Onza cantis V shimano XT?

[prezza]

Hi there

Building an orange alu Elite 1992 which I’ve collected a full Period XT groupset, but also have fitted lots of Onza bits... wondering what ipinion is towards Onza HO cantis with XT levers in comparison to an all Shimano setup?

Also does anyone know if Onza did them in purple as I’ve kinda got a subtle purple theme goin.

Thanks in advance....

Andy

 

[Double-E F]

All Shimano!

 

[prezza]

Cheers....

 

[2manyoranges]

Re:

Actually it's an interesting question...not straightforward.

Unusually for the Big S they got their straddle-wire philosophy totally wrong in the mid late 90s. I'll explain. The power of cantilevers is governed by some very complex geometry.

1 the precise pull ratio on the lever - which is a complex combination of lever length, arc of pull, etc - how much pull being critical
2 the width of the distance between the brake bosses - which can vary massively on different bikes
3 the height of the brake blocks in the cantilever arms - big adjustment on Onzas, less on S - which determine tyre clearance and the arc of block - and the length of the cantilever arms
4 the height of the straddle wire
5 the length of the straddle wire, affected by how much you put the brake blocks in or out on their posts; how many washers on V brakes, of course.
7 the type of brake cable, with thicker, higher quality stainless cables being best
8 the angle of the wall of the rim, which can vary a lot.
9 the quality of the braking surface, from grippy anodised to glassy coated nastiness
10 brake block surface area and compound

And you have to worry about ankle clearance depending on the position of the bosses.

Now...2-5 and 8 all interact. This affects the ACTUAL LEVERAGE being applied to the rim. It a combination of at least seven different variables regarding setup - with straddle wire angle being one of the most important. There are good articles on this on line. Big S introduced the fixed length half straddle wire (the one with the alloy disc) during the 90's. This fixed the length of the straddle wire. Easy for mechanics in shops, good for safety and their liability. Terrible for setting up brakes, since it removed one of the biggest variables in the brake setup. I had a FS bike at that time and it had LX cantilevers (all pre V brake). They were dreadful. Virtually no stopping power at the rear. Plenty at the front. I ripped them off, put on Critical Racing cantilevers with an old-style straddle with an onZa Chill-pill. Aztec cool-stop brake blocks. Now I could play with all the variables. After an hour of playing (and it had lovely XT levers) i got MASSIVE POWER from the brakes. Cantilevers. MASSIVE POWER. All the right angles in each element of the setup. With a low straddle angle, low straddle length. I kid you not, when V's appeared just after, this cantilever set up was as powerful as Vs. Not more, but about equal to.

So.......the answer to your question.

You could set up either onZa or Shimano so that they are sh+t. Particularly if you use the Shimano half-straddle nonsense.
You can adjust more things on the onZas.
Have a play.
I bet you can get the onZas to be WAYYYY more powerful than the Shimanos.

But then...maybe the boss distance on your bike means that Big S will work better. Who knows? But the above gives you all you need to set the brakes up for maximum power.

 

[pete_mcc]

Re:

Onza are lovely but have a nasty habit of cracking at the bolt holes, XT don’t. That sort of makes the decision for me!

You’ll have more luck with purple if you can find a set of Bolder brakes (the design Onza used for their HO brakes) but if I was you I would find some X-lite canti bolt caps and use them with xt.

 

[FluffyChicken]

Shimano, I've never had a problem with properly setup Shimano straddle wires of the M900/735 era
Excellent power and modulation from both with the servowave levers.

Onza just tend to crack, the V-brake version was HOLA.
Don't recall purple version, just silver and black.

 

[2manyoranges]

Re:

You are absolutely right about the cracking thing. Need to keep an eye on the little devils. If you have a preference for XT cantilevers then go with those but use an onZa Chillpill or similar and put a strong conventional straddle wire on them, then you can play with the angles and length of the straddle and get decent leverage in the system.

Remember this: from Sheldon Brown

With automobile brakes, a nice "hard" pedal feel is a sign that the brakes are in good condition. A soft, "spongy" feel at the brake pedal is a sign of trouble, perhaps air in the hydraulic lines. This is not the case with bicycle brakes. A hard, crisp feel to the brakes on a bicycle may be a sign that the brakes don't have much mechanical advantage. You squeeze them until the brake shoes hit the rim, then they stop. Brakes with a high mechanical advantage will feel "spongy" by comparison, because the large amount of force they deliver to the brake shoes will squash the shoes against the rim, deforming them temporarily under pressure. You can feel this deformation in your fingers. The brakes with the rock-hard feel may seem nice on the work stand or the showroom floor, but when it comes to making the bike actually stop, the spongy set-up will do the job better, with less finger pressure and greater margin for safety in wet conditions.

from
https://www.sheldonbrown.com/cantilever-geometry.html

...which only is true if you have a nice strong cable set up, otherwise the spongy feel can be coming from weak main and straddle cables....

and also:

https://bike.bikegremlin.com/1739/canti ... djustment/

This one above is GOOD. It does not repeat the nonsense about '90deg' being the optimum angle. On one of my bikes the best angle for the straddle wire is almost hitting the tyre - very low, with the arms of the brakes very tilted-in. This gives high mechanical advantage and max power at the rim.

 

[2manyoranges]

Re:

well Chicken, you may just be lucky with the distance of the bosses on your frame, but the half-straddle limits the extent you can play with the straddle wire angle and length, and that's a major factor in brake power. Good that yours all just fall into place.

 

[prezza]

Many thanks for all the advice and time taken to fully inform me over my choices. Seen as how I have the full XT grouppo and this will be a garage queen and occasional dry day ride then think I’ll stick with the shimano setup but will look for some purple canti bolts for bling. If anyone has any they wish to part with then drop me a message ....

Thank you all ....

Andy

 

[ishaw]

Re:

Onzas only cracked if they were over tightened. Great brakes if you can get a set that aren't cracked and be careful when setting up.