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Discussion Starter #1
It was not my plan but that's what happened.
I bought and put on a Scootworks pulley. Love it. Replaced my back tire later on with a Pirelli, great tire. Belt noise rubbing, I take it back to the dealer and he says wow your belt is way out of alignment. They re-align but it still rubs and squeals. I'm gettin frustrated so I start checking everything, can't find a thing. Take off the seat and I notice the mud guard appears damaged... badly. The frickin tire is rubbin into it. Set the shock at the highest still rubs a little. Finally take it back to the dealer and oh duh it had a 170/80-15 not a 180/70-15. So i have the larger diameter tire and the pulley. The tire and pulley do wonders on the highway, RPMS are much much lower than stock. The speedometer is 1 mph slow at 70 checked by GPS. I estimate RPMS at about 3000 at 70 which is slightly better than my VTX 1300 was. Not much roll on acceleration at 70 but a downshift brings it on.
Can't have a inner mud guard with this tire though.
So I am happy with the accidental result, except for the removal of the inner mud guard.
 

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I'm not sure about what you are saying. Cuz I have a 170 on back, I have the stock pulley and I don't have any problems. Does the Scootworks pulley make you have to pull the tire closer to the front?
 

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Aye, Jace. The front pulley is bigger, so it pulls the rear wheel in just a bit. That plus adding a larger diameter back tire... and you get qdude's story.
 

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Yeah after reading his post and replying, I did some research I didn't realize that the 170 would have a bigger diameter then the 180. I am going to have to check on things on my bike now. Personally I would like a 200, but that would make the diameter just over and inch larger. The 170 is just under an inch larger.

But I have heard people running 200 with no problems and no modifications. I know that you can remove some inner fenders and run a 240.
 

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Discussion Starter #5
I can tell you with no hesitation, the bigger tire and the pulley will cause the tire to contact the the inner mud guard. But.... the combination sure is nice on the highway
 

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Some people reported that running the 200 Metz they didn't have problems with the shield. I'm running an Avon 200, it's a tall tire. I also dropped the rear 2". I had to cut the shield across the two upper mounting bolts and it still rubs at pot holes. Also haven't ridden two-up yet but suspect it will rub. A new pulley with the Avon would be is asking for trouble. Ma Kaw didn't leave much room in front of the wheel. When the Avon wears down I'm going to figure out a better shield. The taller Avon fixed speedo errors which was a plus.
 

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Discussion Starter #7
If you come up with a mud guard plan let us know. I have a stereo wired through the battery and really need the protection of the guard.
 

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Yeah after reading his post and replying, I did some research I didn't realize that the 170 would have a bigger diameter then the 180. I am going to have to check on things on my bike now. Personally I would like a 200, but that would make the diameter just over and inch larger. The 170 is just under an inch larger.

But I have heard people running 200 with no problems and no modifications. I know that you can remove some inner fenders and run a 240.
Guys, am i missing something, or do i not understand the numbering system of the tires?

On a 180/70-15, aren't the first three numbers describing the width, the second two the height and the third two the wheel diameter? So relating to the 170/80-15, the rubber is narrower and taller.

To my understanding, the height issue qdude is seeing is due to the change from /70 to /80 and not from a 180 tire to a 170 (not taking into account the sprocket change).

I'd appreciate a tire lesson if i'm off base here.
 

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Guys, am i missing something, or do i not understand the numbering system of the tires?

On a 180/70-15, aren't the first three numbers describing the width, the second two the height and the third two the wheel diameter? So relating to the 170/80-15, the rubber is narrower and taller.

To my understanding, the height issue qdude is seeing is due to the change from /70 to /80 and not from a 180 tire to a 170 (not taking into account the sprocket change).

I'd appreciate a tire lesson if i'm off base here.
/70 or /80 is a percentage I believe. Example: 180/70 would be 126mm high,while 170/80 would be 136mm high. (off of the rim)

You know there was a post in the for sale forum that had a Myron pulley. It offers the same % change as the scootworks and has a chrome finish. BUT the interesting part is that I read it sets your rear wheel back a bit. That may be just what is needed to help the larger tire clear the shield. Just a thought, I don't know about the scootworks pulley. Neither pulley should bring it forward though.

Btw, I contacted Myron and have a picture of it if anyone wants to see it. He said it's $385 delivered.
 

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Ok, here's what i found on a site this evening in case you're interested:

First, lets look at metric sizes of today. Ex. 225/70R15. The first number(225) represents the cross section width of the tire at its widest point(sidewall) in millimeters. The second # (70) represents the Aspect Ratio. This a big term meaning that this tire's sidewall height is 70% of the cross section width, or 70% of 225mm. The R means simply Radial tire construction. And finally the 15 represents the rim size.

Now, if you want to go to a wider tire, but you don't want to change the overall diameter/height of the tire the rule of thumb is this:

Take our first example 225/70R15 To go wider you would do this. 235/65R15 wider yet would be: 245/60R15 and one more would be 255/55R15 You see the connection here. When doing what is called a "plus fitment", you increase the width number by 10 and decrease the Aspect Ratio number by 5. That is if you keep the same rim diameter.
 

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/70 or /80 is a percentage I believe. Example: 180/70 would be 126mm high,while 170/80 would be 136mm high. (off of the rim)

You know there was a post in the for sale forum that had a Myron pulley. It offers the same % change as the scootworks and has a chrome finish. BUT the interesting part is that I read it sets your rear wheel back a bit. That may be just what is needed to help the larger tire clear the shield. Just a thought, I don't know about the scootworks pulley. Neither pulley should bring it forward though.Btw, I contacted Myron and have a picture of it if anyone wants to see it. He said it's $385 delivered.
The front overdrive pulley is larger than stock and will pull the tire forward. The rear overdrive pulley is smaller than stock and will move the tire rearward.
I suppose if you put both overdrive pulleys on the tire might remain fairly close to the original postion?
 

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I was so confused I was fixin' to cry...Helek's post looked so smart and I felt so stupid, I had a ruler in my hand that only went to 35mm in a foot. I couldn't understand how anyone could fit a 225mm tire on the back of their bike. So I just got back from using a flashlight and laying flat on my belly holding that ruler up to the back tire on my 900 when it donned on me there must be a decimel that's being left out! Mine is stock and shows right at 17mm (so I used all the brain-power I had left this evening to figure that must be the same as 170, which was written on the side of my tire). Now I must go to bed.
 

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Yes, sorry Bigmoe, I should have said I was speaking strictly about the rear pulley. By "neither pulley" I meant Myron's or Scootworks. ;) Thanks
 

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Discussion Starter #16
Enough that the shock must be set at the highest level to avoid bottoming out.
More specifically 1 inch about
 

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How far forward did the Scooterworks pulley move the tire?
Assuming I got the belt tension about the same, which I think I did, my wheel moved ahead less than a quarter of an inch.
 
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