10t cassette? Check!

[friendly1uk]

http://www.bikeradar.com/mtb/news/article/oneup-components-shark-10-50t-upgrade-for-shimano-xt-46668/

Or not... I'm actually a bit puzzled and late too bed already.. Somebody figure it out for us please

 

[nutnspecial]

Cool, 10% improvement in highgear for standard freehub body cassettes! The 50t is also pretty friggen low- I thought mine was low already @ 36-42 (yeah I don't remember. That's how much you use gear 1 with E, lol) with a 48t chainring.
Good on them for squeezing down another tooth though. Easy to add 'em, but working around the freehub kinda limits the tall gear, as does physics as we drop much lower. I'd take 10% more speedn depending on price vs a chainring that can give alot more. What would be really outstandingly svelte would be just selling the 10t cog and retainer. . . . well, here's hoping.

Thanks, will def be watchin to see the cost and how popular the cassettes become.

 

[Chalo]

Keep in mind that sprockets get less efficient and more damaging to chains as they get smaller.

The reason that development stopped at 11t for so long is that by that point, you lose about as much efficiency dropping from a 12t to an 11t sprocket as you lose in efficiency by pedaling too fast in the 12t. It's a wash.

21 and larger sprockets have negligible losses. From there down to 16t, efficiency losses become measurable. From that point to 13t they become significant, and below 13t every increment smaller has a disproportionate negative effect on efficiency and wear.

10t and smaller sprockets eat power, trash chains which in turn trash all your sprockets, and represent the wrong engineering approach to high gearing ratios. If you need a high gear, use a big ring. Up to 60t is relatively easy to get.

36t to 50t rear sprockets-- and derailleurs that can shift them are a great idea whose time has come. But 11t sprockets are already a bad idea (I lock mine out on my 9-speed bike to spare my chain the abuse) and anything smaller than that is just plain stupid.

 

[nutnspecial]

Interesting. I also would likely find more benefit in a larger chainring. But have no evidence to claim such losses. Are you saying the ~10% increase of high gear ratio with 10t would not only cost 10% efficiency and wear factor, but more?

Very interesting, but I'm pret doubtful. If it's 'measurable' then let's measure it! I'll be surprised if even 10% losses are evident with decent motor power, much less <250w

 

[Hillhater]

Wow! ..i would not want to put any significant motor power through a 10T sprocket !
Way too much chain/tooth loading and wear.
The only purpose for these silly small sprockets is to keep human cadence down.....a motor is happy ( more efficient) on larger sprockets.

 

[ferret]

http://www.bikeradar.com/mtb/news/article/oneup-components-shark-10-50t-upgrade-for-shimano-xt-46668/

Or not... I'm actually a bit puzzled and late too bed already.. Somebody figure it out for us please

A "standard" Shimano style freehub will accept cassettes with 11T cog.
A hub with SRAM's XD freehub or the Hope MiniDriver freehub mentioned in your link will accept cassettes with 10T cog.
There is also a possibility for a cassette with a 9T cog, You will need a Shimano Capreo style hub:
http://www.sheldonbrown.com/capreo.html

Avner.

 

[nutnspecial]

Oh I didn't catch this 10-50t is specific to xd and minidriver. Interesting reading on the 9t capreo as well.

Above I simply want to understand if and how we can say 11 to 10t negatively effects effic and wear by an equal or greater percentage gained by the taller gear.
One would need to take into account total final gearing with chainring, and input power for starters. Also cadence you're applying that power.
Obviously efficiency and wear suffers as mechanics drastically push in reductions, and we do reach limits of physical tooth count and chain size, but I find the claims above too general in criticism of 10 tooth (or 11t) vs effic and wear. There should be some hard numbers available at least on one base data set. Such as the 34t x 10t with 200w VS 2000w > 100rpm crank speed.

So yeah, Imo if you're using it as designed and not dumping huge torque in at low rpms, even 2kw+ should be fairly negligable in negative effects when applied above reasonable rpms for the 10t or 11t. Much less human power.

Hearing from pro cyclists would be interesting, and also maybe serial middrivers can weigh in. I know they wear out drivetrains fast, but figure there's shifting issues and possibly over application of torque vs rpm to be considered. These chains and gears simply aren't designed to take much power in the first place.

 

[friendly1uk]

http://www.bikeradar.com/mtb/news/article/oneup-components-shark-10-50t-upgrade-for-shimano-xt-46668/

Or not... I'm actually a bit puzzled and late too bed already.. Somebody figure it out for us please

A "standard" Shimano style freehub will accept cassettes with 11T cog.
A hub with SRAM's XD freehub or the Hope MiniDriver freehub mentioned in your link will accept cassettes with 10T cog.
There is also a possibility for a cassette with a 9T cog, You will need a Shimano Capreo style hub:
http://www.sheldonbrown.com/capreo.html

Avner.

So no chance of this going on any existing hub motors then. That's a pity. I only fancied it for fake pedaling. It's such a shame to buy nice used bikes with 44T front then swap it for a 50ish of lower value. Which happens when you buy a used bike because of budget limitations, then buy your conversion bits new.


I think I get the wear issue. The chain only pulls on one tooth really, and as that effort moves from one tooth to another, It's nice it the next tooth can take up the job, do it's job, then leave, without drawing through so much of an arc. In the 10T example, a tooth changes angle through quite a few degree's while it's the main load bearing tooth. While bobbing up&down more. It's not a great situation

Thank you ferret and chalo

 

[Hillhater]

Remember also that as the tooth count reduces so does the effective diameter of the sprocket and hence for any given torque,.. (force or road speed),.. the force on that smaller sprocket and chain tension will increase to maintain the torque.
More force , means more load on the sprocket teeth and chain.
Combine that with fewer teeth on the sprocket and sharper chain link angles , and you can see the multiplying effects on wear rates.
Its not ideal, but obviously it will work if needed.
Race karts often run 9T drive sprockets (219 chain) on the motor , and develop over 40hp (30kW) at 15,000 rpm ( used to be even higher !). And you can imagine how long those sprockets last ?
Actually the higher rpm does reduce the torque/loading significantly.