Adding Disc Mounts

[djnotts]

^^ good summary!
i) the most likely until today. A very near miss when a car alongside me decided to turn across me to access a parking site. Had I not been on my disc braked mount I would not have performed such an emergency stop.
So iii) probably most likely. Kicking myself for prevaricating over a Giant Anyroad on Ebay BIN which offered postage and sold in a few hours.

[Brucey]

FWIW this might just be my imagination but in the photo you have posted upthread, it looks a bit like the bosses on the forks may be set a bit low. Lower than those for the rear brake, certainly.

IME this can have a profound effect on braking performance. I have one bike where the bosses are set low and the height difference between the boss centres and the brake block centres is well over 30mm. On this bike I had rubbish brakes using 'standard setups' of various kinds, mostly feeling wooden and a bit feeble, until I took a closer look. The brakes currently fitted are full V brakes, but with levers configured to produce a much shorter cable pull, which I'd normally use with cantis. The brakes feel 'normal' now, and they never did before.

So if you have low set bosses as I suspect and you are currently using flat bars, I would suggest that refitting the V brakes and using Avid speed dial levers might be an interesting experiment; you can fine tune the lever MA until you get the brakes to feel the way you want. If the brake bosses are set very differently front and rear, speed dials might be the only levers that will work easily on that bike, eg. because the rear brake needs a different lever MA to the front.

If the bosses are low enough then you may struggle to get the brake power you want out of almost any conventional cantilever brake, hence V brakes might be one of just a few options.

It is easy to disregard boss height but it can be of overwhelming importance in some cases.

cheers

[cycle tramp]

^^ good summary!
i) the most likely until today. A very near miss when a car alongside me decided to turn across me to access a parking site. Had I not been on my disc braked mount I would not have performed such an emergency stop.
So iii) probably most likely. Kicking myself for prevaricating over a Giant Anyroad on Ebay BIN which offered postage and sold in a few hours.

Sorry to hear about the near miss- however (and despite nsew's view on the subject) have you ever considered something like a strong wide steel basket or a heavy duty front rack fitted to your bike? Very useful - I've just fitted a surly front 'nice' rack to my current bicycle. During my last trip the front rack was loaded with a pair of 48 litre panniers and a massive cardboard box on top, (full of recycling) and i found that cars tended to give me more room on the road - rather than seeing me as something which was in their way i became viewed as a very possible threat to their car's body work

[djnotts]

Add weight? No! I can barely manage more than the flat on most bikes - moderate hills demand my near-touring geared full carbon race replica!

[cycle tramp]

Add weight? No! I can barely manage more than the flat on most bikes - moderate hills demand my near-touring geared full carbon race replica!

What is it with everyone and bicycle weight?
Yes, you can! - What is holding you back from going faster isn't weight, but aerodynamics

Last time I returned from my local farm supply shop, I had a load of 5 kg of mixed corn in each front pannier, 2 kg of dried wire worms, 7 kg of layers pellets as well as some smaller items in my rear panniers- all up the total weight of my purchases came to some 19.5 kg. I got home just fine by bike. The whole weight thing is a scare crow peddled by lazy bike journalists, advertisers and bicycle manufacturers.

[djnotts]

Would it were so. 10 years ago I would have agreed. Severe copd and a "lung age" of mid-90s convinces me otherwise. 8 years ago I was told 2 years to being on oxygen and essentially incapable of independent living. I have cycled and or walked near enough every day since (6526 miles biked last year, so far this year over 600 despite the weather). It can be delayed but is irreversible and progressive. My specialist nurse simply says unbelievable.
I assure you weight matters.
Call me lazy if it makes you feel smug.

[cycle tramp]

Would it were so. 10 years ago I would have agreed. Severe copd and a "lung age" of mid-90s convinces me otherwise. 8 years ago I was told 2 years to being on oxygen and essentially incapable of independent living. I have cycled and or walked near enough every day since (6526 miles biked last year, so far this year over 600 despite the weather). It can be delayed but is irreversible and progressive. My specialist nurse simply says unbelievable.
I assure you weight matters.
Call me lazy if it makes you feel smug.

