Larger rear tire.
 

For anyone wanting to put a wider tire on the rear of the G.Z. a 140.90.15 will fit instead of the factory 130.90.15. Only modification needed is a flat washer behind brake rod next to hub for clearance.

Re: Larger rear tire.
 

Sounds good, may have to invest next time my rear goes bald.

Do you think it would spoil performance though?

Re: Larger rear tire.
 

Rear Tyre that is!



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Re: Larger rear tire.
 

Does not seem to hurt performance in any way.

Re: Larger rear tire.
 

Performance? :lol:

Re: Larger rear tire.
 

What little there is. :poke2: :roll: :2tup:

Re: Larger rear tire.
 

And why would you want to put on a wider rear tire if the stock size is available? It's less than 1/2" wider and what's the advantage, if any?

Re: Larger rear tire.
 

I think the operative word here is "WANT".

Re: Larger rear tire.
 

I just thought a little wider tire would give more tread on the road.But mainly just wanted a little wider tire.I think it looks better than stock.Plus it should last longer.

Re: Larger rear tire.
 

The whole tire is 10mm larger width, 40% of an inch, that's less than 7/16" wider, that's about 3/16" wider on each side of midline measured at the widest point on the tire, so how much extra rubber is in contact with the road surface as the tire is rounded, not flat like an automobile tire? 1/8", 1/4" ? I don't know if that would make any difference but I'm not the expert. IMO I don't think there's much advantage in it but it's your bike. Where are you talking about adding the flat washer to gain clearance for the tire?

Re: Larger rear tire.
 

The washer goes next to the brake hub under the bar that keeps the hub from rotating.The clearance is very close even with factory tire.

Re: Larger rear tire.
 

I just put a Dunlop D-404 140/90-15 on the rear and a D404 130/90-16 on the front.

Results:

This raises the GZ nearly 3/4 of an inch in height for better ground clearance. You will have to put an extension foot on the kick stand by 0.7 inch. This extension worked out well for me as I was having to place a 6"x6" pad on the soft sandy ground we have in Florida to prevent the stand from sinking into the ground. The foot extinsion I made from an aluminium extrusion (piece of a telescope dovetail bar) that I bolted through the kickstand foot front and back - 4"x1.5"x0.7"

The large front tire looks impressive, but required a 3/4 inch raise in the fender. I will have to GPS the speedometer to check on the difference in registered speed, but the standard tire diameter made the speedo read higher than the actual speed so we will see how this works out after a GPS run.

The larger rear tire is a tight fit. It has a larger diameter so it works out to about 1.033 extra gear ratio as compared to the 15 tooth to 16 tooth ratio of 1.067 or about the same as going from a 15 tooth to a 15-1/2 tooth gear (not possible as a 1/2 tooth sprocket) This has a very nice feel for gear spacing and I am not looking for 6th gear anymore.

The seat height is 3/4" higher; The bike feels and looks bigger. The overall ride is about the same, but it is slightly "taller". If your inseam is over 30 inches it makes the bike feel full size instead of 90% scale.

More after I ride the GZ "Fatboy" around for a month. --Dan--
http://s2.postimage.org/1q5hppp7o/P1010806.jpg

http://s2.postimage.org/1q637p7ms/P1010807.jpg

http://s2.postimage.org/1q6esgn38/P1010809.jpg

http://s2.postimage.org/1q6opoq1w/P1010811.jpg

http://s2.postimage.org/1q6ymwt0k/P1010813.jpg

Re: Larger rear tire.
 

IIRC, the steering on the GZ was already a little slow thanks to the wide factory front.

Have you noticed any lag in steering since going to the fat front?

Re: Larger rear tire.
 

No real change in steering feel. The 110/90 seemed to pull into the turn a little more than the 130/90, the 130/90 is very balanced and does not pull either into or out of a turn. I think the brand/style shape of the tire, and face radius are bigger factors in handling differences. I will be able to answer this question better in about a month. I will be at the Sun-N-Fun airshow starting in a week from now. Will be putting 250 miles on the GZ in first and second gear on ground safety plane escort. Most of my GZ driving is below 40 mph. Slow speed steering is more important to me and I see no real difference. --Dan--

Re: Larger rear tire.
 

Oh my that front tire sure fills up the fender. The larger tire will just make the Speedo a little more accurate. The half tooth rear tire is an added bonus. The GZ will happily live with that.

Re: Larger rear tire.
 

Where does the flashing orange light attach on the geezer? :roll: photos?

Re: Larger rear tire.
 

Amber will have to do. The GZ has 2 on each end, left side and right side. :lol:

Re: Larger rear tire.
 

Ah yes, another of those quaint American customs. :whistle:

But where does the "FOLLOW ME" board fit?

Re: Larger rear tire.
 

I can well imagine a bright FOLLOW ME on the back of a vest. Or just a bulls eye for a target. :2tup:

Re: Larger rear tire.
 

