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Lets Get One Thing Straight! (Sprockets)


mokwepa
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.Great answer Billy,

Some find the gearing down of the front by one tooth will not only slow the bike so they can creep along slower in first gear, using it in first gear and maybe over reving it will still get you there and when you back off it slows you much quicker , giving you more time for the next bit of section you are to negotiate.

Also a good answer I noticed it pretty hard to crawl around on my bike in 1st on standard gearing I might well drop a cog off the front and see how it runs.

The bike I rode previous to the one I have seemed a lot easier to ride slower it might well have been geared lower.

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@billyt, steveo, southwester.....I understand 100% what you are saying. Engine braking etc will be slower/tamer with a smaller front and you will be able to creep slower.......however most guys that complain that a bike needs taming are saying so because they have less than perfect throttle/clutch control and the bike lurches forward and is too agressive when appling throttle.

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If you spend a significant amount of time testing the top speed of your trials bike maybe you should buy an enduro bike. I usually drop one on the countershaft to make second my main section gear. The advantage of dropping the front rather than going up a couple on the rear is I don't need to add chain links. The disadvantage is increased chain wear but that's not been a problem so far.

There are a lot of things that affect ridability of a bike that often get blamed on gearing. Clutch engagement and power delivery being the most common. Improper jetting can make a bike feel lethargic in one range while pulling properly in another. This is often mistaken for a gearing issue. A light switch clutch is the other problem sometimes "corrected" with gearing.

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Mokwepa has rather over simplified the issue with his initial statements. A trials bikes will generally go faster as you gear up (i.e. smaller rear wheel sprocket) since the engine produces "excess" power for the speeds they run at. Do that on a road bike and it will probably drop the top speed since the engine torque won't be sufficient to overcome the wind resistance. Were the so called experts he was talking to referring to trials bikes or road bikes? Road bikes were always geared slightly high to give good a good cruising speed without over revving the engine, and most road bikes used to gain a couple of mph by dropping the gearing. Trials bikes are a completely different animal and as most of you pointed out changing the gearing is all about making the bike rideable rather that looking for either more acceleration or more top speed.

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My opinion:

smaller front sprocket = more direct placement of torque to the rear wheel.

This makes every gear "hit" harder at the rear wheel

That is why in muddy sections you select a higher gear to reduce rear wheel spin.

The 2000 Sherco I used to have, when I got it felt like the gears were a half a selection off, had a "useable" first gear and second was a hillside gear and third was almost unusable. So I went with a smaller front sprocket (needed to use a half link though) This made first a tractor gear that was good for tight flat land sections with many turns, second was good for a bit more open sections and some hills and third was great for the bigger and longer hillclimbs. etc. and with Sherco's 4th and 5th are always trail gears.

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Only 2 things are a surprise to me

1) That it's open to debate what a smaller or larger sprocket will do, I thought it was grade 1 bike stuff LOL

It's all about simple leverage principal, a larger wheel has more circumference covers more ground and takes more power to rotate, smaller wheel is easier (front spkt, rear spkt is opposite)

And I lied about 2) I think people change a front simply because it's cheaper than changing rear not because it is better, dropping a tooth on the front is like changing 3 or 4 teeth on the back

Hey!, if I grind one tooth off my front sprocket will bike go slower :)

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YEP..... I know the feeling Rob.

A guy new to trials telling trials riders that have been around the sport since Bou was a baby correction make that Dougie Lampkin (and there are many on this site reading this post) that how we gear our bikes is all wrong! :wall:

Edited by billyt
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Only 2 things are a surprise to me

1) That it's open to debate what a smaller or larger sprocket will do, I thought it was grade 1 bike stuff LOL

It's all about simple leverage principal, a larger wheel has more circumference covers more ground and takes more power to rotate, smaller wheel is easier (front spkt, rear spkt is opposite)

And I lied about 2) I think people change a front simply because it's cheaper than changing rear not because it is better, dropping a tooth on the front is like changing 3 or 4 teeth on the back

Hey!, if I grind one tooth off my front sprocket will bike go slower :)

Only if you grind three off the back as well ........ LOL

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YEP..... I know the feeling Rob.

A guy new to trials telling trials riders that have been around the sport since Bou was a baby correction make that Dougie Lampkin (and there are many on this site reading this post) that how we gear our bikes is all wrong! :wall:

I might be new to trials but ive been riding and around bikes for 26 years to be precise. Age does not always mean experience.

I have gone from a 11 ft to a 10 to make the bike more rideable. Did it make the bike easier to creep slowly......yes, did it make acceleration more responsive. .......yes it did. If I grabbed a handfull of throttle unexpectedly, would the bike respond more aggressively. ......yes it would.

A few guys seem to get what im on about.

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Alow me to explain what initiated this thread.

My father has been riding and competing in all forms of two wheeled events (including trials - now classic trials) for 50 years (he turned 60 this year). He has also built almost every bike hes riden from the ground up.

He bought a 2013 evo300 (the bike im now on). When he bought the bike, the dealer said he put a 10t on the front to make the bike tamer. Pops started out with the basics, fig 8s, little weelies etc and immediately complained that the bike was hard to ride slow as the throttle input was so aggresive and finicky, the bike was lurching forward when he was trying to give a little gas.

Pops then ordered a 11t sprocket, and hey, presto. The bike was now easier for him to ride (as a modern trials beginner). He also then fitted a slow action throttle, which tamed the power down even more.

If a "beginner" needs to tame a bike down, learn from my dads experience. There is a difference between those that CAN ride a modern trials bike and those that are just starting off.

As you will see in the pic, me and my dad have been around bikes for a bit. The pic is of my dads guarage that I look a few months ago, not much has changed except his classic racecar was sold to make space for more bikes.

post-18493-0-12506400-1382670888_thumb.jpg

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Mokwepa

When you put up a post with a title

"Lets Get One Thing Straight! (Sprockets)"

Who was your intended audience with this terse bold statement?

I don't recall any discussion, argument about gearing that needed such a strong title.

You strongly gave an answer to a question that was not asked.

I agree age does not mean wisdom, I think I stated that riders who have been around the sport for a very long time do not need someone new to the sport telling the how to gear their bikes.

While you may have been around dirt bikes in general for a long time all of that dirt bike stuff does not necessarily transfer over to trials bikes or vise versa.

Gearing a bike up for a beginner may end up confusing them. Why? Riders start of with poor technique, it is the norm. The tend to use speed to get up obstacles rather than technique.

Good technique and torque (slow torque) are a trials riders best friends. Gearing a bike up for first gear leaves the rider no where to go when they want to go slow or fast.

Have you considered this, maybe your dad should have learnt to ride in second gear? According to your theory that would have been like gearing the bike up. When he needed torque he could have then shifted down to first. Just my thoughts!

Respectfully

Edited by billyt
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Personally I like a nice low first gear as I can dodge about without clutching to death,.

I would be reluctant to "gear up" all you get is a high first gear which can be hard work in tight stuff.

Mokwepa's dad on a 300 Evo at 60?,there things will draw away in 4th without a cough.

Thing is at our club we get far more new 280/300s than 250s it must be a macho thing.

(saying that I've a 270 but you can't get a 250 Scorp anymore)

Then they try to soften them with flywheel weights,timing,gearing slow action throttles etc

End up with a 300 that has the power of a 250 but doesn't feel as good.

Edited by breagh
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