Cycling UK Forum

Stradageek wrote: ↑13 Jan 2025, 8:09am On a more cycling note, Shimano sealed unit BB extractor. Difficult to keep in place and prone to slip out at just the wrong moment.

Solved by using a crank bolt and large washer to hold it in place - note to self, 'removed said bolt and washer once the cup is cracked loose otherwise you can't unscrew the cup'

I did the same recently, I got a full turn on the cup before I realised why it was actually getting more difficult to turn. Fortunately the cup was plastic so no damage done (the cup cracked but that was replaced). In future I will loosed the crank bolt one turn for every turn of the cup.

I rotate my feet a lot when pedalling and find SPDs allow for this (about 8deg of movement). I have always ended up wearing the steel platform out on the pedal well before the bearings give any problems so have never had to service the pedal bearings. Unfortunately this means I go through pedals every couple of years (about 20k miles).
My current shoes didnt allow the float when they were new due to the rubber sole binding on the pedal and stopping metal to metal contact. This caused knee pain within a few miles, so I filed the rubber down sufficiently until the cleat sat on the steel platform and problem solved.
I also have to protect the cranks and shoes with duck tape to stop excessive wear when my feet rub against the crank due to my heel rotating inward.
Its a small price to pay for avoiding knee trouble.

We recently bought the 6 lead model which didnt seem to be much more expensive and was £20 off in the black friday sale. It was predominately for me as I have flutters which have been getting more frequent recently although nothing has been detected. I had a GP ECG about 18 months back and a holter test about 5 years ago, both clear. As the flutters are very infrequent I doubt this device will be able to capture anything.
My wife has also tried it and I have noticed that for her some of the spikes are inverted on lead II and III indicating left axis deviation, so I will get her to mention this to her GP on the next visit. This would not have been spotted by the 1 lead device.
I am slightly disappointed that the device will only highlight certain conditions (high pulse, low pulse or AF) but maybe this is a legal thing. It does mean to check for anything else you need to do some research.
I would like to point out I am not medically qualified (except a couple of first aid courses, now expired) so all my assesments are based on internet research.

I gave up trying to fit these on 8 speed shimano chains and reverted to pushing the pin out most of the way and then pushing it back in to form the link.. I found the shimano HG40 chains do not have the peened pins which stop you from doing this. I know this method is controversial but I had no failures when doing this.
I have since changed to KMC X8 and SRAM PC850 chains which seem to wear much more slowly (they last roughly 1.5 times the distance), plus the quick link on these is also much easier.

Brucey wrote: ↑13 Nov 2024, 5:18pm

bluespeeder wrote: ↑13 Nov 2024, 9:33am BUT I would be very concerned about the tooth with a chunk missing, so I would replace on that basis. It looks like it could bend or snap....

it is perhaps worth noting that shimano appear to save their heaviest manipulations for steel middle chainrings, so they often look worn out or broken, even when they are new. I'm not sure which tooth has 'a chunk missing'; however I do note that when a new chain is fitted, owing to the pitch mismatch, the most worn teeth conveniently see the least load.

The last pic at about 7 o'clock. It looks like there is a ramp pin there as well so there cannot be a lot of aluminium holding this in place.

The wear looks acceptable to me, I usually retire a chainring when the tips of the teeth get pointy. BUT I would be very concerned about the tooth with a chunk missing, so I would replace on that basis. It looks like it could bend or snap.

I have included a pic showing two chainrings which I think are too worn. The top one has a sharks teeth profile on some teeth. I find when it gets to this stage the wear rate accelerates dramatically.

Barrowman wrote: ↑7 Nov 2024, 6:18pm Dual Pivot Brakes WON'T work with 'old school' Levers ( Weinman in my case) believe me I spent 3 days trying to get them to work together before taking advice.
There is a spring in a Dual Pivot Lever that helps the release. Weinman and similar Levers rely on the spring at the brake only. So the 'pull characteristics' of each lever is only part of the equation.