Off topic, but the portion of airside ground safety the MC escorts perform is primarily keeping a clear path ahead of the planes as they taxi from or to the primary runways through the crowds to any of a dozen plane type specific areas where the local area chairman/staff assign a specific place for each plane. There are about 80 plus bike riders. We usually position the bike just outside and 10 feet forward of the left wing. This is particularly important for the big round engine biplanes and tailwheel planes. Some of the larger planes or those with forward visibility restriction get a bike on both sides. There are some high pedestrian traffic areas which may even require a 3rd bike ahead to clear the taxi way. Sun-N-Fun is the second largest airshow in the US behind Oshkosh. This is a unique airshow as it has a flying portion (show) on each day plus thousands of arrivals and departures daily. Much of the ground aircraft movements are up close and personal so to speak with running propellers and many hundreds of people walking about, golf carts, and cars all mixed together. If it ever flew it is on display; thousands of planes are on display. The volunteer ground safety group wear red safety vests or red shirts, have our warning whistles and horns, plus individual radios for coordinating aircraft moves. The bikes are flagged with a 5 foot fiberglass pole and small orange flag from the rear rear fender. The right mirror is positioned to show eye contact with the pilot. All kinds of additional ground safety jobs will be done in addition to the aircraft movement. Show plane escort from the back hanger to the front line show staging, sorting out odd predicaments that come up, clearing an area in preparation for the warbird flybys (100 or more movements, departures and arrivals for the airshow warbird mass flyover), just about anything safety wise relating to the aircraft ground movement. The daily meeting starts at 7 am and we close movement at sunset. This goes on from 28 March through 3 April this year (2011). Plus many of us arrive The 25th to set up camp and preposition equipment, check radios etc. If you have a bike and like airplanes this might be something you would like to volunteer for. Check Sun-N-Fun.org for contacts. --Dan--

PS: I am starting a new carb question about a specific carb part, in a few minuts if anyone can help with an answer.

Re: Larger rear tire.
 

Who cares about off topic. That was a fascinating bit of info. Sounds like a tremendous amount of coordination and effort by people who care.

Re: Larger rear tire.
 

It is really exciting to do this, just imagine escorting a P-51 Mustang through a crowd of people. The airside ground safety bikes are only a very small portion of the volunteers. Airside you have at lease 100 flag men/women dividing the planes by type and directing them toward different areas designated by type parking or parking and camping areas. Volunteer air controllers, workshop volunteers (metal shop, fabric shop, 10 different shops), security volunteers, medical first responders, emergency services, even the refuse collectors have a large team of volunteers. I'm sure there are a couple of thousand volunteers that work the show, some (the "early birds") arrive in October to start preparations for a end of March first of April event. This air show is a fantastic place to immerse yourself in any facet of aviation (including Motorcycle enthusiasts). The best part is free entrance and free camping for the volunteers. All kinds of evening entertainment, hundreds of seminars to choose from and a few nice parties to attend, all right on the Sun-N-Fun grounds. It makes a great week plus. If you don't get to the show this year, remember when you're frozen in next year this might be a good place to escape for a week of bike riding. --Dan--

PS: For the b
Brits reading this post there is a large group of young British scouts that come as volunteers each year that work very hard in many areas of the Air show particularly with War Bird parking. A great group of young people.

Re: Larger rear tire.
 

Wow, I used to love going to the airshows on the military airfields in England. Just two airports on this island (for international airlines - one passenger, & one freight) so haven't been to one in years. One I especially liked was at RAF Culdrose in Cornwall. A helicopter base, so they got helicopters from all over the world.

Re: Larger rear tire.
 

Update: Back from the air show. Only rode 155 miles in 1 and 2nd gear this year. poor weather the first 3 days limited aircraft arrivals, but last 3 days were perfect. Enough of the airshow, so how did the 130/90-16 front and the 140/90-15 work out? The only thing I can say not described above is 1: raise the front fender 1" higher (or more if you want) as the 3/4" I used is minimal and 2: above 40 mph the bike seems to be more stable, probably due to the greater weight and diameter of the tires giving more gyroscopic forces to the wheels. 3: riding up the raised sides of the taxi ways almost on a paralell coarse ( a 2" to 4" drop/rise) caused no problems. The D404 dunlop tires smoothly rode up onto and off the pavement into the grass with no side pull or any kind of jerk, just a steady ride. The rain soaked grass fields with grass and standing water were no problem to ride through. If you stopped the rims sank into the grassy sandy mud up to the rim/spoke level, much more stable if speed was kept at 10 mph or greater. The wider fat tires seemed to stay on top of the wet grass/mud better and just puched right through at 10 - 15 mph. I may post a fender "how to raise higher" 130mm tire install in the "how to" section in the next week as a seperate topic. --Dan--

Re: Larger rear tire.
 

Glad to hear the show was a success. And you got to scrub in the new tires with all sorts of weather and surfaces.