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:+1They like skinny.
I am not sure if the specs are the same but on my 74 Eldo I run the factory recommended size of 110/90x18 front and back.Gee I wonder why their engineers picked that size instead of something else mismatched. ::)Marc
Formberg , your question doesn't compute ???Dusty
Dusty, help me say it correctly. I thought I was saying what I needed to in my note... Where does my note go goofy? Thanks, Tom
Tom, by definition a 120 metric sized tire is going to be wider than a tire sized with the old system at 4.00 , in fact almost 3/4 wider if the measurements are done correctly . Dusty
Purely by calculating, a 120 is 4.72" wide, a 110 is 4.33" wide. But a 4.00-18 may not actually measure 4.00". For instance: an Avon Roadrider in 4.00-18 size is 116 mm/4.6" wide, 671 mm/26.4" in diameter. Same tire in 120/90-18 is 129 mm/5.1" wide and is 675 mm/26.6" in diameter.
Tom, by definition a 120 metric sized tire is going to be wider than a tire sized with the old system at 4.00 , in fact almost 3/4 wider if the measurements are done correctly .Dusty
OK, so by definition the 120 is not only quite a bit wider than the old 4.00, but maybe so wide as to not have enough clearance within the fender and the stays I guess you're telling me. And going to a 120/90 would make the loop steer like a truck. So, then as Charlie advises, staying with a 110/90 on the front and maybe moving to a 120/90 on the rear should work just fine...and then I probably ought to remove that sump spacer to give myself proper sump to ground clearance. I was hoping to get the look of the old 4.00 sized tire at both ends and in the process provide a bit more ground clearance but not deteriorate the handling - and that just can't be done. Thanks Dusty and Charlie.
On my 1970 Ambo I'm running Dunlop 404's, 110/90 front and 120/90 rear with no problems. Not even close to hitting anything.
garbln - the only reason I've suffered some broken sump fins (outside right on two different sumps) is because of the spacer between the sump and engine - so the prudent thing to do is to remove that spacer and the tire sizes I am running (at 110/90 at both ends) are fine - but I probably will leave a 110/90 on the front and go to a 120/90 for the rear as Charlie recommends. Now I did see that I could get one of the old design ContiTwins K112 in 4.00x18 and run them on both ends - but no doubt, that would degrade this thread into a deeper tire debate and how horrid the old ContiTwins were. Please hold you expert opinions on that score, please.