Is this a problem specific to Weinman levers?

viewtopic.php?p=1537998#p1537998
viewtopic.php?p=1538015#p1538015

these links are saying return springs are in shimano SLR levers as used in the single pivot set up (motion exage in my case)

I have tried to list my findings and thoughts for future reference, please feel free to point out any errors!

single pivot levers are 7mm cable pull per 20deg
dual pivot are 8mm cable pull per 20deg (so less leverage by 12%)
source https://bike.bikegremlin.com/1402/mecha ... atibility/
so its unlikely to run out of range and hit the handlebars if converting to dual pivot

I struggle to understand how dual pivot brakes work with 1 long lever arm and 1 short one. I think force is being transfered from the long lever arm to the short one via the adjustment screw. I cannot convince myself equal force is being applied to each side - does this matter?and could it explain my rims wearing more on one side.

I had the thought, why not just make the brake lever more powerful, then I found this discussion:
https://bicycles.stackexchange.com/ques ... brake-arms :- interesting discussion, I'm not sure who is right!

In the real world, giant speeder measurements (single pivot) made at the caliper; 5mm cable travel, gives 4mm pad travel, from 20mm brake lever travel. roughly 4:1, allowing for measurement errors.
This was measured after taking up the cable slack and using just enough force to close the pad gap, this ties in closely with expected from what I have read, although can no longer find the source.

I have read somewhere that single pivot has 4:1 mechanical advantage (4:1 for the lever, 1:1 for the caliper) and dual pivot has 5.6:1 for the whole system.

using old (single pivot) levers with dual pivot would give 5.6*1.12= 6.27:1 so the dual pivot caliper would be 6.27/4= 1.56:1
real world measurements on the ultegra dual pivot calipers are 5mm movement at pads needs 8mm cable pull therefore 1.6:1 (pretty close)

The reason these ultegra calipers will not fit the giant speeder is the cable entry is 30mm to the left of centre line also it is 65mm above the pivot bolt centre
whereas the cable entry is 45mm from the centreline and 50mm above the pivot bolt on the exage single pivot currently fitted.
I have 105 calipers on another bike which measure 45mm from the centreline so these would fit I think.
The ultegra will put too much strain on the cable outer forming an S shape which will be draggy.
I thought all calipers would be the same in this regard, if anyone knows a source of data for thes dimensions for various different models I would be interested.

Other thoughts: if the pads are fitted at 39mm or 49mm it will alter the mechanical advantage a lot (and the slot is actually 15mm adjustment)
also, where the brake lever bite point is will make a difference to mechanical advantage because the angle of the lever to cable changes, if it gets to 45 deg this could halve the force! although I think the levers may well be designed to generate maximum force at mid range.

I have had steel p clips on my bike which have been fine for the last 30 years (see photos in dual pivot brake query). Make sure they cannot move cos they will rub the frame, I used some insulating tape to pack them out but there may be a better solution. All the weight is through the bottom supports, These just stop the rack moving when you brake and help stabilise side to side. I have plastic p clips on my other bike, again fine but I am wary they may snap with age - hopefully one at a time!

PT1029 wrote: ↑4 Nov 2024, 8:06am "I have just given the old calipers a good clean and they are still sticking on"
By this, do you mean a wipe/clean and apply oil?, if so not enough.
What the caliper needs is fully dismantling, cleaning the rust/crud off the pivot surfaces, greasing and reassembling. Being Shimano calipers, they have to be dismantled from the threaded end of the bolt, not the brake arm end.
What also can affect brake release is where the spring ends push/rub on the brake arms as they move. Make sure the spring is clean where it pushes against the brake arm, and oil/grease, it makes a big difference. Ditto if the brake arm has a plastic sleeve through wich the spring end moves/slides as the brake arms move on/off. I have found where the brake originally had a plastic sleeve on the sprng end, and the sleeve has got worn/lost, the return spring never works as well.
As Brucey says, effective mudgiards are the long term answer.

