'83 rear tire question

I'm looking at getting a Dunlop K205 for the rear of my '83.

Will a 140/70-18 fit my first gen?
How difficult is it to mount and balance yourself??

 

I've changed alot of tires, but I would never ever try and change a tubeless tire by hand with tire irons. Take the wheel off yourself and take it to a shop. They will have a manual tire machine or a cool pneumatic one that will take off and put on in about 3 min. There's big chance you will mess up the bead of the tire if you don't know what you're doing. As for the balance, let them do it. Usually included in the price.If you don't know how to keep your axel square, use proper chain slack, watch out for the axel spacers, or trust yourself w/ a wrench, back away from the bike and let a pro do it.

 

tire size? 130/90-16 for a VF750C, 130/80-18VF750F, 130/90-17 VF750S

 

I don't know if you can put the 140/70-18 on the bike. I'm running a 140/80-18 on the rear right now (Bridgestone Battlax45). The manufacturer approves my taller tire for the rim but not the 70's. The Bridgestones are good tires, I'm going to put a 16-tooth front sprocket on this year though to compensate for the extra-tall tire.

 

I didn't consider the rim/profile effect. So 80 series profile is the thinnest I can run?


BTW, I've run Battleaxes before and didn't care for them.

 

Do motorcycle tire sizes follow the same sizing vein as automotive tires?

In other words, the first # is width, the second # is aspect ratio, and the third is rim size?

If that is the case, the below is also true:
130/90 16 = 640.4 mm Overall static diameter
130/80 18 = 665.2 mm OSD
130/90 17 = 665.8 mm OSD
140/70 18 = 555.2 mm OSD
140/80 18 = 681.2 mm OSD

 

Yeah, you're on the right track. But the 140/70 18 should be 653.2 mm

 

A 140/80 is the same width as a 140/70. The aspect ratio (the 70 or 80 part) is the percentage of height to width. The first part is the width of the tire. If you can fit a 140/80, then a 140/70 will also fit width wise. If will be a shorter tire though. Typically you would go to a 150/70 from a 140/80 to retain the height.

 

Almost everything you say is true. However, the rims of these bikes are very narrow. Therefore, they need the extra sidewall height to step up to the wider 140 mm width. Bridgestone doesn't suggest using the 140/70 profile with a 3.00 inch wide rim, but they allow the 140/80 profile.

 

I have a 140/70 on mine, and it will indeed work. The problem with that size is getting the damn bead to seat... no matter how much soap I used, it just wouldn't get the last little bit. I had to wait until morning, let it sit in the sun for hours, soap it up again, and only then would the bead seat... with 120psi.

using pressure that high was risky, and I wouldn't recomment trying it. The bead seems solid on the rim, but it may be prone to dismounting. I'm only using the tire temporarily.

 

I recommend a 120/70-17 front and a 160/70-17 rear.:biggrin:

 

Well to update everything. I was able to get a few Shinko radial "Canyon R002" 130-80/18 for a decent price. So if anyone out there needs one, let me know.

 

I have a 140/70-18 Bridgs BT45 on my VFR. Ok it has a 3,50 rim but I got that tire from one that buoght a old FZ750 Yam that had fresh BT45 mounted (140/70 rear and stock 120/80 front). It has a 3.00 rim. I can say that the tire profile was werry of on that 3.00 rim, and it had 8-9mm chicken stripes, even non on the front! Bridgs recomend the 140/70 for a 4.00 rim and I can see why. On my 3.50 rim it leave still some 3-4mm chicken stripes when it left none whit a 130/80. Still Bridgs suggest a 3.50 rim is OK.

 

Just use the tire sizes recommended for the stock wheels. If you want more choices, upgrade your wheels.

 

I have an Avon Azaro 160/60 on mine that the PO put on. Looks good and hasn't lost a bead yet. Since it was brand new, I'm going to run with it. But when it comes time to replace it, I'm going to go with 150 or 140.

 

You've got a 160 on a stock wheel?!?!?!?

 

I would NEVER but a 160 on a stock VF rim, Seen them on 3,5 rims, and its not good looking, and you use only 60% of the tread whith, a 3,00 rim even worse! You have a big risk something bad happens!

 

Here's a pic of the bike with the tire.

Personally, I would not go larger than a 150, but the 160 is what the PO installed.

When riding, in a straight line, I only use about 1/3rd of the tire tread. Which, when compared to a stock tire, is about the same footprint. So really, there is no benefit for a larger tire on such a small rim.

The tire is a radial so the sidewalls 'should' be strong enough to handle the side loads.