If IRS is so beneficial then why aren't all of the sport bikes fitted in such a manner?

Not trying to be a smart a$$ but trying to get informed.

 

Because there's good and bad in everything.

IRS is heavier.
IRS costs more.
You can't powerslide as easily with IRS.
If you tow with IRS, as you increase tongue weight you loose ground clearance due to suspension compression.

Jaybee

 

thing is if your towing something ground clearance probably isnt going to be an issue, the axle on your trailer is probably going to be lower that you quad anyway

 

Irs= more g/c which rocks.

 

IRS isn't used on sport quads cause like someone said you can't powerslide as good plus g/c isn't a big factor in racing and it saves weight to use a straight axle. But, for off-road use I would never buy a SRA quad. The axle gets hung up, it drags in mud holes, and it doesn't do as good of a job keeping all the wheels on a surface. Freewheeling means you're more likely to get stuck. And if you're riding on rough trails it won't be as comfortable as an IRS quad. Now, for pretty much hard pack trail or "technical" riding something like a Praire would do ya good. The ride is more stable and feels more planted and controlable but isn't as good of an off-roader. Basically there is a trade off between the two- IRS= better offroad capabilities, smoother ride, but, as some say a tippy feel and not a sport like bike/ SRA= more likely to get stuck but is more stable, better sporty feel.

 

Most sport quads, use a chain and sproket, rather than a shaft. Because there isnt as much of a loss of horsepower to the tires. I would think it would be tough to have independant suspension with a chain and sproket, mainly because the chain drive isnt centered on the rear axle( its always off to one side) and irs wouldnt work too good with unequal length half shafts.

 

You get better wheel articulation over rough terrain than a straight axle.

 

Put simply, IRS sticks too good. While the rear end can be made to slide, you have to work at it. I have heard of more than one person rolling an IRS quad trying to cut donuts with it.

OTOH, if you ride rough trails, there is just no substitute. I went from live axle (Big Bear) to IRS (Arctic Cat 500i), and it was like going from an old truck to a new Cadillac. Much smoother ride, doesn't pound your kidneys to a pulp.

So it all depends on where you are trying to go fast. I have a couple of trails on my farm that only an IRS quad can get through. You aren't faster if you're high centered...

 

Ok, let's look at the core use of a sport bike....speed, control, jumping, handling. It's all about racing. You can not build an IRS that is as light as an SRA system or have the handling capabilities of an SRA. Even race cars still use sophisticated SRA's rather than IRS (in most cases). The exception is if you are using the bike to run mud races. But that comes under the category of "Oh my God, look at the ground clearance!!!". Here are a few prime examples of bikes in that category:

Super Grizz and Monster 700.

So why are sport bikes not fitted with IRS? Handling, control, and weight. And because you would not do THIS to a sport bike.

 

IRS sure is nice on an old back