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Off Road Forks Vs. MX Forks

Posted: Sun Jun 10, 2007 7:48 pm
by vt_motokid
i own a yamaha ttr-125l, and the fork has marked differences between that of other mx bikes, and the yz 125. what are the differences? just for looks? probably not but i would like some answers.thnks

Posted: Sun Jun 17, 2007 3:13 pm
by invader
The YZ has larger, long travel (11.8") upside down forks designed for the highly demanding conditions of motocross racing, to absorb landings from big jumps and for better control at high speeds on rough terrain.
The more affordable TTR-125L is a recreational trail motorcycle, so it has conventional forks with 7.1" of travel, which also allows a lower seat height...

Posted: Sun Jun 17, 2007 3:39 pm
by BuzZz
What Invader said is true, but the real difference, the one that counts, is that the TTR uses a damper rod damping system as opposed to stacked shim damping system.

Basically, damping rod forks use fixed holes drilled in the damping piston, which is really just a long rod, and can hydraulically lock if the fork moves too fast. Like smacking a large bump or landing from a big jump. 1970's technology at it's best.

Shim-type valving allows the use of multiple shim stacks that can regulate the oil flow at both slow speeds, for small chatter bumps, and let the oil blow past the first stack into a heavier shim stack to take the big hits.

All modern MX bikes (since the late 80's) use shims. Some dual sports are starting to use shims nowdays. Playbikes like the TTR mostly all use the cheaper to make damper rods.

Posted: Sun Jun 17, 2007 7:38 pm
by vt_motokid
yeah im new to riding motorcycles, but ive been around them for quite some time......so what im want to know is potentially more dangerous to hit jumps and stuff with an off road bike? or will it just result in damage to the bike?

Posted: Sun Jun 17, 2007 11:47 pm
by BuzZz
That all depends on the size of the jumps you're thinking of hitting.

Smaller jumps that don't launch you more than a few feet into the air..... you're fine with whatever bike you find underneath you.

If you plan on nailing doubles and triples..... you want a bike with shim stacks in the forks and a foot of travel at each end. Leave the TTR at home and take the YZ. :wink:

Posted: Wed Jun 20, 2007 2:06 pm
by vt_motokid
ok i have another random question.......when i build my jumps ( you know, not insane kickers, but,) they're about 4 feet high, i always launch forward on the b ike. do you know what causes this? is it becuase the way i built the jump or is it because of how much speed i hit it with?

Posted: Wed Jun 20, 2007 11:23 pm
by BuzZz
vt_motokid wrote:ok i have another random question.......when i build my jumps ( you know, not insane kickers, but,) they're about 4 feet high, i always launch forward on the b ike. do you know what causes this? is it becuase the way i built the jump or is it because of how much speed i hit it with?
The biggest problem is your bike. You're pushing the limits of what a playbike was designed to do. Your rear shock probably needs more rebound damping, but it has no adjustment.

Hit the jump under acceleration, not at a steady speed......

You can make your jumps less steep..... and tall.....

But to actually solve the problem, you really ought to buy a YZ, or if headlights are important to for some reason, a WR. Or any color bike of similar status.

You will slowly beat your TTR to death. The frame will stretch, the wheels will never be round, the swingarm bolt and axles will bend, stuff will fall off periodically.... and that's before you crash. Add in bars, levers, plastic, mufflers...... you ain't saving money over an MX bike....

Cause we both know, you ain't going to stop jumping that thing to death, are you?

Yeah.... I didn't either.

:wink: