Bike Forums - Dura Ace worth it?

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Quote:

Originally Posted by miamijim (Post 10709041)

Where do they say that 77XX shifters will work with a 74XX derailleur? If I'm reading the charts right they say the 9-speed levers are NOT compatible with pre '97 Dura-Ace (7400).

From SB: And I think there's someting worng with the CTC table. How can a Shimano 8-speed lever not be compatible with and old Dura Ace derailleur but a 9 speed lever is? There's something wrong with the chart. I think its that all the Shimano levers listed are non-DA levers.

Its easy.

Pre '97: Everything interchanges with everything except Dura Ace. Dura Ace must be paired with Dura Ace.

Not quite right, even according to Shimano. The ctc chart explains it all, but it can be a little mystifying to read. Here's how to do it.

Lets look at the Shimano mechanism table.
Non-74xxDA Shimano RD have a 1.7 actuation ratio. The 74xx have 1.9 actuation ratio.
Next: look at the cable pull/shift column. Shimano 8 (ex-DA) pulls 2.8mm/shift, Shimano 9 (all) pull 2.5mm/shift.
If you take a Shimano 8s (ex-DA) shifter and a non-DA RD, you get 2.8x 1.7 = 4.76mm c-c cog spacing (it's actually 4.8 so the cable pull/shift stated is rounded off slightly from the 2.8 shown)
If you mix a 9s STI and a 74xx RD, you get 2.5x 1.9= 4.75mm (also 4.8), which is Shimano 8s spacing

And the same formula means that a 10s STI will shift a 74xx RD in 9s mode (4.35mm cog spacing) [1.9x2.3=4.37]

So it's not luck, nor is it voodoo, it's just math.

I used all dura ace parts (minus saddle/straps and bars=still looking for AX drops! ;))
I only use all dura ace because I have an ocd thing with having all one company. That being said i haven't broken anything and all the parts seem to be of high quality. Worth it? I probly could get away with riding a cheap group on a crappy frame but I don;t think I would enjoy the ride as much. N+1?

Edit: I'll add I don't ride a road bike so I can't comment on on their gearing systems.

Its still fake math and its where the problems arise. Someone takes a 77XX lever and wants to 9s index it with a 74XX RD. Its not going to work.

If you want you bits to work, match numbers, if you want aggravation DO NOT match numbers.

Quote:

Originally Posted by miamijim (Post 10711701)

That's because 77xx won't index 74xx as a 9 speed, it will index as an 8 speed, with an extra useless click.

If you want a 74xx RD to index as 9 speed, you use a 10s STI w/one useless click.

Want 10s 74xx? I guess we wait for Shimano 11 :)

Quote:

Originally Posted by noglider (Post 10710539)

It's funny that we're having this discussion. When dinosaurs roamed the earth and I was in the bike business, Campagnolo was the highest regarded stuff, and rightly so in nearly every case. Even our boss trained us with a response, in case anyone asked us if something, e.g. DuraAce was as good as Campy. He said we should ask them if they're out of their farking mind.

But old man Campagnolo died, and the son knew he had to get with the times, so he diversified the line, and it wasn't made in the old handmade tradition, and it wasn't backward compatible, and so on.

I cant imagine using anything but Campy NR. My gear of choice for the last 40 years.

I thought I had stumbled onto the road forum.