70-series rear tire

When we got home from picking up my brother's Goldwing in Tennessee one of the first things he said was it needed a 6th gear. I had to chuckle because I have felt the same way, as have many other GL1800 owners. When cruising down the highway the whine and clatter of the six cylinder engine makes it sound like it's revving a thousand rpm higher than it really is. It makes you feel the need to shift into a higher gear to putt down the highway like most people are used to on cruisers.

To me a 6th gear would be nice, but I'd also like for final drive ratio to be a little bit taller. First gear almost seems like a granny gear to me, and you run through the gears quickly. A trick people have done for ages to simulate a taller final drive is to install a taller rear tire. Goldwingers are no different. Many people have replaced the stock 180/60 tire with a 180/70 tire. This makes the effective gearing about 6-7% taller. It's not a huge difference but it'll take a couple hundred rpm off at cruising speeds. It also makes the speedometer more accurate. My speedometer reads 64 mph when my GPS reads 60 mph. That's about 6.5% fast. The taller tire will offset that.

I did some research and decided to use a Dunlop E3 180/70 tire. These tires have a stiffer sidewall which people report feels better in the taller tire. Many people say the softer 70-series Bridgestone tires feel like they're 'rolling around'. I found a tire on Ebay and I also found a spare rear wheel. This way I could just swap tires. One day I might even go to the 'darkside' and try a car tire.

My next task was to get the tire mounted and balanced. When I had my Traxxion suspension installed in Evansville I went to Westside Honda to have the tire installed. I waited at the service window for 20 minutes only to be told they didn't have time to mount the tire. I strongly suspect it was because I answered 'no' to the "Did you buy the tire here?" question. They were nice enough to direct me down the street to Steve's Cycles who mounted and balanced the 70-series tire in no time. That weekend I swapped tires. The GL1800's single-sided swingarm setup makes taking the tire off relatively easy.

I like the way the 70-series tire lowers the rpms some. It's not a drastic difference but it's noticeably pleasant. First gear isn't so granny'ish. Second and fourth are more viable for riding around than they were before. My speedometer now agrees EXACTLY with the GPS.

Here is the height difference between the 60 and 70 series tires.

Update 9/2008 - Sigh.....with only 2500 miles on the 70-series tire I picked up a nail. I put the 60-series tire back on and ran in town to do some things. Surprisingly running the 60-series tire again was not disappointing. It made the bike feel different. The bike felt sportier with the 60-series tire...probably because it set lower and had a lower effective drive ratio. With the 70-series tire the bike felt more cruiser-ish. I think I was able to shift through the gears smoother with the 60-series tire.

Since you're not supposed to patch motorcycle tires the 70-series tire is now done. I'm seriously considering going to the 'darkside' and trying a car tire. A 195/55 car tire is similar in height to the stock sized 180/60 motorcycle tire, and a 195/65 is similar to a 180/70. I'm thinking about splitting the difference and trying a 195/60 tire. Darkside discussions.

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