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MG MGB Technical - Wide tire choice

I run a wide tire on my MGB, 205/60/15 on 14x7 wheels. I used to run Cooper Cobras, mainly because they were cheap, and actually they worked quite well, but recently I tried out two different compounds, Toyo T1Rs (195/55/14 actually) and my current Sumitomo HTR 200.

The Toyo's had a directional tread, were really sticky and great in the rain (compared to the Coopers). The Sumitomo's seem to be quite sticky as well and perform well in the wet.

But both tires feel scary on grooved freeways. They cause the car to dart a lot, where the Coopers were minimal. I have negative camber wishbones up front which doesn't help, but again the Coopers ran on the same car and weren't so bad. So I feel like the tread design has a lot to do with it. So I'm wondering what other tires folks have used and if they have had better results on grooved pavement. I'm perfectly happy running a 195 if it means better stability on the freeway.

-Bill
Bill Mertz

Bill,

I don't know the answer, but you might want to clarify the size.

You said, "I run a wide tire on my MGB, 205/60/15 on 14x7 wheels."

If that is right, I might have found your problem, eh?

Charley
C R Huff

I knew those 15" tires looked funny on my 14" wheels.

Right you are.

205/60/14 is the actual size.
Bill Mertz

Bill, I think the problem is in the tread design. Most of the directional treads have very pronounced ribs with rather large voids between. It doesn't appear this way if you just look at the tire, but jack the tire up and spin it and I think you'll start to see the pattern. I had similar problems years ago with my motorcycle with a ribbed front tire and the freeway surface. Those grooves are not straight and the bike would follow every little movement. I changed to a front tire with no pronounced "rib" in the pattern and the problem went away.
Bill Young

Here's a photo of my midget with a 205R60X13 with a directional tread tire. You can see the "rib" pattern pretty well on the front tires.


Bill Young

Yeah I was thinking that might be the issue. The Toyo's were a direction V tread shape, and the Sumitomo's aren't directional, but do have some rather large channels, presumably for wet weather driving. Maybe I should run some shaved slicks and get rid of the problem all together.

On a side note, that's one hell of a Midget you got there.

-Bill
Bill Mertz

This thread was discussed between 25/08/2008 and 27/08/2008

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