3 questions on tires and handling

When I got my Z1 from its original owner it had a metric size rear tire that was wide enough to regularly rub one side of the swing arm and close to the other side. It was dry rotted so I have replaced it with a 4.00-18 per specs.

Does the wider tire offer any handling improvement over the spec tire? Any advantage of a rubber tire versus nylon? And finally is it true that a 1974 Z needs a ribbed front tire for stability?

thanks.

question 1 = When I got my Z1 from its original owner it had a metric size rear tire that was wide enough to regularly rub one side of the swing arm and close to the other side. It was dry rotted so I have replaced it with a 4.00-18 per specs.
Does the wider tire offer any handling improvement over the spec tire?

wg answers = The OEM tire size was 4.00x18 and its replacement would be a 120/90-18 I think. That is about as large as you can go on a Z1 and not rub (18" rear wheel). I don't think having a wider tire vs a more narrow tire will make all that much difference as you really can't mount a significantly wider rear tire. The tire will generally rub on the rear drum brake stabilizer bar FIRST if it is too wide.

question = Any advantage of a rubber tire versus nylon?

wg answers = Not sure what type tire you saw you thought was nylon. In my experience all motorcycle tires are rubber compounds of some sort. Some (well all of them) have bands that are laid across the carcass under the rubber in various patterns and various materials and I believe on material for these bands is nylon. I personally have used Cheng Shin tires in the past on my KZs but am going to try some Dunlop 404s I think for a bit more durability. I generally have gotten about 6K on the rear of a Cheng Shin Hi-Max. The good news is that they are only about $40 a tire. The 404s are slightly more but not all that much. Others have reported good results on other brands and models of tires.

question = And finally is it true that a 1974 Z needs a ribbed front tire for stability?

wg answer = In 1974, the ribbed tire was the state of the art design. Newer designs (non-ribbed bias) are more stable and shed water much better. You actually have MORE contact patch and better traction in dry conditions with NO grooves or ribs in a tire (like a slick) but when the road gets wet, the tire needs to be able to shed water else you will hydroplane. Current thinking puts grooves (in various patterns) in mores street tires rather than ribs. The ribs definitely didn't help handling or stability.

a good narrow tire will definately outperform a bad fitting wider tire .im not sure about the cheng-shin tires but it depends on how hard you ride,i have used there tubes before with no problems though.like wg said ribbed tires were the thing in their day but so was disco and 8-tracks:whistle: if you want to improve the handling of a Z1 tapered steering head bearings and a needle bearing swingarm are good starting places. goodluck,happy wrenching!

Careful George or you will reveal my ignorances. I have owned bikes before this Z1 but it was about 15 years ago. I had a GS400 and a Virago 750. But I was only a rider, no wrenching on bikes at that time. Cars yes, bikes no. Now I'm trying to do better.

I saw a tire with big block letters that said NYLON, I assumed that was the tread compound but your explanation makes more sense.

As far as the ribbed tires go I recently read something (I'm trying to find it) that still recommended ribbed fronts. They may be as far behind as me.

Thanks for the info guys.

I just put a set of Dunlop 404's on my KZ650. Don't know how well they wear, but they drive nice. Got a really good price from JC Motors: stores.ebay.com/JC-Motors-Motorcycle-Accessories
Shipped to me in 2 days, and good customer service when I called.

A wider tire only helps traction when used with a wider rim. A wide tire on a narrow rim will actually give you a smaller contact patch because the inside beads have to be squeezed together forcing the actual tread area into a tighter arc.

Like wireman said, get some tapered head bearings some good bronze bushings or bearing for the swingarm. I've heard that the older bikes don't like radial tires, so I've tried to stay away from them. I did have Kenda Challenger on the back of my 1000 until I swapped to 17" rims. I did like the Kenda and would recommend them.

im not out to carve up any twisties really so Cruising tires it is, Kenda Makes a great tire (I think) and they arent really expensive but are long lasting.

130mph rating and they grab the roads up here.

G'day there,
the Dave Marsden book suggests that the Z's needed and "still needs" a ribbed front tyre. I run Avons on my Z900, with a fully ribbed front, mainly because they look like a "period" tyre, and suit an original Z.
Modern tyres on old bikes look crap to my line of thinking.
I don't have any more problems with the ribbed tyre than I did in the '70's :ohmy:

Sorf,

The Marsden book is indeed where I read that quote about the ribbed tires. Borrowed the book from my local library. Thanks for locating it for me.
What Avon tires are you running?

Everyone,

I'm curious what the general opinion is on the question of ribbed versus non-ribbed with modern tires on Z's. Anybody have any data to support either view?

Thank you all.

CTSZ1,
I'm running the 3.50 Speedmaster MKII - front, and a 4.00 SM MKII - rear.
Back in the old days I always used the Roadrunners, but there only available with a race compound now and are a bit pricey as well

Post edited by: Sorf, at: 2006/02/18 23:54