rebuild the original engine which is still in the
coach. The Transmode is now resting peacefully in the "boneyard" at
Michelin's Lawrence, NC proving center.
Anyway, since Michelin is so familiar with the capabilities of the GMC I
wonder if they would be interested in providing some sponsorship when the
time comes. That assumes, of course, that whoever is trying for the record
feels comfortable using this tire.
Richard Guthart
'77 Birchaven
I've been looking into the tire possibilities and here's what I have learned
so far:
1) Goodyear racing does not offer anything of high enough load rating,
according to Carroll Shelby Ent., the western region distributor for
Goodyear Racing. We would have to have Goodyear custom build something for
us; VERY expensive and hence something we would want to do only as a last
resort.
2) Mickey Thompson Tires, which has provided many of the tires for
Bonneville racers, likewise does not have anything that could take the
weight of our coaches.
3) Standard over-the-road truck tires, whether from Goodyear, Michelin or
Bridgestone, are out of the question, being typically rated up to sustained
speeds of 65 or 75mph at maximum loads.
4) Bridgestone, nothing here, either.
BUT..........................................
5) Michelin's LT (light truck) series appears to be a possibility, depending
on how fast we go. This is the tire that comes standard on some high-end
"passenger" trucks such as the Toyota Land Cruiser, Lexus LX450 and Range
Rover. It also comes in a size (LTX 225/75R16 E 115/112R) and load range E
that fits our coaches.
The LT tires do not list a speed rating label on the sidewall but according
to Michelin Tech. their light truck tires with no speed rating label are
"suitable for sustained speeds at up to 105 mph for up to 1 hour at 100%
load. "
That doesn't mean that they self-destruct at speeds in excess of 105 mph,
however. Maximum load for this size load range E tire is about 2600 lbs.,
this at 80 psi. On my coach (which weighs in at 4400 lbs. on the front axle)
each tire carries a static load of 2200 lbs.
We would want to use the A/S tread version of this tire and could reduce the
rolling resistance and heat build-up by shaving and truing the tread, again
according to Michelin tech.
One more thing...
The engineer (Robert) at Michelin [(800) 847-3435] was very familiar with
the GMC and had an interesting story that I thought I'd pass on:
In 1980 Michelin France sent over to their U.S research center a new test
vehicle - a '75 Transmode! The floor had been partially removed and a test
axle installed which could be raised and lowered. The axle was fitted with
sensors which fed on-board computers to record the various forces and slip
angles experienced by tires under test. Braking and steering forces could be
applied to the axle as the GMC motored along the test track. This was the
primary research test bed for Michelin's passenger tire research from
1980-1993. It was used more or less continually for 8 and sometimes 16 hours
a day. Rear drum brakes were a problem (shoes would be worn out after a
day's testing) so they fit Corvette 4-piston fixed-caliper brakes with
drilled rotors. They also went through a lot of transmissions due to heat
build-up so they fit an automotive A/C condenser as an external oil cooler.
The 455 was very long-lived but eventually had to be replaced. They first
built a replacement engine with entirely new parts from GM but it failed
prematurely so they then rebuild the original engine which is still in the
coach. The Transmode is now resting peacefully in the "boneyard" at
Michelin's Lawrence, NC proving center.
Anyway, since Michelin is so familiar with the capabilities of the GMC I
wonder if they would be interested in providing some sponsorship when the
time comes. That assumes, of course, that whoever is trying for the record
feels comfortable using this tire.
Richard Guthart
'77 Birchaven
