Search found 727 matches

by NetworkMan
10 Oct 2019, 3:24pm
Forum: Bikes & Bits – Technical section
Topic: Single source for rim ERDs?
Replies: 14
Views: 595

Re: Single source for rim ERDs?

Wish I did. I searched for one myself recently but the best I could find was last updated in 2004. Although it listed my Alesa Endeavour (as Rigida) the list is incomplete wiithout ERD. I think a re-rim might be a good first wheelbuilding project for me.

http://www.fa-technik.adfc.de/Komponent ... ge622.html

BTW does anyone know the ERD for the heavy old Alesa Endeavour in 622 36 hole?
by NetworkMan
9 Oct 2019, 8:10pm
Forum: Bikes & Bits – Technical section
Topic: Gear changing strategy; how do you use a triple?
Replies: 61
Views: 2660

Re: Gear changing strategy; how do you use a triple?

531colin wrote:
LittleGreyCat wrote:
531colin wrote:Most of my bikes have 46/34/24 triple, I think there's one with 44/32/22, with 12 or 13 to 34 on the back.
<snip>
However, to-day I was out on a Spa prototype which was geared for a younger man, 48, 38, 28 and 11 to 32 on the back.....and I hardly got onto the big ring at all.<snip> but I want a chainset where I can fit a middle ring smaller than 34T.


Noting that my Spa Wayfarer is geared the same as the prototype apart from the 32 being replaced by a 34, nobody told me that it was "a younger man's bike" which may explain a lot! Back to that in a bit...……………

I had planned to ask, sometime in the future, about lowering the bottom gearing without taking much off the top end.
46/34/24 looks interesting. 12 tooth gap then 10.
Would 48/36/24 be possible? 12 teeth gap between each?
This would give me the top gearing but bring the bottom gearing down.
I'm in
Edit: I wouldn't mind a 36 instead of the 34 on the back, as there doesn't seem to be a big change between granny-1 and granny. Just been out to look and the jump from granny-1 to granny on my MTB is much larger. I have the tooth counts written down and stored somewhere safe.....


I'm 72; the guys in the workshop aren't, so they build the prototypes/test bikes with a sort of "standard" gearing; they will build customers' bikes with any (workable) gearing you want, but you have to tell them what you want!
20 years ago I would have laughed out loud if you had told me I would ever want gearing lower than one to one!

24T chainring instead of 28T is a difference you will notice, its about 14%
I would guess that your front mech. is designed for a 10T difference between big and middle rings, so you need to maintain that. (mine are "MTB" front mechs. designed for 12T big/middle difference)
I think its worth trying just swapping your existing 28T small ring for a 24T one, and see how you get on.....its the cheapest option and it could well suit.
A lot of the other stuff is on the lines of 2 teeth here or there, and the difference is such a small percentage that you may not even notice.

++1
LittleGreyCat
I'm 71 but I realise that it was about 20 years ago that I first converted my Dawes Horizon from 48/38/28 to 48/38/24 after moving from flat Herts to hilly Devon. I have a Spa tourer with same arrangement and I'm about to do the same with my third bike. Just make sure.you have 8mm between chain and front derallieur cage bottom when running with the 28T ring and the rear on your chosen smallest sprocket. That may well be about third from top. You may in any event find the chain goes slack if you try to use small to small with the 24T front but you shouldn't anyway.
by NetworkMan
9 Oct 2019, 3:58pm
Forum: Bikes & Bits – Technical section
Topic: set back seat post ?
Replies: 37
Views: 1711

Re: set back seat post ?

WoodBurner81 wrote:
amediasatex wrote:I am also short of leg and long of torso and run a lot of setback, to counterbalance the cantilever of my upper body. Also tend to run longer stems or long reach bars as my short legs require 52-54cm frames but I prefer a 54-56cm top tube.


sounds familiar

already have a fairly long stem and flat bar setup - mainly for ride position but also wasn’t overly confident using drops when clipping 20kg of 4yr old on rear for school run !


I'm a trendy consumer. Just look at my stupid phone.

