- chainring ratios
After a year with a 1×10 (32x 11-36) I’m much better than I was with it, but simply my knee’s hurt… so I’m thinking of fitting a dual (or triple) setup.
Got a dual crankset in view with a 26/39 front rings and a 120BCD.Posted 4 years ago
How does this sound ratio wise compared to say a classic nine speed triple setup? (are the any chart that make it obvious?)
Also is a the change of BCD going to really limit my choices for replacement rings?
I’m 6’2″ with long legs, have been riding for 10 years with 175mm, without issue. One year with 1×10 and knee’s are now in bits, really hurting. Pedals again I’ve been using for 6 years+ are Times.Posted 4 years ago
Cheers, for the suggestions but I really suspect the 1×10 is the issue, and at 41 I can’t see them improving with time.mboySubscriber
I noticed a couple of BB30 triple ring cranks on eBay last night that you could put a 24/36/Bash setup on if you were worried about the gearing being low enough. That’s currently what’s on my 29er and only time I ever use the lowest gear is after about 6 hours or more in the saddle already. I’d move to 26/39 up front happily…
26/36 bottom gear gives you a ratio of 0.722:1
Your current 32/36 bottom gives you 0.888:1
22/32 bottom on an old 9spd setup gives you 0.6875:1, and next gear down the cassette 22/28 gives you 0.786:1.
With a 26/39 chain set you’d find the bottom gear is nearly as low as on one of your old 9spd bikes, but not quite, but it’s certainly lower than 2nd gear would be.
The only problem you’d have is that for most riding, most of the time, a 32T middle ring is the perfect size. It’s suits about 90% of all riding IMO. With a 26/39 you’d find yourself changing up front quite a lot I think.Posted 4 years agosoobaliasMember
stand on the pedals more?
on the assumption that you are pushing a higher gear, sitting down, think of it as part way to a SS.
that said 32/36 is pretty spinny
proper answer: go and get to know sheldon brown and his gear inch calculator.Posted 4 years ago
I see your 26/39 chainset as being bang in the middle of a 22/32/44 ‘classic’, and you have that huge 36t out back too.
TBH that is concern, & why I wondered if there was any charts mapping this, as yes obviously I’m going to get lower gearings (cheers for the calc’s & description Onza) but I am actually really happy with the 32 for most stuff, so am concerned the 39 will be a huge jump.
Is 26/39 an usual combo, or something along the line of those cheap XT groupsets a while back, with higher overall gearing?
[Mark, can mail me and links to BB30 chainset’s you found and think worth considering…]Posted 4 years ago
Thats fine, but it was the cheapness of the 26/39 that brought it to my attention. I can buy it for less than a new spider and rings for my current E-13 setup and then sell my single ring E-13 crankset to make ‘some’ money back. Cheapskated-ness!
Just found a ringless dual crankset (used) on fleabay…so any idea on whether 80/120 BCD is a ‘norm’ or one of those weirdy sizes that will be gone next year?
EDIT: Especially as I’ve just seen a tripe set with standard 104BCD on the bay. Not as bothered about getting a triple as I once was, could live with dual… Man spending time on ebay, not good..Posted 4 years agomboySubscriber
80/120 will limit your chainring choice in future, but it’s a standard SRAM don’t look like they’re going to drop any time soon, so availability will always be OK as long as your LBS has an account with Fishers.
Going for a conventional triple ring crank, with 104BCD, would open up running 2 rings with a bash for you as well though. And you can choose from all sorts of ratios of ring. With a 29er, your gearing is 10% taller than on a 26″ bike anyway due to wheel size, so personally a big ring is totally redundant to me anyway. In fact, a 39T on the dual setup will be like a 42T outer on a 26″ wheeled bike anyway.
24/36/Bash works well for me, I stay in the 36T for 80% of the time, downshift to the 24T early on climbs and run the chain half way down the block as much as possible, then slowly go up to about the 32T cog on steep/long climbs. The 36T really is an ultimate bailout gear with a 24T cog, really only used after many many hours in the saddle.
All I did to find various different cranksets was type “BB30” in the search field in ebay. Knock yourself out!Posted 4 years ago
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