Benefit Of A Front Freewheel?

[murph82]

I'm getting back into trials and when I used to ride 7 or more years ago it was all about hopes and CK's, FF's were strictly on megamo and montys but now its massively common, whats the benefit? I've a DMR revolver and tensile cranks so can put it either end, but to me it seems weird to put the FW on the cranks where its more likely to be subject to impacts??? Is there a benefit that outways this???

thanks

Edited September 21, 2010 by murph82

[forteh]

The only benefit is that it moves weight from the back wheel, forward to a more central point, makes the centre of gravity more centralised

[Franksx2005]

I'm getting back into trials and when I used to ride 7 or more years ago it was all about hopes and CK's, FF's were strictly on megamo and montys but now its massively common, whats the benefit? I've a DMR revolver and tensile cranks so can put it either end, but to me it seems weird to put the FW on the cranks where its more likely to be subject to impacts??? Is there a benefit that outways this???

thanks

more clearance, more engagements, cheaper to replaces, better gear ratio, cheaper.

[murph82]

more clearance, more engagements, cheaper to replaces, better gear ratio, cheaper.

what is generally the ratio people run , personal pref obviously but i've seen 18/15's about right?

[Franksx2005]

what is generally the ratio people run , personal pref obviously but i've seen 18/15's about right?

What do you ride? im gussing a stock? are you streety or more into pure trials

[Krisboats]

what is generally the ratio people run , personal pref obviously but i've seen 18/15's about right?

Yep, 18:15 is good. Personally i'd stick the freehweel on the front, theres some technical reason for it to engage quicker at the front than the back (i skim read it a while ago so wouldn't wan't to explain it in too much detail) that i think is to do with the cranks rotating quicker than the wheel so gives you more effective engagements per rotation.

Main benefit really is the even weight distribution. Having a heavy back end can make manouverability a bit more tyresome.

[murph82]

Yep, 18:15 is good. Personally i'd stick the freehweel on the front, theres some technical reason for it to engage quicker at the front than the back (i skim read it a while ago so wouldn't wan't to explain it in too much detail) that i think is to do with the cranks rotating quicker than the wheel so gives you more effective engagements per rotation.

Main benefit really is the even weight distribution. Having a heavy back end can make manouverability a bit more tyresome.

makes sense I guess!!!!

Thanks guys

[Mikee]

theres some technical reason for it to engage quicker at the front than the back

I thought it was the other way round. Isn't if you had the freewheel on the back , It would turn a bit more than a full turn for ever full turn rotation of the cranks.... Effectivlley giving you more engagement points. Or am I mistaken?

[Franksx2005]

I thought it was the other way round. Isn't if you had the freewheel on the back , It would turn a bit more than a full turn for ever full turn rotation of the cranks.... Effectivlley giving you more engagement points. Or am I mistaken?

Using an echo sl as an example

it difficult to explain, think of it as one revolution of the crank. if the freewheel is at the front with 1 revolution of the cranks it will only engage 108 times. if the same freewheel was on the rear and the front cog was larger (for a desirable ratio it will almost certainly will be) with 1 revolution of the cranks the rear freewheel will spin more than one revolution wich in effect will give you more than 108 engagements per revolution of the crank.

but having the freewheel on the rear would require a much larger cog on the front, which would mean less clearance, larger bash ring (more weight) and a longer chain (more weight), there probably is more disadvantages too but i cant think of them right now.

Edited September 21, 2010 by Franksx2005

[Dan6061]

i think is to do with the cranks rotating quicker than the wheel so gives you more effective engagements per rotation.

On mods, with 18:12 ration (1.5) you end up with more engagements with a freehub because the wheel turns 1.5times to every full crank rotation. So my Profile on the back with 48 engagements, with the 1.5 ratio I have 72.

[Maladie]

On mods, with 18:12 ration (1.5) you end up with more engagements with a freehub because the wheel turns 1.5times to every full crank rotation. So my Profile on the back with 48 engagements, with the 1.5 ratio I have 72.

So does this mean i have 162 engagements because i'm running 18:12 gearing ratio too, and an Echo SL freewheel.

[TROYston]

If as someone said that you can, in a sense get more power out a FFW, why is neil t so damn good?

Even with a pro2.

[murph82]

On mods, with 18:12 ration (1.5) you end up with more engagements with a freehub because the wheel turns 1.5times to every full crank rotation. So my Profile on the back with 48 engagements, with the 1.5 ratio I have 72.

hold up, am i missing the point??

