Zero Talent

I want to make something along the lines of the predator ergo bike. But I don't really have an idea how the driving system works I see there are basically two sets of chainrings one on the the cranks and one in between the cranks and the cassette. Just wondering if anyone can provide any insight on building one of these.

Quinn8it

the rear drive-train turns a loop of chain between its chainring and a cog fixed to the Front Drive-Trains Spider. The Front Drive-Train then Spins the wheel, which has 4 Metal Fins to create air resistance. the "Double Step Down Drive-Train" makes the wheel spin at double speed.. 75-100mph typically.
the full range of gears on the road drive-train are usable, as well as the ability to change the Cog and Chainring on the rear Drive-Train.

Beyond that it is obviously a custom frame design welded from steel tubing- the only "Proprietary" piece in the Drive-Train is a small piece that was manufactured to allow the Front spider to be mounted, and then driven by the Cog.

I was around for a lot of the Process- which involved Re-Designing one of the old Ergos from the USA Olympic Center. There were a couple of weak design issues that needed to be fixed to make the Ergo perfect.. Predator did a really great job- and it was no small feat! The R+D that went in to this project was huge, and the goal of creating an insane training device that could essentially be repaired/re-built by any bike shop was realized..

Not to be discouraging- but this was a tough project for a bike manufacture...

carleton

Hey, Zero. What's your goal? Are you looking for a winter building project? Want a training tool? Something else?

Zero Talent

I want it as a training to as with school and since it gets dark so early, I can't get out much to ride outside during the week. So I want this as a way of better indoor training.

CliffordK

You could probably build the second idler out of mounting a second bottom bracket, crank spider, and say a 24T 74mm inner ring and a 60T outer ring.

You'll need tension in the first chain. Tandems may use an eccentric bottom bracket, or you could just add a slip joint adjustment.

carleton

It will take you months to figure out how to build this and then actually build it. Not counting the roadblocks and failures along the way.

I'd consider getting a quality trainer or quality spin bike. The Wahoo Kickr seems to get great reviews lately.

Do you have a budget? If so, what is it? Also, even if you build a bike like above, it will cost $$ for materials and parts.

EDIT:

Those types of ergo bikes aren't very popular and are kinda expensive. It's an uncommon solution to a common problem. Find the common solution to the common problem

Quinn8it

The Predator ergo is about as good as it gets for indoor training, it has a highly realistic power curve and is incredibly smooth. While I'm sure that the Watt bike is basically the same or better- the fact that I can roll the Predator in to any Bike shop for a total overhaul made it a better long term choice in my eyes.
That said its not that refined. A bladed wheel spinning 100mph makes an insane amount of noise. I had to rig a fender to keep the air from blowing on me, due to it literally making me too cold to train once I got a sweat going.

The point I'm assuming Carleton was making is: building an ergo like this is a massive project.. Along the lines of building a bike frame up from Tubes, but with very few around to base your design from. The Predator took 18mos- and they had the Training Center ergo to copy..

Buy a Wahoo Kicker, LeMond Rev, Kurt Kinetic, or whatever trainer you can afford and spend your winter actually training.

Quinn8it

Yes- e-centric BB on the rear drive-train... Good call!

CliffordK

I don't see why you couldn't take an old Junker bike, or cheap exercise bike.
Do a little cutting, chopping, and welding, and build an "ergo bike" in a few days.

It might not look quite as pretty.

Your biggest issue would be getting the gearing perfect. It would depend on all the chain rings and sprockets, and the wind resistance and weight of the wheel/flywheel.

In a sense, the Schwinn Airdyne has a similar idea of using only wind resistance for pedalling resistance, but is a different beast.

I thought it was interesting the film clip I saw showed a lot of flex in the bike.

