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sammyd173

Fun With Gearing

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First of all, there is absolutely nothing fun about gearing...

 

With that said, I got my new (to me) '15 260 standard model a week ago. Great bike!

 

Standard 41/10 is too fast for me. I'm 180, ride slab and sand and try to go up big rocks here in California. 

 

So then I put a 41/9 on. Too slow. 1st too slow, second to tall. Read the forums, lots of different opinions. So I tried to do some math, which no doubt someone will correct me on, but here goes.

 

41/10 = 4.1 reduction

41/9 = 4.56 reduction

 

The difference between the two is 11.2%.

 

So the massive difference you can feel between a 9t and a 10t sprocket is just 11.2% in speed.

 

Let's say you want to split the difference - you think that's the goldilocks zone.

 

43/10 = 4.3 reduction. That's a 4.9% difference, i.e. a reduction of speed of 4.9% over stock. So that's what I'm going for.

 

====

 

They say taking one tooth off the front is the same as adding 3 teeth to the rear. Well maybe that's the case for street or MX bikes with much higher gearing, but my (questionable) calculations say that you need to add 4 teeth to the rear to get the same effect as reducing a tooth on the front, and vice versa.

 

41/9 - 4.56 reduction

45/10 - 4.5 reduction - you need to add 4 teeth to the rear.

 

====

Gearing as reported in the '15 manual.

 

Primary - 3.167

1st - 2.8

2nd - 2.385 (This is a 17% increase in speed over 1st gear)

3rd - 2 (19% increase in speed over 2nd gear).

4th - 1.273

5th - 0.815

 

Note the LOWER the number is, the FASTER the bike is going.

 

Let's say you want to know if 2nd gear with a 9t is going to equate to 1st gear with a 10t? Okay, I wanted to know that. Well, we know that a 9t makes the bike slower by 11.2%. So you multiply second gear on this chart - 2.385 - by 1.112 (or 111.2%). Remember, the higher the number, the slower the bike is going, so we are increasing the reduction effect. That value comes out to 2.65.

 

This means that with a 9t front sprocket, second gear will be FASTER than 1st gear with 10t. By how much? About 6%, which is something. So there. Anyway, this is some of the logic I used to try to figure out my gearing without buying a ton of sprockets, maybe it will help someone else!

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With a 9, you just have to gas it more. With the 10 you need to use just a tad more clutch. You could of kept the stock gearing, but then you would have to make the clutch work better. Second with the nine is the same issue, just get the clutch working a bit better. (Plenty of threads on this too.)

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Love the post, thanks!

For what its worth, in the end I went with a learn and work with the clutch approach. Worked great for me, but did take some time to learn it.

Good luck!

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Thanks everyone. I get the overall impression that expert/ pro riders tend to run higher/ faster gearing than lower grade riders. Also the more grip there is, the higher the gearing, generally.

 

We now have 6 of us in San Diego running these bikes and riding together at the weekends. Three of those bikes materialized in the last couple of months. We seem to spend most of our time trying to scare each other riding up large rocks/ slabs. Everyone is running 41/10 gearing. An advantage of keeping stock gearing is knowing what gear others are using for various obstacles/ challenges. A bit like Motocross when you are trying to figure out whether to use second or third off a jump, and you can ask your buddy what he is using.

 

I keep telling these guys, 'Rocks for show, corners for dough!' but they're a motley bunch, so splatters and zaps is where it's at. Last time they went out - I was on kid duty - one guy dislocated his shoulder off a drop-off, and another dude who is a novice looped out and dislocated his elbow and fractured his arm in three places. Both his bikes are up for sale. No idea what gearing he was running.

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2016 standard

 

Thanks for sharing. Was wondering about the 9T on the counter as well. I tend to like to get the bike on the rear wheel and hold it there which the stock gearing does real well. I found that the lower or countershaft sprocket brought the front end down a bit quicker on my Beta 300Evo 4stroke when running in 1st gear....Imagine it would be the same with the new Monty?

 

Thoughts?

Thanks

Tom

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Back when I was road racing 2T GP race bikes, we not only had the ability of changing final gearing, but also could change internal gearing with cassette type transmissions (RS125 & TZ250).

 

On my GG TXT 280, I've tried the 11/42, 10/42 & 10/41 gearing, but like the 10/42 for now and might consider trying 11/43, since both the 11/42 & 10/41 seemed a bit tall. Bummer for your buds getting hurt. Lots of people want to try MotoTrials and quite often they lose interest because there aren't enough others to ride with, or end up getting hurt. Lots of fun, but still need to respect the natural terrain for what it is...

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2016 standard

 

Thanks for sharing. Was wondering about the 9T on the counter as well. I tend to like to get the bike on the rear wheel and hold it there which the stock gearing does real well. I found that the lower or countershaft sprocket brought the front end down a bit quicker on my Beta 300Evo 4stroke when running in 1st gear....Imagine it would be the same with the new Monty?

 

Thoughts?

Thanks

Tom

Good question - I really liked 42/10 gearing on the Beta. So I wondered what the equivalent would be on the Montesa.

