Cycling UK Forum

I just meant leave that much extra slack in the chain, rather than using half-links - normally I'd make the chain at least 1" (two half-links) longer than it needs to go round big front and big rear - but if I want to use a bigger cassette later, for every two extra teeth on the bigger cassette, I want to make sure I have an extra half-link of slack before I trim the chain. The rear mech will cope with an extra inch or two of chain - in this case we're probably talking about an MTB mech, and it's not being used near its capacity. Even with a (medium cage) road mech, it's only likely to be near slack in small/small.

The other weird thing is the bottom bracket. If you get a crank with a chainring bolt hidden behind the crank, and "XD-2" cast on the back, that does want a 110mm JIS BB.

If there isn't a hidden bolt, and it doesn't say XD-2 on the back - like this product (picture is wrong): http://www.spacycles.co.uk/products.php?plid=m2b0s109p3
Then you want a 115mm+ bottom bracket. There are other threads about this. In spite of what they might say.

cavasta wrote:

fatboy wrote:The inner and outer won't be a problem. The issue is that the front mechs are really designed for bigger chainrings, road bike chainlines etc. I found the whole thing a complete faff especially as my shifters don't have a trim function (tiagra do I think!). A friend of mine gave up getting his going and went to his LBS who got it working but moaned that it had taken a lot of faffing.

I guess that's my bank holiday weekend taken care of then.

We have 4503 working fine with 46-34-24 - I think (somone please contradict me if this is rubbish) that the 4503 is designed for for Compact triples - like 50-39-30, so a 48 big ring should be fine.

I'd have gone for 48-36-26, because that makes the jumps a little more even.

willem jongman wrote:The next step depends a bit on the cassette wear. If it is worn, I would replace it with a 28t largest cog (with a new chain).
Willem

If it isn't worn (or even if it is), you can get a 13-28 (13-14-15-17-19-21-24-28) from a 13-26 and a 11-32 cassette (11-13-15-18-21-24-28-32),
by taking the rivets out of a £10 Shimano (not SRAM) 11-32 cassette, and using the cogs that you want. Drilling the heads off the small-cog end of the rivets is easiest way to remove them.
Use the 21-24-28 from the MTB cassette.

You can then also make 13-32, if you prefer that: (13-15-17-19-21-24-28-32), but you'll need to leave the chain 3 half-links longer, and need an MTB rear derailleur (Acera:£15, Alivio £20).

If you don't use the top few cogs on the 13-26 much, you might as well have more lower gears.

OK

Chomp Chomp Chomp Chomp.

Those words were quite tasty, as it happens.

http://en.wikipedia.org/wiki/Two-mass-skate_bicycle

Links at the end.

The common view is that this self-steering is caused by gyroscopic precession of the front wheel, or by the wheel contact trailing like a caster behind the steer axis.

Straw man ?

http://socrates.berkeley.edu/~fajans/Te ... BikeBW.pdf

pete75 wrote:It's either Camapagnolo or Campag never Campy

I guess you meant Campagnolo ?

But since it's pronounced something like Camp-an-Yolo, surely shortening it to "Campy" makes more sense in English ?
Walks quickly away whistling to self.

gilesjuk wrote:

deliquium wrote:

531colin wrote:http://www.spacycles.co.uk/products.php?plid=m2b0s84p1602

Thanks Colin - looks and costs fine

I've had one like that and it was rubbish, go over a bump and it would move.

I wouldn't touch that design either, for the same reason.
I don't think my experience was quite "go over a bump and it would move", but it came undone quite regularly.
If I had to fiddle with a bike with one of those, I'd bin it.

gilesjuk wrote:You want one with two bolts like this:

http://www.chainreactioncycles.com/Mode ... elID=11375

Works for us.

gilesjuk wrote:Or better still this:

http://www.chainreactioncycles.com/Mode ... delID=6257

That too, but BBB branded. I think The Tioga one works slightly better.

We have those on hybrid frames. We also have:
http://www.ribblecycles.co.uk/sp/road-t ... ASTSPIN099
On road bike.

The reason for getting these two-bolt seatposts is that it's much easier to make fine adjustments: you loosen one bolt, adjust the other one a bit, and do up the first bolt again.

But the problem is that they don't have enought setback - even with the saddle right back on the rails. If I'd had a bit of clue about bike setup, I'd have got somrthing else.
Ideally, something with 25-40mm setback, but still with the two bolt adjustment. Does anyone know of a seatpost like that ?

PeterBL wrote:If it works with a MTB front mech

Well, that is specifically a Modified FD-M510. I don't think I could mod a newer FD-M590 the same way.

We also got one of these working with Sora brifters - that needed more metal grinding off the pulley, to reduce the effective radius more.

Then, other folks have claimed success with Alivio front mechs.

After a few months, I think I can post a Shimergo success report.

Veloce 2011 powershift
8-speed shimano rear (Deore LX). Normal cable clamping.
Modified Deore FD-M510 front, with 44-32-22 M442 chainset on 107mm BB.

