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Wildomar, CA
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barnett468
1/8/2019 6:23pm
1/8/2019 6:23pm
I have been using a starcross 5 soft 80/100-21 front and 110/100-18 rear on my 1980 yz250 and riding tracks with a dry, hard, surface like milestone, perris, and elsinore. I just got a 1981 yz 465 and it has a fairly steep steering angle, so it turns pretty decently, so i was considering going with the larger 90/100-21" starcross front in hopes that it would give slightly better traction on flat, hard, dry surfaces then the 80/100-21", but wanted to know if it will make it noticeably harder to turn or lean or if it will try to climb out of ruts etc with the larger tire. Appreciate any opinions on this from those that have run a 90/100-21" front tire on mx type tracks.
I plan on using the starcross soft or hoosier 25 compound (semi soft) rear in a 120 so i can get the beast to hook up at least a little.
Thanks in advance for any opinions/suggestions.
I plan on using the starcross soft or hoosier 25 compound (semi soft) rear in a 120 so i can get the beast to hook up at least a little.
Thanks in advance for any opinions/suggestions.
I like the extra grip I couldn't get the feel out of 80/100. I have been running the 90/100 since, even though I'm from the pnw. I've ridden with them on the tracks you mentioned in socal no problems. Even run it on my yz144! And my yz250.
You might be the 5%....but unless you are a pro rider or professional test rider, probably not.
I always chuckle when “Johnny C class” has a long debate over which brand/size/tread pattern of tires to buy, or if he should run 12 lbs or 13 lbs psi in his front tire, or if that FmF pipe is better than pro circuit...reality is, that dude has no clue what the bike is doing, isn’t riding fast enough for performance flaws in either option to even show up, and couldn’t tell the difference in a blind test. So it doesn’t matter.
The Shop
I am in the 5% group, and actually testing and developing off road bikes and atv's was exactly my job at Kawasaki when I worked in their r & d department in the 80's, although I have slowed down considerably since then.
I’m not in the 5%...even as a vet A class desert guy, I’m an awful test rider. Sand tire on hard pack feels the same to me as a hard tire on hard pack...I just ride the bike. So I won’t be any help for you on this topic.
I have found a real common ground on 90/90s which seem to offer the best of both worlds. My tire choices have been mostly been between Michelin and GoldenTyre (currently running a GT216AAHB 90/90/21 on the front of my Husky 350 and a Michelin SC5 'soft' 110/100/18 on the rear). A couple of times a year I throw a set of Dunlops on for a comparison but always come back to my Michelin/GoldenTyre combo.
lol, that's ok, you are still probably way faster then I ever will be again. You are also in good company, because Rex Staten wasn't a great test rider either. He could simply make any pos haul ass so it didn't really matter. Eddie Warren wasn't a great test rider either. Team Green actually borrowed me from R & D for the ponca and loretta nationals one year and i was assigned to him and 2 other of their best riders and he couldn't tell much difference in different parts either. Believe me, I would consider trading your skills or theirs in exchange for mine in his area, lol.
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I was thinking this might be the case in some instances, but fortunately I am dealing with bikes that are far more similar to each other. At this point I'm leaning towards the larger front, plus, if I get it I can possibly just exchange wheels with my 250 and try both sizes on both bikes. The 250 corners decent now that i finally have it set up the way i want but it pushes/skips, the front tire a little on hard dry turns, but of course that is to be expected, and i haven't tried any other types of tire to compare it to. My other consideration was a hoosier 20 compound front but the hoosier re has not gotten back with me yet to let me know if they make one.
Obviously most any tire works well in a berm, especially if the ground is a bit tacky, but i prefer to take the tight inside of turns whenever possible and there often isn't a berm there.
"currently running a GT216AAHB 90/90/21 on the front of my Husky 350 and a Michelin SC5 'soft' 110/100/18 on the rear)"
I was thinking about another 110/100 for the rear of the 465, but my 250 spins the bejesus out of it if the dirt is a little loose. the engine was built by fmf back in the day, and of course, the 465 makes my 250 seem like an enduro bike by comparison.
The most noticeable difference to me was initiating "turn in" into corners. The 80 went where I pointed it and the 90 would stand the bike up making me have the feeling of falling off to the inside and dabbing my foot. I tossed the 90 and have only used 80's since and every time I ride someone else's bike with a 90 it feels like a pig that won't turn.
Anyway, my plans have temporarily changed because i now have a set of hoosiers coming in the 20 compound, so i will try those first and compare the starcross and hoosier fronts back to back and then decide what my next plan will be. I will try to test them on the elsinore truck track for one, since it is by far the hardest and driest track around.
90/90 is best for a grand prix style track thats faster and rougher. Also works really well off road and in rocky terrain. You can still turn with this size but there is a tendency to want to run out of a rut or just not track well.
90/100 is for high speed high impact and super rough. Such as racing desert, woods, etc. It gives the most cushion and tracks straight and gives great stability because of its footprint. However for quick, fast twitch turning it can be a handful. Most people ive seen dont run this tire at tracks.
Tire size is just one part of the forumla though. Temperature, tire PSI, bike set up, suspension, the bike its self (a suzuki turns better than a yamaha so a crap tire on a suzuki will perform better in turns than a gummy on a yamaha for instance). The most important technical factor I feel is matching the tire with the terrain. Are you in sand/mud? Then dont run an AT-81 and complain at how vague it felt. Pick a MX11.
Post a reply to: 80/100 - 21" vs 90/100 - 21" which is better?