No not at all. I'm really sorry to hear about your health- somewhile back a good friend of my lost a lung. It's a game changer. I appreciate your honesty and your time in sharing this and I'm in awe of what you've achieved - I think this year you've already cycled miles than what I hope to achieve by June. Fair play to you

[djnotts]

Accepted and thank you. I do agree about weight v aerodynamics but for bicycles the two tend to go hand in hand! Full panniers help neither!

[nsew]

A few more thoughts. The frame was designed for canti’s (cable stop bridge on seat stay). The frame bag is compressing the cable housing. It’s not unheard of for mtb cables to be inserted in road levers, resulting in abysmal breaking. 70mm boss spacing leaves 50mm of a gap to remove a 51mm (2”) tyre such as the Vittoria in the photo. Bosses placed 25mm below centre of brake surface are optimal (Roberts built at 25mm drop and 85mm spacing on ATB/mtb’s).The br-cx70’s on eBay fetched £100! I still can’t believe Shimano ended manufacture. Awesome canti’s, probably the finest ever produced.

[Brucey]

FWIW I have seen bosses at ~22mm (on a Manitou SX Ti BITD). Those brakes were super-powerful but obviously had little running clearance and needed frequent adjustment. 25mm is pretty standard but once it gets nearer 30mm the brakes typically become a bit lacking.

With flat bars, using Avid speed dial levers can hide a multitude of sins.

cheers

[djnotts]

Thanks for more thoughts! Having browsed a few frame builders guides in the past re "standards" I have thought of boss height as well as spacing - I don't think these are out of order.
I had a bid on the cx70s, but 100 quid no way! Sell the Davey and add say 500 and could buy a used disc braked "gravel bike" and convert to lower gearing.
For now spend a few quid and more time tinkering and ride when hand/wrist pain not too bad.
My rigid Kona Blink with hydraulic discs and the Kula Easton Ultralite with cable discs will have to get out, on tarmac and off road respectively, more!

[zenitb]

djnotts .. given you have been trying out v-brakes one thing to bear in mind is that even the longer mountain bike ones come in different lengths

They are normally 103mm but ones designed for mudguards are 107mm (i noted you were trying to get mudguards under them in the pic ?)

Also maybe the longer arms would give you more leverage and a softer feel at the lever ?

I ditched the cantis on the Cannondale bike shown in the blog post below over 20 years ago, and apart from upgrading the rear v-brakes from 103mm to 107mm arms (when I added mudguards) have not needed to change it since.

I have a writeup on my blog here if you are interested. (my review starts a bit negative but improves at the end )

http://zenit-b.blogspot.com/2016/10/shi ... shier.html

[Brucey]

Thanks for more thoughts! Having browsed a few frame builders guides in the past re "standards" I have thought of boss height as well as spacing - I don't think these are out of order.

they don't have to be far different from normal (or what you expect) to affect brake performance.

I had a bid on the cx70s, but 100 quid no way!!

yes that is silly money. BR-CX50 are identical apart from the brake blocks, and cartridge versions (which Is what you really want, not the one-piece ones that come with BR-CX50) can be fangled from road brake blocks (provided they have the right type of toe adjustment) easily enough.

BR-CX50 listed as in stock here
https://www.singletrackbikes.co.uk/m7b221s396p18706/Shimano_105_BR-CX50_cantilever_brake_front_or_rear_/Brakes_-_Rim/RS_GB

If I were in your shoes it would be V brakes and speed dial levers; an easy change to make. However I don't think the speed dial lever MA goes high enough to help out all types of cantis if they are not powerful enough. However low straddles, CX50/70 brakes, good brake blocks and your four-finger levers ought to be a pretty strong brake arrangement. One CX50 brake is a £29 experiment.

cheers

[nsew]

The br-cx50/70 has a range of up / down adjustment of 20mm to 37mm so may be a lever that performs well enough at greater than 30mm as the mid point (28.5mm) is considered optimal.

btw Wiggle are a few quid cheaper with free shipping.

[djnotts]

This is where I am at so far! Performance acceptable by non-disc standards, new blocks probably improve further. Imminent health investigations and consequential diagnoses mean to spend on any bike stuff not sensible, but if I am going to be able to continue cycling then I shall try some cx50s or 70s.