Author Topic: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.  (Read 670 times)

Porkins

  • Formerly Nick H. And a long time ago etc, Eurostar
My bike (v. relaxed Dave Yates 853 randonneurish) has 8 speed 7400 rear mech and 7400 brakes, hubs and down tube levers. And a triple Rotor MTB chainset. I've bought some used wheels with an 11 speed Shimano-style DT-Swiss freehub. Which bits do I have to upgrade and what are my choices? As a minimum I suppose I'll need 11 speed cassette, rear mech and right hand lever? I would prefer the lever to be a brifter. Would an 11 speed Shimano brifter work with my 7400 front brake? How about a SRAM brifter and mech instead?

I suppose I could keep my 7400 left hand down tube gear lever and brake lever and rear brake and triple Rotor chainset?

Have I forgotten anything? 

Eta: I'm not interested in electronic shifting.
Another eta: max tyre size is 28.
Yet another eta: maybe the sensible thing is to buy a 9100 groupset for £999, see what works and sell the bits I don't need?

Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #1 on: May 01, 2020, 10:35:36 pm »
I assume the brake is a normal dual pivot? If so, then any modern brifter will work with it (excluding the hydro disk ones).
Triples seem scarce with modern groupsets, but maybe some of them are compatible - I'm afraid I don't know enough about them to help with that...

Porkins

  • Formerly Nick H. And a long time ago etc, Eurostar
Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #2 on: May 01, 2020, 10:50:15 pm »
Thanks.

I'm hoping that the triple chainset is pretty much irrelevant, so long as I'm within the capacity of my new rear mech. My current 7400 mech has a pretty short cage, and it works fine with my chainset, so....

Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #3 on: May 01, 2020, 10:54:17 pm »
If you want matching (ish) brifters for the 3x11 the nearest you can get is a Tiara 4703 left and a 5800 or 6800 right. They’ll be the same shape but slightly different cosmetically.

Though a friction shifter with such a setup is a better bet as - from experience - you’ll have a very hard time making the FD both shift reliably and not rub.

Porkins

  • Formerly Nick H. And a long time ago etc, Eurostar
Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #4 on: May 01, 2020, 10:59:14 pm »
Maybe I could take a leaf out of Lance Armstrong's book by keeping the FD lever on the down tube? I'm not sure I care about matching brifters.

Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #5 on: May 01, 2020, 11:46:57 pm »
Do you need to keep the triple when going to 11 speed? A complete Ultegra R8000 groupset seems to be about £550, less than £400 for 105.

Porkins

  • Formerly Nick H. And a long time ago etc, Eurostar
Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #6 on: May 02, 2020, 02:03:47 am »
Might as well. I like to be able to do the very worst climbs when the bike is very heavily loaded without killing myself. And I can't see how the chainset makes any difference to my other component choices. Am I missing something?  What would I gain by having a double chainset?

eta: I could buy the Ultegra or 105 groupset and sell some of it on..

Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #7 on: May 02, 2020, 03:52:44 am »
What would I gain by having a double chainset?

IMHO, nothing but you probably will lose? All depends on your current ratios on the triple and cassette. When I was putting my "Audax" bike together ( to replace the tourer I had used) many wise heads said "modern doubles can cover the full range of a triple" ! in my view wrong. I in fact went for ultra compact 46x30 double cranks and 11-36 cassette (10sp) but still lost a gear or two at both the high and low end but worse I found the most useful gears were always split across the two rings. After a year I replaced the double with a triple the same as the tourer (9sp, 48-36-24 rings, 12-36 cassette), the most used gears were on the middle ring which I could stay on most of a normal ride and I had extra high and low gears by using the big or small rings, much happier. 9 speed is much more forgiving re component mixing and the chains/cassettes etc are about one third the price of 11 speed

Porkins

  • Formerly Nick H. And a long time ago etc, Eurostar
Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #8 on: May 02, 2020, 04:05:42 am »
I shall have to play with the gear table. Haven't done it for years. It's going to be fun. And I may as well throw the Ultegra 8000 medium cage mech into the mix. I shall end up with an embarrassment of riches.

Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #9 on: May 02, 2020, 09:48:06 am »
DA 7400 started with 6s, with SP brakes, went to 7s with SP brakes, then 8s with SP brakes, and finally 8s with DP brakes (BR-7403) and STIs.

There are many problems with what you propose.

