The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Spicy_McHaggis on May 17, 2008, 10:09:31 PM

Title: Cheng Shin C186 trials tire - will they fit???
Post by: Spicy_McHaggis on May 17, 2008, 10:09:31 PM
Found an okay "off-road" style tire from Cheng Shin.  It's their C186 "trails" tire that is DOT approved.  Sizes available are 3.50-18 and 4.00-18.  Would the 3.50-18 fit on the front?

Thanks...I tried a search but it turned up nothing.

Spicy
Title: Re: Cheng Shin C186 trials tire - will they fit???
Post by: tagordon on May 17, 2008, 10:36:07 PM
Look here for specs for your bike:
http://www.bmbikes.co.uk/bmwmodels.htm
HTH
Troy
Title: Re: Cheng Shin C186 trials tire - will they fit???
Post by: Spicy_McHaggis on May 17, 2008, 10:47:28 PM
Quote
Look here for specs for your bike:
http://www.bmbikes.co.uk/bmwmodels.htm
HTH
Troy

Thanks, I've already got that link, and I know what sizes they call for.  What I am looking for is real-life "I've tried that size and they fit/don't fit".

Spicy
Title: Re: Cheng Shin C186 trials tire - will they fit???
Post by: Semper Gumby on May 19, 2008, 07:09:06 PM
SH - I have installed a 110/90H18 Macadam on the front of my R65.  I will go measure the dimensions and get back to you.  Should be a similar size.

You are going to install a GS fender Right???
Title: Re: Cheng Shin C186 trials tire - will they fit???
Post by: Semper Gumby on May 19, 2008, 07:23:35 PM
OK the Macadam 110/90H18 is 4 1/8" wide and a diameter of about 26".  I had to modify the fender brace to get the fender to fit around the tire.  You will have to have a GS fender with a couple of inches clearence as a street fender will IMMEDIATLY jam the tire in mud and rotation will cease causing the bike to become violently horizontal.  (ask me how I know this)

So my best guess (WAG) is the "yes" the 3.50-18 trials tire "should" work on the front rim.   How good is your relation ship with your tire guy?   8-)

BTW - if the 3.50 trials tire is a rear tire, make sure you install it backwards on the front.  This has to do with the construction of the tire.  It is a long stip of rubber that the ends are vulcanized together.  It is an overlapping seem ( at an angle not a butt joint).  The direction arrow of a rear tire is set up so that this "seem" does not start to un due itself under acceration.  When you move a rear tire to the front you need to turn it backwards so that the rear tire on the front doesn't come undone under braking.

Good luck.  Let us know how it turns out.  (pictures please?  I have contemplated this set up at one time or another)
Title: Re: Cheng Shin C186 trials tire - will they fit???
Post by: nhmaf on May 19, 2008, 11:10:53 PM
Hmm, I generally thought the primary reason for turning rear tires around when mounting on the front of single track vehicles was traction (under braking), which one wants to maximize at the front, while traction (under acceleration) is what one wants to maximize at the back - assuming "normal" rear drive cycles, that is.   This is the reasons for doing this on pedal-powered mountain bikes anyway..
Title: Re: Cheng Shin C186 trials tire - will they fit???
Post by: Semper Gumby on May 20, 2008, 07:57:22 AM
What ever floats your boat.  Just make sure you do it!   8-)
Title: Re: Cheng Shin C186 trials tire - will they fit???
Post by: Spicy_McHaggis on May 21, 2008, 08:33:44 PM
Cool, thanks for the testing and reply!  It's gonna be awhile before I do it...when I bought the bike it had new tires on it 25 miles ago...so...I don't need them now.

Thanks again...!

Quote
OK the Macadam 110/90H18 is 4 1/8" wide and a diameter of about 26".  I had to modify the fender brace to get the fender to fit around the tire.  You will have to have a GS fender with a couple of inches clearence as a street fender will IMMEDIATLY jam the tire in mud and rotation will cease causing the bike to become violently horizontal.  (ask me how I know this)

So my best guess (WAG) is the "yes" the 3.50-18 trials tire "should" work on the front rim.   How good is your relation ship with your tire guy?   8-)

BTW - if the 3.50 trials tire is a rear tire, make sure you install it backwards on the front.  This has to do with the construction of the tire.  It is a long stip of rubber that the ends are vulcanized together.  It is an overlapping seem ( at an angle not a butt joint).  The direction arrow of a rear tire is set up so that this "seem" does not start to un due itself under acceration.  When you move a rear tire to the front you need to turn it backwards so that the rear tire on the front doesn't come undone under braking.

Good luck.  Let us know how it turns out.  (pictures please?  I have contemplated this set up at one time or another)