Rohloff + Suspension
I wasnt sure wether to post this in the Suspension or Drivetrain forum, so i put it here!!
What kind of effect can a Rohloff Speedhub have on rear suspension designs if any? Ive read only good things about it so i cant imagine any really negative effects but something must change because of the weight in the back.
Im especially interested what effect it could have on a faux-bar design as that is what i ride. Im assuming different desings, different effects?
He runs a Rohloff on his FS Niner
Originally Posted by PsyCro
I have run Rohloff Speedhubs on a lot of bikes, including my current FS RIP 9.
Pros: 100% reliability in shifting, no matter the conditions.
Shifts whether standing still, going forward, or backwards !
Can shift through a stack of gears instantly with a twist of your wrist.
Impervious to outside conditions, sealed oil bath gears, very low maintenance.
Much less prone to crash damage than other shifting systems.
Stronger rear wheel setup, no dish, shorter spokes.
Lasts for years and years...you can hand it down to your son/daughter when you are too old to ride!
Cons: Initial cost.
Adds around 5lb weight to the bike.
Takes about 1 year to run in properly..
The Rohloff speedhub sits in the centre of the rear wheel, so it's affect on the wheel rotation / effort is minimal. It adds around 5lb to the bike, but if you were running a 27 speed gear set before the Rohloff, subtract this from the overall Rohloff installation weight.
Setting up is quite straightforward, the only fiddly bit is getting the shifter cables routed and cut to the right length.
As far as the weight whilst riding the bike goes....I never even notice it.
Unless you have to carry your bike on your trails, you won't either.
Jumping: The extra weight of the Rohloff on the rear wheel gives the bike a nice slight rear wheel down attitude during the flight, but it's never obtrusive in any way. I jump my RIP 9 a lot, and the Rohloff hub never intrudes in my jumping at all.
I've been running Rohloff for many years on many different bikes over a LOT of miles, and I have NEVER had a single problem with any of them...ever!
I've seen quite a few frame advertised as being compatible with the Rohloff hubs, but don't they work with anything really? I assume you'd have to use a chain tensioner on a vertical dropout, but other than that, why would a company feel the need to clarify whether these hubs work with their frames?
Kona had two versions of the A FS SS frame with sliding dropouts that worked without tensioners. And the new Kona Bass should be usable with a tensioner free Rohloff as well, all you need is the Rohloff compatible dropout, which you can buy from Misfit Psycles. The advantage is that they have a concentric BB pivot so there's no chain growth.
Cove Bikes G-spot and the Dean Ti FS frames are also concentric BB pivots.
My Kona A is my favourite foul weather bike, snow, water, mud... it just charges through it.
If your FS frame doesn't have a concentric BB pivot then you need a tensioner, but other than that it is just like any other geared rear end for effects on the suspension.
So, how much are those hubs, anyway?
Please tell me that you made a mistake about adding 5lbs. Is 5lbs. the weight of the Speedhub and hardware before you subtract the weight of the 27 speed drive train? ( Chain rings, derailleurs, shifters etc. ) I was led to believe that the total increase in weight was only one to two pounds! I'm thinking of an Intense 5point5 29er and a Rohloff is a possible option but I don't want it to be 5lbs. heavier than it could be.
Originally Posted by Rainman
The trouble with having an open mind is that people will insist on trying to put things in it.
A Rohloff hub, gearbox and shifter is about 1800gms which is about 500 gms more than an XT drivetrain, so it's about 1 pound heavier than a typical geared drivetrain. My 2004 Kona A sits at 28.25 pounds with 2.35 Kenda Kinetics and a Fox Talas fork.
Before the US dollar slipped so far the hub was about $1300US, not sure what it is now, must be close to $1500US.
Below is a weight worksheet I put together. Based on your existing derailleur-based drivetrain components, and what options you'll need for your setup, you can get an idea of how much total weight a Speedhub adds to a bike. Tensioner-less, non-disc installations can save 400g over a full disc + tensioner setup.
**Net** weight increases for me have been in the 1.5 lb / 700g range (complete bike).
Obviously, the weight of the rear end is impacted more significantly. Eliminate the 1050g of your typical XT rear end components (hub, cassette, derailleur and rotor). Replace it with 2300g of Speedhub goodness (hub, cog, rotor, tensioner and miscelleneous bits).
You've just realized an ~1150g / 2.5 lb. gain in unsuspended mass on your suspension bike.
Surely this inhibits the ability of the rear end to flow with rough terrain, right? The numbers say it must, but I've yet to feel hampered by it, or notice a difference compared to the derailleur bikes I sometimes ride. I think of it this way: the 2.5 pounds added to an XC rig is probably lighter than the weight gain some DH'ers experience just by running a fat, heavy tire, an overbuilt rim, and a bolt-on rear hub... and they're certainly using their rear suspension to its full potential.
As for positive effects: Dave Weagle helped me choose ideal gearing for the three dw-links I've installed Speedhubs on. Steve Domahidy from Niner had some recommendations for neutral gearing for my RIP9 frame. With my wife's two single pivot bikes, I've been able to match the chainring diameter to the pivot location, to minimize any unwanted chain torque effects on the rear end. These are certainly advantages on a Speedhub-equipped full-suspension frame that aren't possible with a multi-ring derailleur setup.
<a href="http://www.booboodog.net/images/speedhub-weight-worksheet.gif" target="_blank"><img src="http://www.booboodog.net/images/speedhub-weight-worksheet-s.gif" border="2"></a>
∑ MTBR Hiatus UFN ∑
Boy, the chain tensioner, chain guide and Speedbone do add up in a hurry don't they. That's almost half pound right there. That'll be why I've only had the 500gm "penalty" on my Kona A builds.
Originally Posted by rockyuphill
Yeppers. I'm wishing Haro would do their Speedhub friendly suspension with sliding dropouts, but they're non-commital.
∑ MTBR Hiatus UFN ∑
Suspension isn't an issue
Rohloff has quite a few different mounting options, so it will mount to almost any frame.
Single pivot bikes (and faux-bar) are typically optimized to pedal best in one of the three chainrings (I think the middle ring more often than not but sometimes between the middle ring and granny - anyone else have different experience?). In any case, due to the single chainring of the Rohloff which will likely be comparable to the size of your current middle ring, you may enjoy a bit of increased pedal efficiency.
The suspension may respond a bit slower, due to the extra weight of the rear wheel but I've never found it to be an issue and I don't have any hard numbers to quantify this theory. All in all, I've been very happy for many of the same reasons others have listed:
-Rear weight bias good for jumps/drops.
-Easy to shift into any gear at any time
-Always stays in gear, inspiring confidence to stand and mash away
-Impervious to outside weather conditions
-Single chainline and chainring
On the downside, there's the cost. ...Ouch! There's also the fact that it's built into the wheel, which can be expensive/inconvenient if you are hard on wheels and rely on others to build/true them for you. If you can build wheels yourself, all the better.