1) SP brakes won't work well with 11s STIs; the brake pull is different.
2) DP (BR-7403) brakes also won't work well with 11s STIs.  It won't be as bad as with the SP brakes but it will be a bit crap.
3) No 7400 series RDs have a very large total capacity; nor will they handle sprockets larger than ~27T. Either or both will stop you from running a triple setup.
4) the shift ratio of the 7400 RD is different from all other shimano RDs. In a nutshell, the cable pull for DA 8s is about the same as other shimano 9s. It won't do anything very useful if you connect it to an 11s STI.

My advice is to use the 7400 kit as it is and appreciate it for what it is, rather than bodge about with it and end up with something hopeless.

If you do make changes, they need to be very carefully thought through.

cheers

Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #10 on: May 02, 2020, 01:31:42 pm »
2) DP (BR-7403) brakes also won't work well with 11s STIs.  It won't be as bad as with the SP brakes but it will be a bit crap.

Would they be likely to be any worse than the subsequent Dura-Ace iteration BR-7700 with 11sp Ultegra ST-6800 STI levers?  I'm using this combination on one bike, and the braking function is excellent - much better than I was expecting given the SSLR/NSSLR mismatch.  I actually have a set of BR-7403 calipers, but never tried them with NSSLR levers.

The 7700/6800 setup is only marginally less good than the superb all-NSSLR combination of Ultegra BR-6800 dual pivots with the same levers, and noticeably better than those levers with long-drop BR-650 calipers, which is still fairly decent (and better than the Campagnolo Super Record or Modolo Master Pro or Modolo Supertitanium SLK90 I used in the late 80s - although that might be partly due to the much lower friction cables and improved brake-block compounds available these days).

Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #11 on: May 02, 2020, 02:56:49 pm »
AFAIK BR-7700 ought to have a similar caliper MA to BR-7403.  If that caliper  works for you with NSSLR levers, great, but it isn't quite as good as it could be.  In any brake setup the actual reach of the brake can vary the caliper MA by about 25%; i.e. if the actual reach is short, this can 'save' a setup which has a slight mismatch. Cables and brake blocks make a big difference too of course.

cheers

Porkins

  • Formerly Nick H. And a long time ago etc, Eurostar
Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #12 on: May 02, 2020, 05:38:58 pm »
Thanks chaps.

I already have a triple with the 8 speed 7400 rear mech. I built it 10 years ago and it all works fine, even under the heaviest load. It exceeds Shimano's published limit for the mech capacity, but I think the capacity varies according to the diameter of the rings. Shimano publishes just one number, which has to apply to people with a 52 big ring. But my MTB chainset has a big ring of only 44.  I have 24/34/44 at the front and 12 to 26 at the back, and it's all very slick. As the 7400 mech works with my triple, I'm hoping the short cage Ultegra 8000 would also work...it looks the same length. I'd pair it with the 12-25 cassette. So my total capacity would be one tooth less than it is now. Does that sound doable? 

I never suggested pairing the RD-7400 with an STI 11 speed lever, that would be daft. Got to have the 11 speed cassette, mech and lever. 

As for the front brake, I suppose I could try the 7400 brake with the 8000 brifter, and if it's not nice I'll buy the 8000 front brake. The left brake lever, the rear brake, the front mech lever and the front mech can stay as they are. I'm quite attached to my 7400 brakes, which I've had from new since the early '80s.

eta: Here's my forbidden ratio, 44 x 26. I would never use it, but it does work.


Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #13 on: May 02, 2020, 07:42:36 pm »
Your  extant triple setup must exceed the stated capacity of a 7400 series RD by a small amount; is  the chain tensioned properly in both small-small and big-big? I've run similar setups using shimano short arm mechs of the period (on my MTB, BITD) and I couldn't use the small-small combinations safely because of slack running. However this was a reasonable trade for me because the chain was better tensioned the rest of the time; important on a MTB with no suspension.

To a first approximation the size of the chainrings doesn't matter; it is the interval between them that is important because this determines how much extra chain slack is generated/used.  A secondary effect is that the chain wraps a slightly larger arc round a bigger ring than a smaller one so there is a small difference, but it is no more than ~1T or so, whether it is  52T-20T or 44T-20T.  What you do 'gain' when you use smaller chainrings is more bang for your buck in terms of %age gear range per T of chainring difference.

I think RD-R8000 has a slightly larger capacity within which it shifts well; the pulleys are larger diameter and they are set further apart. However it is a single pivot RD so it also loses some total capacity because the whole mech can't swing backwards and still keep the chain tight, not like a mech with twin sprung pivots can.  With a following wind you can usually squeeze about 2T extra over what shimano say, but be guided by that; they say 35T for the SS model and 39T for the GS model.

