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New Model | Made-In-The-USA | 29er AM HT | ZenFab

7K views 56 replies 21 participants last post by  Phinox 
#1 ·
Excited to be able to post some initial info on a new Private Label frame by ZenBikeFab

Switchback is working with ZenFab to make the first prototypes become a reality.

Switchback will be field-testing the frames, and offering any feedback needed to finalize the prototype frames so ZenFab can take the next step to making the frame become a reality!

Text Infrastructure Bicycle frame Line Font


We (Switchback/ZenFab) are going to bring everyone Along For The Ride and show you some behind the scenes info on what it takes to bring a new frame like this to market.....

Hope you enjoy....and stay tuned! This is going to be a lot of fun!

Thanks, Scott
 
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#38 ·
Mostly agree.

On the head tube comment, my point is that people often blame chainstays when 29'ers feel hard to manual/wheelie, but raising the handlebars 20mm, or shortening the top tube, can feel like taking 20mm off the chainstays.

Same with top tube length. Lots of people have been happily running 50mm stems with "normal" top tube lengths since forever. Since when do top tubes need to be 1-2" longer so people can run 35-50mm stems? At some point it's just too long.

Something I find very curious, is that so many people blamed long chainstays and wheelbases for 29'ers having slow or dead feeling handling.... yet the bike industry is doing a lot of things to 27.5" bikes to slow down the handling, like longer top tubes, 17"+ chainstays, longer wheelbases.

In the end it's personal preference based on riding style and terrain...I think this ZenFab thing looks great.
 
#44 ·
Mostly agree.

On the head tube comment, my point is that people often blame chainstays when 29'ers feel hard to manual/wheelie, but raising the handlebars 20mm, or shortening the top tube, can feel like taking 20mm off the chainstays.

Same with top tube length. Lots of people have been happily running 50mm stems with "normal" top tube lengths since forever. Since when do top tubes need to be 1-2" longer so people can run 35-50mm stems? At some point it's just too long.

Something I find very curious, is that so many people blamed long chainstays and wheelbases for 29'ers having slow or dead feeling handling.... yet the bike industry is doing a lot of things to 27.5" bikes to slow down the handling, like longer top tubes, 17"+ chainstays, longer wheelbases.

In the end it's personal preference based on riding style and terrain...I think this ZenFab thing looks great.
Top tubes need to be longer in order to keep the same cockpit length. If you shorten the stem and top tube, you end up with a shorter bike. If you shorten the stem but lengthen the TT, you end up with a bike that fits the same but steers differently. It's that difference that I think is also better.

Chainstay length is integral to bike handling, but it's not the only thing. I would rather have shorter CS and longer TT, but an XC rider may want longer stays and a shorter front center in order to feel more balanced between the wheels. The longer wheelbase/longer reach/longer TT thing is because people like the way those bikes feel. You see it on DH bikes, and it's spilling over into aggressive 26" FS and 29" HT bikes, and now it's getting elsewhere. The longer wheelbase can be a burden, but it's usually not a big deal, up until a point, as long as the stays are short and tucked up under. At some point bikes do get ungainly, that's true, but I really feel that you have to have to be messing with really slack head angles to get there. Most out-of-the-saddle moves are way better with shorter stems and longer from centers.

To be honest with you, I don't think the bike industry knows what they're doing with 650b wheels. As a rider who dropped 29" wheels because I couldn't get an FS bike with appropriately short chainstays, I went to 650b because I could. Now the industry is going 650b full force, but they forgot why...many manufacturers are doing it just because bigger wheels...negating the geometry benefits that come from having smaller-than-29" wheels as they do so. Honestly...it's not impossible to get 17.2" chainstays on an FS 29er, but manufacturers gave up and jumped on board 650b, where they're still failing to see that you could have even shorter, happy medium 17" stays and 6" of travel with a little bit of effort.

Anyways...I think people blame 29ers for slow handling because people started building 18" stayed bikes to fit the tires which made them sluggish, then steepened the HA which made them nervous and twitchy. I think that turned a lot of riders off, and then went looking at 650b before the industry caught up to themselves and realized how to make 29" wheels ride better.

anyways...I'll stop ranting, but I'm all in favor of a balanced bike vs. super short and hyper aggressive. Especially if this toes the line between burly all mountain and XC race. A nice trail oriented, balanced ride would be sick.
 
#5 ·
Yeah, have to agree, I'd stay FAR away from any press fit BBs and stick to the old and trusted threaded BBs - much easier to service/remove if necessary, cheaper to replace, no creaking. I'm thinking they'll do an EBB for those who want to run SS, that's the why of the huge BB.
 
#11 ·
Hate to be a hater, but if I was putting out a new frame, I think I would want constructive criticism. I echo the BB30 sentiments above, but even more aesthetically upsetting is the kink in the downtube. Myriads of frame builders do it, and myriads of other builders know how to get around it. I applaud the short chainstays, but would just love to see a straight downtube.
 
