Tires I don't understand!!!

Hello my dear xj friends. I'm hoping I can get some more help from you guys. So the problem I'm having this time is... my front tire is getting old. It's pretty bald and cracking. It's side wall says it's a 3.5-19 The 19 is followed by a .57 but I'm not sure if that's important. 3.5-19.57 Would be how it reads if it is important. The problem I'm having is I can't find these tires anywhere, and I don't know what tire is equivalent to my tire. You know what I mean? Like a 110-90-19 or something. I really don't know how to compare the 3.5 to anything else. Also if somebody does know off the top of their head what size tire I should get, can you please tell me what size to get for my wife's bike which is a 3.00-18

 

The numbers you listed don't make a lot of sense to me but if you post what you have for a bike, somebody will have the tire sizes for you.

mikeg

 

Tire sizes: In the old days, it was easy. A 3.50-19 was a 3 1/2" wide 19" tire. Your wife's bike has a 3.00-18, which is a 3" wide by 18" tire.

Then came the metrics. a 100/90-19 is a 100mm wide, 90% aspect ratio 19" tire. Aspect ratios (the relationship between a tires width and "height") is something that really didn't matter until the new "low profile" and radial tires came along.

ROUGHLY speaking, a 90/90-19 is approximately equivalent to the old 3.00 or 3.25 size, 100/90-19 would be closer to the old 3.50 size, all in 19" of course (the "-19" part.) A "dash 18" would be an 18" tire.

Here's a good source for sizes and comparisons: http://totalmotorcycle.com/photos/tire- ... /index.htm

 

Found this while looking around:

http://www.webbikeworld.com/Motorcycle- ... e-data.htm

Good charts too

 

I have a a 110/90 R19 on the front and MP90 H18on the rear of my 82 SECA 750. I would like to put the same tire on the front but what the heck size is the back?

 

Seca750: its probably a 130/90- 18 on the back any wider and it may rub. Also I am amazed a 110/90 doesn't rub on the front. if you get a new tire I might suggest checking your stock size and seeing if it should actually be a 100/90

 

What would be the widest tire i could put on the back?

Thanks for the info!

 

Be careful ! wider than Mfg suggested tires WILL make your bike handle Worse.
Skinny rims NEED skinny tires or the tire gets squeezed onto the rim and handles badly .. regardless of misguided notions that the "girlzz' like fat tires

 

+1. Max tire width SHOULD be determined by max recommendation for that rim width, NOT by "what can we squeeze in there."

 

That R19 indicates a radial tire. Probably not a good idea on this motorcycle. ALWAYS a bad idea to mix radial and belted.

 

Glad I have to replace both of them! Ok then 100/90 on the front and 120/90 on the back! This gives me alot more options than just 3.50!

Love the knowledge!
SECA 750

 

my XJ1100 has a 110/90-19 on the front and a 130/90-16 on the rear. I check the manf. specs and thats what it calls for

 

I think the 750 Seca came with a 120/90-18 rear stock.

The PO on my bike had installed "A huuuge tire!" as he put it. It was a 140/90-18.. Unfortunately it rubbed on the swingarm causing noise and making it difficult to walk the bike.

I swapped it with a 130/90-18 and it seems to have plenty of clearance now.

 

i wouldnt recommend radial tires on an xj. in my experience radials are better for wide tire bikes (newer sport bikes) and heavy bikes (cruisers). for bikes like an old seca, ive seen much better performance out of bias ply tires. the thing most people hate about them, is when you throw the bike down hard in the corner, the bike feels unstable until you get it layed over all the way, then it smooths out and digs in nicely. radials just dont have enough flex for a light bike with a narrow tire IMO. learn to ride stock size bias plys and you will be the king of the road.