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-   -   Slack/Play in the drivetrain? (https://www.bikeforums.net/showthread.php?t=888887)

velotnt 05-10-13 07:46 AM

Slack/Play in the drivetrain?
 
Hey guys!

I had my heart set on the Windsor Knight from Bikesdirect.com but they didnt have my size. Turns out Chris from BD told me they werent getting new shipments of current Ultegra equipped 6700s but the next shipment they get, it'll be Ultegra 6800 11 speeds at $1k+! At more than $1k I was priced out, I happened to check out craigslist and found an Ultegra 6600 Windsor Knight. Scooped it up for $400 lightly used and in great condition, what a steal!

Went for a ride yesterday and noticed a little bit of 'play/slack' when I start pedaling after coasting. So for example, I'm riding on a flat road, spin for a while and I decide to give my legs a quick 5 second rest and stop pedalling. When I resume pedaling it's as if I have to move the cranks a 1/8 inch before I feel the drivetrain start to engage or 'bite' and start to accelerate. I've ridden singlespeeds for a while and really like the direct feel as soon as I put my weight on the pedals, but with this road bike there's just that little bit of slack that when I put my weight on the pedals the freewheel(or cassette?) takes a second to catch.

Any solutions or am I just not use to road bikes?

Thanks!

bobotech 05-10-13 08:00 AM

Huh? I'm not really sure what you are describing. I have around 8 bikes (none single speed) and when I pedal, the bike moves. If you are saying that something is slipping, then yes, there might be a problem. Like if the chain skips a few teeth upon initial application of torque, then yeah, your chain and/or cassette might be worn down to the point of slippage.

Try riding up a steep hill in a high gear (really mash it) and see if the chain skips a lot there. That will really show up slippage.

Seems like to me that you are describing a non-issue if chain slippage isn't occurring.

You also have to remember there is a ratcheting mechanism in the freehub so engagement of anything could be delayed a tiny bit because the rear wheel isn't fixed to the cassette itself.

velotnt 05-10-13 08:28 AM

There isn't any slipping but I think you brought up a good point that may be what i'm referring to. I think it's likely the ratcheting mechanism as there is just that little bit of delay that bugs me. Is there a way to adjust or reduce that delay?

bobotech 05-10-13 08:45 AM

The delay part is kind of what I don't understand what the big deal is about. When you come to a stop, you back pedal the pedals so the pedal that you are going to push off with is like at 3 o'clock and you rest your foot on it which automatically takes out any slack in engagement. Then when you go, you push down and hop on the saddle and then take off.

If you really want a tighter ratchet, I guess you would spend hundreds of dollars on a Chris King freehub which would have finer engagement but it really is a total non-issue. Then spend the money to have the rear wheel rebuilt.

http://www.jensonusa.com/!zfmmJALawi...FQ9dQgod10wAEQ

FBinNY 05-10-13 09:17 AM


Originally Posted by velotnt (Post 15610287)
There isn't any slipping but I think you brought up a good point that may be what i'm referring to. I think it's likely the ratcheting mechanism as there is just that little bit of delay that bugs me. Is there a way to adjust or reduce that delay?

From what you describe,I suspect you're talking about normal engagement delay in the ratchet mechanism. This is determined by the ratchet's design, specifically the number of engagements per revolution. As a rule, larger ratchet rings have more steps per revolution, so odds are an external freewheel would have more engagements per revolution and therefore quicker engagement than the smaller internal ratchet of a freehub.

If you back pedal one cassette revolution (note rear sprocket teeth, and count that many chain links of movement) you can determine the fineness of the ratchet. You can also back pedal slowly until the freehub clicks, then note the amount of pedal movement until the next click. The gear ratio determines how far the crank will move for any amount of rear hub dwell, so even if the ratchets are identical, a higher gear will seem to have coarser dwell.

velotnt 05-10-13 09:33 AM


Originally Posted by bobotech (Post 15610366)
The delay part is kind of what I don't understand what the big deal is about. When you come to a stop, you back pedal the pedals so the pedal that you are going to push off with is like at 3 o'clock and you rest your foot on it which automatically takes out any slack in engagement. Then when you go, you push down and hop on the saddle and then take off.

