PlanetMinis Forums banner
1 - 7 of 7 Posts

·
Registered
Joined
·
4,659 Posts
Discussion Starter · #1 ·
I have a Z50R set up for motard. It uses the stock 8 inch wheels right now. I would like to upgrade from the spring forks to an oil bathed setup such as SP5's or CRF70 forks. Regardless of my choice, it is pretty much impossible to use the Z50R wheels in the CRF type forks. So I would naturally go with a 10" CRF50 front wheel. So my question is: Is it bad to have different size wheels front and rear? I ask because people are always converting their bikes to 12/12 or 17/17 or whatever. Is this just to lower the front end or is there a handling issue with different wheel sizes? So will an 8/10 setup be fine for motard?
 

·
Registered
Joined
·
7,611 Posts
hmmm I hope you don't mind me jumping on this thread, I also need to know about motard tire sizes...I want to do a 12/12 set-up for plated street use and am wondering what size tires and what rim widths to use
 

·
Registered
Joined
·
178 Posts
arlindsay1992 said:
I have a Z50R set up for motard. It uses the stock 8 inch wheels right now. I would like to upgrade from the spring forks to an oil bathed setup such as SP5's or CRF70 forks. Regardless of my choice, it is pretty much impossible to use the Z50R wheels in the CRF type forks. So I would naturally go with a 10" CRF50 front wheel. So my question is: Is it bad to have different size wheels front and rear? I ask because people are always converting their bikes to 12/12 or 17/17 or whatever. Is this just to lower the front end or is there a handling issue with different wheel sizes? So will an 8/10 setup be fine for motard?


The reason for matched sizes (diameter & usually width) is for a balanced feel of the motorcycle. The reason most guys make the sizes the same is because MX set ups usually have a larger wheel in the front for traction and control need in dirt, and the rear is usually smaller for torque and traction. Putting the smaller "matched" wheel in the front levels the bike out by bring the front end down to help with cornering on pavement which is much more depending on the front end being down with a centered/slightly forward weight bias. The downside of you going to a 10" in the front would be the tire would be considerably narrower making you front end very twitchy, especially with the much wider stock rear. Also, epending on overall outside diameter of you rear (with relation to the front), you bike could either end up raked back or forward more than you would like. In short...diameter affects front end height, affecting rake, affected center of gravity which all affect handling. The width of the tire often affects the sharpness of turn in, lean angle, and stability (side affect of sharpness) at speed....sorry if this just makes more questions.
 

·
Registered
Joined
·
4,659 Posts
Discussion Starter · #5 ·
A Z50R tire actually has about the same diameter as a CRF tire because the sidewall is so tall. My tires are 407mm tall or 19 inches tall. So the tire diameter will not mess up my rake much. But the forks might. How much longer are CRF70 forks compared to CRF50 forks? +1? +2? More? So I guess I'm only worried about the skinnier tire and the length of the fork now.
 

·
Registered
Joined
·
4,659 Posts
Discussion Starter · #7 ·
Well, the rear of my bike is about 2 inches higher than a stock Z50R. A friend of mine is gonna measure his 70 forks. I think I'm going to end up with SP-5's because then I don't have to worry about mounting up the brake cable. My only real IF at this point is if the fork is too long.
 
1 - 7 of 7 Posts
Top