Not wanting to add even more confusion here but did you switch from drops to flats on this bike? I only ask because drops provide extra reach in themselves so that switching to flats would decrease the reach unless you changed the stem for a longer one. Did you use the same stem? Did you notice the reduced reach? If so, did that feel better or worse or the same?
.... Or have I misunderstood completely! :?
by NetworkMan
9 Oct 2019, 11:44am
Forum: Bikes & Bits – Technical section
Topic: Which 9 speed triple for light tourer
Replies: 8
Views: 722

Re: Which 9 speed triple for light tourer

Another one for Brucey.
Do you recall a discussion about relative durability of 24T-28T chainrings in steel vs. alloy? I thought that steel might be more durable but IIRC you said not necessarily. Spa have these rings in Spa Zicral at £11.50, Stronglight steel at £7.50, Stronglight Dural at £11.00 and Stronglight Zicral at £17.00. (Although I have a TA 24T 7075 alloy already, the prices are now a little OTT so no thanks). What do you think? 60 kg. rider, probably only about 150 watts, not a masher.
by NetworkMan
9 Oct 2019, 11:25am
Forum: Bikes & Bits – Technical section
Topic: Gear changing strategy; how do you use a triple?
Replies: 61
Views: 2660

Re: Gear changing strategy; how do you use a triple?

Another acronym, the DNS or Deliberate Non Shift.

Coming home with the shopping I'm on the middle ring and there is a short steep section just before I arrive. Although middle-to-big is inefficient and not all that low, it is low enough for this short hill and the bike arrives home on the middle ring ready for the next outing. Of course the DNS is only applicable when the terrain is familiar.
by NetworkMan
8 Oct 2019, 6:29pm
Forum: Bikes & Bits – Technical section
Topic: Cassette question
Replies: 43
Views: 2728

Re: Cassette question

8 and 9 speed chains are cheap and tedious to clean so I tend to change them at 0.5% elongation or less. Cogs and rings seem to last well. Rotating chains? Not for me - too much bother!
by NetworkMan
8 Oct 2019, 6:22pm
Forum: Bikes & Bits – Technical section
Topic: set back seat post ?
Replies: 37
Views: 1711

Re: set back seat post ?

With a long torso and short legs are you sure it's not a longer stem you need. Do you know the seat angle of your frame? That might be a clue.
by NetworkMan
8 Oct 2019, 12:15pm
Forum: Bikes & Bits – Technical section
Topic: Alivio Vs tiagra?
Replies: 13
Views: 2930

Re: Alivio Vs tiagra?

Brucey wrote:
NetworkMan wrote:IIRC it is Tiagra 4700 ten speed that is the oddball. Apart from that, 7 to 10 speed road shifters will work with 7 to 9 speed mountain bike rear derailleurs.


yes

There are some really ancient Ultegra road systems, 8 speed I think, that are different but I don't think there are any other exceptions.


Not quite. All shimano index systems 6s to 9s use the same shift ratio, apart from Dura-Ace 7400 series (6s, 7s, 8s). The shift ratio of 7400 series is such that the cable pull per click is shorter for any given number of speeds. Thus if you attach a 9s shifter to a 7400 series RD, it shifts quite well on 8s, (but with one spare click). If you want to use a 9s Dura-Ace derailleur (or any other shimano RD 6-9s) with 7400 shifters and a matched cassette then you can use a different cable attachment point in the RD so that the shift ratio is increased to be the same as a 7400 rear mech.

Ultegra/600 (in all its indexed incarnations 6-9s) has the same shift ratio as everything else does, and is not the same as Dura Ace 7400.

cheers

Yes, and my apologies. Ironically I just got back from shopping on the bike with 8 speed (old Ultegra I think) bar-end levers. There is a label stuck on the RH lever which reads, "Not compatible with Dura-Ace rear derallieur." Bought about 5 years ago and probably true for modern kit but for the wrong reason!
by NetworkMan
8 Oct 2019, 9:03am
Forum: Bikes & Bits – Technical section
Topic: Which 9 speed triple for light tourer
Replies: 8
Views: 722

Re: Which 9 speed triple for light tourer

Brucey wrote:I've not used these ambrosio cassettes myself but this one

https://www.sjscycles.co.uk/cassettes/1121-ambrosio-9-speed-cassette-shimano-compatible/

looks like a good candidate for conversion into a useful touring cassette; it can be had in

11-13-15-17-19-21-24-28-32

so ditching the 11T and adding a 36T gives you

13-15-17-19-21-24-28-32-36

with the only 'break' in the shift ramp sequence being between the 32T and the 36T sprocket.

Better yet it is not at all expensive; just £12.99

cheers

That's the same as the Shimano HG200/201 11-32 9 speed I'm using at the moment. It's not the same as other 11-32's which start 11,12. ....
by NetworkMan
7 Oct 2019, 8:30pm
Forum: Bikes & Bits – Technical section
Topic: Alivio Vs tiagra?
Replies: 13
Views: 2930

Re: Alivio Vs tiagra?