If you really want a tighter ratchet, I guess you would spend hundreds of dollars on a Chris King freehub which would have finer engagement but it really is a total non-issue. Then spend the money to have the rear wheel rebuilt.

http://www.jensonusa.com/!zfmmJALawi...FQ9dQgod10wAEQ

Well, from a stop it is a non-issue. I ride in the city so dealing with crappy pavement, inattentive pedastrians, and traffic. I stop spinning pretty often, so when I resume there's that delayed engagement that bugs me (instead of engaging rightaway). It's not a big issue and really more of an annoyance. Thanks for your help gents

Bill Kapaun 05-10-13 09:38 AM


Originally Posted by velotnt (Post 15610114)
........When I resume pedaling it's as if I have to move the cranks a 1/8 inch before I feel the drivetrain start to engage........

1/8" or 1/8 turn?
If 1/8 turn, you may have gummy pawls in the freehub mech.
1/8"??? It's going to take some distance to accelerate the crank just to "catch up"on a moving bike.

Telly 05-10-13 10:11 AM

@velotnt, if you don't mind me asking, how much do you weigh?

cny-bikeman 05-10-13 11:15 AM

The combination of having to turn the cranks far enough to engage a pawl, added to the fact that the outer portion of the mechanism is moving, with the added variable of fairly high speed, could easily result in a delay of 1/8 turn, especially if you also pedal at relatively low rpm's. If by singlespeed you mean fixed gear then yes, you need to get used to a freewheel bike (has nothing to do with whether it's a road bike). Every benefit has a cost.

Gerryattrick 05-10-13 12:18 PM

If you've been riding single-speed (fixed or not?) for a while and this is your first geared bike for a long time it may well feel less "tight" to you starting off. If it does bother you why not ask some friends with road bikes for a ride on theirs so that you can make a like-for-like comparison.

velotnt 05-10-13 02:52 PM


Originally Posted by Telly (Post 15610776)
@velotnt, if you don't mind me asking, how much do you weigh?

about 160lb after a chipotle burrito.

ThermionicScott 05-10-13 03:17 PM


Originally Posted by velotnt (Post 15612003)
about 160lb after a chipotle burrito.

How about 30 min later? :lol:

Telly 05-10-13 03:20 PM

The question must of sounded odd, but there is a point to it!
I also had a similar problem a while back, which turned out to be (very) loose spokes in the rear wheel which flexed because of my weight (310+lbs) giving the whole drive-train a spongy feeling when I started to pedal after freewheeling. It kinda felt like I had a spring between the rear gears and the wheel rim which had to flex slightly in order for the power to be transmitted to the rear wheel. It's kinda hard to put it down in words and I finally figured it out when I had my previous wheels correctly tensioned and could instantly tell when the spokes needed tensioning again because of the springy/sponginess.

Jmcg123 04-06-21 07:53 AM


Originally Posted by velotnt (Post 15610114)
Hey guys!

I had my heart set on the Windsor Knight from Bikesdirect.com but they didnt have my size. Turns out Chris from BD told me they werent getting new shipments of current Ultegra equipped 6700s but the next shipment they get, it'll be Ultegra 6800 11 speeds at $1k+! At more than $1k I was priced out, I happened to check out craigslist and found an Ultegra 6600 Windsor Knight. Scooped it up for $400 lightly used and in great condition, what a steal!

Went for a ride yesterday and noticed a little bit of 'play/slack' when I start pedaling after coasting. So for example, I'm riding on a flat road, spin for a while and I decide to give my legs a quick 5 second rest and stop pedalling. When I resume pedaling it's as if I have to move the cranks a 1/8 inch before I feel the drivetrain start to engage or 'bite' and start to accelerate. I've ridden singlespeeds for a while and really like the direct feel as soon as I put my weight on the pedals, but with this road bike there's just that little bit of slack that when I put my weight on the pedals the freewheel(or cassette?) takes a second to catch.

Any solutions or am I just not use to road bikes?

Thanks!

I have created an account not because I have the answer to your issue but only as someone suffering from the same issue. I absolutely hate it, every time you pedal you have to overcome about 15 degrees of slack in your rotation before you even get any engagement. I did take a look at it and it would seem to be the back sprocket set engaging with the inner mechanism. I think I'm going to have to get a new wheel as it is driving me insane. My friends bikes have it around 5 degrees which is likely a normal amount.

tlockett 08-07-22 04:33 PM

Hello, I have the same issue with a brand new bike. When I start to pedal after coasting the pedals turn at least an 1/8 of a rotation before engaging the chain. This is extremely annoying. Clunk after clunk after clunk when restarting to pedal. I can't imagine this is an intentional design. When I start pedaling the pedals should engage immediately, yes? Hoping to find a solution here if it's just a matter of adjustment. At the very least, I'd like to find a term that describes this condition so that I can directly refer to it to an expert, if there is such a term. Thanks all!


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