 I think that even the RD-R8000-SS model is an ugly great thing by comparison with RD-7400 or RD-7402; same goes for the RH 11s STI too. I'd be very put off by the size difference between an 11s STI on the right and a standard DA LH brake lever on the left; your hands would sit in different places on the hoods too.

FWIW it may be possible to do something clever with a shiftmate and use the 7400 series RD that way.

NB an 11s 'road' cassette won't fit on a 8/9/10s freehub body unless you machine the back of the first carrier; normal 11s 'road' cassettes and freehub bodies are longer.  There is an exception though;  stock 'road' 11s cassettes that fit the 8/9/10s freehub bodies are CS-HG700-11 and CS-HG800-11; however both these are only available in 11-34T.  I have not tried with an 11-25 11s cassette but if machined as required the 25T sprocket will end up very close to the spokes; having aero spokes on the drive side might make a worthwhile difference here.

Also you don't say what chainrings you are running but 11s chain is 11/128" vs 8s chain which is 3/32". Not every set of 8s chainrings accept 11s chain at all, and those that do don't all shift well on a triple; specifically the chain can be reluctant to unship off the middle ring and in addition the lateral spacing of the chainrings may not suit the (externally) narrower chain; if this happens the chain 'rides on top' of the middle ring or the small ring following a downshift. All suck it and see stuff.

Your gain would be..... three extra sprockets. And a Frankenbike.  'Not worth it' would be my vote.     I've not done it myself but others tell me that you can adapt the shift ratio of a 7400 series RD and make it work with 9s; this would give you one extra sprocket in return for much less risk and much less messing about. By the same token 10s ought to be possible too, and if DT levers won't do any more, a 10s STI isn't quite so absurdly large as an 11s one either, so that might again be an easier route.

cheers

Porkins

  • Formerly Nick H. And a long time ago etc, Eurostar
Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #14 on: May 02, 2020, 08:04:39 pm »
This all started because I bought wheels with an 11 speed Shimano-compatible DT-Swiss freehub. I'm committed to these wheels. Is there a way to swap the 11 speed HG freehub for an 8 speed UG one? I had assumed it was impossible, so I didn't even consider it.

zigzag

  • unfuckwithable
Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #15 on: May 02, 2020, 08:46:25 pm »
just put a spacer and an 8-sp hg cassette on your new wheels.

Porkins

  • Formerly Nick H. And a long time ago etc, Eurostar
Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #16 on: May 02, 2020, 08:52:42 pm »
That would be simple, wouldn't it!

Edit: a solution for £17. That would seem to be the most I can spend.  ;D

Porkins

  • Formerly Nick H. And a long time ago etc, Eurostar
Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #17 on: May 11, 2020, 06:20:22 pm »
OK, got the 8 speed HG cassette, lovely.

Now I need the spacer. I'm trying to learn about the history of HG 9, 10 and 11 speed cassettes and it's making my head hurt. This article is helping me: https://www.slowtwitch.com/Tech/Cassette_How-To_-_Part_2_3257.html   

I think the procedure for an eight speed cassette is the same as it would be for a nine speed.   And I think the spacer I need is a 1.85mm 11 speed splined one   https://www.bike24.com/p259996.html. Is that right?

Just to reiterate, I'm fitting an 8 speed HG cassette to an 11 speed Shimano freehub.

Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #18 on: May 11, 2020, 06:24:23 pm »
That plastic ring that came with the wheels that you didn't know what it was so you stuffed it in a drawer? That's the thing you need.

(Actually I don't know if DT Swiss bundle them, but other manufacturers do, or used to. That thing you linked to looks right)

Porkins

  • Formerly Nick H. And a long time ago etc, Eurostar
Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #19 on: May 11, 2020, 06:30:22 pm »
It's a second hand wheel, and if it was bundled with a spacer when new, I didn't get it. But I suppose it has to be the 1.85mm splined thingy doesn't it? The other kind is 1mm non-splined, and it can't be that, so....

Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #20 on: May 11, 2020, 06:49:21 pm »
If you have a shimano 'road' 11s freehub body, yes you need a 1.85mm spacer. It definitely needs to be metal and it also needs to have cutouts in it too if the 8s cassette had rivet heads that protrude out the back (some do)

cheers

Porkins

  • Formerly Nick H. And a long time ago etc, Eurostar
Re: Dura Ace 7400 brakes with 11 speed brifter? And other Qs.
« Reply #21 on: May 11, 2020, 07:02:33 pm »
Ah yes, mine does have the rivet heads. Now I know what those cutouts are for, thank you Brucey.,