GS 450S Tires

[Anonymous]

I have an 80 GS450ST it is in need of new tires the one on the rear is a 110-90-18 the front tire is a 100-90-18. Can a 120-90-18 fit on the rear? Does the 110 mean 110mm width? What does the 90 mean? I know the 18 is the rim size.

[blo]

My GS450 ex does not accomodate a 120 (mm) rear tire. I found 110 to be the maximum before it touches the swing arm. But since you already have a 110 tire, a visual inspection should tell you if there is enough clearing for 10 more millimeters. I wouldn't do it though. You really don't need wide tires on these bikes. The 90 in 110/90-18 is the profile. That is the height related to the width in per cent.

[bgmart450]

I got 120-90-18 rears and 100-90-18 fronts on both 450's with no issues, but the front seems like its as close as it'll get.

[IanFrancisco]

I have an old thread here that you can search. Same bike - '80 GS450ST. I went with Avon AM20 90/90-18 front and AM21 110/90-18 rear. Dunlop GT501 in 100/90-18 front would not fit. Cost me a 15% restocking fee. Same for GT501 in 120/90-18. Maybe a 120/80-18 would have fit but with the AM21 110/90-18 rear there is only about 3/8in. clearance at the widest part of the tire to the swing arm on each side. Close enough! The 90/90-18 and 110/90-18 are way bigger/wider than the OE 3.00-18 and 3.50-18 Continentals. The Avons went on without hassle too, which has to be worth something. I mounted them myself. Didn't worry bout balancing and have no issues even at 85mph. There are some ceramic beads that are supposed to work great for continual dynamic balancing of the tire. I may try those. Requires 1oz. of beads for small bikes and special valve stems that won't get clogged by the beads.

The Avons have been great tires. I'm proud to have some wear showing on the shoulders of the tires as I have been able to get some serious lean angles in the canyons this summer. They don't slip on wet patches unless there's some slime in the mix. Still look new after 4,000 miles. Haven't used them in the rain but UK guys like their wet weather grip and they ride a lot in the rain over there.