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What Rake Will I Need With A New Size Wheel?

by | Nov 25, 2019 | DIY (Do It Yourself), Motorcycle Wheels, With Modification

You may be wondering, what rake will I need with a new size wheel? There are several considerations you need to keep in mind when you install a larger wheel on your Harley or motorcycle. Changing the rake of the frame is one of them. Rake is a measurement in degrees that indicates the angle of the steering neck in relation to the ground.

In the image above, you can see the acute angle of approximately 40 degrees as noted by the word “RAKE.” The trail measurement is taken from directly below the axle to the imaginary point where the steering head rake would touch the ground. The trail measurement is made from the steering head rake angle at the point it meets the ground back to the centerline of the axle.

This measurement is the most important with regard to driveability. Typically, a factory motorcycle is set between 4” to 6”. The smaller the number, the more nimble the handling at slow speeds. However, you will lose some stability at high speeds. When leaning more toward the 6” side of the spec, you will lose a little bit of turning radius. On the other hand, you will gain high-speed stability when traveling in straight lines such as you would on the highway. Installing a giant oversize front wheel commonly seen in custom baggers utilize rake kits to keep the trail closer to the 6” measurement.

Upgrading Your Front Wheel

Now that you see how the trail measurement works, envision replacing the original front wheel with a bigger wheel. Doing so will move the front axle higher, causing the rake angle line to move further away from the centerline below the axle. When the trail number gets too high, it can make steering the bike feel heavy. Your bike will not be very safe or much fun to ride in this state. This is one of the reasons you will need to adjust the rake.

21" x 5.5" fat tire compared to 23" x 3.75" skinny tire
If you are riding a touring model Harley like a Road Glide, Street Glide or a Road King, you can run up to a 21” x 3.25” wheel in the front and you will not need to change anything aside from the location of the fender. If you choose a 23” wheel, you will need to change out the triple trees to bring the trail number back to a safe, rideable measurement. Some people swear by running a 23” wheel without changing anything, but this is extremely risky.

That same set of triple trees will work for the correction you need to make in order to run the 21” x 5.5” Bulldog series fat front tire. The Bulldog 21” is a fatter tire with a larger tire profile. The fat 21” tire is approximately the same rolling diameter as the skinny 23” wheel assembly. If you run a skinny 23” or a fat 21” you will need to replace the triple trees and add about 6 to 7 degrees of rake to your frame.

Choosing A Rake Kit

The 23” x 5.5” Bulldog Fatty share similar rolling diameters, as well. These wheels lift up the front of the bike enough that triple trees alone will not take care of the problem entirely. For these setups, we recommend running a rake kit. These kits include a new steering neck that gets attached to the bike one of two ways.

One type of rake kit requires cutting a straight line down the frame behind the neck and welding on a new insert that moves the neck outwards and upwards. This configuration will correct the trail measurement when combined with the raked trees in the kit.

There is also a bolt-on rake kit that allows you to bolt on a new neck where the existing triple trees are bolted to the stock neck location. The two kits cost exactly the same but do have two slightly different looks. The bolt-on necks tend to sit in a more forward position to the wheel than the weld-on necks. Installing rake kits and triple trees are best left to professionals who have the experience and skills to get the job done correctly.

To recap, in order to get the proper rake with new-size wheels:

  • The 21 x 5.5 inch and the 23” skinny wheels need triple trees to correct the steering geometry.
  • The 23 x 5.5 inch and the 26” & 30” wheels will need a rake kit to ensure they steer properly.
  • 32” and 34” wheels will require some fab work on the frame. This work should only be trusted to a reputable frame shop.

Get The Financing You Need To Achieve The Correct Rake

Now you know the answer to the question, what rake will I need with a new size wheel? Regardless of the type of rake kit or triple trees you need, you can get financing to purchase these parts and more through SNAP FINANCE. We work with the best manufacturers in the business including SMT Machining, American Suspension, Bad Dad and Fat Katz.

Ensure that the rake works with your new wheels and lead the pack with your newly tricked-out motorcycle!

SNAP Financing
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