Is there a negative side to a clutch mech?

markb84

markb84

Likes Dirt
Whilst looking at another thread I was considering the effect of chain growth on short cage mechs and a thought came to mind.

With a clutch mech the spring force holding the chain taught is much higher than on a non-clutch mech, when suspension on most bikes compresses this causes chain growth which is effectively causing the cage to swing out to lengthen the chain.

Therefore would this increased spring force have an effect on suspension performance? I'm sure it would be fairly small especially on high speed compression but I do recall that manufacturers used to have issues with the way chains affected suspension performance. So do modern suspension designs overcome this or would it potentially impact performance (slightly).

I love the clutch mech on my bike and am happy with the performance of my suspension. I'm just pondering.
 
cameron_15

cameron_15

Eats Squid
Manufacturers still do have issues with chain growth effecting suspension performance.

There would be a tiny, tiny, little bit of resistance added by the extra tension on the rear mech.

If you want to learn more about the effects of chain growth on suspension performance, GT have made a very good video(well, advertisement) about it.

http://www.youtube.com/watch?v=5nGoqF7CNR8
 
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The Duckmeister

The Duckmeister

Has a juicy midrange
On the couple of occasions I've ridden with a clutched derailleur I haven't picked any difference in suspension performance.
 
moorey

moorey

call me Mia
Yet to run one myself (getting close), but thats surely been factored into the design. 2 mates run clutched, one on heckler and one on sb66, and can't say that its ever seemed to be a problem. It they are being widely used on DH bikes, some with big chain growth, I think we can say it isn't an issue :noidea:
 
indica

indica

Serial flasher
moorey said:
I think we can say it isn't an issue :noidea:
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Can we?
Or is it something the manufacturers are ignoring? Surely you can't believe that they care about customers more than continuing to sell us new and upgraded stuff every year that we don't need?
 
markb84

markb84

Likes Dirt
indica said:
Can we?
Or is it something the manufacturers are ignoring? Surely you can't believe that they care about customers more than continuing to sell us new and upgraded stuff every year that we don't need?
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^ See this is where my thinking is. So much focus goes into the positive spin of new technology, and having purchased a clutch mech I have to say I love it and it is great.

There is rarely any summary of the compromises that have been made in order to get to that point:

We made it lighter (by the way it's weaker now)
We made it faster (but it doesn't handle so well)
We made it hold the chain better (but the low speed compression performs worse)

I don't expect any company to sell the negative side of their product but I do think it's worth consumers pondering when a new technology is released "did they take anything away to make this work?"
 
udi

udi

swiss cheese
I think any difference is negligible. Most bikes don't have a whole lot of chain growth, and thus its effect on the derailleur is heavily leveraged. The more leverage over it, the less calculable effect on suspension feel.

If you have a Shimano clutch mech, you can also adjust the effect of the clutch from firm all the way to nothing - so you have full control over the situation anyway. I can't really feel anything even at a fairly firm setting though, however it does have a direct impact on the shifting force required to change gears, so it's nice to dial it back a bit if you don't need it super stiff.
 
ChopSticks

ChopSticks

Banned
Only negative thing I have found with SRAM type 2 is a knocking sound when suspension is compressed usually goes unnoticed on the trail.... But annoying nonetheless.... i pt it down to the clutch slipping
 
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MARKL

MARKL

Eats Squid
indica said:
Can we?
Or is it something the manufacturers are ignoring? Surely you can't believe that they care about customers more than continuing to sell us new and upgraded stuff every year that we don't need?
Click to expand...
I am sure that Sramano are working on 'new' clutchless derailleurs to sell to us in a couple of years time to replace our new shiny clutched derailleurs offering increased lightness, suspension sensitivity and reduced kickback or whatever else marketing can invent...
 
Reubs

Reubs

Likes Bikes and Dirt
You weigh how much? 70? 80? 90kgs? Do you reeeeeeally think that a tiny little bit of extra resistance is going to be noticed when you hurl your ass down a bumpy trail?
 
D

Dirtydan

Likes Bikes
Can I ask does anyone actually think that the chain length grows more from suspension movement than from moving up to a bigger chain ring or gear on your cluster. If it has such a little effect (if any by changing gears) how can it have a noticeable effect on suspension.

Just a thought.
 
moorey

moorey

call me Mia
Dirtydan said:
Can I ask does anyone actually think that the chain length grows more from suspension movement than from moving up to a bigger chain ring or gear on your cluster. If it has such a little effect (if any by changing gears) how can it have a noticeable effect on suspension.

Just a thought.
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The pull of the cable releases the clutch.
 
moorey

moorey

call me Mia
creaky said:
I didn't realise that either. If that is the case, why is the downshift (i.e. to easier gear) stiffer with the clutch engaged compared to not engaged ?
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Dunno. Just had my mate point out on his, that the cable pull disengages it to shift. Thats one for the true tech heads:noidea:
 
The Duckmeister

The Duckmeister

Has a juicy midrange
moorey said:
Dunno. Just had my mate point out on his, that the cable pull disengages it to shift. Thats one for the true tech heads:noidea:
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Just quietly I reckon your mate is talking through his hat. The clutch mechanism is entirely contained within the cage knuckle and completely separated from the cable attachments, which are on the opposite side of the derailleur body. There is a noticeable difference in shifting when the clutch is turned on or off.
 
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