ChinaRiders Forums - View Single Post - Zongshen RX3: 21-inch Front Wheel

SpudRider · 11-07-2016, 12:39 AM

I would be remiss if I did not mention the CSC Cyclone RX3 has retained the original wheel geometry with the stock tires. CSC made certain the size 130/70-17, C6017 tire installed on the Cyclone RX3 was actually a little smaller in diameter than the original, 15-inch rear tire.

Measuring the stock tires delivered with my CSC Cyclone RX3, I see the front tire is about 1-inch larger in diameter than the rear tire.

I introduced an imbalance in the wheel geometry when I installed a knobby tire with a more aggressive tread on the rear wheel of my RX3. In general, knobby tires are larger in diameter than the stock tires. For example, the size 5.10-17, Shinko, 244 rear tire has a diameter of 25.63 inches, as specified at the Shinko website.

http://www.shinkotireusa.com/tire/244-series

However, if you examine the Shinko 244 tires which will commonly be chosen for the 18-inch front wheel, they have the following diameters.

Shinko 244 Tires

Size 3.00-18 Tire: Diameter = 24.69 inches
Size 3.50-18 Tire: Diameter = 25.55 inches
Size 4.10-18 Tire: Diameter = 25.16 inches

All of these tires are actually smaller in diameter than the size 5.10-17, rear tire. In fact, the size 3.00-18 tire is almost one inch shorter. Given the knobby tires I prefer to mount, it's easy to introduce an imbalance in the original wheel geometry.

In contrast, here are the diameters of the tires I have currently mounted with the 21-inch front wheel.

Michelin T63 Rear Tire (Size 130/80-17): Diameter = 26.14 inches

https://www.denniskirk.com/michelin/...prd/643293.sku

Cheng Shin C858 Front Tire (Size 2.75-21): Diameter = 27.4 inches

http://www.csttires.com/int/moto/dual-spor/c858/

In this case, the front tire is approximately 1.25 inches larger in diameter than the rear tire, which allows me to re-establish the original wheel geometry supplied by Zongshen and CSC.

Based upon your tire preferences, and whether you have a 19-inch front wheel, you might not have any changes in wheel geometry. However, given my tire preferences, I can retain the original wheel geometry with a wider selection of tires after switching to the 21-inch front wheel.

11-07-2016, 12:39 AM	#20
SpudRider Join Date: Jul 2008 Location: Idaho Posts: 25,054	I would be remiss if I did not mention the CSC Cyclone RX3 has retained the original wheel geometry with the stock tires. CSC made certain the size 130/70-17, C6017 tire installed on the Cyclone RX3 was actually a little smaller in diameter than the original, 15-inch rear tire. Measuring the stock tires delivered with my CSC Cyclone RX3, I see the front tire is about 1-inch larger in diameter than the rear tire. I introduced an imbalance in the wheel geometry when I installed a knobby tire with a more aggressive tread on the rear wheel of my RX3. In general, knobby tires are larger in diameter than the stock tires. For example, the size 5.10-17, Shinko, 244 rear tire has a diameter of 25.63 inches, as specified at the Shinko website. http://www.shinkotireusa.com/tire/244-series However, if you examine the Shinko 244 tires which will commonly be chosen for the 18-inch front wheel, they have the following diameters. Shinko 244 Tires Size 3.00-18 Tire: Diameter = 24.69 inches Size 3.50-18 Tire: Diameter = 25.55 inches Size 4.10-18 Tire: Diameter = 25.16 inches All of these tires are actually smaller in diameter than the size 5.10-17, rear tire. In fact, the size 3.00-18 tire is almost one inch shorter. Given the knobby tires I prefer to mount, it's easy to introduce an imbalance in the original wheel geometry. In contrast, here are the diameters of the tires I have currently mounted with the 21-inch front wheel. Michelin T63 Rear Tire (Size 130/80-17): Diameter = 26.14 inches https://www.denniskirk.com/michelin/...prd/643293.sku Cheng Shin C858 Front Tire (Size 2.75-21): Diameter = 27.4 inches http://www.csttires.com/int/moto/dual-spor/c858/ In this case, the front tire is approximately 1.25 inches larger in diameter than the rear tire, which allows me to re-establish the original wheel geometry supplied by Zongshen and CSC. Based upon your tire preferences, and whether you have a 19-inch front wheel, you might not have any changes in wheel geometry. However, given my tire preferences, I can retain the original wheel geometry with a wider selection of tires after switching to the 21-inch front wheel. __________________ Spud "Never argue with an idiot. He will drag you down to his level, and beat you with experience." Mark Twain 2015 Zongshen ZS250GY-3 (RX3) 2006 Zongshen ZS200GY-2 (Sierra 200) 2005 Honda XR650L 2004 Honda CRF250X 1998 Kawasaki KDX220 Mods made to my Zongshen ZS200GY-2: http://www.chinariders.net/showthread.php?t=6894 Last edited by SpudRider; 11-07-2016 at 02:22 AM.
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