Derailleurs...what do you look for in yours?
Comments
-
so the good old chain stays then.
Unless we all want to ride SS that is...
couldn't someone improve on the design of the chain though - I mean it's really old - you'd only need to improve the rivets in a chain to sort out the majority of breakages.
Anyway the OP wanted ideas for a derailleur.Not really active0 -
cee wrote:belts are not really indestructible...think about the belts in a car engine....they can stretch/split get teeth wear, and need replaced when they have not really snapped....
That's certainly true, but then the replacement schedule on a cambelt is usually tens of thousands of miles or several years, running at several thousand rpm for hours at a time. Don't know about you, but my cadence is a little slower
yeehaamcgee wrote:but why, is what I'm saying. If they had any advantage, then they WOULD be getting used on machines where performance is everything.
High-silica tyres give a huge advantage for road motorbikes, but nobody uses them on the track... Same goes for heated grips, comfy saddles, top boxes and big screens
Why do all racers wear leather? If goretex is so good they'd be wearing that, right yeehaamcgee wrote:why would a belt take an angled line any better than a chain?
A narrow belt does, like the v-belt in my lathe's gearbox, it'll deal with a huge deflection, something like 4 or 5 times what you see in a bike driveline But a wide belt like bikes would use probably would deal worse, not better, with deflection. I think this probably confuses people a bit.Uncompromising extremist0 -
im pretty sure chains are stronger than belts. Engines with chain driven camshafts have longer service intervals than belts.
The replacement of the chain drive for bikes is a nice idea as an experiment but it is trying to solve problems which dont exist. the whole belt drive idea is an attempt to try summat new and im sure i saw the idea on an orange p7 a couple of yrs ago and was designed for single speed. of course its good to try new things, but some ideas are plain sh1t regardless of who came up with them.
If any thing was going to be improved i would say cables need improving so they dont stretch (especially if you run shimano) for longer servicing interval. lower friction, better sealed outers (im thinking some kind of micro assembly similar to the way a dogs arse works when it parks its brekkie, a super supple sleeve which is bonded to the cable and can pass inside the main outer cable)0 -
belts might not provide any real advantage, but we need new things to progress the indudtry, for incetance, when sus forks were first introduced they had 10mm of travel, flexed like noodles, had very little damping, and did very little good, and im sure people said "sus forks are no good, our rigids do fine" but people persisted and slowly people started to believe in them, now look at us, we all strugle to cope with the idea of a rigid bike, very, very few of us ride a bike that has no sus.I like bikes and stuff0
-
somethings have met their natural evolution though, the chain drive on a bike is light, efficient, tough, quiet and not too pricey. I dont see where it can be improved apart from the cables.
Striving for perfection is an outstanding human trait and what puts us at the top of the food chain. but sometimes people are trying to fix problems which dont exist.0 -
I'd like to see some more alternatives. Gear drive... A wee row of little cogs all along the stay, just waiting to eat your trousers. Or hydraulic drive like on the front-wheel-drive dirt bikes. That'd be awesome. Or electric transmission, you pedal a dynamo to power a motor, and use the chainstays as the conductors.Uncompromising extremist0
-
I had a chain driven camshaft on an old Mazda. It had no replacement schedule. The reason for that is, they never broke.Northwind wrote:cee wrote:belts are not really indestructible...think about the belts in a car engine....they can stretch/split get teeth wear, and need replaced when they have not really snapped....
That's certainly true, but then the replacement schedule on a cambelt is usually tens of thousands of miles or several years, running at several thousand rpm for hours at a time. Don't know about you, but my cadence is a little slower
High-silica tyres offer better lifetime, but less grip, so they're not used (much) in motorsports.
Leathers offer more protection when crashing than goretex. Lots of bikers still wear leathers.
Heated grips? I've know several bikers who detest them, it actually makes their hands feel even colder, because their palms are all nice and warm it feels as though the rest of their hands are blocks of ice.
What I'm saying is that there is no performance advantage to belts. You're swinging this into a fit-for-purpose argument.0 -
Northwind wrote:cee wrote:belts are not really indestructible...think about the belts in a car engine....they can stretch/split get teeth wear, and need replaced when they have not really snapped....
