9sp road cassettes range from 11-21 to 12-27 and from $30 to $200+... shimano.. sram.. take your pick.
i'm also shopping for a new cassette for my DH bike.. but i'm tempted to just stay with a more standard 11-34 mtb cassette...
a road cassette offers tighter gear spacing, but a mtb cassette offers a broader gear range, which I think is more important.. especially if you're doing any freeriding or super-d..
there are obvious benefits to the tighter gear spacing for road, as you sit and spin, spin, spin and you want to micro-manage your cadence at any pace, etc... but dh is more sparatic.. so what is the big advantage to the smaller cassettes?
Can you still not run a short cage w/ a mtb cassette?.. (X9 or X0 short cage w/ 11-34 for example). If not, then that's one advantage to the smaller cassettes... weight is another.. anything else?
For the sake of ~75g, I think i'll take the broader gear range and not look as cool... anyone else?
I would reccomend a shimano Ultegra RD cassette... I've ridden the SRAM stuff, and i've snapped them in half.
For the most part, if you are going down a hill, you don't need a mountain cassette, simply because most of the time you arn't even going up any hills. I've convinced several riding buddies into trying out road cassettes on their FR/Dh bike, and none of them have gone back to a mountain cassette.
Personally, I run an Ultegra 11-23, with a 38T front ring on my bikes. The 2nd gear is identical to the 4th gear on a Mountain Cassette, which is where I usally start my run in... Plus, you can still pedal up some hills in first gear if need be.
The best way to figure out which cassette size to get, is find out which gear is the easiest gear you use on your mountain cassette on a normal basis, then count the teeth, and try to make that your second gear on a road cassette.
fair enough and all makes sense... I understand that you don't necessarily "need" the mtb cassette gears... but what do you consider the main advantages of teh road cassette.. or the disadvantages of running an mtb cassette?
I'm not challenging any preferences or concepts, just wondering if i'm missing anything beyond weight, tighter gears, and perhaps better clearance by running your der. against a smaller cassette..... those are all nice touches, but i'd be willing to sacrifice them if I need to pedal up the odd section... which isn't rare on the trails/courses i'm familiar with.... do you find an appreciable difference with shifting and/or chain tension.. chain slap.. etc...
i just ordered my new road casset tonihgt, it was a 11-25 tooth i beleve and looking into a short cage derailure. the cassets are lighter and look better and preform better
I run a 38t up front and 11-23 Dura Ace rear. I needed a new cassette near the end of the year and decided to try out a road cassette. I found out that I run in the 16 cog the most for when I ride around and any hills that I have to go up, I normally walk anyways (even with the mtb cassette). The close ratios are great for quick shifting which I think is the biggest advantage. Chain slap I haven't had an issue with. I kept my mid cage derailleur on and don't know if that really helps with the chainslap, and I haven't noticed any negatives from keeping the mid cage. I was able to get the Dura Ace for $140, not much more than a PG990 and I was coming from an older PG970 style cassette. So I did save quite a bid of weight (410-159).
Other than weight and slightly slower shifter there isn't much diff between the two.
One HUGE advantage is having a shorter derailer. with a smaller derailer, you have to put tighter and tighter gear ratios on, as the derailer can't compensate for the chain stretch. It has disadvantages, such as a less broad range, but it has advantages, such as smashing itself less often.
I run it because there isnt a huge 'jump' in between different gears...when you max out a gear, just click it down one, and you are exactly where you need to be. Wheras with a MTN cass, you spin a gear, then drop into a lower gear that is alot lower than it should be. The tighter shifting is wayyy better for racing, and keeping a better pace.
It's just a matter of time before someone markets the "DH Cassette" aka rd cassette.
It's just a matter of time before someone markets the "DH Cassette" aka rd cassette.
That would be Sram. They now make an 11-26 PG970 DH. It has tougher cogs though. That's nice. If it's enough get a 11-23 Dura-Ace or Ultegra. You can save big weight with those and they shift REALLY nice.
One HUGE advantage is having a shorter derailer. with a smaller derailer, you have to put tighter and tighter gear ratios on, as the derailer can't compensate for the chain stretch. It has disadvantages, such as a less broad range, but it has advantages, such as smashing itself less often.
looking at the SRAM tech manuals.. the chain length compatibility is:
Total: 30t (short cage XO) Max sproket: 34t Min sproket: 11t Front difference: 22
I am interpreting this to mean that w/ a single chain ring I can run the short cage w/ an 11-34, since 34-11 30t.... the smaller cassette would still offer even more clearance though..
Anyone know why the DH cassette (12-26) is 100g heavier than sram's 12-26 road cassette? I don't see why a dh cassette would need to be tougher... i'm pretty sure i know some roadies who'll put as much power through they're drive train as any DH'er... Zable? McEwan? O'Grady?. etc...
i'm pretty sure i know some roadies who'll put as much power through they're drive train as any DH'er... Zable? McEwan? O'Grady?. etc...
I think road riders actually put down more power... The correct statement would be "some dh'ers put down as much power as road riders"
Of all the DH racers, I think Rennie has the higest wattage compared to an elite road rider??
MITCH
so we agree.. i was being sarcastic... so why a heavier/tougher for DH?.. maybe due to the snap starts and snap sprints out of corners.. whereas on road you most likely already have some power to the drivetrain before you bust into a full on sprint... and you're don't glide - spring - glide - sprint compared to dh. i.e. smoother power delivery on road... i'm thinking an ultegra / dura-ace cassette is plenty tough though, and way lighter than the sram DH.
any comment on an X-0 short cage working w/ an 11-34 or 11-32 cassette w/ single chain ring?
Bit late reply to this thread but I've just been out on my bike doing some street, stalls etc. and managed to snap one of the rings on a road cassette Sram PG950, it snapped into three or four bits of about 2 teeth each, I guess roadies aren't going to go from nothing to full torque?
iv got sram x9 with a normal mtb cassette for now. i would like to put a road cassette on but would i have to replace my mech? and if its 9 spd (im looking at either 105 or dura ace would i be able to use my mtb chain?