Rear Tire Change Time

 

At just under 4000 miles in the pic above I am into the wear bars on the OEM rear tire, an IRC GP-212R.  I took one more ride and it was getting smooth in some spots in the center with a total mileage of 4150.  This did include a variety of multi-speed rides, off pavement perhaps 10% and one 22 hour, 1078 mile ride at mostly WOT speeds of 45-60 mph.  Many of our day rides are 35-55 mph speed limit areas.

I was very pleased with the overall handling of the IRC tires for both pavement and off pavement.  I found that airing down from the recommended 29F/33R pressures to 20F/25R for gravel roads was worth doing if we were going to on gravel for a while.  More stable and a little more forgiving on the my rear end too.  😉

The 2021 Honda ADV150 scooter uses somewhat unique tire sizes at this time.  Front is 110/80-14 and Rear is 130/70-13.  

Because of a lack of dual-sport or adventure tires in the correct sizes for the ADV150 scooter I had to look around for alternative sizes.  Currently I was only able to find dual-sport tires in 130/60-13 or 150/70-13.  I have read about an Indonesian rider mounting a 150/70-13 tire and it barely cleared the shocks, but was concerned about rubbing with tire flex since I weigh quite a bit more than most of the Indonesian riders.  Because of this I chose to use a 130/60-13 tire.  

The first number of the tire size is the Section Width or Cross Section.  This tells you how wide the tire is in millimeters.  Stock size is 130mm.

The middle number of the tire size is the Sidewall Aspect Ratio. This indicates how tall the tire is as a percentage of the width of the tire.  The sidewall height or "aspect ratio" of a 130/70-13 tire is 70% of 130mm which would be 91mm.  In regards to wheel diameters, it's not always an exact representation of the measurement of the wheel, but rather the industry standard for that size.

So this meant that my alternate choice in tire sizes gave me a shorter height tire, (130 x .6 = 79 mm), or put another way, the outside diameter is smaller.  This means for the same revolution, less distance is traveled.  Revs/Mile changed from 1001 to 1054. The consequence of this is that my speedometer now reads 2 mph faster than I am actually going, (GPS verified), and that my top speed is 2 mph slower than with the correct size tire.  I can live with this for now and hopefully by the time I need another tire, there will be more options in the correct sizes.

I chose to give the Dura HF903 tire in 130/60-13 a try for the new rear tire.  It was very cost effective at around $40.

The Dura has a nice deep and chunky tread pattern and does a little better in mud than the OEM IRC 212 tire did.  I'm pleased with it so far after the first 300 miles or so of street and dirt/gravel.

On to removing the rear wheel!  The Honda ADV150 requires a bit more parts removal than I am accustomed to on motorcycles, but is average for scooters.  Before you can remove the rear wheel you first need to remove the complete exhaust, the lower shock bolt, then pivot the shock back and up and tie it out of the way, the inner rear fender and lastly the right side swing arm, the last fastener being the 24mm axle nut that rotates with the rear wheel.

Here is a list of tools required to remove the rear wheel:

And the tools I used:

I like to use an old muffin tin or mold for keeping track of my fasteners when I remove them and I label each spot for the fasteners I remove with masking tape and a sharpie as I remove each subassembly.

Here is a 5 minute video of the wheel removal process.  I'm no pro at doing videos, but tried to cover the process without it being painfully long.

Here is a picture of the old and new tires:

You can see that the new tire is slightly smaller in diameter than the old one, as previously discussed.  It has no effect on handling and only a minimal impact on top speed and speedo accuracy.

I did add a 82º metal valve stem while I had the tire off.  Blue was on sale. 😀

The re-assembly of the rear wheel is very strait forward, just a reverse of the removal.  It is suggested that you clean the axle splines and apply some multi-purpose grease of your choice before re-installing the rear wheel.  I used some wheel bearing grease, but a good Moly based grease would also be a good choice.  Personal preference there.  

For convenience, I have referred to the fasteners by the size tool required to remove and install them, not the size of the threaded diameter.  Honda give general torque specs by the size of the threaded diameter for fasteners not specifically called out in the Factory Service Manual.  Torque values for the fasteners are as follows:

M14 head right side swing arm bolts = 29 Ft/lbs

M24 Axle nut = 87 Ft/Lbs

M12 head flange bolt for lower shock mount = 20 Ft/lbs (upper nut that I did not remove is 18 Ft/lbs)

M5 Allen bolt for left side of rear outer fender = 2.5 Ft/lbs or 31 In/lbs (not very tight!!)

M10 head hex bolts for the right side of the rear outer fender = 7 Ft/lbs

M10 acorn nuts for the exhaust manifold = 21.3 Ft/lbs

M14 head flange bolts for the muffler mounting to the swing arm = 36/Ft/lbs

I made a video of the re-assembly in real time, but because I left the radio on, youtube blocked it for copyright restrictions and it's too large to upload directly to the blog.  Add the frustration of iMovie to that and my apologies, no re-assembly video at this time.

Thanks for reading, I hope this is useful for others.  😀

EricV