On Mon, 11 Oct 1999, John Wiseman wrote:
John,
I'm cc'ing the Triumphs list, as I get questions like this pretty often.
I hope you don't mind.
> Well, perhaps we should have called it the Valvoline RainOffs :-) I got
> to go down and watch FP on Friday [ a friend from high school was
> third in a Lotus ] and at least one of the spitfires looked pretty good!
> [ although Joe Hufager (sic) is just too
> much ].
The RainOffs... pretty good. I like that.
Yep. Huffaker is def. a force to reckon with.
> BTW, I have been running my reconstructed tr6 in D/SP autocrossing
> events this year and having been thinking about getting some real tires
> and wheels. Have any suggestions about what make sense?
John - you happened to touch a subject that I am very familiar with...
I've been using the Hoosier D.O.T. radials for three or four years. I
happen to have been using the road race compound, but I have driven other
cars with the autox compound and those come up to temp a lot faster and I
would strongly reccomend those (the autoX compound). They don't last very
long, but they stick like glue.
As for wheels, in DSP, there are no retrictions on wheel width. Depending
on what your actual goal is, I would do one of the following:
1. if you're into DSP and wanna stay there (actually ESP next year!), then
get the widest wheels you can get. Run the 225/55-15 size Hoosiers. Note:
they'll (the 225's) fit on even 5.5 inch rims, so if you're on a budget,
go with the tires first then change the wheels. There are (from time to
time) various 8 inch rims that show up with the 4 by 4.5" wheel pattern.
Note: that I have seen JK Jackson searching for these wheels for his
wife's DSP TR6, so that's gotta say something. Failing that, you can't
loose with 7 inch Panasports... see "2". Also, don't be fooled into
thinking used wheels are a "good deal". It took me _two years_ to find a
4th 4 spoke "mag" a few years back. Besides - the newer wheels are _way
stronger_ than the old ones.
2. If your goal is to "move up", then pay attention. SCCA AP rules (and E
Prod) limit you to 7 inch rims. So the Panasport 7 inch is a real easy
decision. If you wanna use other brand wheels, good luck, but I found a
set of 5-spoke Revolutions that are 7 inch wide, "zero" offset and 4 inch
"back-space". These fit really well - no interference.
On my "new car", I happen to be running in AP, so I run 23 X 9 X 15
slicks. With those and the Revolutions, there are _no_ interference problems.
On my DSP car, I'm using 5.5" 4-spoke American Racing wheels, called by
some "Formula Libre". The back space on these wheels requires spacers, so
I had to have some 1/4 inch from spacers made (to eliminate interference
with the upper A arms) and 3/8 inch spacers in the back (to keep the tire
from rubbing the "upper bumps stop perch", aka - the body inside. I also
run tire pressures in the upper 30's range (36/38 or 38/40 depending on
the day and the surface that I'm running on, grippier surpaces warrant
higher tire pressures as the sidewall flex is pretty large - even with the
super stiff Hoosier sidewall construction. Note: the spacers and those
wheels with the stock lugs are pretty "iffy". I check the lugs pretty
closely several times per year to make sure they aren't cracked or anything.
On the "race car", I'm running 1/2-20 X 3 inch Moroso studs. Much
stronger than the stock TR6 lugs!
Other than that, there's not a lot of choice.
I'll also point out that with 225/55-15's there is no interference with
the wheel edges of the fenders. Unless you are sprung with stock springs.
If so, you might have some rubbing on extreme cornering. I run the Moss
"comp" springs (blue), and the rears are rated at around 500 pounds/inch.
This is a _lot_ stiffer than stock, maybe 50% more.
But I'll also point out that the 225/55's will lower the car about 1.5
inches from stock, so the roll center is a lot "closer to the ground". In
short, my car has very little body roll with all the above stuff (plus
the Addco 7/8" front bar and 3/4" rear bar.
> There is one other TR6 in our local region who
> is running
> Kumhos [205/50-15] on 7" wide wheels. I'm not sure if wider would be
> much better, but in his
> case he has a shock conversion kit that may limit tire width.
