Tire advice?

[xsgeoff]

Please excuse the dumb noob questions, this is my first bike.

I need new tires, and the manual has listed:
Front - 3.25H19-4PR
Rear - 4.00H18-4PR
Obviously these are old designations that can be hard to find.

The PO had on the bike (wire wheels):
Front - 100/90-19
Rear - 120/90-18

I like the look and feel of these size tires. I want to get the similar sizes in Bridgestone BT45 (http://www.bridgestone.com/products/motorcycle_tires/products/battlax/bt45.html)

It appears from their listing that the front should be no problem, they make a tube-type 100/90-19, so I can match that up exactly.

The choices for rear tires are a little more sparse. The only choice in tube-type for 18" is a 4.00-18 (strange they would still manufacture under an old tire code system?). If I am correct, this would be basically equivalent to a metric 100/100-18?

So, my questions are:
- Is it safe to have that 120/90 tire when the Yamaha recommendation was 100/100 (4.00)?
- And since the only BT45 choice for a 120/90-18 is a "tubeless", if I want that sizing, is it safe to run a "tubeless" tire with an inner tube?

Cheers!

 

[XSLeo]

Let me ask you a question. Does Bridgestone or any tire maker know if you have spoke or mag wheels on your bike? Do you think they care?
They can't know what your bike or any bike has for wheels.
They do know that if their tire gets used on a spoke wheel it better not fail because of a tube.
The way people like to sue they would lose a bunch of money fighting them.
So yes it's safe to run a tube in a tubeless tire.
Leo

 

[xsgeoff]

Thanks, this was my suspicion, but I have no experience with this sort of thing!

Upon further inspection, it appears my current front tire is a "tubeless" type with a tube inside.

 

[5twins]

The closest "metric" equivalent for the 4.00 is a 110. That 120 you have will be OK but it does slow down steering and handling (harder to flick into turns). Wear it out then replace it with a 110 or a 4.00 if you can find one. My bike came to me the same way, with a 120 on the back. It seemed to be OK but there was a real difference (for the better) when I put the more suited and proper 110 on there as a replacement.

 

[xsgeoff]

Thanks, the problem is I am in Germany, and any modifications away from stock have to be approved. This bike already has the approval for the 120/90 tires from a PO. Not sure how much work/money it would take to get the TÃœV approval for a new tire spec.

 

[rezsst]

i put 110's on front, looks tuff. michelin commander ll rear, hard rubber last long. was recommeded to me by jd750ace. great tire.

 

[5twins]

If you tell them that the 120 was actually the wrong tire size and the 110 is correct, maybe it won't be so difficult.

 

[Rgconner]

You can get the exact tires your bike is specified for from here:

http://www.reifenwerk-heidenau.de/?lang=en

They are true bias tires like the originals, as well as classic treads.