V brake pads - full monty versus inserts

[Sweep]

Any advantage between inserts and the full thing complete with confusing washers?

On price, quality, whatever?

I tend to use inserts as they are so easy, but have the uncomfortable feeling that I am being diddled and that they are somewhat thin,

[Gattonero]

To be fair, you want to replace the pads frequently to preserve the rim: at some point you are likely to get grit and thin fragments of the rim embedded in the pads.

V-brake pads made for Mtb's are thin because you wanted to leave as much room as possible to remove the wheel. So don't worry that you're somewhat been fooled: back in the day we all had to use cantilever, and the original pads were really hard and would last forever, but the braking action was nowhere near the one from modern pads.
In a nutshell: get pads that would give you good braking performance, that is paramount, not saving £2 or3

As far as the inserts, some tent to be really annoying to be fitted, IIRC on Shimano holders the Aztec pads would be a struggle and with the modern pads on concave/convex washers it takes seconds to set them up.

[Brucey]

if you are using MTB style 70mm holders the inserts vary in thickness quite a lot. Most are around 4mm but some fibrax ones (eg 'Rhino' in red/black compound) are nearly 6mm and some (eg clark's gold/elite ones) are slightly thicker still, although they may not last longer because the wear rate of these soft inserts is higher too. At this thickness new inserts can hinder wheel removal on some bikes.

On cantis/Vs I'm not sure I'd want them to be much thicker than that TBH, because the brake arm travels in a short arc and unless the top edge of the brake insert is chamfered quite a lot, the contact between the rim and the insert changes height dramatically, i.e. the brake block moves down the rim. This effect is less bad on older frames, which have the bosses closer together. It is also less bad on 'parallel push' brakes because the effective pivot position of the pad is different.

Fibrax 'rhino' inserts (from ~£2.99/pair on flea-bay)

have a decent chamfer to the top edge; plenty of others don't, so if you have narrow brake tracks on your rims, choose accordingly. This model Fibrax also have a shaped heel, which helps with setting the toe-in when the inserts are new, and (until it wears away) helps 'snowplough' crud/water off the rims in normal use. I think some Aztec inserts have a similar feature.

A good thing is that if you want, the full thickness of the insert can be used, right until the holder is about to touch the rim. It is a good idea to pick bits out of the brake blocks at intervals, and I have even recut slots where necessary too. Even in a 6mm thickness insert, the slots are only 2.5mm deep or so (less than that with the fibrax); wear 2.5mm deep slots in 6mm thickness inserts to nothing and the insert is arguably only about half-worn, and is ready to be recut. BTW if you cut the slots very deep from new, the brake insert would move around too much, I think.

cheers

[Sweep]

thanks for the replies.

Will track those pads down brucey - sound interesting - I recently bought a job lot bag of another sort of Fibrax pads off ebay.

How do you do the cutting - with a stanley knife? And the "vertical" cut sounds easy enough - what about the "horizontal" one at thebottom though?

[gaz]

There is no "horizontal" cut. That is the shaped part of the pad that gets inserted into the holder.

[Brucey]

you can recut the slots in the working part of the insert face using a saw, a file, a dremel tool or even an angle grinder.

I usually cut any fresh slots with a compound angle to them, so that there is some 'plough' effect at the slot edge (which helps to keep the rim clear of water and grit, much as the 'snowplough' end of the brake block does) and so that the slot is angled between a tangent and a radius so that debris is liable to be thrown clear if it is centrifuged off the wheel.

Obviously the slots need to be wide and deep enough that pieces of grit don't get trapped in them. To help with this, it is a good idea if the slots taper in width along their length, so that anything in a slot finds it less and less likely to get jammed the further it goes.

cheers

[The utility cyclist]

Inserts every time, the quality of pads and choice and rigidity given by the metal holder makes for far better braking.

[Sweep]

you can recut the slots in the working part of the insert face using a saw, a file, a dremel tool or even an angle grinder.

I usually cut any fresh slots with a compound angle to them, so that there is some 'plough' effect at the slot edge (which helps to keep the rim clear of water and grit, much as the 'snowplough' end of the brake block does) and so that the slot is angled between a tangent and a radius so that debris is liable to be thrown clear if it is centrifuged off the wheel.

Obviously the slots need to be wide and deep enough that pieces of grit don't get trapped in them. To help with this, it is a good idea if the slots taper in width along their length, so that anything in a slot finds it less and less likely to get jammed the further it goes.

cheers

Many thanks for your patient reply as always brucey but fear that that is all a bit beyond me. Or maybe the words tangent and radius just brought back memories of northern teenage maths lessons.

