wanting to put bigger rear tire on 79 xs400 any ideas on size

[supergizzman]

wanting to put bigger rear tire on 79 xs400 any ideas on size i want to keep the stock rim, anyone put a big street bike tire on a stock xs400 wheel i was thinking of putting a 110/90 - 18 but i dont know any ideas?

 

[Ruined1]

If your stock rim is 16" which I think it is, a 110/90-18(inch) isn't going to fit the rim. If you want a bigger tire, you need a bigger rim.

 

[supergizzman]

My wheels an 18 inch

 

[HoughMade]

If your stock rim is 16" which I think it is, a 110/90-18(inch) isn't going to fit the rim. If you want a bigger tire, you need a bigger rim.

'79 stock rims are 18"

I have not done it, but I have heard of people running 110s without any problem and up to 130s with trimming.

 

[OliverB]

A 110/90 on that rim should be fine and not have clearance problems. That's what I'm going to do on my '79 resto this Winter. A 90/90 front and 110/90 rear should look pretty much like O.E. sizes. Don't forget tubes unless someone upgraded the bike to newer mags with "Suitable for Tubeless Tires" marked on a spoke.

 

[bcware]

I am running 100/90/18 in the front and 110/90/18 in the rear on my '78. The chain guard needed to be trimmed for the rear. The front hugs the fender well. The speedometer is way off at highway speeds with this size. The tires are Kenda tubeless that I run with tubes.

 

[OliverB]

The speedometer is way off at highway speeds with this size. The tires are Kenda tubeless that I run with tubes.

Interesting. I have a 100/90x18 IRC on the front of my '80 and have checked the speed with cars a couple of times and it seems to be spot on. The cars had been checked with GPS, too.

 

[bcware]

I am not comparing my speedo to gps or anything, but my friend has a digital speedo on his 09 fz1 and when mine says 75 his says like 90. These Kenda tires seem to have a profile different from other common tires. I had to cut my chain guard with 110/90/18 in the rear while other brands don't need cutting for clearance until they hit 130. The front 100/90/18 is also only a few millimeters from the fender; it's very tight, but clears.

What were you running in the rear?

 

[supergizzman]

will there be clearance issues on the swing arm

 

[bcware]

With a 110/90/18 in the rear? No. At worst you cut the back of your chain guard off.

 

[supergizzman]

Sweet ill be sure to order the tire

 

[OliverB]

I am not comparing my speedo to gps or anything, but my friend has a digital speedo on his 09 fz1 and when mine says 75 his says like 90. These Kenda tires seem to have a profile different from other common tires. I had to cut my chain guard with 110/90/18 in the rear while other brands don't need cutting for clearance until they hit 130. The front 100/90/18 is also only a few millimeters from the fender; it's very tight, but clears.

What were you running in the rear?

The rear on my '80 is stock U.S. Size of 120/90x16. My son's '81 had a 130/90-no mods. Yeah, diff brands are not all the same size in a given tire size. Won't know on the'79 until I get a new BT45 rear tire.

 

[henso]

I puted on my xs 400 81' 18 -110(80 -hight) tier . It fited perfectly, nect tier will be 120 for my xs 400.

 

[FUBAR]

clarify me if I'm wrong but the tire size number mean the following:

ex. 110/90 16

110 - tire width in mm
90 - side wall heigh as percentage of the tire width (90% of 110mm)
16 - rim size in inches

pretty sure this is how it was back when i worked in the tire shop for cars anyways. maybe it will help visualize before you buy