I have to confess I didnt fully dismantle the caliper due to time constraints, but I will next time I clean. I did ease the back nuts off by about 5mm to get a cloth and toothbrush on the inner surfaces, so a bit more than a wipe! I did spot the plastic sleeves (which I must have flipped previously to get more force) were pretty heavily worn and one cracked slightly so not ideal. I have been unable to ascertain whether the spring may have lost some grunt with age, use and corrosion but possibly this is a factor and new ones seem impossible to source.
On yesterdays ride the calipers did work better and released fully although how they perform in the wet remains to be seen. One trick I have found is twanging the cable below the crossbar if the brakes do not release fully. This does imply part of the problem is friction between the cable and outer at the rear. The cable is stainless about 3yr old so a replacement is worth a try. I get the impression the length of the outer is critical as well so I will try tweaking this.
Regarding mudguards, if there was more clearance I would use it to go to 28c tyres! I think the bike originally came with 21c tyres. I did use mudguards for many years but after going to 23c and moving to muddy shropshire I got too much clogging with mud build up under the mud guard. The real solution around here in winter is probably a gravel bike with disc brakes but I like my old bike too much.

Barrowman wrote: ↑3 Nov 2024, 5:56pm Carlton

You need Levers with an integral return spring. As I Sussed out after 3 frustrating days trying to get some to work with old school Weinman Levers .

Bluespeeder

Don't appear to have my modified rack any more but I do have the/an L bracket .
Drop me a pm with your address if you want it .

Thanks for the offer but I am now going down the route of making the existing set up work better. The calipers are struggling to pull the cable through the rear section of outer. I am wondering if the return spring has lost some of its spring after 30 years. I will try and source a new one and maybe try a new die drawn cable too.

Carlton green wrote: ↑3 Nov 2024, 1:56pm For me what’s been a real benefit is changing to stainless steel die drawn inners, much operating friction has been taken away and brake performance has increased.

If you must have dual pivot brakes then consider having them on the front only, it’s a bit if a bodge - nicer to call it pragmatic - but if it works then whatever. I like things tidy and matching but, at the end of the day, bikes are there to be ridden.

Is it the "die drawn" that makes the difference, or stainless v galvanised? I am currently using stainless inner with shimano SLR outer, I'm not totally impressed and wonder if an unlined outer would work better. Maybe the SLR is more aimed at buried cables where the outer runs from lever to caliper continuously.

Not sure about one dual pivot and one single, I get confused enough as it is.

Pebble wrote: ↑3 Nov 2024, 1:06pm Is this a SpeederLite that you have ?

It is a giant speeder, I bought it in '93 I think. It says it's 0.9mm tubing and stays so possibly not the lite version. I am surprised you can fit 28c tyres, how much clearance does that leave?

Brucey wrote: ↑3 Nov 2024, 11:58am the pivots in all brakes are prone to misbehave if they are placed in the firing line of all the crud off the rear wheel. Arguably DPs are slightly worse than SPs here because they seem to seize up more easily. A more conventional rear mudguard would better protect the brake.

Nice idea but I only have about 4mm clearance between tyre and caliper mount with 25c tyres. Even this is getting clogged with mud at the moment so proper mudguards would be a nightmare. I am trying to find the least worst solution!

531colin wrote: ↑3 Nov 2024, 11:56am

PT1029 wrote: ↑3 Nov 2024, 6:33am ………

If you keep the old brake levers, they will have a different cable pull to that which the dual pivots are designed for. In you case I think the brakes will thus be more powerful, but need more lever movement, so keeping them in adjustment is a bit harder as the lever moves more/closer to the handle bars (or lever movement is the same but you have to adjust the pads very close to the rims).

^^^^^^^^THIS is the important bit, isn’t it?

As you have P clips on the seat stays it should be easy to get the rack stays out of the way of the brake cable…. for example, turn the P clip round the other way will move the stay about 10mm sideways….or move it up out of the way, or cross the left and right stays……or bend the stay out of the way…..

I am coming to the conclusion that keeping the old brakes is the way forward if I can get them to release properly. I am concerned even moving the rack support out of the way the bend in the cable outer will be too severe with the new calipers.
I have just given the old calipers a good clean and they are still sticking on. They work fine with the caliper off the bike so I think it must be the bend radius of the outer cable . I will try a slightly longer outer and see if that helps.