That's certainly true, but then the replacement schedule on a cambelt is usually tens of thousands of miles or several years, running at several thousand rpm for hours at a time. Don't know about you, but my cadence is a little slower
aye of course....but I was only countering someones suggestion that belts dont break like chains do.
however....the cambelt is at least partially protected by the cover....fan belts (or those all singing all dancing fan/alt/aircon belts) however need replacing much more often than cam belts. doesn't take much of a nick to need replacing.....for instance..if you fill up with oil and forget to put your oil filler cap back on :oops: :oops: :oops:Whenever I see an adult on a bicycle, I believe in the future of the human race.
H.G. Wells.0 -
yeehaamcgee wrote:What I'm saying is that there is no performance advantage to belts. You're swinging this into a fit-for-purpose argument.
No I'm not... You're trying to define performance in too narrow a manner, or too simple maybe- "performance" isn't a sliding scale from 0 to 10, it takes in many different factors and things can perform in one field but not another. So frinstance:yeehaamcgee wrote:High-silica tyres offer better lifetime, but less grip, so they're not used (much) in motorsports.
The other advantage of high silica tyres is better grip when cold, and better grip when wet. . They have less performance in terms of traction but that's not all that matters- if maximum traction isn't your main concern then a super-sticky tyre is no longer high performance, in fact it'll be a very poor performer on a winter commute.Uncompromising extremist0 -
How does that apply to belt drives? WHY would we want belt drive?
(and I still think you're making this a fit for purpose argument, whereas, ironically, belt drives are less fit for the purpose of bicycle transmission than chains)0 -
yeehaamcgee wrote:How does that apply to belt drives? WHY would we want belt drive?
Well... I don't Just didn't like your argument, don't neccesarily disagree with your point . But there are some advantages or potential advantages (since there's not really enough real world applications out there to say how it'll really work) as discussed in this thread. And since the big disadvantage is gearing, once you take that away (ie, you are a weirdy beardy singlespeeder ) then the application changes and the performance arguments change too. Uncompromising extremist0 -
right, how about this, what are the metrics by which you can measure the performance of a chain or belt drive?
Weight, strength, durability, ease of repair, ease of fitting?
For virtually all those, a chain is better than a belt. Feel free to add your own points if you want.
(I'm enjoying this discussion, by the way - it's rare that one goes on this long here without turning into a slanging match ) 0 -
Yeah, me too.
<edit for different info I just found, looks like my first post was wrong>
OK, weight should come out in favour of the belt. Info here:
http://www.gates.com/ptdesign/trek.html
http://www.bikeradar.com/news/article/interbike-gates-expanding-belt-drive-reach-23455
80 grams for the carbon-reinforced belt apparently. I was told 240g but that appears to be wrong.
Also, the sprockets can be different, you don't have metal-on-metal wear so an all-alloy design is quite practical (though the drive face is bigger). I'd expect an aluminium belt sprocket to come in less than a steel chainring without the lifespan sacrifice of an alloy chainring. Plastic's even a possibility, some motorbike belt conversions use delrin sprockets on an alloy carrier.
Durability and lifespan- belt should win hands down, if done right, though the question of what mud will do to them isn't answered yet. Same goes for maintenance, belts don't need lubed and the cleaning should be simple, though we'll need to see how that really works out. Gates say they expect twice the lifespan of a well maintained chain.
Ease of repair- chain wins by a mile (not to mention ease of replacability, ie, no need to stock 50 different lengths of belt as chains can be shortened). But belt should need repairing much less often. So, not sure, we'd need to see rela world performance here to give any sort of sensible answer.
Likewise ease of fitment, chains are always going to be easier but they'll need fitted more often. Looking at the Dirstrict, the fitting's actually going to be pretty simple, you break the frame by removing the dropout I think, so 2 bolts. Not quite as fast as a chain but not a chore either.
Another metric is flexibility, where chains just plain win, as a result of being able to run traditional gearing not rohloffs etc. And I guess efficiency, but these belts should be comparable to chains.Uncompromising extremist0 -
hmm. interesting.
I'm not sold on the wear lifespan of the belts though. If you have two materials, of differing hardnesses (is that a word?) being forced against each other, then the softer one WILL wear out. So, either the belt wears out, or the "sprocket" does.
Biggest issue of all as far as I'm concerned is the requirement to completely overhaul suspension designs.
