tajimirich

Hi all

My previous bike was an 80s/early 90s, butted and lugged, steel framed, single speed one - a fixie when I bought it, it had a (from memory 16 tooth) freewheeling hub on the other side of the wheel, so I flipped it because I enjoyed having the option to coast - and because of the simplicity of the chainset I was able to take away any give in the chain - so when I applied pressure, the chain would instantly respond.

On my new bike , a geared bike (Giant Contend 2, with most of the crucial parts upgraded from Shimano Claris to Tiagra or Ultegra), the chain seems to hang a bit lose, so when I apply pressure it jars and knocks taunt a bit because of the slack in the system before catching. It makes a bit of a 'thonk' sound and I feel like I'm kicking a very yielding brick wall. This is hard to understand because the chain doesn't actually seem to hang lose - it's visibly taunt - it's just that, I guess, the system of springs and levers is inherently a bit slack?

I don't like this, it seems like it must be a bit rough on my rear derailleur's hook, if not the whole system - including the chain, the chainring...

But I'm wondering - is it something that can actually be fixed on a gear'd bike? I know that the chain could be in perfect sync with the chainring on my single speed bike because there was not spring'y rear derailleur for it to feed through...

Is there a way I can make it so my pedals respond instantly to my applying pressure, instead of the aforementioned thonk'ing catchup of slack?

I've other mysteries about this bike I'd love to solve here, I'll see how this one goes ^_^ I live in Japan, for future reference, and I can't quite get the answers I'm looking for from my bike guy all the time.

WhyFi

You're probably taking about slack before the teeth in the hub engage. If so, get a DT Swiss hub with 54t ratchet upgrade.

tajimirich

Thanks mate, I don't see a 'like' button here but I like ur post

What i'm getting feels very much like my old bike did when the chain was hanging down a bit, and it just had to pick up that slack in the chain before it ran well. On the single speed'er it was fixed by tightening the chain, so that's kinda what I was looking for - whether or not a 'tightening' thing would work on a geared bike.

As for your suggested hub, that looks really cool - I'm watching a video about it - is that the only way road bike riders would solve this problem in the past?

Russ Roth

WhyFi has probably nailed it, you're dealing with the time it takes for the pawls to engage the splines in the freehub mechanism. Instant engagement with 72 engagement points was the big selling point for Chris King. Even their new r45 has, per the name, 45 engagement points which usually prevents that hard hit engagement feel. I9 has a high number as well. Also doesn't mean you have cheap hubs either, I've had that same issue with Dura Ace and XTR hubs, even my new XT have it, not really a big deal.

Dean V

I doubt the freewheel in his single speed sprocket is any quicker to engage than what his geared bike is.

tajimirich

Yeah, Dean V seems to be digging me, I think it's more to do with my chain set up having some inherent slack in it, and wondering if there's any way to take the slack out of a gear'd bike? It really feels more like a loose chain jolting because there's slack - it feels identical to how my old bike felt before i tightened its chain.

Dean V

If the freewheel is dragging it will overcome the tension in the chain from the rear derailleur.
This would make the chain droop on the top when coasting and create a slack feeling to the drive on engagement.

tajimirich

Hi guys

I actually gave talking to my bike shop guy another try, and it turns out my rear chain rings being Claris and my front chainring being Tiagra (8 speed vs 10 speed) is the reason

dabac

I doubt that. The pitch is the same for both.
I’d go for dragging freewheel or the number of POEs.

WhyFi

You know, it was late and I read "single speed" and "fixed" in his post, so my addled mind just went to fixed gear.

Yeah, agree with you and others that there's the possibility that his hub isn't freewheelin' quite so freely and it's throwing a bit of chain forward, though hub engagement could still be contributing.

cxwrench

Nope, that's not the reason. And when you tightened the chain on your old single speed that much you actually made it slower by creating more drag.

Iride01 

If not any of the other things, your chain might just be too long and the DR is near it's ability to take up any more slack. Also, there might be something that is making your freehub not be so free. Did you decide to not trust the mfr and use your own lube, or perhaps it's just really cold where you are currently and that's caused the freewheel innards to be a little slow and drag?

tajimirich

Hey mate, well you give me more thought. I vastly preferred my freewheeler when it was in sync with the chainring, instant feedback takes a lot of stress off components and my joints, I felt.. I enjoyed it I didn't tighten the chain much, just made it so that it didn't sag when i put power into the pedals - you know? anyway it was done in australia at the suggestion of a pretty savvy bike shop owner in melbourne so I tend to reckon he had the right idea~
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Hey mate, I must not have been clear enough in my OP but I'm no longer on a freewheeler bike, I've switched to a gear'd bike and that's the one I'm trying to tighten up.

It is a bit cold here good idea, I know it made my wheels feel underinflated until I rode them for a few km and the air inside them heated up...

I'm coming to the conclusion that I can't really fix this particular problem in the same way I fixed it on the freewheeler, because the rear derailleur is seemingly built to flex, so there'll always be some flex in it... that's only a hunch though

big chainring 

Did yuor single speed use 1/8" chain. Stiffer laterally than 3/32". Old inch pitch had a different feel too, and many track guys hung onto that for awhile because of its stiffer quality.
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cxwrench

More/tighter chain tension creates more wear. Looser/less tension is faster and doesn't wear chain/ring/cog as much. On a geared bike the only thing you can do to make drivetrain engagement faster is increasing the points of enagement in the freehub. The most commonly available hub you can do this with is the upper end DT Swiss.

I've worked for the US National track team and UCI trade teams at World Cups so I'm fairly savvy myself.

Litespud

the RD has nothing to do with this, unless your chain is so long that the upper run of chain between the chainring and the rear sprocket is sagging. When you stand on the pedals, all of the force is being exerted on the upper run - the RD just manages the slack “lower run” of chain, but that portion of the drivetrain is not involved in transmitting force from the pedals to the rear wheel. Another possibility is that the freehub/freewheel is sticking slightly, so that the rear sprocket continues to rotate even after you stop pedaling, thereby “feeding” extra chain into the upper run and creating chain slack that has to be taken up when you resume pedaling. Is the upper run taut under normal circumstances, or is there any chain sag/slack? I really think you have a slowly-engaging freehub/freewheel, and that the lag you’re experiencing is simply a characteristic of that component

Iride01 

Not sure what you mean at all. Most all bikes are geared. Even fixie's.

Are you wanting to meet by the flagpole after school? <grin>

popeye

Are you skipping a tooth on a worn cassette? When you put your foot on the pedal all the slack is taken out.