 

Primary Reduction Beta - 63/18 = 3.5

Primary Reduction Montesa - 3.167

 

So Beta has a reduction effect that is 10.5% higher, meaning it will run 10.5% SLOWER than the Montesa with the same gearing. That's about the difference of one tooth less on the front sprocket. So 42/10 on the Beta is like 42/9 on the Montesa. I think.

 

The Montesa has a lot more power than my Beta 300 4t, so I'm willing to run this bike with faster gearing.

 

The only time I really want for lower gearing than stock on this bike is when I'm at a dead stop and in the middle of a pile or rock and am bouncing an clutch-flicking my way out, or when the front is very high on a tricky part of a hill, from a dead stop again. But when doing an event as opposed to pleasure riding, this scenario happens to me a lot .

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You'll probably get used to standard after a while, everything in 1st gear. When we first got the 4rt's we'd run 10/42, slowed it down a little, but kept the very useable 1st gear without being too snappy off the bottom end. Then i got fed up of altering the chain, taking chunks off my knuckles and just learnt to ride 10/41.

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Thanks everyone. I get the overall impression that expert/ pro riders tend to run higher/ faster gearing than lower grade riders. Also the more grip there is, the higher the gearing, generally.

 

We now have 6 of us in San Diego running these bikes and riding together at the weekends. Three of those bikes materialized in the last couple of months. We seem to spend most of our time trying to scare each other riding up large rocks/ slabs. Everyone is running 41/10 gearing. An advantage of keeping stock gearing is knowing what gear others are using for various obstacles/ challenges. A bit like Motocross when you are trying to figure out whether to use second or third off a jump, and you can ask your buddy what he is using.

 

I keep telling these guys, 'Rocks for show, corners for dough!' but they're a motley bunch, so splatters and zaps is where it's at. Last time they went out - I was on kid duty - one guy dislocated his shoulder off a drop-off, and another dude who is a novice looped out and dislocated his elbow and fractured his arm in three places. Both his bikes are up for sale. No idea what gearing he was running.

The slower gearing will help slow the crashes. I`ve seen guys all my life come out and ride almost anything, (Once) and never see them again. Trials is about turns and obstacles. Any bike will roll over anything. They all have the same things in common. Tires, handlebars and foot pegs. You either learn how to do it correctly or quit (crash) and fade into a memory.
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I've got 10/44 gearing on mine, the bike had 10/42 on it when I first bought her, found that too fast. Mind you, I use the clutch on this bike far more than I did for the beta, just helps to lift the front with no run up and in very tight turns, also winding the bike up in mud, releasing the clutch slow and timing the throttle right. Sometimes she grips like stink and surprises me! Anyways I find with 10/44 I've used 1st, 2nd and 3rd in sections successfully. Its so wet here having the first three gears usable is important

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I think you are thinking about it the wrong way. The sprockets dont make it any slower or faster, the engine rpm does. And by changing sprockets you change the speed at a certain RPM.

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With the characteristics of this motor I like the stock gearing, often I find first just runs out a little early as it is, and I'm a rank amateur.  Not to bikes, but to trials.  I also have a Gas Gas 250.  With stock gearing I find the Montesa much more user friendly than the Gas Gas with just about any gearing.  I find myself going too slow rather than too fast, so I'm leaving it stock geared and loving it.

Edited by desmo_kid
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I think you are thinking about it the wrong way. The sprockets dont make it any slower or faster, the engine rpm does. And by changing sprockets you change the speed at a certain RPM.

 

You do o change the range of speed available in any gear  -the speed of the bike at tickover (min rpm available) will be slower on a bike with lower gear etc.

 

Most people use min rpm a lot more than they ever use max rpm in any given gear.

 

I guess also mechanical advantage is changed so with a lower geared bike the effect of the engine torque will be greater at the back wheel. This maybe enhances the feel of a bike being easier to ride with lower gearing -easier to ride just off the throttle and not needing to slip the clutch to build up torque.

 

I like stock gearing and use first for majority of sections. But then I always have used speed over ability to get through sections! :hyper:   :hyper:      

The Mont with good low down torque and a long rev range allows first gear to be maxed out 

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Like HRMAD, I am also in Muddy Wales and have recently been running 10:44. It certainly does make 2nd gear my primary gear but 1st has become pretty much redundant. I like 1st gear. I miss it a lot and want it back in my life.

 

I also found that on a long, very steep hill climb section 3rd gear seemed to run out of speed and I dare not kick up to 4th as I knew it would stop pulling.

 

The bike had 10:43 when I got it last year; 1st was my primary gear then but, now I'm used to a 4 stroke, I think I could liven bottom gear up a bit if I run 10:41/42 without compromising 2nd and 3rd too much? if so, I will buy new C&S with a spare 44T for winter trials.

 

I did read the original thread up till about paragraph 3 but my attention span ran out (much like 3rd gear at 10:44!!), cos it reminded me too much of double maths class back in school!! :D

 

 

 

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