See, the trouble is, we can't just have the chain's drive wheel being in line with the swingarm axis - or you'd get incredible amounts of pedal induced bobbing - although suspension feedback into the cranks would be minimal.0 -
yeehaamcgee wrote:Biggest issue of all as far as I'm concerned is the requirement to completely overhaul suspension designs.
See, the trouble is, we can't just have the chain's drive wheel being in line with the swingarm axis - or you'd get incredible amounts of pedal induced bobbing - although suspension feedback into the cranks would be minimal.
Yup. Or y'all could buy proper manly hardtails.Uncompromising extremist0 -
are you just trying to start an argument now that we've come to a logical, amenable conclusion? 0
-
yeehaamcgee wrote:hmm. interesting.
I'm not sold on the wear lifespan of the belts though. If you have two materials, of differing hardnesses (is that a word?) being forced against each other, then the softer one WILL wear out. So, either the belt wears out, or the "sprocket" does.
Biggest issue of all as far as I'm concerned is the requirement to completely overhaul suspension designs.
See, the trouble is, we can't just have the chain's drive wheel being in line with the swingarm axis - or you'd get incredible amounts of pedal induced bobbing - although suspension feedback into the cranks would be minimal.
Like the old cove G spot. And to an extent, most speshes and Konas...0 -
Which part of it is like the old cove G-spot? suspension feedback, pedal bob, or pivoting round the BB shell?0
-
What was that Kona that the singlespeeders use, A-line or somesuch?
Are there any current suspension designs with the BB on the swingarm rather than on the main frame? I have absolutely no clue what that would do to the suspension response and handling , all sorts of odd things possibly, but it gets round chain/belt growth and feedback. You could have a very long swingarm as well which ought to be good for traction. I visualise something that looks basically like an Idrive, except without the "I" Uncompromising extremist0 -
yeehaamcgee wrote:Which part of it is like the old cove G-spot? suspension feedback, pedal bob, or pivoting round the BB shell?
Pivot around the BB shell (concentric pivot to bb axle).
The Kona was the same.
No pedal feedback, but minimal anti squat which counters the suspension sag or bobbing from accelerating.0 -
None of the konas or speccys pivot around the BB though. They might be close but It would still be enough of a difference to mean a slack belt.0
-
It would, but I was pertaining more to the antisquat charecteristics with those two specific bikes.
There was a Kona with a BB pivot for singlespeeders, and Scwhinns first rocket too (though used an extra link)0 -
Not that I know of these days, apart from possibbly some cheap catalogue bikes.Northwind wrote:Are there any current suspension designs with the BB on the swingarm rather than on the main frame?
They used to refer to them as an Unified Rear Triangle design (URT)
They had some major drawbacks, not least of which is that your whole body becomes part of the unsprung weight.
Also, the suspension action really only worked if you were sat down. When standing up, you already had your weight on the swingarm, so the suspension action was effectively locked out.
If you were sat down, it felt really strange, because your feet would move back and forth relative to your riding position - in fact it felt a little as though your frame had snapped!
The advantage was that you had no chain growth, so you got no pedal feedback, and minimal pedal-induced bobbing.0 -
You mean the anti-squat characteristics that effectively, don't exist, and have to be counteracted with MASSIVE amounts of platform damping?supersonic wrote:It would, but I was pertaining more to the antisquat charecteristics with those two specific bikes.
There was a Kona with a BB pivot for singlespeeders, and Scwhinns first rocket too (though used an extra link) 0 -
-
"but they pedal so effectively" :roll:
I-drive, however. mmmm. Love it. Especially now that they've simplified it. I remember trying to fix the bearings in a 1st gen model, and was frankly stumped.0 -
Yep, antisquat and low pedal feedback, works great.
DW to an extent (VPP moves). I assume the Marin is similar.0 -
the old g-spot was bb concentric 4 bar (or faux bar cannot remember)0
-
Faux bar, so it was a single pivot.0
-
Nahm the marin's (Whyte's) quad link has way more pedal feedback than the I-drive. I-drive is unique in it's partial isolation of the drivetrain.supersonic wrote:Yep, antisquat and low pedal feedback, works great.
DW to an extent (VPP moves). I assume the Marin is similar.0
