All 2st Gear Ratio and Chain Link Sizing Tables

Here are a collection of Gear Ratio and Chain Link Sizing Tables that I have compiled for the Husky CR/WR125 and WR250/300 bikes.


The tables below show Gear Ratios for various combinations of front and rear sprockets. These can be used as a guideline for changing the acceleration and/or speed characteristics of your bike. The 1st table is 12T front sprocket, 2nd table is 13T front sprocket, and 3rd table is 14T front sprocket.

I have also included an example of how to use the tables as reference.




The table below shows the relationship between Gear Ratio and Chain Link Sizing. Please note that the distance from center of front sprocket to center of rear sprocket was assumed 650 mm +/- 5mm. This distance is used to estimate the number of chain links required. I recently swapped rear sprockets and went from 13:52 to 13:50. I had to remove a link (actually 2 since it is 1 outer and 1 inner link). I went from 116 links to 114 links... And yes I counted them to verify the calculation just because I am a geek.

The main take-away from this chain link sizing table is to estimate "relative changes". In other words, you want to compare your current gear ratio and your new gear ratio. The chain link size will indicate if you will be potentially adding or removing links. When purchasing a new chain, my recommendation would be to add several extra links to the total quantity... just in case. As a reminder, you will always need a even number of links. If the calculation indicated an odd amount such as 113 links, then you will need to plan for 114 links. Most likely 112 links could be too short depending upon where your rear axle is positioned in the swing arm.




The tables below estimate typical speeds per gear. NOTE: This is only a guideline and it is influenced by a number of factors such as gear ratio, wheel size, tire size, and rpm ranges.

The primary drive ratios for these bikes were taken from the 2008 owner's manuals. They should be applicable to the 2009-2012 bikes as well, since I do not believe these have changed.

The only difference between the CR125 and WR125 tables was the rear wheel and tire sizes. The primary gear ratios are the same for these bikes.

For the WR250/300 table, the primary gear ratios reflect the 5 gears in this bike. The 6 gear was "blanked out" since it is not applicable.

2008 CR125



2008 WR125



2008 WR250/300:
Note: Gear ratios on 2008+ WR250 are same as 2002 CR250.
I'm not sure which model year Husky changed to the "close ratio" transmission.
If someone knows, you are welcome to post below to help educate the group. Thanks!




2002 CR250, WR250, and WR360:
Note: Earlier model years had different transmission between CR250 and WR250. Also, the WR360 had 6 speeds.

Yes, I could email it to you. You can also right-click on the picture and save a copy to your computer. These pics are stored in my photobucket account and loaded to this thread.

If people are interested, I could upload the Excel spreadsheets that were used. These could provide you a starting point so that you can do what-ifs and change tire sizes, gearing, etc., and see the speed impacts.

To all,
Here are the Excel spreadsheets. The 125 spreadsheet has both CR and WR on separate tabs. This was done since the wheel sizes were different. The internal gear ratios are same for both bikes.

Troffer88,
I don't have a WR360 set up currently. Let me do some searching for a WR360 manual to get the primary gear ratios. I will add it to the collection.

I found a 2002 owners manual online which had data for the CR250, WR250, and WR360. I updated my post above and attached 2 new Excel spreadsheets. The 250 spreadsheet was redone and now includes the 2002 CR250, 2002 WR250, and 2008 WR250/300. The 2002 WR360 was created as a separate file.

I also edited my 1st post and add pictures for quick reference.

Enjoy!