Gear ratio as you say dictates the turns of rear wheel relative to size of freewheel being used and cog at either end. Wether you have a 22 tooth cog pulling an 18tooth freewheel (approx 1.2 turns of wheel for one rev of crank) with 72 pick ups or the same freewheel to a 12 tooth cog (1.5 rev's as you say) there is still only 72 pick up points in that freewheel, that wont change as its hardware, it is what it is surely?

I was wondering if by having it on the cranks it puts less stress on the pawls as there is no preload through the chain? In my mind, it makes sense to be on the cranks as anyone whos changed one will know their bastards to get off, the principle of using it in whatever application will tighten it using the riders full body weight and strength in their legs as they ride ( is there a splined freewheel and crank set up where the FW fits on the crank similar to a B'guard on the RS7 cranks and then holds it in place with a lock ring,or even on a hub, a big spline with a lock ring like normal cassettes/?? that seems so obvious?????!!!???) so if the bugger gets stuck its a new crank not a new hub/wheel/rebuild so more cost effective, but if on the the freewheel is better protected and the bits facing regular impact are cheap to replace IE a sprocket???? plus if a sprocket is mashed and stuck sticking in a vice and smashing the crank with a rubber mallet or hammer and wood block will save the crank?

I get the idea of balancing the bike and lighter rear end etc, i guess it just depends, that to me is extreme, everything is weighhhhhhh (geddit?) lighter han years ago, we were riding MTB hubs with 7/8 speed blocks and mechs! if you got the money to replace smashed up fw's then fair play, if you haven't i guess protect it on the wheel?

vote guys, in an anoraky sortof way it will be interesting to see what the opinion is and wether people relatively new to the sport, ielast 3-4 years just do it because its whats done. Thinking back now, single speed hubs with fw's would have saved me and my mates loads of money as several fecked the FW and had to get a whole new hub. Say a dmr Revolver and tensile 60 is 60 quid plus rim and build, a hope which was only 36 points back then was something like £150 + rim, build, and gearing!

Edited September 21, 2010 by murph82

[murph82]

So does this mean i have 162 engagements because i'm running 18:12 gearing ratio too, and an Echo SL freewheel.

It cant surely? They are there, cast or forged or whatever. The greater number of points just means that there is less slack between when you begin the pedal stroke and the point that the power engages in the FW and drives the wheel.

Ie a hope with 48 points will need no more than 7.5 degrees of a revolution of the crank to engage it, a tensile sixty will need only 6. Doesn't sound a big difference but consider that the further away from the centre of the drive cog (freewheel or chainring) the further the physical stroke is, so shorter cranks and more engagement points equal faster engagement from your foot. Also more pick up points at speed mean that your more likely to get drive down quicker as otherwise you could effectively be chasing the engagement point like on shite bottom end shimano freewheels!

Edited September 21, 2010 by murph82

[Revolver]

If as someone said that you can, in a sense get more power out a FFW, why is neil t so damn good?

Even with a pro2.

He was not born, he was created. He is a machine.

[murph82]

If as someone said that you can, in a sense get more power out a FFW, why is neil t so damn good?

Even with a pro2.

not sure if i said that or someone else, i was only asking but to me it would seem it doesn't make a difference, the chain tension is the same amount whichever way round so should think the power question is void, i'm thinking its purely a weight distribution/clearence vs protecting your equipment decision?

[trialsmax04]

if you have a pro 2 i would swap. Not a great fan of the chain going round all the time!

[murph82]

if you have a pro 2 i would swap. Not a great fan of the chain going round all the time!

No i've got a DMR revolver with an ACS claw and some shite specialized isis cranks but getting some tensiles and need to replace FW so wondered what the benefits were of sticking it on crank when i come to swap over!

[Franksx2005]

hold up, am i missing the point??

Gear ratio as you say dictates the turns of rear wheel relative to size of freewheel being used and cog at either end. Wether you have a 22 tooth cog pulling an 18tooth freewheel (approx 1.2 turns of wheel for one rev of crank) with 72 pick ups or the same freewheel to a 12 tooth cog (1.5 rev's as you say) there is still only 72 pick up points in that freewheel, that wont change as its hardware, it is what it is surely?