#15 ·
But do you really need 16.2" chainstays? I have 16.7" stays on my XC bike now, and it's a little too unstable in turns. It's a 650b bike, so it's different, but if I were custom building a hardtail, I'd want about 16.7" to 17.2" adjustable. 16.9" sits nicely in the middle for a fixed dropout.

I agree that the competition is tough in this area, but the honzo is a taiwan made pig, the taro breaks and has 135mm rear, the ROS is overpriced, the gremlin evo is aluminum, the vassago is a little too "XC", and the cromags are either extremely expensive or made in taiwan.

edit: give me a cheaper price or a higher end tubeset like the vassago, and I would flip. This paired with a 60-65mm BB drop and 68* HA/120mm fork would be perfect.
 
#20 ·
Hi Everyone,

Zen = middle ground. We wanted to sit between the ROS9 and XC style frames. (You'll see what we mean when we post the GEO chart later)
The curved DT allows for fork crown clearance and makes the tube land straight at the headtube avoiding a sharp angle and possible gusset. BB 30 to allow BEER components EBB for Single Speed set-up. This allows us to make dropouts that are strong and fixed.
True Temper, Columbus, Reynolds, etc make great tubes, so we select the best tube for the location on the frame rather than sticking with a brand for the whole frame and compromising the design.
We know there are several ways to accomplish an awesome 29 Steel hardtail, but this is our take on it.
Thanks for playing!
David
 
#27 ·
Hi Everyone,

Zen = middle ground. We wanted to sit between the ROS9 and XC style frames. (You'll see what we mean when we post the GEO chart later)
The curved DT allows for fork crown clearance and makes the tube land straight at the headtube avoiding a sharp angle and possible gusset. BB 30 to allow BEER components EBB for Single Speed set-up. This allows us to make dropouts that are strong and fixed.
True Temper, Columbus, Reynolds, etc make great tubes, so we select the best tube for the location on the frame rather than sticking with a brand for the whole frame and compromising the design.
We know there are several ways to accomplish an awesome 29 Steel hardtail, but this is our take on it.
Thanks for playing!
David
So what's the deal, will we see some fancy OX downtubes? or 853 stays? are straight 4130 that shoots lazers out its bum and "totally stokes, bro" retired BMXers from the 80s?
 
#33 ·
RE: Chainstay length. Who can say without actually riding the bike?

I 100% preferred the geometry of the Titus Fireline Evo and Yelli screamy over the Kona Honzo which had shorter stays. Going sub 17" usually means a curved seat tube, ride quality and weight suffer as a result. Plus designers of sub-17" stay frames typically go to super long top tubes and super short head tubes to help keep the front end down- ironic since being easy to wheelie is the allure of short chainstays, and the wheelbase ends up being the same as a bike with longer stays and a normal top tube length.

I haven't ridden a chromag surface, but the geometry looks spot on. Straight seat tube, 17" stays which is pretty much as short as you can go with a straight seat tube with normal angle. Head tube and top tube lengths that make for a correct wheelbase and a bike that can corner and manual without feeling squirrelly on high speed rocky trails. The titus is similar but I do wish there were more size options.

This zen fab thing looks nice.

It does depend on your trails. I definitely prefer stability at speed/on steeps over low speed agility.
 
#36 ·
The shorter head tubes are usually for reduced bar height, which is a huge problem as travel grows and axle to crown heights get out of control. I would much rather have a 100mm headtube and be able to stack spacers and get riser bars than a 125mm headtube and have to run flat bars with a slammed stem, like my enduro.

The stays are a matter of personal taste. I Think I could get along with super shorties, but I'd rather BUY a more balanced setup that can corner well as well as be flicked around, and still climb well and all that. Too short and the rear end gets unsettled, as shiggy said. Too long and the bike is sluggish. 16.9" is a good length regardless of wheel size.

Finally, the longer reach/top tube is great as speeds get faster and body English gets...englisher. The short tt with a long stem days are done. Give me an aggressive front end that can be put where I want it even at high speed any day. The only exception is on xc bikes where you're doing a lot of ups and downs. The longer stems are great for weight balance when you need to climb constantly. The only problem is going down, where things get sketchy. I think you'll see the long reach geometry hit lots of bikes in the future, as it just makes sense. Maybe not a 25" top tube some people are pushing, but I can't imagine myself on a bike with a reach of less than 17", and I'm 5'11"
 
#39 ·
Good luck to you. I have a Vassago VerHauen made by Zen and it is a great riding bike.

If this one is like the VerHauen in ride feel and build quality, you will have a winner on your hands.

I would definitely ditch the BB30 shell and go for a threaded BB setup. I have had a few bikes with BB30 and PF30 and the system sucked. One thing I look for in new frames is threaded BB.

Also I would suggest "saddle" guides all around for full housing runs. My one complaint with the VerHauen is the shift cable routing under the down tube.
 
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