----- Original Message -----
From: "Alain" <triumphworks@gmail.com>
To: <triumphs@autox.team.net>
Sent: Thursday, March 03, 2005 3:25 PM
Subject: TR4A tire question
> Need some tire advice.
>
> I have original 4.5" wide x 15" wire wheels. I am debating getting
> some larger tires than I have on the car right now, orginal spec
> P165/80R15s.
> My question is: will 185/70s work for a 4.5" rim
I think you are pressing your luck. A rule of thumb is that the rim width
should be at least 70 percent of the section width. 4.5" is 114.3mm 114.3
is 62 percent of 185.
114.3 is 65 percent of 175.
114.3 is 69 percent of 165.
The lower the aspect ratio, the more important this becomes, so 185-70s
would give you more problems than a regular 185, and 185-60s would be more
problemetic yet.
You say these are the original 60-spoke Dunlop wires? I think they have
about all they can do to deal with fresh 165s. I'm not saying that they
won't work, but I am saying that the combination of over-wide tires for the
wheels, the camber-challenged TR4 stock front end, and the whippy wire
wheels probably add up to a setup that would not be any faster around the
old skidpad than the 165s.
I use 165s on my Dayton 4.5" wide x 15" wire wheels.
If you really want to get the most out of 185 or wider tires, put on 6-inch
Panasports.
I have sticky 175-60-13 on 6-inch wheels for autocrossing my Lotus. I'd go
to 185s if I could get what I wanted for compound and price.
> and are there any clearance issues.
I don't know. TR4 cars do seem to have a lot of wheel space. I have been
told that you can put TR6-size stuff on TR4 cars, but have not tried it.
Phil Ethier West Side Saint Paul Minnesota USA
1970 Lotus Europa 65/2597, 1992 Saturn SL2, 1993 Suburban, 1962 TR4 CT2846L
pethier@isd.net http://www.mnautox.com/ http://www.lotusowners.com
"TOOLS? Hell, any fool can work with tools. It takes a real mechanic to
work with this junk." -Orv Ethier, 1921-2004. First Shot Naval Vets, Pearl
Harbor Survivor.
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