MacRetro chat and rides thread

[dyna-ti]

As to the 203, tbh i reckon it would be fine, given its actually when you think of it, 20mm difference, which is 10mm all round, which isnt even a 1/2", and yeah a washer, or preferably a single thick washer will lift it. I have seen to many spaced out this way without any issues whatsoever to say it is a danger.
That said, a proper torque, and maybe a pinch beyond for its age would be prudent.

But is it really needed ?, as Rob said. Im about 14stn and 160/180 mini monos on sintered stops me quite spectacularly. In fact way better than the modern X2's, though I reckon thats down to that poncy tech lever.

 

[RobMac]

Re:

I can't remember the formula but even a small increase in rotor size equates to a much larger breaking force in proportion to rotor size. What I'm trying to say is a 10% increase in rotor size wont equate to a 10% increase in breaking force it'll be greater than that.
Does that make sense :?

 

[dyna-ti]

It does actually Rob, but on the figures front I also remember the increase in actual braking power being purported as 15%.
I know some manufacturers list 180mm max bitd, but again I think thats because the 200+ was just so uncommon. But later forks likely didnt appear have anything else added metal wise as the specs would probably allow 50% increase to cover maximum strain failure.

When I look at the revelation fork ive on the cove, which is touted as a freeride fork, the PM mounts to me look actually quite narrow, and certainly look flimsier than early forks like manitou. I know its not flimsy as ive yet to hear of a mount breaking off but i suppose they must :?
But even there I'd think the IS mount would be the prone one, as the process for it parting company is shear, and metal does not like shear. PM mounts are in compression and tension, both of which are secure. The upper bolt in compression should be fine, just the lower, but again you need a considerable force to pull a bolt straight out, and it would need to be straight, not in an arc as a mount bolt would be, and be reliant on something else failing.

Next fail point would be the entire leg to snap, but the internals would be pretty much holding it together, so maybe not as catastrophic blood and guts landing.
Anyone seen that ?, i have but on carbon forks, and although touted as too big a rotor, most using such would be offroad and under considerable strain anyway :? and magnesium lowers are very strong, especially when forged and they are forged.

My tuppence worth.... er maybe like ... £4.50

 

[RobMac]

Re:

The 10% figure I used for illustration purposes only.

 

[RobMac]

Re:

BTW all this talk about forks failing what about the frames, head tube, a point in fact K***** Giant Athem frame failure if Giant were aware he was running 203mm discs I doubt they would have honoured the warranty claim, not saying that was the cause of that fail.

 

[velomaniac]

Re:

There are some great youtube compilations of frame failures. Seems to happen alot at the headtube area quite possibly due to the modern fashion for hammering your bike down steep techy trails with lots of jumps and the use of Aluminium as a frame material. I suspect manufacturers such as Giant do honour warranty failures even if the rider might be at fault because they are building bikes for an extreme sport. Afterall to a firm as big as Giant a replacement frame is a drop in the ocean but bad press is BAD !

 

[epicyclo]

...I know its not flimsy as ive yet to hear of a mount breaking off but i suppose they must :?...

The fork leg may not break, but I have a fork where the disk mount sheared off and took a substantial part of the lower with it.

 

[jimo746]

Re:

If the front brake fitting was a PITA then the rear was just as bad :facepalm:
So today I said "F*ck It!!" and have gone with Magura rim brakes instead.
:mrgreen:

 

[RobMac]

Re:

Yawn! That's me back in hospital as of Friday evening at least I'm saving on my heating allowance AND free WiFi

 

[keithyr]

How long are ye in for rob?