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Discussion Starter · #1 ·
Has anyone tried the Sportec M1 120/65/17 front? I have been using the 120/70/17 front but the dealership I buy my tires from only has the 120/65/17 in stock. Any advice or comments on this tire setup would be appreciated.

Thanks
 

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I have not used it but I am going to put a set of M1's on my second set of wheels for street use. The obvious diff is the 65 profile VS the 70 which would in fact lower the front end just a smidge and aid with ease of turn in, however the 65 will probably have a bit firmer ride than the 70 as it won't be as forgiving.

BD
 

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I was going to buy 65 for my front but I was told not too.. I guess 65 makes your rims bent easily if you hit a bump.

Plus, wouldn't be contact path smaller on 65????:confused:
 

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I know the R6 guys switch their 120/60's for 120/70's for better turning. i dont know why u'd wana regress your tire size so to speak
 

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Looneybomber said:
I know the R6 guys switch their 120/60's for 120/70's for better turning. i dont know why u'd wana regress your tire size so to speak

Yes its true they do becasue they get more contact patch, BUT they also raise the tubes to compensate for the 70 as well.

BD
 

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Assuming identical construction and rubber compounds, the 120x17 front tire with the shortest profile will turn in the quickest and offer the most feel. And that will be true even if you adjust the front ride height of the bike to so it is consistent from tire to tire. Also, the shortest profile tire will likely have the smallest contact patch while leaned over.

Why? The shorter the profile the stiffer the sidewall. The tire with the shortest profile will have the stiffest sidewall and deflect the least when a turn is initiated. This means the bike will respond quicker to steering input. Since the stiffer sidewall deforms less, the contact patch will be smaller when leaned over too.

The whole idea behind the 16.5" tires, which are as tall as 17" tires, is to get a taller sidewall so the sidewall deforms more and the contact patch can be larger. The larger contact patch offers more ultimate grip. A 16.5" tire handles bumps a bit better when leaned over as compared to a 17" tire.

This the idea behind the Dunlop 120/75R17 slick as well.

If you want the front tire that offers the most grip, get the 120/70R17.

Scott
 

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Discussion Starter · #10 ·
120/65/17

Thanks Scott, that's the information I was looking for to help me make my decision between the 65 and 70 for now or in the future. I don't think the quicker steering & slightly better feedback would make up for the better contact patch and grip of the 70. The M1 70 worked great at Road Atlanta last Monday!!
 
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