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Message started by J Mac on 02/20/23 at 14:03:06

Title: Torn bead on new tire.
Post by J Mac on 02/20/23 at 14:03:06

I'm mounting some new Shinko 733/734 tires. The front went on with no problem. I went oversize on the rear (150/80-15), and I couldn't get the last 1/8 of the bead to tuck in. The bottom of the bead started shredding (see photo). It's about a thumbnail sized flap. I've changed a few tires in my life, and the best I can come up with is that the oversized tire isn't compatible with manual installation on a stock rim with the measly tools I have. Even if it hadn't torn, I doubt I could have come up with the leverage to finish that extremely stiff bead.

Should I start over with a regulation tire or glue that flap down with something and have the shop finish the mount? I'm thinking that little flap is not a safety concern, but I've been known to be wrong.

https://imgur.com/a/00lC8D6

Title: Re: Torn bead on new tire.
Post by Dave on 02/20/23 at 16:49:27

A 150/80-15 tire is not a good fit for a 2.75" wide rim. The sidewalls will be squeezed in too far, and the result is the tread profile will be rounded excessively.

I have attached a chart that shows the recommended fitment for tires and rims. A 150/80 tire is made for a 3.50" wide rim....and can be mounted on a rim that is 3.00" wide - it is not recommended for a 2.75" rim.

There are some members who have run the 150/80 tire - if you do get it mounted be careful to check the clearance of the bolt heads inside the rear fender, as they can rub on the sides of the tire.

Title: Re: Torn bead on new tire.
Post by J Mac on 02/20/23 at 17:08:39

Thanks, Dave! I had read a while ago that somebody was running the 150/80, but that doesn't mean I should have tried it. Perhaps he had a wider rim, but I didn't bother to check. I knew something wasn't kosher during my installation attempt. I've never had this kind of trouble. What a waste of a tire ....

Title: Re: Torn bead on new tire.
Post by J Mac on 02/20/23 at 17:26:53

And or course Shinko doesn't make a rear tire in the Savage stock width! There aren't many choices for our rear tires in the US anymore. All I could find were Dunlop and IRC. Last time I was in this game there were a lot more choices.

Title: Re: Torn bead on new tire.
Post by badwolf on 02/20/23 at 19:03:58

If you were going tubeless, you may have messed-up the tire. BUT with a tube I have run FAR WORSE. You have only messed up the thin surface layer. The cords are much deeper.
A lot(most) of us are running 140/90's. I ran a couple of 150/90's, and it can be done, BUT everything has to be just right.
You can't take that tire back now so you might as well put it on. Harbor Freight has 24'' tire irons cheap, but be VERY careful with the tube. Lay the tire in the sun to warm it up, and use plenty of lube, Armor All is my choice.

Title: Re: Torn bead on new tire.
Post by J Mac on 02/20/23 at 19:18:47

Thanks, Wolf. I can see the cords when I lift up the flap. I put some black silicone sealant in the area to cover up the cords. I totally get where you're coming from regarding tubeless vs. tube. This is a 140/80, not 90. I never thought about Armor All. Interesting. Are y'all running stock rims? What about the contact patch that Dave alludes to? Thanks for the reply!!

6D6F7C627C7E666F677C0E0 wrote:

Title: Re: Torn bead on new tire.
Post by TheSneeze on 02/20/23 at 20:47:40

Judging solely on the picture, it doesn't look like much lubrication is being used? Maybe it was wiped down for the picture. Lubrication is your friend!

Title: Re: Torn bead on new tire.
Post by badwolf on 02/20/23 at 20:55:22

I run a 3.50 x 15 cast rim from a 02' Murader, tubeless.
The chart Dave posted is a good guideline. But some ''Darksiders'' ran car tires on the stock spoked rim!
Dave ( I love the guy, and he has helped me more than once ) is a engineer and does things mostly in a approved way.
Some of the rest of us do things in,,,,,,,let's say ,,,a unproven way.
If you can get that tire on the rim without pincing the tube give it a go. Try varying the air pressure to see what works the best. Start too low, ( say 15-18 lbs it will feel mushy going around the block ) go up 3 or 4 lbs, try it, repeat till it is too high ( 40-45 lbs ), and back off to the sweet spot for you.

Title: Re: Torn bead on new tire.
Post by Dave on 02/21/23 at 03:43:19

454E5670424E4C442F0 wrote:

A 130/90-15 tire is almost exactly the same size as the original 140/80-15, and there are a lot of tires in that size. If you want a tire that provides good handling and isn't bulky and beefy - this is the size to buy.

A 140/90-15 tire fits and is a bit larger than the original. Tread width varies a bit with each model - but most members who use this larger size do so to get a bit taller gearing and to improve the straight line stability for road use. The extra weight and size of the tire does slow down the acceleration and handling a small amount.

The reason I don't like squeezing a wide tire onto a rim that is narrower than recommended - is that the tread profile becomes more rounded and handling and tread wear can be affected. The center of the tire wears faster when the tread tire is squeezed onto a narrow rim....and the motorcycle is a bit more tippy feeling as there is a narrower strip of rubber touching the road.....and there is tread over on the sidewalls that you will never use as it is rolled over too far. You are likely going to have an issue with the bolt heads under the fender rubbing the sidewall of the tire.....you can remove the bolts and replace them with bolts that have shorter heads.

Since you already have the tire you might as well try and use it......I am not sure if you will find a dealer that will install a damaged tire for you, as they might be worried about liability issues.

Lube is very important when pulling a tire on the rim, as well as keeping track of where the valve stem is located. You want to valve stem to be located where the tire will last be slipping over the rim...this allows the bead to drop into the recessed area where the spokes penetrate the rim. (If you do it the other way the valve stem prevents the bead from dropping into the recess).

I have tried a number of lubes....you do want to use one that dissipates when you are done so that the tire doesn't stay lubricated and spin on the rim once it is mounted and inflated. Dish soap mixed with water, vegetable oil, or WD40 can all be used.......I have not tried using Armorall as the silicone might result in a slippery bead.

Title: Re: Torn bead on new tire.
Post by J Mac on 02/21/23 at 07:02:20

5C676A7D6C607B7D666E637C0F0 wrote:

A 130/90-15 tire is almost exactly the same size as the original ...

Thanks again, Dave, and everybody. I like what you've said about the 130/90-15. I might try that and see if anybody wants my 150/80-15.

Title: Re: Torn bead on new tire.
Post by oldNslow on 02/22/23 at 10:49:51

I've mounted quite a few motorcycle tires of different sizes and types on a lot of different bikes over the years. I'm right now running my second Shinko 140/90(model 712) tire on my 2006 S40. Without exaggeration those two tires were the most difficult motorcycle tires I have ever struggled with. Part of that is the 15" rim. The same brand tire on the 19 inch front rim is a piece of cake. So don't feel too bad about damaging the bead on a 150.

When my existing rear wears out I'm going to take Dave's advice and buy a 130/90.

Title: Re: Torn bead on new tire.
Post by J Mac on 02/22/23 at 15:17:50

Thank you, sir. I had no trouble with the front wheel either. I had no business messing with a 150. I certainly don't want to fool with bolt heads under the fender. I punted on that one and ordered a Dunlop 130/90 for under $90. I'll give the 150 to anybody for the cost of shipping. At least I learned something about the physics of a tire and pushing the beads toward the center well of the rim when mounting.

6F51505C4E52533D0 wrote: