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2019 750 street
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Discussion Starter · #1 ·
I have been lurking here for a while, but still could not seem to find an answer for my question. I know for the rear tire that stock size is 140/75r15 and you can go up to 160/80r15 with no mods on stock wheels.

The front is where my question comes from. Stock size is 100/80r17. I know quite a few poeple run 110/80r17. One person ran a 120/90r17 but had to remove the front fender to get it to fit. He did not specify if the fender was the issue or if that wide of a tire was rubbing on the fender mounting bolts. If it was a tall clearance issue, wide clearance issue or both.

My question is: my front tire size that I would like to run is a 110/80r17 or a 120/70r17
Can the 120/70r17 fit with no mods? I don't want to remove the fender. The 110 would be slightly taller so I know it'll fit tall clearance wise. I just don't know if the 120 will fit wide clearance wise.
 

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2017 Street Rod 750
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55 Posts
Not sure why you are trying to go for that wide of a tire, but increasing the width of the front tire by about 3/4 of an inch will negatively affect handling. A 120/70R17 is about 3/4" wider and 1/3" taller than the stock 100/80R17. You may not notice much of a difference going straight but cornering will be affected in a way you won't like. Same goes for the rear, going up a size may not show terrible results for you, but anything more than is going to affect handling badly, not to mention many times will wear out the center tread faster since you are essentially squeezing a wider tire onto a thinner wheel than was designed.

Now I don't have a street 750, I have the street rod, so I can't tell you if it will physically fit on the bike or not, but even if it does, are you sure you want to change how the bike handles that much?

Changing tire sizes on your car or truck may not have much of a noticeable effect, but on a motorcycle can cause drastic changes, and you don't have nearly the protection on a bike as you do your car.

But I digress, at the end of the day it is your bike, your choice. Maybe someone who has done the size swap can chime in with their experiences with some some pros and cons. A bike that doesn't handle well is an unsafe bike in my opinion, so if you are doing this for aesthetics I would advise against it.
 

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"Loose Nut" from Houston, Texas
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Another issue about putting a wider tire on a stock rim, the bead of the wider tire will be pinched in narrowing the side wall and actually making the tire taller. Many have attempted to do what you are doing and we're unhappy with final results. If you want, custom wheel to accommodate the wider tire with new fender would be the way to go, but very costly. Would make a cool looking bar hopper, but not good handling on a bike if you actually plan to ride it much.
 

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2019 750 street
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Discussion Starter · #4 ·
From my reading in here, I haven't read one complaint from those who have put a wider tire on. At least not for the 110 tire. Only read one person with the 120, but he did give it praises
Some tire companies actually recommend a 110 wide tire for a 2.5 inch rim, so I'll probably stick with that. I know about putting too wide of tire on a rim, just wasn't sure if the 120 was considered too wide for the rim, or just too wide for the bike in general. I knew the rim size, just wasn't sure if bike tires bead the same way as car tires and how the sidewall flexes upon riding if you are too wide.
The original tires are not that great, especially in the rain. Unfortunately stock size is limited to pretty much just the stock tires it seems. So upping or shrinking the tire size is what I would need to do. Also the slight extra In tire height would be nice, helping with the amount I could lean the bike in turns. I know it's not a sport hike by any means, but honestly I don't feel like I lean that far over before my pegs start to scrape.
 

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I ran with that exact size combination (120-70/17 & 160-80/15) for a little over a year. See post for reference:

The combination did take some getting used to, turning in was quicker than stock and it did take a month or so to get used to. Other than that, no issues. I originally changed to eliminate exhaust scraping and it worked as intended. Note that I also changed from stock suspension to heavy duty progressives in the rear to prevent potential rubbing.
 

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2019 750 street
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Discussion Starter · #6 ·
I ran with that exact size combination (120-70/17 & 160-80/15) for a little over a year. See post for reference:

The combination did take some getting used to, turning in was quicker than stock and it did take a month or so to get used to. Other than that, no issues. I originally changed to eliminate exhaust scraping and it worked as intended. Note that I also changed from stock suspension to heavy duty progressives in the rear to prevent potential rubbing.
Your post was one of the many I had read. The only thing that threw me off was the fact you were using the 12.5 progressive shocks. I knew that lowering the bike since stock is 13? Adjusted the amount closeness the tire was in the rear. But also noted that if the back goes down, usually the front will go up some from the offset. And I didn't know if that would cause enough of a difference between the two sizes.
 

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Your post was one of the many I had read. The only thing that threw me off was the fact you were using the 12.5 progressive shocks. I knew that lowering the bike since stock is 13? Adjusted the amount closeness the tire was in the rear. But also noted that if the back goes down, usually the front will go up some from the offset. And I didn't know if that would cause enough of a difference between the two sizes.
In my case specifically, the front went up a negligible amount. I use tacomaworld for all of my tire size/ ratio determinations. With dropping the rear suspension .5", the 160/80-15 raised the rear back up by .76" (sidewall height difference from stock).

Overall the changes amounted to +.26" in the rear and +.16" up front. To me the difference seemed negligible, and since both front and rear tires widths increased, steering characteristics did not change by any large degree. By "turning in being quicker," I meant this as a result of being able to lean the bike further which again took some getting used to. That being said, I have since back to 13" shocks and a 19" front wheel on my 750 and I've had no issues.
 
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