But thanks, honestly.

I think i will stick to inserts.

Used to use discobrakes but on my last order found that they had boosted their prices to close to other suppliers.

[Brucey]

regarding insert thickness, this photo shows several types; CW from top 'clarks XTR type', Clarks gold/elite, Fibrax Rhino.

various insert thicknesses

Regarding slot cutting, this shows the compound angle that I'd use on a left-side brake block

a picture is worth a thousand words

cheers

[Brucey]

BTW one-piece moulded brake blocks look as if they are chunky and ought to have a longer wear life than skinny inserts for XTR-type holders. Indeed this is sometimes the case. However such one-piece brake blocks contain a metal frame (inner support structure, typically a zinc die casting) which will wreck your rims if you wear the brake blocks just a little too much.

The exact position of the metal frame is unknown; all you can say is that it is 'somewhere below the bottom of the slots'. It may vary from batch to batch even with the same type of brake block. Unlike XTR type holders, it certainly isn't obvious when the frame is about to gouge into the rim or anything.

Out of curiosity I have prodded various one piece brake blocks with a pin in order to determine where the frame is, and in many cases it is about 1mm below the bottom of the deepest grooves in the moulding. (BTW if there are brake blocks which are consistently different to this that you know of, do say.)

In any event it usually cannot be assumed that it is in any way safe to wear the brake block beyond the grooves; in addition, should the brake blocks twist at all in service, they can wear through to the frame (eg at the heel) whilst the grooves are still visible at the toe end.

This Kool-stop brake block is typical;



and (unusually) has a wear line marked on it. I doubt there is very much thickness of friction material beyond the wear line, at least on a consistent basis.

So I recently looked at my XTR type holders and thought 'ooh blimey there isn't much brake pad remaining' and indeed there wasn't. But actually, upon reflection, I was probably better off than if I was just about to wear to the bottom of the grooves in a one-piece brake block, with the crucial difference that I'd more easily be able to see when metal-to metal contact would occur.

BTW insert thicknesses (measured on 70mm inserts) are;

Clarks XTR type, black ~4.5mm
Clarks XTR type, red ~5.0mm
Fibrax Rhino ~5.75mm
Clarks gold/elite ~6.0mm

cheers

[MikeF]

On one mini V Aztec I'm now using Swissstop Green. They squeal very little, seem long lasting with not aggressive rim wear, and provide all the stopping I need. They've now been on the bike for just about 3500 miles. But they aren't cheap! Rear braking is minimal so those pads, Aztec on this bike, hardly wear at all.

Rim wear is a factor when choosing pads.

Edit. Must be having brain fade For Aztec above read Tektro

[Sweep]

Thanks for that last post of your brucey.

Yes I had vaguely wondered/worried about that issue with fixed "one piece" pads.

So you have decided me - I will be sticking to the inserts.

These, by the way, are the inserts I recently bought after my move (possibly permanent) from discobrakes.

20 pads for about £5.75 including postage:

https://www.ebay.co.uk/itm/Shimano-Tekt ... 2749.l2649

Not fitted, yet alone ridden with any yet, so can't say how they are.

But in truth I didn't think the discobrakes pads were great, just OK.

Whatever the pad, I keep the rims clean/ish and regularly check for debris in the pads.

[Brucey]

if those are the base model fibrax insert, they ought to work OK. They are certainly a good price.

cheers

[pwa]

My touring bike has cantis fitted with vee brake blocks/pads. On the rear I currently have some upmarket Kool Stop units with Salmon inserts. On my tungsten carbide CSS impregnated rims they wear down extremely slowly and provide very good braking. But they do tend to squeal a bit under moderate braking.

On the front I have a pair of blocks (complete units, not inserts) that came with some Tektro cantis. I put them on because they were lying around when I needed some blocks, thinking that they would probably be okay in the short term. But on the CSS rims they brake as well as the Kool Stop units and don't squeal. Make of that what you will.

(All my brake blocks get "toed in" by a small amount when they are installed)

[Sweep]

if those are the base model fibrax insert, they ought to work OK. They are certainly a good price.

cheers

Thanks for the thumbs up on those brucey. Yes they are fibrax pads. Have used their cables as well and find them fine.

May get some more of those pads before they disappear as i am moving towards standardising on v brakes on my several bikes. Rather to my surprise have grown to like them.