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110,120 or 130 tires

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Hi all,

Any experiences you could share around driving with a 120 or 130 rear tire on a RMZ-250 (08) with stock engine?

Application would be mostly woods/enduro, has anybody had issues with 250 not pulling the wider tires around as well as one might want?

much appreciated

-p

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Most motocross guys would hate it,..the bigger you go the more the bike wants to stand up and go straight in the corners,possibly the harescramble guys would never know the difference or even like it , I dont know.

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I'm a motocross rider and I've tried it, I wouldn't bother if I was you, stick to 100/90-19. The bike will handle better and be more responsive, but this is only my opinion, others might say different. I went to a really soft sandy track a while ago, and I mean the sort of sand thats hard to stand in let alone ride. I thought I'd put on a 110 for some extra footprint. I couldn't really tell if it made a difference that day because the track was so difficult anyway, but I kept it on for the next practice at a regular soft dirt to hardpacked track and the bike was obviously slower (my bike has a DEP S7 full system) and it didn't handle the same. I was really having to wind the bike up and feather the clutch through the corners to get the speed up, and I don't normally ride as aggressive as that. I went back to 100 and all was good again. Even if it is for Enduro's and Hare Scramble type riding it will have the same effect, and although a motocross rider will probably feel it more you still want handling and responsiveness to be optimum. I really didn't think I gained anything from it.

This is my first 250f after coming from a 250 2st education. Unless your running a heavily modded bike I would say stick as close to standard as you can drivetrain wise. I have learned with this bike that there are a few things that sap its power and slow it down:

1) O-Ring chains - as good as they are it's overkill-it saps power noticably.

2) Wider Tyres - see above!

3) Sprocket changes - standard is 12-48 (4.00) I run 13-50 (3.85) for long wide open tracks but you do lose some of that responsiveness on a standardish engine. When I drop back to 12/48 I really feel it pulling my arms when I'm accelerating out of corners.

My friend has the same bike, and we went to a local track thats quite tight one day, he was kicking my ass and I wasn't happy, we swapped bikes - I was gapping him on his. I had 13-50 and his bike was using 12-48! That was the only difference, other than his having an Akrapovic system and mine Dep.

4) Chain tensioner - I did my valve clearances one day, shimmed the inlets, then the next time I was out on the bike I started it and noticed the cam chain was sounding a bit more noisy(whirry) than usual, but not enough to really worry me to strip it down and check - I mean you always hear it a bit don't you! Anyway, I took it out and the bike was SLOW! I came in, cleaned the engine around the auto tensioner, pulled it out, reset it then popped it back in. The noise went away and the bike got back to normal power. I'm not sure how it overtightened in the first place, but it did. These bikes feel like brutes when your hauling round a track, and for that reason its easy to forget that they're only little engines, it doesn't take much to sap it's power. I spoke to the MVRD GP team a while ago, and the guy mentioned to me that they run a manual cam chain adjuster on their RMZ's as they feel the auto one puts too much pressure on the chain, this backed up my findings. He did say they had to adjust it after every Moto though!

Not all related to tyres but hopefully its good info for someone.:busted:

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Thanks helix and Kev250 excellent info -i hadn't thought of the corner handling much. I do MX maybe only 2 times a month and woods about 4-5 so thought the wide tires might grip better on mud,sand and rock but looks like i would lose more than i win.

I did notice the O-ring (or X-ring) change did make a difference, good info on the gearing as i need to change mine. Would you stick with 13/50 or go back to stock overall?

stupid question, where does the chain tensioner sit?

Thanks

-p

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Good info Kev. We have experimented with gearing,it seems everyone wants to gear these bikes taller,...and we tried it...but once you have a few mods and proper jetting and pipe with a touch more top end pull,...we definately liked stock gearing better for the mx tracks here. We actually have settled on 12/47 for most all tracks now and he likes it best.

We do have a vortex ignition that lets it pull a bit more on each gear.

That bike will never see one of those big heavy wider tires again for us either.

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my rmz has about 8 more hp than a stock bike, and i was having some traction issues, i did try the 110/90 rear, but yer it did feel as tho it wanted to stand up a bit more in the corners like a 450, but in saying that not a big differance, and it did slightly help with the traction, also running stock 12.48 gearing, i like the strong bottom end, and i never run o-ring chains on my lites bikes, on the 450 only.

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hi all, i did go for the 110, and i loving it i like the extra grip and dont mind the wight. next change is the none o-ring :-)

thanks for all the input!

-p

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A good compromise is the new Dunlop M51 (100/90 x 19). It is wider than any other 100 I've tried and right now it is worn to the point where I usually get rid of a tire and it still works great. The front was a little weird feeling when new but once it got a little time on it it also has been excellent...

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hey float can you tell me what was weird about the front mx51 tire? Ive been using bridgestone 403/404 and noticed the dunlop 80/100/21 was almost an inch smaller in height than the bridgestone 80/100. I ordered a 90/100 mx51 which should be same height. I think it was transworld mag also recomm 90/100 size in the mx51 for better front end tracking

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hey float can you tell me what was weird about the front mx51 tire? Ive been using bridgestone 403/404 and noticed the dunlop 80/100/21 was almost an inch smaller in height than the bridgestone 80/100. I ordered a 90/100 mx51 which should be same height. I think it was transworld mag also recomm 90/100 size in the mx51 for better front end tracking

When I first got it it felt like the center knobs stuck out more than the side knobs. It was great in ruts but when you transitioned off of center it felt like it would loose traction (although it never did). That went away after five rides or so and it works great everywhere now. Not sure about the 90/100 though...

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