Zongshen RX3: 21-inch Front Wheel

[rjmorel]

Spud ......"I wish a set of stronger fork springs were available for the RX3. Stiffer fork springs would significantly increase the off road capability of this bike. "

Can the fork caps be drilled to accept a valve like an inner tube has then you could add a little air to stiffen them up. I think I remember them doing that back in the 70's on MX bikes. Rj

http://www.ebay.com/itm/NOS-YAMAHA-M...JYi2a6&vxp=mtr

[SpudRider]

Originally Posted by rjmorel

...Can the fork caps be drilled to accept a valve like an inner tube has then you could add a little air to stiffen them up. I think I remember them doing that back in the 70's on MX bikes. Rj

http://www.ebay.com/itm/NOS-YAMAHA-M...JYi2a6&vxp=mtr

I suspect the increased air pressure might cause the fork seals to leak.

[Coloradogoose]

Originally Posted by rjmorel

Spud ......"I wish a set of stronger fork springs were available for the RX3. Stiffer fork springs would significantly increase the off road capability of this bike. "

Can the fork caps be drilled to accept a valve like an inner tube has then you could add a little air to stiffen them up. I think I remember them doing that back in the 70's on MX bikes. Rj

http://www.ebay.com/itm/NOS-YAMAHA-M...JYi2a6&vxp=mtr

I can't speak for all bikes, but most of the ones I've seen with a schrader valve on top of the fork were actually to release air, not add it. Over time air pressure can build in a fork and reduce the supple feel that a spring provides. Without an adequate negative spring (pushing down to help initiate travel) adding air pressure to a fork will cause it to feel really sticky at the top of the travel. It's a great thought though, and with a way to add some negative pressure it could work as long as the seals hold.

[Coloradogoose]

Spud, Thanks for checking on all of that for me. I'm getting closer to being able to order my RX3. I've planned for a 21" wheel, new rotor, progressive shock, fork oil, and new tires. The snow in the high country is melting fast and I'm excited to ride!

[SpudRider]

My Honda CRF250X and Honda XR650L both have schrader valves on the fork caps. The fork valves on these two Honda bikes are only designed to release air pressure.

[2LZ]

Originally Posted by SpudRider

My Honda CRF250X and Honda XR650L both have schrader valves on the fork caps. The fork valves on these two Honda bikes are only designed to release air pressure.

Indeed. I had to buy fork caps with Schrader valves back in the day for my Husky because the ATF back then would foam up badly under MX conditions and almost make the front end a rigid by the end of a 20 minute moto.
As you already know, the "air spring" in the fork is adjusted by the fluid level. I've found there to be "some" leeway in adding or dumping some fluid to stiffen or loosen the fork action without blowing the seals. Always an option.

[Coloradogoose]

Originally Posted by SpudRider

I called Buchanan's and requested them to verify the 21-inch spoke data. They said they will check their invoice and send me an email and/or phone message in a day or so.

Still in the process of getting my KLR ready to sell, so not quite ready to order, but wanted to check if there was a final word on this. I'll be using a rim I already have so as long as I have a way to reference the front hub measurements when ordering I should be good. Thanks!

[SpudRider]

Originally Posted by Coloradogoose

Still in the process of getting my KLR ready to sell, so not quite ready to order, but wanted to check if there was a final word on this. I'll be using a rim I already have so as long as I have a way to reference the front hub measurements when ordering I should be good. Thanks!

Yes, I called Buchanan's and they verified the spoke specifications. I don't know if other spoke manufacturers employ the same method of measuring spokes, or if this method is unique to Buchanan's. However, if you send these specifications to Buchanan's, they will make custom spokes for you which will lace a 21-inch rim to the RX3's front wheel.

'Gauge' is the diameter of the wire used to manufacture the spoke.

Gauge: 10

The 'neck' is the length measurement of the spoke taken from the head of the spoke to the bend of the spoke.

Neck: 1/2 inch

The 'length' measurement is taken from the bend of the spoke to the end of the threaded portion of the spoke.

Length: 8-15/16 inch

The 'bend' measurement is the angle the head bends away from the major length of the spoke.

Bend: 25 degrees

Gauge: 10
Neck: 1/2 inch
Length: 8-15/16 inch
Bend: 25 degrees

I am going to ask Buchanan's if these spoke specifications are stock for the front wheel of another motorcycle.

[SpudRider]

The 21-inch front wheel has really transformed my RX3 for the better. The larger front wheel not only negotiates obstacles better; raising the front of the bike has also improved the performance of the shock absorber and the rear brake. Here are a few photographs from my recent rides on the RX3.

[rjmorel]

"The 21-inch front wheel has really transformed my RX3 for the better. The larger front wheel not only negotiates obstacles better; raising the front of the bike has also improved the performance of the shock absorber and the rear brake."

Spud, in which way did raising the front of bike improve shock and R. brake? Just curious. rj

[SpudRider]

Originally Posted by rjmorel

Spud, in which way did raising the front of bike improve shock and R. brake? Just curious. rj

Here is an older photograph of my RX3 with the 18-inch front wheel.



Here is a recent photograph of my RX3 with the 21-inch front wheel.



The larger front wheel has lifted the front axle about 1.5 inches higher, which has placed more weight on the rear wheel. Placing more weight on the rear wheel shifts more suspension duty to the Progressive shock absorber, which is clearly superior in performance and suspension travel to the forks. Shifting more weight to the rear wheel also improves the power of the rear brake, and allows the rear brake to function more effectively without locking up. The improved rear braking is observable at all times, but is particularly noticeable when riding downhill on loose terrain.

[BlackBike]

I was originally shocked at the look of the 21 on the front of the rx3. Now have grown used to the idea and certainly know of the benefits.

How did you originally feell about the look after you first installed it.?

[SpudRider]

Originally Posted by BlackBike

I was originally shocked at the look of the 21 on the front of the rx3. Now have grown used to the idea and certainly know of the benefits.

How did you originally feell about the look after you first installed it.?

In my book, performance always trumps appearance. However, I have enjoyed the appearance of the 21-inch front wheel from the beginning, and I continue to enjoy its appearance. The 21-inch front wheel makes the RX3 look more like a dual sport bike, and more important to me, it also allows the RX3 to function more like a dual sport bike.

[SpudRider]

As I mentioned earlier, the RX3 saddle is also more comfortable after switching to the 21-inch front wheel. If you compare the two photographs above, you will notice the saddle is much more level with the larger front wheel. With the smaller front wheel, it seemed I was always sliding forward, into the fuel tank, especially when riding downhill.

[BlackBike]

Originally Posted by SpudRider

In my book, performance always trumps appearance. However, I have enjoyed the appearance of the 21-inch front wheel from the beginning, and I continue to enjoy its appearance. The 21-inch front wheel makes the RX3 look more like a dual sport bike, and more important to me, it also allows the RX3 to function more like a dual sport bike.

True true, with the varied terrain seen in your pics, it is certainly an asset