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Gear Ratios for DH/FR

5K views 45 replies 24 participants last post by  cactuscorn 
#1 ·
Hey everyone,

In the middle of building up components for a new DH rig this spring and i'm trying to decide what size cassette to get. I have a 34 single ring up front cuz i wanted something a little smaller (coming off a big 40T and MRP guide that was burllllly). I'm debating about what size gears to throw on back since this is going to be a 90% shuttled/DH rig for whistler and DH riding, but i still would like a little bit of ability to huff it up some hills on the not really steep stuff. Just curious what everyone out there is running and if they'd recommend a specific brand/model of cassette.

thanks!
 
#4 ·
I run a 37 tooth up front with an XT 11-32 in back. Works pretty well for the occasional climb, but since this occasion is about 1% of my riding on the bike I'm thinking of going to something more like 11-26 or 11-28.
 
#6 ·
I have a VP Free with a Sram PG990 11-34 and a 32 ring up front, I like being able to climb, but on the other hand I dont like being in a high gear when Im blasting down. So i Might drop in a 36 and see how that works.
 
#7 ·
the bottlerocket has a 34t in front and 12-27 ultegra road cassette in the back. more than enough for mach-looney when its wide open, low enough to get up whatever i need to get up and the tight spacing of the road cassette makes for snappy shifts.
 
#12 ·
tacubaya said:
22-36 front, 11-34 back....... I can't climb continuously without the 22 ring.... maybe the trails I ride are very steep?
I'm with Tacu on this one. I run the same set up for that very reason....no way to even try to climb most of the singles I ride on the 36T, even with the 34 out back.

Also, for me, 32 or 34 up front is too limiting as well....spins out far too quickly for my taste. I would run a 38 but it just does not combine well with the 22...
 
#13 · (Edited)
if were talkin straight dh racing here, climbing isnt really much of a factor besides the occasional short up so gearing around such is not a full time goal. with that in mind, im ready for anything cuz experience says it all depends uppon the course and conditions of the day. a 36 - 11/23 should suffice for most events but i also carry a 38 and 40t ring plus a 11/26 in the spares box. obviously i have bash rings to fit.

sorry to hear yer hurt but aint it grand to fill the down time with a new build? beats tv all to hell.
 
#15 ·
my dh rig is 38t front and 11-27 rear and my freeride/allmountain is 36t 22t front and 11-34 out back. Had a 34 but I was topping it out and not getting enough speed so I went with the 36t it gave me just what I needed.
 
#16 ·
bingo! the 22/36 was a great addition to the 11/34. i fought it for a long while cuz i dont like anything more than a 12t jump. i was wrong and the shiftin performance rocks thanx to rf rings, and sram 991 chain and 990 cassette. this isnt new news but if ya havent tried it yet, yer missin out.
 
#23 ·
agreed. rf makes a quality, light ring at a reasonable price. its not cheap but it wont fold up under torque like a cheapy, costin ya more than gettin good stuff the 1st time. unless i was trippin over stacks of 20's or ridin it all the damn time, id get a sram 970, 980, xt or a 105 dependin on desiered ratio and manf preferance. both the 970 and 105 give a good bang for the buck.
 
#24 ·
yomattyo said:
so you think the 34 in front will be too small? kinda seems like it will be for now. it's just what came on the cranks i got so i'd need to pick up a new one.... any suggestions on models? is a 100$ cassette really worth it?
depends how @nal u are about weight. if your going with a road cassette(ie 11-21,12-26), you can get a cheaper model, and still be less weight than a regular MTB casette. if you wanna get real light weight, you can splurge on an ultegra with the Ti sprockets and youll shed more weight. also dont get tricked and buy a SRAM "DH" casette. all it is a road casette with steel rings. heavy and unneccesary.

as for chainring upfront, you wont get any lighter than an e.13 guide ring.
 
#26 ·
the point of small rings on dh rigs is ground clearence and chain slap/loss. hence road cassettes and short cage ders. most shimano users even run road ders. it doesnt hurt that theyre much lighter than mtb bits either.

the other part of this is dh stuff gets destroyed fast and alotta folks buy cheaper parts rather than bay big bucks on a regular basis. that said, it doesnt always pay to go cheap. too cheap and the part cant take a hit whatsoever or just fails due to the punishment without ever hittin the floor.

btw, dura ace has ti cogs, not ultegra. i think it was still the largest 3 in 9 spd. both are nutty expensive too. the sram 970 dh cassette has a great spread without costin a ton. not sure why a cheap stamped steel shimano road cassette is ok but a sram dh unit is a "trick".

a nice advantage of the ultegra and dura ace (if ya can find em in 9 spd) is the use of a alloy carrier vs the stamped steel cogs and plastic spacers of the cheaper srams and even lower level shimano. the wide carrier spreads the load far better and keeps alloy freehub bodies from gettin chewed up. hope, for example, reccomends these but doesnt insist on them. a little fine file work goes a long way and youll replace it when the engagement dies far before a steel cassette kills it.
 
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