Lee Smith
Cheekywig
Hi, does anyone know what is the maximum tyre width you can get away with on an 16" rear XS400 Special II & the 18" front? thanks.
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Max Tyre Width
- Thread starter Lee Smith
- Start date
Hi! I have the same question. I own a 1980 XS400 with 18'' rear wheel. I have taken the bike apart to rebuild it and want to buy new tires before putting it back together, but I don't remember how much room I got between the tire and chain. Right now I have 110/80-18 rear tire and the exact width is 4.2inch (106mm). I'm looking for Heidenau K60 4.00-18 tire for rear. According to Heidenau Spec sheet It has 4.88inch (124mm) max width and 4.25inch (108mm) minimum width, not sure which is the right thread width 
.
But does anyone know if 4.88inch will fit?
I also looked at the Heidenau K60 110/80-18 specs and it show max width 120mm and minimum width 109mm, which is weird. So im not sure what the exact tire width is.
.But does anyone know if 4.88inch will fit?
I also looked at the Heidenau K60 110/80-18 specs and it show max width 120mm and minimum width 109mm, which is weird. So im not sure what the exact tire width is.
Last edited:
amc49
XS400 Junkie
Looking for flying pigs there, so many do that.
There is no exact measurement that will come that close as the part is rubber and varies, Two of the exact same tire will even be different if coming off a different set of molds and vary up to 1/4". The /80 or /90 changes it even more. That is the percentage of height the sidewall is to width of tire and it alone will change the width of tire even at the same marked width, say 110 here. Nothing weird about it. The rim width too affects the ending tire width and wildly, just it will take the same exact tire up to variance of again up to 1/2" or 12 mm. The 4.88" given there is probably using a much wider rim than you have. The bead and rim edge type (tube or tubeless) can easily change the tire width too, it easily can cover one step or more in the /XX number by the way the rubber flares out from the rim edge. I've seen 1/4" there alone.
Meaning that advertised figures of a tire size are often garbage, you have to actually fit the tire to the rim to really tell.
Measuring to the chain is often a mistake, you have to consider the swing arm front loop which is commonly the limit.
There is no exact measurement that will come that close as the part is rubber and varies, Two of the exact same tire will even be different if coming off a different set of molds and vary up to 1/4". The /80 or /90 changes it even more. That is the percentage of height the sidewall is to width of tire and it alone will change the width of tire even at the same marked width, say 110 here. Nothing weird about it. The rim width too affects the ending tire width and wildly, just it will take the same exact tire up to variance of again up to 1/2" or 12 mm. The 4.88" given there is probably using a much wider rim than you have. The bead and rim edge type (tube or tubeless) can easily change the tire width too, it easily can cover one step or more in the /XX number by the way the rubber flares out from the rim edge. I've seen 1/4" there alone.
Meaning that advertised figures of a tire size are often garbage, you have to actually fit the tire to the rim to really tell.
Measuring to the chain is often a mistake, you have to consider the swing arm front loop which is commonly the limit.
Thank you very much for explaining!
By looking at some tire/rim size tables, the 4.00 tire on 2.15 wheel shouldn't be too bad and too oversized.
I'll try and figure out how much room I have on the front loop.
I know that many people have used 4.00-18 Continental TKC80 on the same bike with same wheel, I think the TKC80 isn't much more lower or smaller than the K60, maybe a bit wider.
By looking at some tire/rim size tables, the 4.00 tire on 2.15 wheel shouldn't be too bad and too oversized.
I'll try and figure out how much room I have on the front loop.
I know that many people have used 4.00-18 Continental TKC80 on the same bike with same wheel, I think the TKC80 isn't much more lower or smaller than the K60, maybe a bit wider.
amc49
XS400 Junkie
That tire width is commonly used even OEM at that width rim so that part OK. I would think it fits fine in that swingarm, most middleweights can carry a 4.00 tire on the back. I ran them all day long back in the '60s