Both these ratios = near enough 1.5

with a 18-12 ratio and the 72 click freewheel on the cranks

in one 360 degrease revolution of the crank the freewheel will engage 72 times

with a 28-18 ratio and a 72 click freewheel on the rear

in one 360 degrease revolution of the crank the freewheel will engage 112 times

So a freewheel at the rear would effectivly give you more engagements but you would have to run a large cog to get the same ratio

[murph82]

Both these ratios = near enough 1.5

with a 18-12 ratio and the 72 click freewheel on the cranks

in one 360 degrease revolution of the crank the freewheel will engage 72 times

with a 28-18 ratio and a 72 click freewheel on the rear

in one 360 degrease revolution of the crank the freewheel will engage 112 times

So a freewheel at the rear would effectivly give you more engagements but you would have to run a large cog to get the same ratio

I see where your coming from! However, and if i'm wrong i apologise, your working out the number of clicks from the freewheel realitive to the gear ratio, ie a 60 click freewheel on a 18-12 will give 90 engagement points?

What this doesn't do is increase the engaement points to effect of "upgrading" the freewheel. The number of engagement points dictates the no of degrees the freewheel needs rotating before it comes to the next engagement point so a 60 click will have a 6 deg rotation between points (6x 60=360 deg) that wont change regardles of gearing ratio? Therefore what your working out is the number of clicks you will hear rather than the number of engagment poins you will actually be riding with?!?! make sense?

[Franksx2005]

I see where your coming from! However, and if i'm wrong i apologise, your working out the number of clicks from the freewheel realitive to the gear ratio, ie a 60 click freewheel on a 18-12 will give 90 engagement points?

What this doesn't do is increase the engaement points to effect of "upgrading" the freewheel. The number of engagement points dictates the no of degrees the freewheel needs rotating before it comes to the next engagement point so a 60 click will have a 6 deg rotation between points (6x 60=360 deg) that wont change regardles of gearing ratio? Therefore what your working out is the number of clicks you will hear rather than the number of engagment poins you will actually be riding with?!?! make sense?

Yeah that makes sence, im working out how many clicks in a 360degrease turn of the crank, your working out how many degrease you have to turn the cranks to get to an engagement point.

[murph82]

Yeah that makes sence, im working out how many clicks in a 360degrease turn of the crank, your working out how many degrease you have to turn the cranks to get to an engagement point.

the freewheel will only ever click the amount of times it states ie 60/72/108 in one full rotation of the freewheel wether on the cranks or the hub, pick up will never change, only the number of clicks you hear will differ with gearing.

I got my maggy bits sorted, good old tarty!

[Mark W]

The 'feel' changes too - you get effectively more clicks at the pedals if you have it on the back (as long as it's not a 1:1 ratio or something like that). As people have said, if you're running 22:18 (for example), one rotation of the cranks would give 1.2 rotations of your hub. As a result of that, at the pedals it will feel like you'll have 108 x 1.2 engagements (about 132 clicks) assuming you're using a 108 click freewheel. Because of that, it'll feel like you have more engagements, and it'll engage faster because of that. If your freewheel is on the front you have no mechanical advantage over it so it's the same amount of clicks 'at the pedals'.

If you get a bashring, you'd have to be pretty unlucky to hit your freewheel hard enough to damage it, so it's not really much of an issue in that sense, and certainly not a reason to not run FFW compared to the advantages of it.

[murph82]

right......i'm confused as F*ck now

Think i better stick it on the crank so i can see how it feels as only ever ridden with rear freewheel mechanism!

hang on, i get it..............apologies, if you stick itn the crank you would need a freewheel multiplied by the ratio as the wheel would rotate the freewheel 1.2 or however many times, yeah, i guess it would mean that to get the same feel at the pedals you need a hub with the freewheel x ratio to get the same feel! The speed of engagement wouldn't change though would it? ie no of degrees in rotation before it picks up????? defo on the front it is then?

Edited September 21, 2010 by murph82

[Mark W]

I'll try and simplify it...

Freewheel (18t, 108 click) on the rear, fixed sprocket (22t) on the front. Gear ratio = 1.2222. 1.2222 x 108 = 132~. 360° of crank rotation divided by 132 = 2.7° of crank movement between each click.

Fixed sprocket (__t) on the rear, freewheel on the front (18t, 108 click). Gear ratio = doesn't matter as your freewheel's on the front. 360° of crank rotation divided by 108 = 3.3° of crank movement between each click.

Because of that, it feels like you have more clicks if you run your freewheel on the rear with a fixed sprocket (of greater size than the freewheel) up front.