Topic: 78' 750A Rear Tire Question

[Maine Ride]

Hi Everyone. Newbe tire question. I am replacing the tires on my bike and the recommended size for the rear tire is elusive for several dealers in my area. I am wondering if it is possible to move up a size to a P130 90-R17? That is apparently a far more common and available size.

Thanks!
John

[raymond10078]

I can't answer your question, but I did some searches on your behalf.  From what I've read, it appears that a 130 is too wide for our rims . . . .

https://www.denniskirk.com/irc/rear-durotour-rs-310-110-90h-17-blackwall-tire.p64377.prd/64377.sku

http://forums.sohc4.net/index.php?topic=51643.msg549788#msg549788

http://forums.sohc4.net/index.php?topic=58852.msg638078#msg638078

[Sam Green Racing]

Hey Kandy, where have you been? I get you a Knighthood and you go missing on us. 

Sam.

[Maine Ride]

kandrtech thank you for the research. A local dealer called me later in the afternoon and had located a proper dimension set. Thank you for again, I am excited to get the 750A on some new sneakers!

[raymond10078]

Sam,

I've been bogged down with:

• a one-week vacation (to visit my son who is in the Air Force now)
• another week of work-related training
• another week at work trying to catch up, and
• a boss that says I'm spending too much time on the internet

The last one affects me the most.  He's actually not correct, but it is his perception, and I have to deal with that.  I'm the type (at work) that will spend the entire day at my desk.  While others go to the break room, and stand around and BS, I'll be taking my mental breaks by doing some internet "work".  It seems like my actions are noted with others are not.  Unfair, but I can't fix them - just have to deal with it.

[raymond10078]

Maine Ride - what type/size of tires are you getting?

[Maine Ride]

I have ordered

IRC 294 which is 100/90H19
&
IRC 313 which is 110/90H17

Both tires running about $100 a piece.

[Grnrngr]

The Dunlop on the back of my '76 is 4.50h17, the Goodyear on my spare wheel for it just says MT90...

http://www.johnnysvintagemotorcycle.com/Parts/Tires/Goodyear.aspx

all the way at the bottom..heck, for $50, I might just get one myself.

[chickenman_26]

The Dunlop on the back of my '76 is 4.50h17, the Goodyear on my spare wheel for it just says MT90...

http://www.johnnysvintagemotorcycle.com/Parts/Tires/Goodyear.aspx

all the way at the bottom..heck, for $50, I might just get one myself.

Do you realize how old that Goodyear Eagle is? Those tires haven't been made since around 1983. Might be okay to put on a bike just for display, provided you could get that rock-hard tire onto the rim. But I wouldn't suggest actually riding on it.


Stu

[chickenman_26]

A local dealer called me later in the afternoon and had located a proper dimension set.
I have ordered
IRC 294 which is 100/90H19
&
IRC 313 which is 110/90H17
Both tires running about $100 a piece.

John,
Those are RS-310 Durotour tires. Good tires, but that dealer, or at least the parts counter guy, isn't very knowledgeable about sizing. You may have gotten away with a 120/90 on the rear, but I believe you'll find the 110 not good at all. And it'll have a lower load/speed index than the 4.50 did. I suggest having them return it for either a 120 or 130. The 120/90H17 would be a #314. The 130/90 is #306.

[Grnrngr]

The Dunlop on the back of my '76 is 4.50h17, the Goodyear on my spare wheel for it just says MT90...

http://www.johnnysvintagemotorcycle.com/Parts/Tires/Goodyear.aspx

all the way at the bottom..heck, for $50, I might just get one myself.

Do you realize how old that Goodyear Eagle is? Those tires haven't been made since around 1983. Might be okay to put on a bike just for display, provided you could get that rock-hard tire onto the rim. But I wouldn't suggest actually riding on it.


Stu

Well, kinda like an oil thread, I probably wouldn't run it on a tubeless wheel, but it wouldn't bother me to run that tire in a tubed application. Personally, like I said, I have one on a wheel now, has enough tread to run, which I will when it's time comes, but I don't like the tread pattern, so probably won't get another one. Guess I should have been more specific, my intended point was more like I would DEFINITELY NOT put a 110/90 on the rear, the MT90 is about a 5.10 tire, so a bit bigger than the 4.50 tire shouldn't hurt, and there are other new tires out there in a similar size. By all means buy a new tire...
Dave

[Maine Ride]

Tires are on. It was a chilly moist cold 14 mile ride to the shop but it was worth it. Ended up with a 120 on the rear. It looks good. On next to the next issue, a sticky parking brake currently stuck on. The center push button seems frozen. Let the fun continue :-)

[chickenman_26]

Tires are on. It was a chilly moist cold 14 mile ride to the shop but it was worth it. Ended up with a 120 on the rear. It looks good. On next to the next issue, a sticky parking brake currently stuck on. The center push button seems frozen. Let the fun continue :-)

Try pulling out on the outer button, then push the center in. There's an adjustment for the slack on that cable. If it's too far off from specs, the release button can be hard to operate.

Stu

[Xjbear]

The proper size is 130/90-17 and 100/90-19 tho I'm putting 130/70-17 Avon am26 this time and lowering the rear shocks. 110 or 120 is just to skinny for the weight and design of the bike, just sayin:)

[78unknownA]

im running a 130/90/...17? i dont know stock rear size rim... running a 78 cb750a, all stock for the most part, lowered the stock shocks and everything all good.