Quinn8it

I may be wrong- but i think the original Training Center models (also mentioned in Marty N's book) were made by Nagasawa, and while they were great, they had issues- especially around tensioning the rear drive-train and connecting the 2 drives...

as for gearing:
if you mimic the predator and have a ring/cog driving a Road Double, the gear range clicking through the 20gears is insane.. I put a 48x14 on the rear drive, and I've never used the big ring on the road double.

as for flex. The Predators weakness is the Steer Tube.. the design allows TT length to be adjusted by sliding the steer tube, and most flex comes from there..
Ill say that its not as bad as that video makes it look- and its not as much an issue on a trainer bike as the same flex would be on a real bike.

carleton

No offense, man. But this is the most ridiculous thing I've heard on this forum in a long time.

You are going to tell a jr racer that he can become a master welder/bike builder "in a few days".

You really think that his biggest issue will be gear choices??? In this entire project...picking which chainrings and cogs to use will be his biggest obstacle?

What are you smoking?

Quinn8it

#goodcop /badcop

Zero Talent

I actually wouldn't be building this i already talked to a master welder and he is willing to do it. So the construction is not the issue I was simply asking about the design of the middle chain drive. What type of cog is on the outside of the middle chain drive.

Quinn8it

If you are going to pay for it why not just buy a frame from Predator? IIRC they have one left...

And aren't you in Los Angeles?

Zero Talent

Yeah, it'll maybe cost $500 from my welder. So much less. Yes I am in LA.

carleton

These are around $2000. There are MUCH cheaper and better options that you can buy tomorrow and be riding by Wednesday.

Understand that training on one of these won't necessarily make you faster on the track. It's just a training device.

You can have one of these for around $1,100 without a power meter and $2,000 with a power meter and probably find one in stock at a shop TODAY!



It seems that you think this custom ergobike is somehow a *better* training tool that stuff that's out there off the shelf. It's not. It's not.

carleton

$500? I seriously doubt that.

He's doing more work than it would cost to build a custom steel bike. Not to mention the added cost of the wheel, cassette, cranks, and various other components.

The $500 you may have heard may be his labor charge. But, you'll have to buy the rest. Even then, I think $500 is a very low estimate. Paint alone for something that size costs $200.

I'll bet you $25 that this project doesn't' come to fruition for some seen or unseen reason. Seriously, if you actually make this, I'll send you $25 cash.

Buying a quality trainer like the ones listed above will be your best option. PERIOD.

Quinn8it

I paid less than $2K for the Predator Carleton

carleton

Less than $2000 or less than $500?

carleton

Ahem: https://predatorcycling.com/product/ergobike/

This thing is $2500 with no cranks, no bars, and no saddle!!!!!

Ya'll are crazy.

You can get a top of the line cycleops spin bike with power meter and programmable resistance (like a computrainer) for that much...from a local bike shop!

carleton

The Wahoo Kickr is $1,100 and you use your own bike! Use your iOS or Android device to get power readings:



I believe this also has programmable resistance.

But, spending $2500 for a wind trainer seems cool, too...If you are into that sort of thing.

:-|

Quinn8it

I paid less than retail because I was the first person to put down a deposit and then ended up waiting well over a year for them to have mine ready.

the Predator is infinitely better than the Cyclops- resistance feels better. It's made for your bars and saddle, and cranks -so position is identical to your track bike..

but all of this is pointless-
Because Predator has at most 1-Frame left, and they are not building more.. It had basically never really been available retail AFAIK.. There was 1 run of 10-frames..

Oh- and Carleton- did you forget that you think there is no reason to train with power?

Zero Talent

Yeah I realize $500 is the labor charge. I have everything else already for it. Just need to understand how the system really works. My friend had one of these made out of an old frame and I rode it, way nicer than any spin bike I've ever ridden. So thanks for the spin bike suggestion but if I got another indoor cycling apparatus it would definitely be one of these.

Quinn8it

I assume Aram paid nearly $500 just to CAD Draw and make the piece that fits inside the Rotor Spyder and also threads the Lock Ring on... It was the hardest part of the process..

Also there were at least 3 prototypes welded to get the design right

carleton

You got lucky. Not sure if OP will get that lucky.

This is why my first suggestion was the $1100 powerless cycleops. It's rock solid for standing starts. Does not budge even under me.