We last saw Katz Bikes at the Eurobike Outdoor Expo in 2010 when they were showing off their 145mm Alps trail bike. We were immediately drawn in by the concealed drivetrain, but it unfortunately all went south for the Swiss brand from then on. In 2011, they had to shut down as the Euro crisis and ensuing financial problems hit their bottom line hard. The project was shelved, but Holger Katz, the brains behind the brand, kept riding his bike for the next decade and claims he hasn't had to perform any maintenance on the drivetrain in that time.
Now, Holger has returned with an updated version nearly a decade after his company shut down. Thankfully, he hasn't abandoned the concept that first inspired him to start making bikes and the concealed drivetrain returns again. The drivetrain uses a Rohloff SpeedHub 500/14 with 14 gears that sits in the rear wheel. This gearbox provides a 526% range, but weighs more than 1700 grams.
Under the carbon fiber shell at the bottom bracket is a chainring built by Katz and a standard Shimano 11 speed chain that is tensioned by a ratchet and passes through the chainstay to meet the Rohloff. The final piece of the puzzle is a rubber seal that allows the chainstay to move with the suspension action while keeping contaminants at bay. The protective element of the design is obvious, but other advantages apparently include quicker and cleaner wheel removal, easier bike washing and a totally silent drivetrain thanks to a tensioned chain.
Furthering his maintenance-free ethos, Katz uses a "triple sealed system" for the bearings on the bike, every bearing apart from the main pivot is a sealed needle bearing with "additional seals and protective construction". The main pivot uses double row spherical bearings with the same protections. Katz says that he's never had a customer asking for replacement bearings in the past ten years.
Bike design has obviously changed a lot in the past decade so Katz has made plenty of changes to the bike we previously covered. The travel has been boosted up to 155mm in the rear, which is mated to a 160mm X-Fusion Revel fork at the front. The head angle has been seriously slackened from 67.5° way down to 64 degrees and the bike has been stretched out to a 1200mm wheelbase. The final modernizing touch is an increase in wheel size from 26 to 27.5+, which means the bike should also be able to fit 29" wheels with standard size tires.
Geometry
Stack 595mm
Reach 400mm
TT horizontal 570mm
Seat tube 395mm
Head Angle 64°
Seat Angle 74°
Chainstay 467mm
BB height at 2.8/3.0 tires 345mm
Wheelbase 1205mm
Currently, Holger has only one frame which he is using himself and no plans to start selling again. However, he is open to speak to investors who may see his concept as a potential opportunity.
There has to be a way! Come on think!
To be honest: ever felt that your suspension is working worse with a DH-casing tire which adds 500-600 grams compared to a Enduro tire? i think nobody does. except you imagine it and then you also can feel 1 gram if your imagination is just strong enough.
look at timing chains, they last hundreds of thousands of kilometers.
HA!
You're so right... add on that the spoiled brat that will claim he can feel the frame flexing with his prostate!
The truth is that weight is NOT the top priority. There are so many other factors that matter more...
Don't know of a derailleur/cassette combo that adds 1700 grams - the quoted weight for the bare gearbox in the rear wheel. That's around 2.5 lbs of weight more on the hub than an XO derailleur/cassette combo, or if you want real boat anchor, 1.5 for SX eagle. Ofc, I assume whoever's shelling out $$$ for a nice internal hub isn't cross-shopping with SX eagle...
There's a host of other potential benefits here, but it sure isn't weight. "Centralizing" mass on the rear wheel isn't ideal either.
Katz has been riding quite a few interesting bikes over the years. I'm curious to see the next evolution.
Also, it's interesting how I can't find a single photo of the non-drive-side of the bike design. I'm curious about the suspension pivot/BB/drivetrain integration that's hidden behind the rubber boot thing.
$790 for the gray one and $820 for the binged out gold one.
I almost bought the gold one but only 27.5 no 29.
TBH, I really want to get one and lower it to 100mm for my dirt jumper, but I have no idea where I would get the necessary parts.
Simply true
a chain which is not always lubricated, has a much bigger power loss than a jockey wheel. you can loose up to 20% with a dry/rusty chain. and this is a loss in percentage, not an absolute loss like the jockey wheel. so a dirty chain is one of the things which makes you the most possible powerloss besides tires with too little air.
Concept isn't revolutionary in any case but the idea is quite good IMO.
-the geo is unusual. I'm not criticizing, but i'm curious how you arrived at that geo. How tall of a rider is it intended for?
-similarly, the chainstays are very long. Could someone looking to implement your design run more conventional 420-440mm chainstays using your drivetrain and linkage?
-why not tuck the rohloff in to the bb region?
Love the project, and the aesthetics.
Rolhoff hubs are far behind us in term of alternative transmission, especially because they`re heavy and kill the balance of the bike. Try to bunny up and to manoeuvre in tight switchbacks with a Rolhoff!
All the time mate!
-No ballancing poblems
-The bike, actually feels better with the speedhub!
-All the "goods" that will drive you away from the derailleur...
Central gear boxes are much more logical, for many good reasons: they offer a well-balanced bike with a low center of gravity, both wheels almost weigh the same, no risk to damage a derailleur, the gearbox is dust-proof and needs rare maintenance ... Pinion make good stuffs, even if the 12speed version has -had?- some cracking issues....
...
This said, I still prefer classic derailleur transmissions. A Box 9spd set up will be my next purchase.
Less is more, more is less ;-)
Cheers!
We adapt to the idiosyncrasies, that’s all! (if we didn’t e wouldn't be able to ride a bike at the first place!)
Happy trails!
I wonder how much longer the chain lasts?
The weight penalty is much less than 1700g, compared to an exposed-drivetrain bike also running a Rohlhoff.
The weight penalty is roughly 500g, or 1.1 pounds in freedom units.
IMO the weight penalty is small compared to effects of tire and wheel choice. What's more important is that there is nearly 1.5 more pounds of sprung weight on the rear axel, which will negatively affect suspension performance. But then again that effect is probably outweighed (pun intended) by choices in suspension and frame design which are probably not fully modern compared to those from bigger bike manufacturers.
Its heavy, and unsprung. so why not just move it to be concentric with the BB?
As for inefficiency- I'm with @KATZbikes all the way: it's not much of difference and that is talking about a new gearbox, which will become more efficient as it wears IN rather than out.
Weight is a factor, BUT for one thing my alloy Transition Sentinel was the same weight exactly AND -as I mentioned- with a gearbox it's sprung weight, which actually has a positive effect on suspension performance. Same reason E-bikes work so well pointed downwards.
The only actual downside imo is $$$ / €€€
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Are you able to support your position with some valid arguments?