Cycling UK Forum

My experience and comments on the 3 systems:

STi / Ergo / Tap needs different cable outers so the pull does not change when the handlebars are turned, if using brake cable outers there is a small change in length which leads to the mech moving slightly. This probably didn't matter with 5 speeds, but with more speeds (9/10/11) may mean a noisy drive chain or inadvertent gear change. Multi cog changes can be a pain as multiple pushes are needed to go across the cassette - I often need this due to wide spacing between the 2 front chainrings, to maintain cadence a double and multi shift is required.

Bar end changers have some advantages / disadvantages (at least for me): In friction mode you can use whatever number of sprockets you like at the back, this is quite useful if your bike is multipurpose, e.g commuting / fast day ride / touring in flat, hilly and mountain areas. Banging your knees on them is an additional hazard as you start / stop. A double shift can be more tricky than the other systems as two hands are definitely required at the same time. Braking and shifting is not so easy. Shifting across as many cogs as you like is easy and just one move, rather than many taps or pushes.

Down tube shifters are lighter, easier to maintain, cheaper and allow any combination of gear shifts simultaneously with one hand - I regularly shift both front and rear mechs with my right hand with the rear shifter in the crook of the first finger and thumb and the front changer operated at the same time with either of the said digits - this does not take long to master.

As for pros the current STi / Ergo / Tap systems are a must for speed as others have said.

Well I've just measured everything up with a digital vernier:

The "27.2mm" seat post is a very consistent 27.15mm wherever I measure along its length - so there or there abouts on specification.

The "27.2mm" seat tube internal diameter is actually 27.45mm all around - at least for the top 5mm which is as far as I can get the fangs of the vernier into. The above 27.2mm seat post seems to rattle equally as it is inserted down the seat tube so I'm guessing the internal diameter of the tube does not change by much as you go down.

I'm going to get a "27.4mm" seat post and see how I go. I've found a silver one in price range - anyone know if a black version (at a similar price) in this rarer diameter is available?

https://thecycleclinic.co.uk/products/k ... increments

(edited for minor typo)

drossall wrote:Yes, they should be a snug fit. I'm a bit confused by your proposal to get a smaller-diameter post though, because you appear to need a larger one?

You're correct that the Radial site says that you need a 27.2mm post. That's odd, because that's the standard size for 531DB steel tubing. I'd have thought that alloy tubes would take larger posts. And indeed, the review on Cyclist UK says 30.8. Might be best to take the frame along to a shop where you can try some, and buy what fits.

Slightly odd too if, as the Radial site says, the tube has a 27.2 internal diameter, and takes a 31.8 clamp. That's a heck of a thick tube wall, isn't it? Or am I missing something? I've not had many alloy bikes.

Idea behind getting a slightly smaller diameter post is so a shim can be fitted all the way round it to even out the pressure, the current 'correct' seat post is such a near (but seemingly incorrect) fit the shim may have to be either wafer thin or only go part way round.

The seat post size in the review you linked is for a different (carbon) frame. 27.2mm is a very common seat post size with alloy frames e.g:

http://www.wiggle.co.uk/felt-fr40-road- ... agra-2017/
http://www.wiggle.co.uk/verenti-techniq ... oad-bike-1
https://www.evanscycles.com/focus-cayo- ... e-EV308649

Home made shim or LBS suggestion is the way I may need to go.

I bought a new aluminium frame:

https://www.radialcycles.co.uk/bikes/fr ... frame.html

This states "Seat post size 27.2", however when I insert the correct sized post:

https://www.ribblecycles.co.uk/system-e ... #pid=22919

It is a very loose fit. After inserting 100mm or so of the post it still 'rattles' in the seat tube with a couple of mm sideways play at the very top of the seat post (which is 300mm or so from where the seat post enters the seat tube).

I'm not sure if clamping this seat post into the frame will leave it held only by about 10mm of (now distorted) seat tube which over time may lead to the post creaking and not being safe if it fails at the clamping point. If the seat tube distorts (by bending in at the top) it may then dig into the post. I could try a cola can shim but not sure if the existing gap is big enough using the above post.

On all the other bikes I have ever had the seat post was a snug or tight fit in the seat post, they have never rattled. I've not fitted a post to a brand new frame before so perhaps this is common - with the play going away once the clamp is done up and any slack is taken up?

Options seem to be:
Fit it and see how I get on (may be ok??? but unsure if this will fail or damage either part)
Get a smaller diameter post and shim it (bit hit and miss with ordering seat posts and making home made shims).
Get a 27.4mm post and seeing if that is better, this may not fit at all and seem more difficult to find in my preferred price range (up to £20 or so):

New but a bit pricey http://www.chainreactioncycles.com/thom ... p-prod6066
New, but unavailable https://www.amazon.co.uk/Thomson-Elite- ... B00NINMHCA)
Second hand for 753? http://hilarystone.com/seatposts272.html

I had something vaguely similar once, are you 100% sure you have threaded the chain through the cage correctly? - I missed this once, fortunately I spotted it before I took the bike out.

