Is it totally neutral? Doesn't brake jack/squat have to do with the caliper rotating as it moves along the wheelpath?
How does running a brake inboard affect suspension under braking?
- Thread starter Lollapalooza
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My understanding is that with same-sized chainring and cog, you'd have an effect similar to a parallelogram floating brake. By having a slightly smaller front chainring you could tune in a bit of squat. Also, a smaller ring would give a ratio advantage that would let you run a smaller disk (if I'm not thinking backwards)
I'm also quite interested in this and would love to hear what others think.
I'm also quite interested in this and would love to hear what others think.
Assuming the pivot and drive output were concentric (which they'd need to be for practical purposes), yeah this is correct. Basically now you put the lower half of the chainline under tension (instead of the upper chainline like you do under pedalling acceleration). And yes, you could create a mechanical advantage with the gearing that means you don't need as big a rotor for a given amount of braking power, but you still need a certain sizer rotor to dissipate whatever heat you generate, and a larger one will still be better than a smaller one in that respect. One of the Kiwi nutters (Metzy on here I think) tried it, sounded like a cool idea but dunno if it was really practical.
surely you could put a chain tensioning cog on the lower chainline and tune the braking performance to either squat, jack or stay neutral by altering the angle of the chain
about the rotor you could use a smaller rotor, as long as the amount of metal on it is the same as a larger one, equal heat will be dissipated.
about the rotor you could use a smaller rotor, as long as the amount of metal on it is the same as a larger one, equal heat will be dissipated.
wtf? why is he asking about a brake mount location and getting replies about chainring sizes? somebody help me with this math. i don't see how 2+2 = popcorn.
because the size of the chainrings used affects the way the bike will handle under braking.. and how the bike will handle was the question he posed.
think of a normal floating brake, you can tune it to squat, jack or remain neutral by altering the angle of the floating arm relative to the rear axle and main pivot. The chain in this case acts as the floating brake arm, so the size of both chainrings used determines the way the suspension will act under braking.
think of a normal floating brake, you can tune it to squat, jack or remain neutral by altering the angle of the floating arm relative to the rear axle and main pivot. The chain in this case acts as the floating brake arm, so the size of both chainrings used determines the way the suspension will act under braking.
When he says "Inboard" he means running the brake caliper attached to the frame side of a "gearboxish" design. The rear sproket on the wheel will be fixed and allow braking forces to be controled from the drive side through the chain. Sort of like engine breaking on a 4stroke dirtbike if your familiar with the concept.
bikenweed: yes that bike looks awesome especially the rear end, looks liek it would handle very will with all the weight low and centered and the high pivot.
personally i would have gone for the smaller rotor/ bigger chainring myself tho. the bike would squat slightly under braking which would sink the rear possibly at the same rate as the forks with both brakes applied.. and also the reverse would be true under pedalling so you get a measure of anti-squat when pedalling.
personally i would have gone for the smaller rotor/ bigger chainring myself tho. the bike would squat slightly under braking which would sink the rear possibly at the same rate as the forks with both brakes applied.. and also the reverse would be true under pedalling so you get a measure of anti-squat when pedalling.
The size of your braking track (ie SWEPT surface area) has a lot to do with how hot your brakes get, and smaller diameter rotor ALWAYS means this will be lower. Smaller area dissipating heat energy at a given rate = higher temperatures required to do it. In other words, you are more likely to overheat your brakes.
defiantly cool stuff!Such a sick bike...
A little off topic, but do you have any shots that show the width of the pivot? Seems like an awkward area of the frame to widen. To me it looks like you would hit your ankles on the pivot and the swing arm a lot. I don't know, maybe its (the pivot) no wider than what you would find an an orange or morewood?
it does look a little wide, but i think the skinny steel tubes make the gearbox look very wide.
the actual pivot location on an orange would be alot slimmer but if you took a cross section just above the BB the bike above is probably not too much wider as the orange swing arm gets wider towards the rear end.
the actual pivot location on an orange would be alot slimmer but if you took a cross section just above the BB the bike above is probably not too much wider as the orange swing arm gets wider towards the rear end.
fair point, but if you look at say a 260mm rotor for a MX bike, its only 30% bigger in terms of diameter than a typical 200mm DH rotor, yet it has to potentially stop 100kg+ of bike + rider weight.. traveling at 90mph. much much more momentum is produced that on a MTB.
The reason it can do this without fading is primarily the amount of material used, (after all the rotor is effectivly a heat sink) thus the negative effects you describe can be cancelled out
of course there are other factors too, rotor design, pads, pistons and brake fluid all contribute to a cooler brake.