IIRC it is Tiagra 4700 ten speed that is the oddball. Apart from that, 7 to 10 speed road shifters will work with 7 to 9 speed mountain bike rear derailleurs. There are some really ancient Ultegra road systems, 8 speed I think, that are different but I don't think there are any other exceptions.
by NetworkMan
7 Oct 2019, 7:40pm
Forum: Bikes & Bits – Technical section
Topic: Which 9 speed triple for light tourer
Replies: 8
Views: 722

Re: Which 9 speed triple for light tourer

I'm not intending to change my 48 and 38 rings because it's too risky. The Sora front mech I have is intended for 50 and 39; I'm pretty close and it works fine.
by NetworkMan
7 Oct 2019, 11:36am
Forum: Bikes & Bits – Technical section
Topic: Front mech question
Replies: 6
Views: 430

Re: Front mech question

You should check and consider the chain line. It might be that the MTB chainset was fitted using a road chainline, better to suit the Tiagra shifter upfront. The fact that you couldn't shift onto the big ring is consistent with the fact that road front shifters pull less cable than MTB ones. Shimano used to make flat bar shifters to suit road FDs, but it's probably a bit late for that now!
by NetworkMan
6 Oct 2019, 9:58pm
Forum: Does anyone know … ?
Topic: changing a cassette - Shimano Sora
Replies: 23
Views: 2367

Re: changing a cassette - Shimano Sora

Just remember that 32 to 34 is only about 6% lower or about half a gear so don't expect too much.
by NetworkMan
6 Oct 2019, 12:11pm
Forum: Bikes & Bits – Technical section
Topic: Which 9 speed triple for light tourer
Replies: 8
Views: 722

Which 9 speed triple for light tourer

I can't decide which of two 9 speed triples arrangements to use on my Spa Ti Audax. Both are based on a 12-27 cassette. V1 uses the 12-27 with 24,38,48 to get a range of 23.5 to 106 inches. V2 uses a modified version of the 12-27 with 28,38,48 to get a range of 23.1 to 97.7 inches.

http://www.ritzelrechner.de/?GR=DERS&KB ... 2&UF2=2111

I've used 24,28,38 before so I can make it shift OK. The modified 12-27 removes 12T and 13T and adds 13T top and 32T bottom to get 13-32. Both V1 and V2 give a nice closely spaced range of gears except for the 27-32 jump of V2. V1 has a quite a jump from the 24T to 38T front at the top of the hill; after getting to, say, 45.4 inches on the little ring a triple shift at the back is needed to get to 52.9 on the middle ring. This is possible using one push on the STI however. Clearly V2 offers a higher top, though I doubt I'd use it much if at all. Both need 39T rear mech. capacity.

Any views greatly appreciated. I'd rather not change the 38T and 48T rings since the front shifting works so well and I'd rather not risk altering it. Costwise there's little in it; V1 needs a 24T chainring, V2 needs a 13T top sprocket since I already have a 32T sprocket.

Edit:
I forgot to mention. Arguably V1 makes the 38T a more useful general purpose ring since the three gears in the middle are 53-67 inches.
by NetworkMan
3 Oct 2019, 3:19pm
Forum: Bikes & Bits – Technical section
Topic: Spa Audax crash damage – fork?
Replies: 53
Views: 2920

Re: Spa Audax crash damage – fork?

slowster wrote:As you say, we need an insider. I suspect Reynolds deliberately do not publish details of non-standard tubing because they do not want inexperienced framebuilders using it and they (and the top framebuilders) do not want customers asking for it, since most customers would not know whether it was appropriate for them and would only be asking because it's 'special' and the 'best' (just as many want 953 because it's the 'best', even though it might not be suitable for them and their use). Publicising the existence of such tubing would also undermine the marketing cachet of a brand having tubes custom drawn for them, because it would highlight the fact that frames built with such custom drawn tubesets are unlikely to be true custom frames.


A few clues re the 853 Thorn fork in the mega brochure:-
"Reynolds made the 853c blades and lightweight 853 steerer especially for us Reynolds even made the tooling for the tight-radius bend that I’d requested."
My reading of that is that Reynolds make them a fork (remember Thorn don't weld/braze themselves anymore) using off the shelf parts and bend the blades to Thorn's profile. I just don't believe that an off the shelf steerer would not be good enough. Tony Oliver says that 753 can't be cold set and I suspect that 853 can't either. Note that it does not say that Reynolds made the tooling to cold draw (or however they make 'em) a butted fork blade to Thorn's own design.