Rear is fine. When new, I seemed to get some under-shift, but that seems to have sorted itself out. I wonder if this is to do with being over-zealous about grinding the ends of the gear cables flat, and cooking the plastic inners at the ends of outer cables.

At the front, there are five positions, four clicks. The paddle moves 1 or 2 clicks, and the button releases two clicks. The M510 allows the pulley to be easily removed, and ground down to a smaller radius, to suit the Campy shifters. Also ground down the spring stop on the pulley, to reduce cable tension. I don't use single clicks - I use it like a 3-position MTB shifter.

[Edited: "six positions, five clicks" -> "five positions, four clicks" (I can't count) ; non-standard BB size]

SCR
You know you want to. You're already playing.

nez dans le guidon wrote:The hidden advantage of traditional toe straps is that you've always got two toe straps with you to tie things with. I keep two in my saddle bag, even though I use clipless pedals. Yeah, all right, I have cable ties in the bars too, but they're not as secure as a toe strap.

Yes. I was given a load of nylon toestraps when a local bike shop closed. They're rubbish as toe-straps - they only seem to last about 120 miles. But they're great for tying things up!

JEJV wrote:

hubgearfreak wrote:

JEJV wrote:What exactly are the functional, quantified, benefits of clipless pedals

what do you mean by quantified?

Something like average power measured over 15minutes, ideally on power cranks, to show where in the cycle work is being done (or undone).

Here's something vaguely in the right area:
google:Sanderson Hennig Black in-shoe pressure distriobution

The subjects are using toe clips & straps. Ah. It's not clear to me whether the subjects have cleats as well as straps.

Look at figures 1 & 2. In figure 2, the vertical scales differ by 10x between positive and negative impulses.

It's a pity the authors didn't split figure 1 into "recreational" & "competive" groups, because figure 2 implies that there would be a significant difference in the torque vs. angle curves in figure 1 between the two groups.

There doesn't seem to be any training for the "recreational" group. Looking at figure 2, I suspect that the recreational group isn't used to foot retention devices at all -= the "competetive" group are acheiving the same power with smaller positive impulses.

I wonder if the authors had given the "recreational" group toeclips & straps for a few months before the testing, the gaps in figure 2 would have reduced a lot.

531colin wrote:I pull back at the bottom with clipless. (You know...like walking!)

But even with flat pedals, we do that to some extent.
The graphs in figure 1 suggest that the work done near the bottom of the stroke is ismall compared to the work done near 90 degrees after top-dead-centre, so either:
- This is a marginal effect, but perhaps important to elite cyclists.
- Special (tiring) effort is required to do significant work at this point in the cycle
- There's a psychological advantage in being able to pull back harder.
Or some combination of these.

ANTONISH wrote:Pedals with toe clips enable the foot to be closer to the pedal axle which means that the ankle has a greater range of movement than is the case with SPDs, other clipless systems are ( Time, Speedplay) are better in this respect.

Maybe the next thing is to eliminate the through-spindle, and have an offset pedal that puts the foot even closer to the axis. The bearings are going to have a hard time though...

So with Speedplay, it looks like we'd be ~1.3cm lower than with SPD-SL's. Which is particularly good if you're tall.

aprildavy wrote:The greatest advantage is that when I am tired my legs are in right place. I am more confident on putting in sharp bursts of speed over very busy roundabouts etc, where the ability to pull up on the upgoing leg can deliver more power than pulling up on the underneath of the toe clip.

- I read that as "my feet are in the right place"
Right - with clipless, you can finely adjust the location of the cleats, which would be hard with toestraps. I guess that really would be a benefit if you have a highly tuned setup - I don't think I understand what's going onwell enough to really make use of that.

531colin wrote:

JEJV wrote:But my (anecdotal) understanding is that clipless pedals can (and frequently do) cause injuries that would not happen with less rigid toe-straps, and that knee injuries for cyclists were rare or non-existant before "clipless" pedals.

This is completely wrong. My knees are better with clipless, there is free float in clipless, with anything else you are fighting against resistance for a bit of float.

Is sideways float necessary, and if so, is it necessary for everyone ?
Shimano & Look sell zero float cleats.
One of the folks I've met on club runs seems to do 50+ miles most days (and has done for years), with Speedplay pedals set at zero float.
So is float necessary (for at least some people), or a way of putting some tolerance into the setup ?

531colin probably has a lot of clue about setting a bike up.

Float in the plane of the pedal can't compensate for a saddle that's too high, or too far forward, but toe-straps have a bit of give.

I perceive regular threads here & on Bikeradar on the lines of "My knee hurts".

Are these people with the saddle in the wrong place ?

Were these people getting knee, hamstring injuries when everyone had toestraps ?

531colin wrote:Off road clipless is brilliant.....instant engagemant,.complete security of foot on pedal, no toestraps caught in the heather....clipless winter boots are great, but I cant do boots and toeclips

hubgearfreak wrote:

JEJV wrote:What exactly are the functional, quantified, benefits of clipless pedals

what do you mean by quantified?

Something like average power measured over 15minutes, ideally on power cranks, to show where in the cycle work is being done (or undone).

Has anyone done this kind of thing ?