I saw that too and was wondering what is meant by that. My only (big) guess is that having a prime number in the mix would mean that the chain would not keep lining up with the same links on the same teeth. However I think this is only true if the number of links in the chain is a prime number as then, whatever the number of teeth on the sprocket, it will reduce the times the same tooth goes into the same link. However I may have got completely the wrong end of the stick!

PS The number of links will be an even number, which is not prime. But it may be that the number of links is better if it is not a exact multiple of the sprocket or chain ring as this will lead to the same link being on the same tooth every time the chain goes round. E.g. 13t x 39 with a 104 link chain. More important on single spocket systems like hub geared or fixies where the chain could stay permanently in sync.

Lithium Ion batteries are not easy to charge safely so I would ditch the Lithium Ion battery and use a PP3 rechargeable (about 8.4V from memory) and charge this from the dynohub via a diode and suitable resistor. The 7V or so can be created from the PP3 using an LM317 regulator to power the Di system. You can then simultaneously charge and draw current from the battery. Hope that makes sense to someone who can solder and tinker with electronics.
Please only try the above if you know what you are doing!

fredN4 wrote:22/34! quicker to get off and push it?

Perhaps, but nowhere near as easy to push a bike uphill than ride it.

There are reports of some LED headlights messing up wireless bike computers. I think the low power mode switches on and off the LED at high frequency to make it appear dimmer, without wasting energy in a dropper resistor. This high frequency switching may interfere with the wireless communication. I'm not sure if the latest kit is better in this respect.

I can trim the FD in the middle ring with the STI

Can this be done whilst on the move from the lever or by tensioning the cable whilst at the side of the road / workshop? If it can be done on the move from the lever I might reconsider STI for my set-up!

I have a Tiagra 10 speed triple front changer (fd4603?) on a 9 speed 48, 38, 28 setup.

The things I found were that the curve of the cage is optimised for 50, 39, 30 teeth chainrings and the further away from these you may find the performance is compromised as you try to set how high up the seat tube the cage is - I think optimal height is so the middle chainring is in line with the slight recess in the back of the cage rather than the outer plate being 3mm above the large ring. This is a bit tricky to set.

Also the cage is probably designed for the width of a 10 speed chain. I'm running a wider 9 speed chain so may be having to trim the position (via a friction dura ace bar end lever) more often? I can't comment of suitability of Sora shifters, if the chainring spacing is the same that is a good start. With Sora shifters it may be better to get a Sora front changer as you can't trim the position of the changer with STI.

Over all my set up is not a problem for me but YMMV! I will probably try a 24 inner at some point, I hope this won't be a problem as I understand the middle and outer ring changes are more sensitive to size on a triple.

Thank you cycleruk but my bad. I meant to put A530 as the ones I have, that I find are slippery and have poor bearings. Have changed original post but thank you again for your post.

I'm looking to get some double sided pedals (MTB SPD + flat) for commuting, short trips and to use when I need to wear normal shoes at the destination. I've tried 2 of the shimano offerings (M324 and A530) but both have their problems (M324 heavy, A530 slippery). Anyone have alternatives that are not too expensive? I've found these (http://www.bicimarket.com/Componentes-P ... 12914.html) but I'm not sure how durable they are or if available to the UK?

I'm not interested in the ones with pins as these can cause serious damage to shins if you are not wearing shin guards - a work colleague had cuts to the bone and scars after a tumble.

I have both the M324 and A530 Shimano pedals. The M324 have been good if a little heavy, the rubber seal ring on the inside perishes and falls off after a few years - I replaced it with a cut down small tie-wrap to keep the dirt out. I found the A530 to be pretty bad and I wish I had not got them as the non SPD side is slippery and the left pedal developed an annoying click after a few hundred miles. YMMV! As they are virtually un-serviceable they will probably end up in the bin.

A 'quick fix' for a standard compact chainset is to fit a 46t outer chainring. These should be available as original equipment part as most cyclocross chainsets in a groupset have a 46t outer. However when I looked a year ago I could not find OE stock for an individual 46t chainring so got a non OE from SPA.

With a 46t outer rather than 50t with an 11t top sprocket will give a top gear of 112" rather than 122".
With a 46t outer rather than 50t with a 12t top sprocket will give a top gear of 103" rather than 112".

I find having top gear of 103" is plenty high enough for me, I never used the 50x11 combo so was just carrying around an 11t sprocket for nothing. I swapped for a 46t front with a 12-27 at the back.

A 46t outer chainring will reduce the amount of cross chaining and reduce the number of gears you need to change at the back to maintain cadence when switching between chainrings.