If you're running 7 inch rims, you might as well run 225's if you can get
'em. On the narrower rims, I wouldn't go too much lower than 55 profile,
as the 55 series tires are a major PITA to get onto 5.5 inch rims. I have
to use a different tire shop to mount tires for me everytime. ;-)
The Kumho principle advantage is cost. They cost maybe $50 per tire less
than the Hoosiers. They also seem to last pretty long, but that's not
necessarily a good thing. Read on.
With respect to shock conversion, I think that going to the adjustable
shocks is "real nice", but unneccesary. Think about it. You spend $xxx
for the kit and then you install it and then you're limited in how
everythings goes together (e.g. tire width).
For around $100 - $130, you can get your shocks "rebuilt" by Apple (or
others, I might point out) and "revalved" to a "heavy duty" setting. This
is alot less expensive than converting to Konis or Spax (who just bought
the farm, reportedly) as those kits start at $250 or so and go up from
there, Moss list for the Koni conversion is $380, so expect to pay at
least $300 for it... and then you have to put it in. I'd spend the $130
to get the rears rebuilt and then $100 for a new front bar and then $100
for a rear bar and my car would handle a lot better than spending $300
_just for the shocks_. But it's your decision.
Besides, how many folks really understand how to tune the shocks. Really.
You don't need to tweek them until you're getting down to trying to
figure out how to get fractions of tenths of a second from your times.
In the case of tire width, the difference between 205's and 225's is
almost one inch of width, that's a _lot_ and the car handles totally
different with the 225's.
If you like really, really wide tires, the 8 inch rims and 235 or 245
wide Hoosier bias ply tires might fit the bill, but I have no idea about
their availability anymore.
Personally, I'd strongly recommend the Hoosier Radials. At least for now.
Keep in mind that Hoosier Radials didn't exist 5 years ago and at that
time _everyone_ ran Yokohama A008's. Now the only people that run the
Yoko's are folks that have 5 year old tires (and a few that have managed
to find a set or two laying around... the Yoyo's are getting very hard to
come by). The tire technology changes "real fast", and if you take the
time to look at the Solo II Nationals results, you'll see who that
"winners" are in the various classes.
The principle advantage to the Kumhos is that they are cheaper e.g. less
expensive.
> It would be nice to be able to drive to events [about 20 mile round
> trip] on competition tires if possible.
Take this thought completely from your mind. It's not worth it to ruin
your autox tires driving to/from events. At $170 each for Hoosier
radials, for example, you'll be replacing tires at least twice a year
(you didn't say how many events that you do, but presuming 6 - 8 events
and a 20 mile drive... plus, the "race tires" from Hoosier (in
particular) and the others in general are really not meant to drive in
the street - one encounter with a stray nail or even a very sharp stone -
kiss a tire goodbye... and those things pick up _everything_ from the
road. Even leaves!
And race tires only have a limited number of "heat cycles" in them. Once
you violate that limit... you might as well be racing on $99 for 4 tires
from Pep Boys. Really.
If you're serious - change the tires at the event. I can change 4 on my
car in 20 min. Plus everyone comes over to give you a bunch of crap, err
to socialize while you're changing them.
The point is that the most benefit comes from driving the car on the
course, not driving to/from the event. Keep the tires good for driving on
the course. You will do better if only because of the seat time.
> Any thoughts would
> be appreciated [ might also help me beat a few more VW GTI's :-) ]
I've got more advice if you need it, drop me a line.
I've been pretty successful with my DSP TR6 over the last 4 years, and
the only reason I built an AP car was that I had trouble sourcing new NOS
stock TR6 cams that would be "unprotestable" with SCCA. It's getting sort
of hard to get new stock cams... besides, I get to play with gears and cams,
and all kinds of stuff I couldn't do in DSP. Well, legally, anyway. Granted,
the car is 5X more expensive, but - you get the idea.
Hmmm. Maybe I should build another DSP car!
And I love it when I trounce a VW or better still a Honda... I get
excited just thinking about it.
> thanks and take care
> John Wiseman
> 76 TR6
Later,
rml
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