Sprinting Question

fauxpas

Can today's rear deraillers cop a gearchange on the fly?

I took off beside some cars today with the front on the big 53 and I think I was in the middle of the rear 9. I maxed out round 40kph but didn't slap the rear up a gear for fear something might snap...

Will a 105 cop that or is it a sprinting thing to take off in the gear you want to max out at?

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alfeng

Based on my short-cage, 9-speed Shimano 105 (5500?) rear derailleur, your derailleur should be fine -- for sprinting, a short cage rear derailleur is slightly better (more efficient) than a long cage rear derailleur.

If you encounter ANY hesitation in your derailleur moving the chain to a smaller cog, then it is because of the cable balking in the housing ... lube the cable AND/OR replace the housing.

If you have any reservations, put your bike on a trainer (vs. a workstand) to verify that everything is in working order when everything is at-speed ...

fauxpas

Kewl, I'll give it a go... I have a 105 short cage with 12-24 cassette...

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fauxpas

Something else I thought of... for me to up a gear while peddling like a bitch, all I do is blip the paddle...

But is it the same on campys? How do campy brifters work?

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alfeng

BETTER -- but, only by a small amount when shifting to smaller cog ... but, Campagnolo shifters are much more efficient when shifting to a larger cog OR chainring.

alfeng

It occurs to me that you want to know the hand dynamics of using the Campagnolo shifters ...

"Intuitive" is how someone once described the shifting -- I finally appreciated that to be a valid descriptor BECAUSE the chain moves in the direction that you are pressing the shift lever OR thumb lever.

If you want to move the chain DOWN to a smaller cog, you press the thumb lever DOWN on the right (rear) lever.


If you want to move the chain OVER to a larger cog, you press the shift lever on the right shifter in THAT direction.

Want to move the chain DOWN to a smaller chainring? Press the left thumb lever DOWN.

IF you want to move the chain to a larger chainring, press the left lever in THAT direction.

How great is that?!?


A real world advantage is that you can shift multiple cogs with a single shift in-either-direction ...

Some people say they can move the chain across the entire cogset in a single shift with their Campagnolo ERGO shifters; but, I have never been able to shift more than three at a time.

djk202020

I can shift through 8 at a time with my campy's. Never thought this would be useful but after switiching from shimano I love this feature and use it all the time

fauxpas

So I understand that if I sprint and realise I took off in too low a gear and want to take my RD to a smaller sprocket, that would be easier to do with my Shimano STI, but there are lots of benefits for having campy kit...

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alfeng

Well, I guess it is SUBJECTIVE, but in addition to being able to shift more than one cog with a Campagnolo shifter, I think it is generally easier to shift a Campagnolo shifter.

ONLY a person who has arthritis in their thumb joint(s) ... or, possibly some other (?) physical handicap ... should avoid Campagnolo shifters.

In fact, if you ever have occasion to watch video of "tour" riders, when SOME riders are shifting their Shimano STI shifters, they execute the shift with what I would suggest is an exagerated hand-and-arm motion with their elbow flailing out ... THAT shows a real (but, unnecessary) lack of confidence in the Shimano shifter being capable of executing the shift to a SMALLER cog, IMO.

fauxpas

Never seen that... but I'm not really concerned about a shimano campy debate, more back to my original question about drivetrains being able to cop a gearchange on the fly...

I certainly have no shifting issues with my STI stuff...

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leestevens

When i am about to sprint i will drop down one or two cogs, if it is an uphill sprint one cog, downhill sprint then two cogs. Choose my moment and go. If i need to change more gears i tend to sit down, Take pressure of the pedals. I am still pedalling flat out mind you and change down another gear, stand up and rip into it again. Occasionally i will need to jam it down another cog whilst going flat out and my Shimano groupset handles it well.
On the Shimano Campag debate, i cannot see a reason why you would need to change down 8 cogs at a time, that is to big a jump if you want a sprint. i rode a club mates bike which had Campag group set and found it hard to get my thumbs around to the shifter especially when i was standing. yet i can change gears from any position using the Shimano levers. My two cents worth.

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leestevens@


http://www.riverlandcyclingclub.com/

Eastway82

You shouldn't have any problem shifting on the fly - you might need to fractionally ease pressure on the pedals for half a stroke just to get it started, but you can probably do that without sitting down.

carpediemracing

if you've installed and adjusted things properly, your drivetrain can take a full on shift (out of the saddle, no easing up, no thought to when to shift). it might be loud or unsettle your bike (or in the old days jerk your foot out of a triple-binda set so tight your toes turn purple) but your bike will shift. in the old day I used a single right-side bar end shifter and chopped my bar so the shifter sat right in the palm of my hand.

if shifting under full gas you may unclip (also you may skip your rear wheel, wrench your bars if not tightened, bend them if you're really strong, etc). I've had to crank my pedals down a little more than normal, to the point where I can't unclip with just my foot - I have to hit my shoe with my hand to unclip.

I use campy ergo. if you have your levers up high (like a climber) then it'll be virtually impossible to shift from the drops while at full gas. you will probably lose a lot of wattage if you try and sprint from the hoods. drop your levers down so you can shift from the drops without any contortionistic maneuvers. with shimano I'm sure you can do the same but I don't seem to get along with STI so don't have enough experience to say so.

good luck
cdr

fauxpas

Sweet... I've tried some medium strength changes are they have been fine... will start full power changes and see how she goes...


cheers,

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